CN103953915A - Method for recycling startup drained water working medium and heat of secondary reheating boiler through high-pressure heaters - Google Patents

Abstract

The invention discloses a method for recycling a startup drained water working medium and heat of a secondary reheating boiler through high-pressure heaters, and relates to a method capable of comprehensively recycling the startup drained water working medium and the heat through a non-startup furnace water circulating pump used by a supercritical secondary reheating boiler of a power station. During startup of the supercritical secondary reheating boiler of the power station, four high-pressure heaters which are connected in series on the side of a steam turbine are used as water-water heat exchangers, the startup drained water of the secondary reheating boiler are gradually cooled and depressurized on the side of a shell, and the heat is gradually released from high-enthalpy startup drained water and then enters a deaerator; lower-enthalpy high-pressure fed water at an outlet of a water feeding pump gradually absorbs the heat and then enters a coal economizer on the side of a tube. By virtue of double sets of specially-designed control logic of a unit DCS (distributed control system) on the high-pressure heaters, all the high-pressure heaters can complete the total startup process of the secondary reheating boiler and the working mode of a regenerative system safely and economically. Under various startup working conditions, the working medium and the heat can be comprehensively recycled in the total startup process, and the recycling effect is superior to that of a direct current furnace startup system of a startup furnace water circulating pump. By virtue of the non-startup furnace water circulating pump and sub-systems thereof, the capital investment, the operation cost and the maintenance cost are greatly reduced, and iron pollution is avoided.

Description

High-pressure heater reclaims the method for the hydrophobic working medium of double reheat boiler startup and heat

(1) technical field:

The method that high-pressure heater of the present invention reclaims the hydrophobic working medium of double reheat boiler startup and heat relates to the method that can comprehensively reclaim the hydrophobic working medium of startup and heat without starting boiler water circulating pump that the overcritical double reheat boiler in a kind of power station uses.

(2) background technology:

The overcritical double reheat boiler in power station must be Once-through Boiler.

The power station overcritical double reheat boiler startup system of prior art is an important component part of the overcritical double reheat boiler plant in power station, the object that startup system is set is in boiler startup, underrun and furnace shutting down process, by starting system made and maintaining the minimum mass flow in water-cooling wall, to protect water-cooling wall safety; Meet unit safety, economic start and stop simultaneously; Performing low-load running of machine set and carry out rapidly accident treatment, and realize as far as possible the requirement of working medium and heat recovery.

What the power station supercritical DC furnace startup system of prior art was commonly used has 4 kinds:

A has startup boiler water circulating pump, has the direct current furnace starting system of atmospheric drainage flash tank, drain tank, drainage pump.(Fig. 1)

B has startup boiler water circulating pump, the direct current furnace starting system of the hydrophobic in line condenser of boiler startup.(Fig. 2)

C, without starting boiler water circulating pump, has the direct current furnace starting system of atmospheric drainage flash tank, drain tank, drainage pump.(Fig. 3)

D is without starting boiler water circulating pump, the direct current furnace starting system of the hydrophobic in line condenser of boiler startup.(Fig. 4)

When A kind direct current furnace starting system is normally worked at startup boiler water circulating pump, it is generally acknowledged, except Once-through Boiler crosses a few minutes of the phase of expansion, can reclaim working medium and heat comprehensively, but in fact in order to make separator water level control valve and corresponding pipeline, valve exempt from excessive thermal shock, be admitted to atmospheric drainage flash tank from Once-through Boiler igniting start to have an appointment 20% startup flow always, this part working medium and heat have substantially all lost; Still can clean boot Once-through Boiler in the time starting boiler water circulating pump fault, but deteriorated to C kind direct current furnace starting system.

When B kind direct current furnace starting system is normally worked at startup boiler water circulating pump, it is generally acknowledged, except Once-through Boiler crosses a few minutes of the phase of expansion, can reclaim working medium and heat comprehensively, but in fact in order to make separator water level control valve and corresponding pipeline exempt from excessive thermal shock, be admitted to condenser from Once-through Boiler igniting start to have an appointment 20% startup flow always, this part heat basic loss has fallen; Still can clean boot Once-through Boiler in the time starting boiler water circulating pump fault, but deteriorated to D kind direct current furnace starting system.

C kind direct current furnace starting system is in the time being furnished with liquid level control bypass valve, and small part operating mode can reclaim working medium and heat; Boiler startup is hydrophobic while entering atmospheric drainage flash tank, can be subject to serious iron pollution, and now not only heat can not reclaim but also working medium also should not reclaim; Due to atmospheric drainage flash tank be generally arranged in boiler structure or near, atmospheric drainage flash tank exports later pipeline and is low pressure pipeline, is easy to arrange, is easy to hang, and makes A kind and C kind direct current furnace starting system once obtain more employing; Due to misgivings oxygen-eliminating device superpressure, A kind and the C kind direct current furnace starting system quantity of being furnished with liquid level control bypass valve are little.

D kind direct current furnace starting system is in the time being furnished with liquid level control bypass valve, and small part operating mode can reclaim working medium and heat; The hydrophobic in line condenser of boiler startup is without iron pollution, and recyclable whole working medium, can not reclaim heat.B kind and D kind direct current furnace starting system obtain more employing in recent years; Due to misgivings oxygen-eliminating device superpressure, B kind and the D kind direct current furnace starting system quantity of being furnished with liquid level control bypass valve are little.

C kind and D kind direct current furnace starting system are in the time being furnished with liquid level control bypass valve, small part operating mode can reclaim working medium and heat, the representative condition that liquid level control bypass valve allows to open is that oxygen-eliminating device pressure is not not less than tri-conditions of 2.7m higher than 11.0MPa, steam-water separator water level higher than 0.5MPa, steam-water separator pressure and meets simultaneously, to guarantee oxygen-eliminating device safety.

High-pressure heater is a part for power station steam turbine group heat regenerative system, for reducing the cold end loss of power station thermodynamic cycle, improves the thermal efficiency in power station.That the typical high-pressure heater of prior art Double reheat steam turbine group is generally is horizontal, U-shaped heat-transfer pipe, shell-and-tube heat exchanger; 4 grades of arranged in series, accept respectively that steam turbine ultra-high pressure cylinder steam discharge, high pressure cylinder draw gas, high pressure cylinder steam discharge, intermediate pressure cylinder prime draw gas; And the steam condenser of separate type is set; For the boiler feedwater of stepped heating feed pump outlet.The hydrophobic of high-pressure heater refluxed step by step, the hydrophobic oxygen-eliminating device that is back to of No. 4 high-pressure heaters, the hydrophobic outlet of every high-pressure heater is all furnished with outlet drain regulating valve, be subject to unit DCS (dcs) monitoring, in order to regulate the hydrophobic water level of controlling each high-pressure heater at target interval, make the energy-saving effect of heat regenerative system maximize and prevent turbine water induction, guarantee Steam Turbine safety, economical operation.

High-pressure heater is conventionally with steam turbine host-initiated; The common sliding pressure operation of oxygen-eliminating device.

It is the phenomenon that the steam-water separator water level occurring in the time that water screen system starts to steam jumps, the hydrophobic pulsed of boiler startup increases that water-cooling wall crosses expansion, its reason is working medium severe fast-descending in water screen system, it is a kind of transient process, approximately 3,4 minutes duration, the hydrophobic incremental integration value of boiler startup is 30 to 50t to 1000MW grade Once-through Boiler representative value.

(3) summary of the invention:

Technical problem to be solved:

As mentioned above, the direct current furnace starting system that A kind and B kind are furnished with startup boiler water circulating pump can reclaim working medium and heat comprehensively, but normally work for making to start boiler water circulating pump system, startup boiler water circulating pump recirculation subsystem need to be set, start boiler water circulating pump warming-up subsystem, start boiler water circulating pump entrance subcooled water subsystem, startup boiler water circulating pump high pressure washing and moisturizing subsystem, the cooling water subsystem of startup boiler water circulating pump low pressure, 6kV/10kV station-service electric power system, DCS control system; System complex fault is many, to stove water endoparticle thing sensitivity; Starting boiler water circulating pump need to work under supercritical pressure and hot conditions, domesticly still can not produce, and 2 1000MW grade units arrange and start boiler water circulating pump and subsystem thereof, and power station investment approximately increases by 2,000 ten thousand yuan; After start-up course completes, start boiler water circulating pump system still in pressure-bearing hot stand-by state, the year energy consumption cost units up to a million of stand-by heat, in addition annual inspection, maintenance, the recondition expense that also will drop into units up to a million.Is furnished with the startup system that starts boiler water circulating pump from ignition of the boiler, until crossing finish to have an appointment 20% the startup flow of expanding always, water-cooling wall is admitted to air suspended type flash vessel or condenser, the heat of this part working medium can not reclaim, and what be admitted to air suspended type flash vessel hydrophobicly often becomes the major reason that feedwater iron-holder exceeds standard.

Therefore, can find a kind ofly need not start the double reheat boiler startup system that boiler water circulating pump can reclaim again working medium and heat comprehensively and have substantial economics, be the Important Techmical Progress in double reheat boiler startup system field, power station.

Solve the technical scheme that its technical problem adopts:

High-pressure heater of the present invention reclaims method and the aforementioned A kind of the hydrophobic working medium of double reheat boiler startup and heat, B kind direct current furnace starting system difference, do not use the hydrophobic method of returning to economizer entrance of startup that starts the outlet of boiler water circulating pump supercharging steam-water separator water storage tank to reclaim working medium and heat, but the high-pressure heater of 4 series connection of postponement steamer pusher side is as the enabled instruction of power station steam turbine group heat regenerative system, during the overcritical double reheat boiler startup in power station, 4 series connection high-pressure heaters of steamer pusher side are used as to water water heat exchanger, at shell-side, to the hydrophobic echelon pressure and temperature reducing of double reheat boiler startup, high enthalpy starts after hydrophobic echelon is emitted heat and enters oxygen-eliminating device, in pipe side, after absorbing heat, the high-pressure feed water echelon of the feed pump outlet of lower enthalpy enters economizer.Because the exchange capability of heat of 4 high-pressure heaters is by 100%BMCR flow design, have the heat exchange area of enormous quantity, DC furnace start-up drainage flow is from igniting to boiler band minimal once-through circulation load, flow mobility scale is 0 to 30%BMCR/0 to 25%BMCR, when 4 series connection high-pressure heaters are used as water water heat exchanger, terminal temperature difference can be no more than 10K.

When high-pressure heater is used as water water heat exchanger between the Once-through Boiler starting period, what pipe sidled is the high-pressure feed water of feed pump outlet, what shell-side was walked is that boiler startup is hydrophobic, crosses the front pipe effluent amount that expands and substantially equates with shell-side flow, oxygen-eliminating device pressure rising from ignition of the boiler to water-cooling wall; Water-cooling wall completes boiler to start-up course after crossing and expanding and proceeds to before full direct current operating mode, and pipe effluent amount is constant, and shell-side flow starts hydrophobic amount by maximum and drops to gradually 0, corresponding, and oxygen-eliminating device pressure is dropped to and stopped rising to slow decreasing by climbing speed; A few minutes inner casing effluent amount of only crossing expansion at water-cooling wall is quite greater than pipe effluent amount, if be again to start under very hot state operating mode, and likely fast rise of oxygen-eliminating device pressure, for guaranteeing that oxygen-eliminating device safe operation takes following measures:

Before water-cooling wall crosses and expands, oxygen-eliminating device maintains low water level, crosses a few minutes inter-sync of expansion enter low enthalpy condensate water at water-cooling wall;

Before water-cooling wall crosses and expands, separator maintains low water level;

Select built-in deaerator, oxygen-eliminating device maximum allowable working pressure is brought up to 2.0MPa;

Connect a pipeline to condenser low voltage bypass entrance from oxygen-eliminating device air removal section, quck-opening valve is above installed, control oxygen-eliminating device pressure;

Adopt above 4 measures simultaneously.

Very hot startup is the operating mode that most probable causes oxygen-eliminating device superpressure, like this, no matter cold start, warm starting, hot starting, hot start, very hot startup all can will start safely hydrophobic introducing oxygen-eliminating device, reclaim working medium and the heat in the overcritical double reheat boiler startup process of power station comprehensively, obtain the effect that better more fully reclaims working medium and heat than the direct current furnace starting system of being furnished with startup boiler water circulating pump.

High-pressure heater is to guarantee that high-pressure heater admission stop valve and high-pressure heater admission non-return valve tightly do not leak and can real-time verification as the necessary condition of water water heat exchanger between the Once-through Boiler starting period, is provided with pressure sensor and observable drain valve can meet this condition between each high-pressure heater admission stop valve and high-pressure heater admission non-return valve state of the art good, each high-pressure heater admission stop valve and high-pressure heater admission non-return valve.

Check and revise the flow area of the import of drawing gas and the Kv value of separator water level control valve (31) of No. 1 high-pressure heater (44), the large flow of guaranteeing to cross expansion at very hot startup water-cooling wall by time, steam-water separator (6) is no more than 1.0MPa with the pressure reduction of No. 1 high-pressure heater (44) shell-side.Check and confirm that the draw gas strike plate of import of No. 1 high-pressure heater (44) is enough to bear the hydrophobic impact of boiler startup, can not damage U-shaped pipe group, if desired reinforcement strike plate; Check and revise hydrophobic outlet flow area, the Kv value of No. 1 HP heater drainage control valve (48) and the HP heater drainage entrance flow area of No. 2 high-pressure heaters (45) of No. 1 high-pressure heater (44), the large flow of guaranteeing to cross expansion at very hot startup water-cooling wall by time, the shell pressure of No. 1 high-pressure heater (44) is not higher than 8MPa; Check and revise hydrophobic outlet flow area, the Kv value of No. 2 HP heater drainage control valves (49) and the HP heater drainage entrance flow area of No. 3 high-pressure heaters (46) of No. 2 high-pressure heaters (45), the large flow of guaranteeing to cross expansion at very hot startup water-cooling wall by time, the shell pressure of No. 2 high-pressure heaters (45) is not higher than 5.4MPa; Check and revise hydrophobic outlet flow area, the Kv value of No. 3 HP heater drainage control valves (50) and the HP heater drainage entrance flow area of No. 4 high-pressure heaters (47) of No. 3 high-pressure heaters (46), the large flow of guaranteeing to cross expansion at very hot startup water-cooling wall by time, the shell pressure of No. 3 high-pressure heaters (46) is not higher than 3.4MPa; Check and revise hydrophobic outlet flow area, the Kv value of No. 4 HP heater drainage control valves (51) and the HP heater drainage entrance flow area of oxygen-eliminating device (22) of No. 4 high-pressure heaters (47), the large flow of guaranteeing to cross expansion at very hot startup water-cooling wall by time, the shell pressure of No. 4 high-pressure heaters (47) is not higher than 2.3MPa; Hundred parts of ratio characteristics such as No. 1 HP heater drainage control valve (48), No. 2 HP heater drainage control valves (49), No. 3 HP heater drainage control valves (50), No. 4 HP heater drainage control valves (51) are.

4 high-pressure heater housing design pressure of double reheat unit are quite higher than the required pressure bearing when reclaiming the hydrophobic working medium of double reheat boiler startup and heat.4 high-pressure heaters, in boiler startup process, to starting hydrophobic as same distributed temperature-decreased pressure reducer that has a huge exchange capability of heat, start hydrophobic heat and pass to feedwater with countercurrent heat exchange method, reduce hydrophobic after enthalpy and are reclaimed by oxygen-eliminating device.

The present invention includes steam-water separator (6), steam-water separator water storage tank (7), water storage tank outlet shutoff valve (53), separator water level control valve (31), No. 1 high admission stop valve (40) that adds, No. 2 high admission stop valves (41) that add, No. 3 high admission stop valves (42) that add, No. 4 high admission stop valves (43) that add, No. 1 high-pressure heater (44), No. 2 high-pressure heaters (45), No. 3 high-pressure heaters (46), No. 4 high-pressure heaters (47), No. 1 HP heater drainage control valve (48), No. 2 HP heater drainage control valves (49), No. 3 HP heater drainage control valves (50), No. 4 HP heater drainage control valves (51), oxygen-eliminating device (22), oxygen-eliminating device decompression exhaust steam valve (52) and unit DCS (dcs), between the Once-through Boiler starting period, No. 1 high admission stop valve (40), No. 2 high admission stop valve (41), No. 3 high admission stop valve (42), No. 4 high admission stop valves (43) that add of adding of adding of adding are all in close stance, and shell-side and the extracted steam from turbine system of the shell-side of the shell-side of No. 1 high-pressure heater (44), No. 2 high-pressure heaters (45), No. 3 high-pressure heaters (46), No. 4 high-pressure heaters (47) are reliably isolated, steam-water separator water storage tank (7) startup is out hydrophobic through water storage tank outlet shutoff valve (53), separator water level control valve (31) enters the shell-side of No. 1 high-pressure heater (44), after cooling, reduce pressure through No. 1 HP heater drainage control valve (48), enter the shell-side of No. 2 high-pressure heaters (45), after cooling, reduce pressure through No. 2 HP heater drainage control valves (49), enter the shell-side of No. 3 high-pressure heaters (46), after cooling, reduce pressure through No. 3 HP heater drainage control valves (50), enter, the shell-side of No. 4 high-pressure heaters (47), after cooling, reduce pressure through No. 4 HP heater drainage control valves (51), enter oxygen-eliminating device (22), feed pump (15) sucks low pressure feed water from oxygen-eliminating device (22), after supercharging, become high-pressure feed water, through feed pump outlet valve (14), flow through the successively pipe side of No. 4 high-pressure heaters (47), No. 3 high-pressure heaters (46), No. 2 high-pressure heaters (45), No. 1 high-pressure heater (44), after cascade raising temperature, enter economizer (5), complete comprehensive recovery of working medium and heat, in the time that very hot startup water-cooling wall crosses hydrophobic the passing through of large flow startup of expansion, No. 1 HP heater drainage control valve (48), No. 2 HP heater drainage control valves (49), No. 3 HP heater drainage control valves (50), No. 4 HP heater drainage control valves (51) standard-sized sheet, oxygen-eliminating device (22), with the low enthalpy condensate water of stepping, is controlled the pressure of oxygen-eliminating device (22) not higher than 1.5MPa.

The control logic when control logic of the outlet drain regulating valve of high-pressure heater in the time that high-pressure heater is used as water water heat exchanger is used as heat regenerative system from high-pressure heater is completely different, unit DCS (dcs) must have the different control logic of 2 covers, switches in good time.In the time that high-pressure heater is used as water water heat exchanger, the outlet drain regulating valve of No. 1 high-pressure heater is for controlling the pressure differential between No. 1 high-pressure heater shell-side and No. 2 high-pressure heater shell-sides; The outlet drain regulating valve of No. 2 high-pressure heaters is for controlling the pressure differential between No. 2 high-pressure heater shell-sides and No. 3 high-pressure heater shell-sides; The outlet drain regulating valve of No. 3 high-pressure heaters is for controlling the pressure differential between No. 3 high-pressure heater shell-sides and No. 4 high-pressure heater shell-sides; The outlet drain regulating valve of No. 4 high-pressure heaters is for controlling the pressure differential between No. 4 high-pressure heater shell-sides and oxygen-eliminating device.Adjusting target taking the outlet drain regulating valve of each high-pressure heater as governor motion is the shell pressure of each corresponding high-pressure heater, regulate desired value and instant oxygen-eliminating device pressure, steam-water separator pressure relevant, the shell pressure desired value of No. 1 high-pressure heater is that steam-water separator pressure subtracts 1.0MPa, and the shell pressure desired value of No. 4 high-pressure heaters is that oxygen-eliminating device pressure adds 1.0MPa; It is poor that the shell pressure desired value of No. 2 high-pressure heaters is that No. 3 high-pressure heater shell pressures add No. 1 high-pressure heater and No. 4 high-pressure heater shell pressures of 0.54 times; It is poor that the shell pressure desired value of No. 3 high-pressure heaters is that No. 4 high-pressure heater shell pressures add No. 1 high-pressure heater and No. 4 high-pressure heater shell pressures of 0.2 times.Control logic when above-mentioned high-pressure heater is used as water water heat exchanger, its objective is that the heat exchange amount that makes under the premise that security is guaranteed to start between hydrophobic and high-pressure feed water maximizes.

When cold start, warm starting, hot starting, hot start, very hot startup, steam-water separator pressure is got respectively 6MPa to 9MPa, and lower value is got in cold start, and very hot startup is got high value, and warm starting, hot starting, hot start are got median; In start-up course, steam-water separator pressure can be used aperture and the fuel regulation of super-pressure bypass valve, high pressure bypass valve, low voltage bypass valve.

Separator water level control valve (31) is a cage spool control valve, Deng hundred parts of ratio characteristics, valve casing can bear supercritical pressure, large flow when its Kv value should ensure can cross expansion by very hot startup water-cooling wall in the time that its inlet outlet pressure differential is 0.5MPa.Because separator water level control valve (31) import and export pressure ratio is little, without serious cavitation, without being split into 2 or 3 control valves in parallel.

Oxygen-eliminating device (22) is built-in deaerator, the highest permission operating pressure 2.0MPa, Steam Turbine at full capacity sliding pressure operation of deaer pressure is no more than 1.3MPa, Once-through Boiler in the time of very hot startup oxygen-eliminating device pressure not higher than 1.5MPa; Oxygen-eliminating device (22) is provided with oxygen-eliminating device decompression exhaust steam valve (52), in the time that oxygen-eliminating device (22) occurs pressure higher than the unusual service condition of 1.5MPa, opens fast, and steam enters the low voltage bypass entrance of condenser (25); In the time that oxygen-eliminating device pressure returns to 1.0MPa, oxygen-eliminating device decompression exhaust steam valve (52) cuts out automatically.When oxygen-eliminating device decompression exhaust steam valve (52) is opened, oxygen-eliminating device decompression exhaust steam valve (52) outlet pressure is no more than 0.7MPa, and the built-in energy dissipator of condenser (25) can be accepted safely; The relieving capacity of oxygen-eliminating device decompression exhaust steam valve (52) in the time of inlet pressure 1.5MPa is 0.075BMCR mass flow.

When closing, water storage tank outlet shutoff valve (53) shell-side and the supercritical pressure of No. 1 high-pressure heater (44) reliably can be isolated; Between water storage tank outlet shutoff valve (53) and separator water level control valve (31), being provided with pressure sensor and observable drain valve closes tightly to confirm water storage tank outlet shutoff valve (53).

When power station supercritical DC furnace reaches after minimal once-through circulation load, steam-water separator (6) is dry state, micro-superheat state, separator water level control valve (31) complete shut-down, each HP heater drainage control valve complete shut-down, close water storage tank outlet shutoff valve (53), tightly isolate the shell-side of steam-water separator water storage tank (7) and No. 1 high-pressure heater (44); The control logic of the outlet drain regulating valve of unit DCS (dcs) to each high-pressure heater is switched to high-pressure heater water level control model; Open each high-pressure heater air inlet stop valve; Start each high-pressure heater and recover heat regenerative system mode of operation.

The present invention does not need steam-water separator water storage tank (7) that the various direct current furnace starting systems of prior art must have to pipeline thermal back-up system between separator water level control valve (31), because after No. 1 high-pressure heater recovers heat regenerative system mode of operation, steam turbine high-pressure cylinder draws gas and makes the shell-side of No. 1 high-pressure heater (44) and No. 1 high-pressure heater (44) shell-side to the pipeline between separator water level control valve (31) remain on hot; Otherwise 4 high-pressure heaters are also the good preheating that each high-pressure heater is returned to heat regenerative system state as the process of water water heat exchanger.

The present invention utilizes 4 high-pressure heaters of steamer pusher side between the power station supercritical DC furnace starting period, as water water heat exchanger, to DC furnace start-up drainage echelon pressure and temperature reducing, high enthalpy starts hydrophobic echelon and emits heat, makes to start hydrophobic enthalpy and is reduced under various start operating performances and is all applicable to oxygen-eliminating device safe retrieving.The unit DCS (dcs) of particular design has ensured each high-pressure heater to two control logics of high-pressure heater, all can complete safely, economically the heat regenerative system mode of operation that Once-through Boiler starts overall process and reduces the cold end loss of power station thermodynamic cycle under 2 kinds of different working modes.

The present invention is better than there is the direct current furnace starting system that starts boiler water circulating pump to the recovering effect of working medium and heat between the power station supercritical DC furnace starting period.

The present invention is applicable to design power station of new generation overcritical double reheat boiler startup system, in the time of high-pressure heater and the bid of oxygen-eliminating device system, meet the aforementioned additional through-flow requirement as water water heat exchanger, can not increase a lot of expenses, but can significantly reduce boiler island investment.

Adopt benefit of the present invention to be:

Cold start, warm starting, hot starting, hot start, very hot startup all can reclaim working medium and the heat in the overcritical double reheat boiler startup process of power station comprehensively, and recovering effect is better than there is the direct current furnace starting system that starts boiler water circulating pump.

From ignition of the boiler, water-cooling wall crosses and expands until minimal once-through circulation load all can reclaim working medium and the heat in the overcritical double reheat boiler startup process of power station comprehensively, and recovering effect is better than there is the direct current furnace starting system that starts boiler water circulating pump.

Without starting boiler water circulating pump and subsystem thereof, significantly reduce capital expenditure, eliminate import and rely on.

Without starting boiler water circulating pump, save station service.

Without starting boiler water circulating pump, maintenance, maintenance workload is little, possesses expense low.

To separator water level control valve pipeline thermal back-up system, save stand-by heat system energy consumption without steam-water separator water storage tank.

Operation is simple, safety, reliable, and operating cost is low.

Without iron pollution.

The operting differential pressure of separator water level control valve is little, without serious cavitation, significantly reduces cost.

(4) brief description of the drawings:

Fig. 1 has the direct current furnace starting system structure chart that starts boiler water circulating pump atmospheric drainage flash tank drainage pump

In Fig. 1, do not draw and start each subsystem that boiler water circulating pump needs, to avoid system construction drawing too numerous and diverse.

Fig. 1 illustrates as an example of single reheat unit example the direct current furnace starting system structure chart that starts boiler water circulating pump atmospheric drainage flash tank drainage pump, does not draw ultra-high pressure cylinder and secondary low-temperature reheater, secondary high-temperature reheater.

Start boiler water circulating pump (8) in Once-through Boiler start-up course, to sucking the hydrophobic supercharging of startup that starts boiler water circulating pump (8), be pressed into economizer (5) recovery working medium and heat through starting boiler water circulating pump outlet valve (9); Start from Once-through Boiler igniting, 20% the startup flow of always having an appointment is admitted to atmospheric drainage flash tank (33), makes separator water level control valve (31) and corresponding pipeline maintenance hot, exempts from excessive thermal shock; Cross a few minutes of the phase of expansion at water-cooling wall, start the increment that boiler water circulating pump (8) cannot occur pulsed and start the hydrophobic economizer (5) of sending back to, drive large separator water level control valve (31) and open water storage tank drain valve (32) and increment is started to the hydrophobic atmospheric drainage flash tank (33) of sending into can control the interior water level of steam-water separator (6) in normal range (NR).The startup of sending into atmospheric drainage flash tank (33) is hydrophobic, if water quality is qualified, via drain tank (34), drainage pump (35), start that drain recovery valve (21) is recovered to condenser (25) but often due to serious iron pollution, working medium should not reclaim, thermal loss, defectively hydrophobicly enters trench through blowoff valve (27).

For being easier to understand the function of direct current furnace starting system, the main portion cover that has not only drawn direct current furnace starting system in Fig. 1 has also briefly drawn main portion's cover high temperature superheater (1) of Once-through Boiler body, pendant superheater (2), low temperature superheater (3), water-cooling wall (4), a high temperature reheater (10), the main portion's cover high pressure cylinder of part (17) of a low-temperature reheater (11) and steam turbine and accessory system thereof, high pressure main inlet throttle-stop valve (16), high pressure bypass valve (13), intermediate pressure cylinder (20), reheat stop interceptor valve (19), low pressure (LP) cylinder (24), low voltage bypass valve (23), condenser (25), condensate pump (26), low-pressure heater (28).High-pressure heater (12) is a kind of expression of simplifying, and practical double reheat unit high-pressure heater system is composed in series by 4 conventionally; Height adds admission non-return valve (29) and height, and to add admission stop valve (30) be to coordinate this simplification expression accompanying drawing number.Low-pressure heater (28) is a kind of expression of more simplifying, and practical low-pressure heater system is composed in series by 4 conventionally; The admission of low-pressure heater (28) and be hydrophobicly all simplified.

Fig. 2 has the direct current furnace starting system structure chart that starts the hydrophobic in line condenser of boiler water circulating pump startup

In Fig. 2, do not draw and start each subsystem that boiler water circulating pump needs, to avoid system construction drawing too numerous and diverse.

Fig. 2 illustrates as an example of single reheat unit example the direct current furnace starting system structure chart that starts the hydrophobic in line condenser of boiler water circulating pump startup, does not draw ultra-high pressure cylinder and secondary low-temperature reheater, secondary high-temperature reheater.

Start boiler water circulating pump (8) in Once-through Boiler start-up course, to sucking the hydrophobic supercharging of startup that starts boiler water circulating pump (8), be pressed into economizer (5) recovery working medium and heat through starting boiler water circulating pump outlet valve (9); Be admitted to condenser (25) from Once-through Boiler igniting start to have an appointment 20% startup flow always, make separator water level control valve (31) and corresponding pipeline valve keep hot, exempt from excessive thermal shock; Cross a few minutes of the phase of expansion at water-cooling wall, start the increment that boiler water circulating pump (8) cannot occur pulsed and start the hydrophobic economizer (5) of sending back to, drive large separator water level control valve (31) and startup drain recovery valve (21) and enter condenser (25) through Backpack type temperature-decreased pressure reducer (54) and can control water level in steam-water separator (6) in normal range (NR).All startups of sending into condenser (25) are hydrophobic is all reclaimed but thermal loss as working medium.

For being easier to understand the function of direct current furnace starting system, the main portion cover that has not only drawn direct current furnace starting system in Fig. 2 has also briefly drawn main portion's cover high temperature superheater (1) of Once-through Boiler body, pendant superheater (2), low temperature superheater (3), water-cooling wall (4), a high temperature reheater (10), the main portion's cover high pressure cylinder of part (17) of a low-temperature reheater (11) and steam turbine and accessory system thereof, high pressure main inlet throttle-stop valve (16), high pressure bypass valve (13), intermediate pressure cylinder (20), reheat stop interceptor valve (19), low pressure (LP) cylinder (24), low voltage bypass valve (23), condenser (25), condensate pump (26), low-pressure heater (28).High-pressure heater (12) is a kind of expression of simplifying, and practical double reheat unit high-pressure heater system is composed in series by 4 conventionally; Height adds admission non-return valve (29) and height, and to add admission stop valve (30) be to coordinate this simplification expression accompanying drawing number.Low-pressure heater (28) is a kind of expression of more simplifying, and practical low-pressure heater system is composed in series by 4 conventionally; The admission of low-pressure heater (28) and be hydrophobicly all simplified.

Fig. 3 has the direct current furnace starting system structure chart of atmospheric drainage flash tank drainage pump without starting boiler water circulating pump

Fig. 3 illustrates as an example of single reheat unit example without starting boiler water circulating pump the direct current furnace starting system structure chart of atmospheric drainage flash tank drainage pump, does not draw ultra-high pressure cylinder and secondary low-temperature reheater, secondary high-temperature reheater.

In the whole start-up course of Once-through Boiler, comprise a few minutes of crossing the phase of expansion, the water level in steam-water separator (6) is regulated by water storage tank water level bypass valve (18), separator water level control valve (31) and water storage tank drain valve (32) combination; Start and hydrophobicly enter oxygen-eliminating device (22) part heat via water storage tank water level bypass valve (18) and can reclaim, enter atmospheric drainage flash tank (33) part through separator water level control valve (31) and water storage tank drain valve (32) and start hydrophobic not only thermal loss, because serious iron pollution also should not reclaim working medium.

For being easier to understand the function of direct current furnace starting system, the main portion cover that has not only drawn direct current furnace starting system in Fig. 3 has also briefly drawn main portion's cover high temperature superheater (1) of Once-through Boiler body, pendant superheater (2), low temperature superheater (3), water-cooling wall (4), a high temperature reheater (10), the main portion's cover high pressure cylinder of part (17) of a low-temperature reheater (11) and steam turbine and accessory system thereof, high pressure main inlet throttle-stop valve (16), high pressure bypass valve (13), intermediate pressure cylinder (20), reheat stop interceptor valve (19), low pressure (LP) cylinder (24), low voltage bypass valve (23), condenser (25), condensate pump (26), low-pressure heater (28).High-pressure heater (12) is a kind of expression of simplifying, and practical high-pressure heater system is composed in series by 3 conventionally; Height adds admission non-return valve (29) and height, and to add admission stop valve (30) be to coordinate this simplification expression accompanying drawing number.Low-pressure heater (28) is a kind of expression of more simplifying, and practical low-pressure heater system is composed in series by 4 conventionally; The admission of low-pressure heater (28) and be hydrophobicly all simplified.

Fig. 4 is without the direct current furnace starting system structure chart that starts the hydrophobic in line condenser of boiler water circulating pump startup

Fig. 4 illustrates as an example of single reheat unit example without the direct current furnace starting system structure chart that starts the hydrophobic in line condenser of boiler water circulating pump startup, does not draw ultra-high pressure cylinder and secondary low-temperature reheater, secondary high-temperature reheater.

In the whole start-up course of Once-through Boiler, comprise a few minutes of crossing the phase of expansion, water level in steam-water separator (6) is controlled by separator water level control valve (31), start hydrophobicly through starting drain recovery valve (21) and Backpack type temperature-decreased pressure reducer (54) in condenser (25) recovery, start hydrophobic thermal loss.

For being easier to understand the function of direct current furnace starting system, the main portion cover that has not only drawn direct current furnace starting system in Fig. 4 has also briefly drawn main portion's cover high temperature superheater (1) of Once-through Boiler body, pendant superheater (2), low temperature superheater (3), water-cooling wall (4), a high temperature reheater (10), the main portion's cover high pressure cylinder of part (17) of a low-temperature reheater (11) and steam turbine and accessory system thereof, high pressure main inlet throttle-stop valve (16), high pressure bypass valve (13), intermediate pressure cylinder (20), reheat stop interceptor valve (19), low pressure (LP) cylinder (24), low voltage bypass valve (23), condenser (25), condensate pump (26), low-pressure heater (28).High-pressure heater (12) is a kind of expression of simplifying, and practical high-pressure heater system is composed in series by 3 conventionally; Height adds admission non-return valve (29) and height, and to add admission stop valve (30) be to coordinate this simplification expression accompanying drawing number.Low-pressure heater (28) is a kind of expression of more simplifying, and practical low-pressure heater system is composed in series by 4 conventionally; The admission of low-pressure heater (28) and be hydrophobicly all simplified.

Fig. 5 high-pressure heater reclaims the method structure chart of the hydrophobic working medium of double reheat boiler startup and heat

Core knowledge property right of the present invention is between the Once-through Boiler starting period, to have introduced No. 1 high-pressure heater (44) of steamer pusher side, No. 2 high-pressure heaters (45), No. 3 high-pressure heaters (46), No. 4 high-pressure heaters (47) as water water heat exchanger, by hydrophobic the startup of the high enthalpy temperature that is cooled to oxygen-eliminating device (22) to accept safely, reclaim working medium and heat comprehensively.One of the heat reclaiming is made up of 2 parts,, the startup of high enthalpy is hydrophobic to be absorbed by high-pressure feed water through water water heat exchanger liberated heat; Two, the startup slightly higher than deaerator storage tank water storage temperature be hydrophobic carries heat with hybrid mode and enters oxygen-eliminating device.

Steam-water separator water storage tank (7) startup is out hydrophobic through water storage tank outlet shutoff valve (53), separator water level control valve (31) enters the shell-side of No. 1 high-pressure heater (44), after cooling, through No. 1 HP heater drainage control valve (48), enter the shell-side of No. 2 high-pressure heaters (45), after cooling, through No. 2 HP heater drainage control valves (49), enter the shell-side of No. 3 high-pressure heaters (46), after cooling, through No. 3 HP heater drainage control valves (50), enter the shell-side of No. 4 high-pressure heaters (47), after cooling, enter oxygen-eliminating device (22) through No. 4 HP heater drainage control valves (51).Feed pump (15) sucks low pressure feed water from oxygen-eliminating device (22), after supercharging, become high-pressure feed water, through feed pump outlet valve (14), flow through the successively pipe side of No. 4 high-pressure heaters (47), No. 3 high-pressure heaters (46), No. 2 high-pressure heaters (45), No. 1 high-pressure heater (44), after cascade raising temperature, enter economizer (5), complete comprehensive recovery of working medium and heat.

When power station supercritical DC furnace reaches after minimal once-through circulation load, steam-water separator (6) is the micro-superheat state of dry state, the water level to 0 of steam-water separator water storage tank (7), separator water level control valve (31) complete shut-down, No. 1 HP heater drainage control valve (48), No. 2 HP heater drainage control valves (49), No. 3 HP heater drainage control valves (50), No. 4 HP heater drainage control valves (51) complete shut-down, continue to close after 120 seconds water storage tank outlet shutoff valve (53); DCS (dcs) recovers the water level control model to No. 1 HP heater drainage control valve (48), No. 2 HP heater drainage control valves (49), No. 3 HP heater drainage control valves (50), No. 4 HP heater drainage control valves (51); Open successively high admission stop valve (43), No. 3 high admission stop valve (42), No. 2 high admission stop valve (41), No. 1 high admission stop valves (40) that add of adding of adding of adding No. 4; No. 1 high-pressure heater (44), No. 2 high-pressure heaters (45), No. 3 high-pressure heaters (46), No. 4 high-pressure heaters (47) return the heat regenerative system method of operation.

For being easier to understand the function of direct current furnace starting system, the main portion cover that has not only drawn direct current furnace starting system in Fig. 5 has also briefly drawn main portion's cover high temperature superheater (1) of Once-through Boiler body, pendant superheater (2), low temperature superheater (3), water-cooling wall (4), a high temperature reheater (10), a low-temperature reheater (11), secondary high-temperature reheater (58), the main portion's cover ultra-high pressure cylinder of part (56) of secondary low-temperature reheater (59) and steam turbine and accessory system thereof, high pressure cylinder (17), super-pressure main inlet throttle-stop valve (55), single reheat combined emergency stop and governing valve (60), double reheat combined emergency stop and governing valve (61), super-pressure bypass valve (57), high pressure bypass valve (13), intermediate pressure cylinder (20), low pressure (LP) cylinder (24), low voltage bypass valve (23), condenser (25), condensate pump (26), low-pressure heater (28).

4 high-pressure heaters and related valve, given new figure and Reference numeral.

In Fig. 5, do not draw unit DCS (dcs) in order to avoid figure is too complicated.

Reference numeral in Fig. 1, Fig. 2, Fig. 3, Fig. 4, Fig. 5:

1 high temperature superheater, 2 pendant superheaters, 3 low temperature superheaters,

4 water-cooling walls, 5 economizers, 6 steam-water separators,

7 steam-water separator water storage tanks, 8 start boiler water circulating pumps, 9 start boiler water circulating pump outlet valves,

10 high temperature reheaters, 11 low-temperature reheaters, 12 high-pressure heaters,

13 high pressure bypass valves, 14 feed pump outlet valves, 15 feed pumps,

16 high pressure main inlet throttle-stop valves, 17 high pressure cylinders, 18 separator water level bypass valves,

19 reheat stop interceptor valves, 20 intermediate pressure cylinders, 21 start drain recovery valves,

22 oxygen-eliminating devices, 23 low voltage bypass valves, 24 low pressure (LP) cylinders,

25 condensers, 26 condensate pumps, 27 blowoff valves,

28 low-pressure heaters, 29 height add admission non-return valve, 30 height add admission stop valve,

31 separator water level control valves, 32 water storage tank drain valves, 33 atmospheric drainage flash tanks,

34 drain tanks, 35 drainage pumps, 36 No. 1 are high add admission non-return valve,

37 No. 2 high add admission non-return valve, 38 No. 3 high add admission non-return valve, 39 No. 4 high add admission non-return valve,

40 No. 1 high add admission stop valve, 41 No. 2 high add admission stop valve, 42 No. 3 high add admission stop valve,

43 No. 4 high add admission stop valve, 44 No. 1 high-pressure heaters, 45 No. 2 high-pressure heaters,

46 No. 3 high-pressure heaters, 47 No. 4 high-pressure heaters, 48 No. 1 HP heater drainage control valves,

49 No. 2 HP heater drainage control valves, 50 No. 3 HP heater drainage control valves, 51 No. 4 HP heater drainage control valves,

52 oxygen-eliminating devices decompressions exhaust steam valves, 53 water storage tank outlet shutoff valves, 54 Backpack type temperature-decreased pressure reducers,

55 super-pressure stop valves, 56 ultra-high pressure cylinders, 57 super-pressure bypass valves,

58 secondary high-temperature reheaters, 59 secondary high-temperature reheaters, 60 single reheat combined emergency stop and governing valves,

61 double reheat combined emergency stop and governing valves.

(5) detailed description of the invention:

Below taking the overcritical double reheat boiler in power station of a 1000MW grade as example, in conjunction with Fig. 5, further illustrate high-pressure heater of the present invention and reclaim the method for the hydrophobic working medium of double reheat boiler startup and heat:

The method that high-pressure heater of the present invention reclaims the hydrophobic working medium of double reheat boiler startup and heat comprises steam-water separator (6), steam-water separator water storage tank (7), water storage tank outlet shutoff valve (53), separator water level control valve (31), No. 1 high admission stop valve (40) that adds, No. 2 high admission stop valves (41) that add, No. 3 high admission stop valves (42) that add, No. 4 high admission stop valves (43) that add, No. 1 high-pressure heater (44), No. 2 high-pressure heaters (45), No. 3 high-pressure heaters (46), No. 3 high-pressure heaters (47), No. 1 HP heater drainage control valve (48), No. 2 HP heater drainage control valves (49), No. 3 HP heater drainage control valves (50), No. 4 HP heater drainage control valves (51), oxygen-eliminating device (22), oxygen-eliminating device decompression exhaust steam valve (52) and unit DCS (dcs).

Check and revise the flow area of the import of drawing gas and the Kv value of separator water level control valve (31) of No. 1 high-pressure heater (44), the large flow of guaranteeing to cross expansion at very hot startup water-cooling wall by time, steam-water separator (6) is no more than 1.0MPa with the pressure reduction of No. 1 high-pressure heater (44) shell-side.Check and confirm that the draw gas strike plate of import of No. 1 high-pressure heater (44) is enough to bear the hydrophobic impact of boiler startup, can not damage U-shaped pipe group, if desired reinforcement strike plate.Check and revise hydrophobic outlet flow area, the Kv value of No. 1 HP heater drainage control valve (48) and the HP heater drainage entrance flow area of No. 2 high-pressure heaters (45) of No. 1 high-pressure heater (44), the large flow of guaranteeing to cross expansion at very hot startup water-cooling wall by time, the shell pressure of No. 1 high-pressure heater (44) is not higher than 8MPa; Check and revise hydrophobic outlet flow area, the Kv value of No. 2 HP heater drainage control valves (49) and the HP heater drainage entrance flow area of No. 3 high-pressure heaters (46) of No. 2 high-pressure heaters (45), the large flow of guaranteeing to cross expansion at very hot startup water-cooling wall by time, the shell pressure of No. 2 high-pressure heaters (45) is not higher than 5.4MPa; Check and revise hydrophobic outlet flow area, the Kv value of No. 3 HP heater drainage control valves (50) and the HP heater drainage entrance flow area of No. 4 high-pressure heaters (47) of No. 3 high-pressure heaters (46), the large flow of guaranteeing to cross expansion at very hot startup water-cooling wall by time, the shell pressure of No. 3 high-pressure heaters (46) is not higher than 3.4MPa; Check and revise hydrophobic outlet flow area, the Kv value of No. 4 HP heater drainage control valves (51) and the HP heater drainage entrance flow area of oxygen-eliminating device (22) of No. 4 high-pressure heaters (47), the large flow of guaranteeing to cross expansion at very hot startup water-cooling wall by time, the shell pressure of No. 4 high-pressure heaters (47) is not higher than 2.3MPa.Hundred parts of ratio characteristics such as No. 1 HP heater drainage control valve (48), No. 2 HP heater drainage control valves (49), No. 3 HP heater drainage control valves (50), No. 4 HP heater drainage control valves (51) are.

4 high-pressure heater housing design pressure of double reheat unit are quite higher than the required pressure bearing when reclaiming the hydrophobic working medium of double reheat boiler startup and heat.4 high-pressure heaters, in boiler startup process, to starting hydrophobic as same distributed temperature-decreased pressure reducer that has a huge exchange capability of heat, start hydrophobic heat and pass to feedwater with countercurrent heat exchange method, reduce hydrophobic after enthalpy and are reclaimed by oxygen-eliminating device.

The control logic when control logic of the outlet drain regulating valve of high-pressure heater in the time that high-pressure heater is used as water water heat exchanger is used as heat regenerative system from high-pressure heater is completely different, unit DCS (dcs) must have the different control logic of 2 covers, switches in good time.In the time that high-pressure heater is used as water water heat exchanger, the outlet drain regulating valve of No. 1 high-pressure heater is for controlling the pressure differential between No. 1 high-pressure heater shell-side and No. 2 high-pressure heater shell-sides; The outlet drain regulating valve of No. 2 high-pressure heaters is for controlling the pressure differential between No. 2 high-pressure heater shell-sides and No. 3 high-pressure heater shell-sides; The outlet drain regulating valve of No. 3 high-pressure heaters is for controlling the pressure differential between No. 3 high-pressure heater shell-sides and No. 4 high-pressure heater shell-sides; The outlet drain regulating valve of No. 4 high-pressure heaters is for controlling the pressure differential between No. 4 high-pressure heater shell-sides and oxygen-eliminating device.Adjusting target taking the outlet drain regulating valve of each high-pressure heater as governor motion is the shell pressure of each corresponding high-pressure heater, regulate desired value and instant oxygen-eliminating device pressure, steam-water separator pressure relevant, the shell pressure desired value of No. 1 high-pressure heater is that steam-water separator pressure subtracts 1.0MPa, and the shell pressure desired value of No. 4 high-pressure heaters is that oxygen-eliminating device pressure adds 1.0MPa; It is poor that the shell pressure desired value of No. 2 high-pressure heaters is that No. 3 high-pressure heater shell pressures add No. 1 high-pressure heater and No. 4 high-pressure heater shell pressures of 0.54 times; It is poor that the shell pressure desired value of No. 3 high-pressure heaters is that No. 4 high-pressure heater shell pressures add No. 1 high-pressure heater and No. 4 high-pressure heater shell pressures of 0.2 times.Control logic when above-mentioned high-pressure heater is used as water water heat exchanger, its objective is that the heat exchange amount that makes under the premise that security is guaranteed to start between hydrophobic and high-pressure feed water maximizes.

When cold start, warm starting, hot starting, hot start, very hot startup, steam-water separator pressure is got respectively 6MPa to 9MPa, and lower value is got in cold start, and very hot startup is got high value, and warm starting, hot starting, hot start are got median; In start-up course, steam-water separator pressure can be used aperture and the fuel regulation of high and low pressure bypass valve.

Between the Once-through Boiler starting period, No. 1 high admission stop valve (40), No. 2 high admission stop valve (41), No. 3 high admission stop valve (42), No. 4 high admission stop valves (43) that add of adding of adding of adding are all in close stance, and shell-side and the extracted steam from turbine system of the shell-side of the shell-side of No. 1 high-pressure heater (44), No. 2 high-pressure heaters (45), No. 3 high-pressure heaters (46), No. 4 high-pressure heaters (47) are reliably isolated.

Steam-water separator water storage tank (7) startup is out hydrophobic through water storage tank outlet shutoff valve (53), separator water level control valve (31) enters the shell-side of No. 1 high-pressure heater (44), after cooling, reduce pressure through No. 1 HP heater drainage control valve (48), enter the shell-side of No. 2 high-pressure heaters (45), after cooling, reduce pressure through No. 2 HP heater drainage control valves (49), enter the shell-side of No. 3 high-pressure heaters (46), after cooling, reduce pressure through No. 3 HP heater drainage control valves (50), enter, the shell-side of No. 4 high-pressure heaters (47), after cooling, reduce pressure through No. 4 HP heater drainage control valves (51), enter oxygen-eliminating device (22), feed pump (15) sucks low pressure feed water from oxygen-eliminating device (22), after supercharging, become high-pressure feed water, through feed pump outlet valve (14), flow through the successively pipe side of No. 4 high-pressure heaters (47), No. 3 high-pressure heaters (46), No. 2 high-pressure heaters (45), No. 1 high-pressure heater (44), after cascade raising temperature, enter economizer (5), complete comprehensive recovery of working medium and heat.

In the time that very hot startup water-cooling wall crosses hydrophobic the passing through of large flow startup of expansion, No. 1 HP heater drainage control valve (48), No. 2 HP heater drainage control valves (49), No. 3 HP heater drainage control valves (50), No. 4 HP heater drainage control valves (51) standard-sized sheet, oxygen-eliminating device (22), with the low enthalpy condensate water of stepping, is controlled the pressure of oxygen-eliminating device (22) not higher than 1.5MPa.

Water storage tank outlet shutoff valve (53) has the ability of reliable isolation supercritical pressure, is provided with pressure sensor and observable drain valve and closes tightly to confirm water storage tank outlet shutoff valve (53) between water storage tank outlet shutoff valve (53) and separator water level control valve (31).The condition that water storage tank outlet shutoff valve (53) is opened is: steam-water separator pressure is not higher than 9.0MPa; No. 1 high adds that admission stop valve (40), No. 2 are high adds that admission stop valve (41), No. 3 highly add admission stop valve (42), No. 4 high admission stop valves (43) that add are all closed tightly; No. 1 HP heater drainage control valve (48), No. 2 HP heater drainage control valves (49), No. 3 HP heater drainage control valves (50), No. 4 HP heater drainage control valves (51) are all positioned at the initial aperture region of aperture 70% to 80%; Unit DCS (dcs) enters water water heat exchanger control model; Feed pump (15) is working properly, and position left by feed pump outlet valve (14); Above condition meets simultaneously, with logic.

Separator water level control valve (31) is a cage spool control valve, waits hundred parts of ratio characteristics, and shell can bear supercritical pressure, and its Kv value should ensure can cross by very hot startup water-cooling wall the large flow of expansion in the time that inlet outlet pressure differential is 0.5MPa.

Oxygen-eliminating device (22) is built-in deaerator, the highest permission operating pressure 2.0MPa, Steam Turbine at full capacity oxygen-eliminating device operating pressure is no more than 1.3MPa, Once-through Boiler in the time of very hot startup oxygen-eliminating device pressure not higher than 1.5MPa; Oxygen-eliminating device (22) is provided with oxygen-eliminating device decompression exhaust steam valve (52), opens fast during higher than 1.5MPa when oxygen-eliminating device pressure, and steam enters the low voltage bypass entrance of condenser (25); In the time that oxygen-eliminating device pressure returns to 1.0MPa, oxygen-eliminating device decompression exhaust steam valve (52) cuts out automatically.When oxygen-eliminating device decompression exhaust steam valve (52) is opened, oxygen-eliminating device decompression exhaust steam valve (52) outlet pressure is no more than 0.7MPa, and the built-in energy dissipator of condenser (25) can be accepted safely; The relieving capacity of oxygen-eliminating device decompression exhaust steam valve (52) in the time of inlet pressure 1.5MPa is 0.075BMCR mass flow.

Unit DCS (dcs) coordinates to control steam-water separator (6), steam-water separator water storage tank (7), water storage tank outlet shutoff valve (53), separator water level control valve (31), No. 1 high admission stop valve (40) that adds, No. 2 high admission stop valves (41) that add, No. 3 high admission stop valves (42) that add, No. 4 high admission stop valves (43) that add, No. 1 high-pressure heater (44), No. 2 high-pressure heaters (45), No. 3 high-pressure heaters (46), No. 4 high-pressure heaters (47), No. 1 HP heater drainage control valve (48), No. 2 HP heater drainage control valves (49), No. 3 HP heater drainage control valves (50), No. 4 HP heater drainage control valves (51), oxygen-eliminating device (22), oxygen-eliminating device decompression exhaust steam valve (52) safety, complete economically Once-through Boiler start-up course.Complete after start-up course, unit DCS closes water storage tank outlet shutoff valve (53) and isolates reliably steam-water separator water storage tank (7) and No. 1 high-pressure heater (44) shell-side, and unit DCS recovers high-pressure heater heat regenerative system mode and moves.

Once-through Boiler underrun and furnace shutting down process are the inverse process that Once-through Boiler starts.In the time that minimal once-through circulation load is arrived in the downhill race of Once-through Boiler load, the pressure downhill race of steam-water separator (6) is to 9MPa or lower, No. 1 high admission stop valve (40), No. 2 high admission stop valve (41), No. 3 high admission stop valve (42), No. 4 high admission stop valves (43) that add of adding of adding of adding of tight closing, make No. 1 high-pressure heater (44), No. 2 high-pressure heaters (45), No. 3 high-pressure heaters (46), No. 4 high-pressure heaters (47) exit heat regenerative system state, unit DCS (dcs) is switched to water water heat exchanger control logic, No. 1 HP heater drainage control valve of DCS instruction (48), No. 2 HP heater drainage control valves (49), No. 3 HP heater drainage control valves (50), No. 4 HP heater drainage control valves (51) are all positioned at the initial aperture region of aperture 70% to 80%, when visible water level appears in steam-water separator (6), open water storage tank outlet shutoff valve (53) is regulated steam-water separator (6) under DCS controls water level by separator water level control valve (31), DCS coordinates to control No. 1 HP heater drainage control valve (48), No. 2 HP heater drainage control valves (49), No. 3 HP heater drainage control valves (50), the aperture of No. 4 HP heater drainage control valves (51), make No. 1 high-pressure heater (44), No. 2 high-pressure heaters (45), No. 3 high-pressure heaters (46), the shell pressure of No. 4 high-pressure heaters (47) is in desired value separately, blowing out is hydrophobic through water storage tank outlet shutoff valve (53), separator water level control valve (31) enters the shell-side of No. 1 high-pressure heater (44), after cooling, reduce pressure through No. 1 HP heater drainage control valve (48), enter the shell-side of No. 2 high-pressure heaters (45), after cooling, reduce pressure through No. 2 HP heater drainage control valves (49), enter the shell-side of No. 3 high-pressure heaters (46), after cooling, reduce pressure through No. 3 HP heater drainage control valves (50), enter, the shell-side of No. 4 high-pressure heaters (47), after cooling, reduce pressure through No. 4 HP heater drainage control valves (51), enter oxygen-eliminating device (22), feed pump (15) sucks low pressure feed water from oxygen-eliminating device (22), after supercharging, become high-pressure feed water, through feed pump outlet valve (14), flow through the successively pipe side of No. 4 high-pressure heaters (47), No. 3 high-pressure heaters (46), No. 2 high-pressure heaters (45), No. 1 high-pressure heater (44), after cascade raising temperature, enter economizer (5), complete comprehensive recovery of working medium and heat.

Ask that the hydrophobic amount of blowing out is quite less than confluent shutdown period, the pressure of oxygen-eliminating device (22) glides, safer compared with start operating performance.

Claims (10)

1. a high-pressure heater reclaims the method for the hydrophobic working medium of double reheat boiler startup and heat, it is characterized in that: the present invention includes steam-water separator (6), steam-water separator water storage tank (7), water storage tank outlet shutoff valve (53), separator water level control valve (31), No. 1 high admission stop valve (40) that adds, No. 2 high admission stop valves (41) that add, No. 3 high admission stop valves (42) that add, No. 4 high admission stop valves (43) that add, No. 1 high-pressure heater (44), No. 2 high-pressure heaters (45), No. 3 high-pressure heaters (46), No. 4 high-pressure heaters (47), No. 1 HP heater drainage control valve (48), No. 2 HP heater drainage control valves (49), No. 3 HP heater drainage control valves (50), No. 4 HP heater drainage control valves (51), oxygen-eliminating device (22), oxygen-eliminating device decompression exhaust steam valve (52) and unit DCS (dcs), between the Once-through Boiler starting period, No. 1 high admission stop valve (40), No. 2 high admission stop valve (41), No. 3 high admission stop valve (42), No. 4 high admission stop valves (43) that add of adding of adding of adding are all in close stance, and shell-side and the extracted steam from turbine system of the shell-side of the shell-side of No. 1 high-pressure heater (44), No. 2 high-pressure heaters (45), No. 3 high-pressure heaters (46), No. 4 high-pressure heaters (47) are reliably isolated, steam-water separator water storage tank (7) startup is out hydrophobic through water storage tank outlet shutoff valve (53), separator water level control valve (31) enters the shell-side of No. 1 high-pressure heater (44), after cooling, reduce pressure through No. 1 HP heater drainage control valve (48), enter the shell-side of No. 2 high-pressure heaters (45), after cooling, reduce pressure through No. 2 HP heater drainage control valves (49), enter the shell-side of No. 3 high-pressure heaters (46), after cooling, reduce pressure through No. 3 HP heater drainage control valves (50), enter, the shell-side of No. 4 high-pressure heaters (47), after cooling, reduce pressure through No. 4 HP heater drainage control valves (51), enter oxygen-eliminating device (22), feed pump (15) sucks low pressure feed water from oxygen-eliminating device (22), after supercharging, become high-pressure feed water, through feed pump outlet valve (14), flow through the successively pipe side of No. 4 high-pressure heaters (47), No. 3 high-pressure heaters (46), No. 2 high-pressure heaters (45), No. 1 high-pressure heater (44), after cascade raising temperature, enter economizer (5), complete comprehensive recovery of working medium and heat, in the time that very hot startup water-cooling wall crosses hydrophobic the passing through of large flow startup of expansion, No. 1 HP heater drainage control valve (48), No. 2 HP heater drainage control valves (49), No. 3 HP heater drainage control valves (50), No. 4 HP heater drainage control valves (51) standard-sized sheet, oxygen-eliminating device (22), with the low enthalpy condensate water of stepping, is controlled the pressure of oxygen-eliminating device (22) not higher than 1.5MPa.

2. high-pressure heater according to claim 1 reclaims the method for the hydrophobic working medium of double reheat boiler startup and heat, it is characterized in that described water storage tank outlet shutoff valve (53) has the ability of reliable isolation supercritical pressure, between water storage tank outlet shutoff valve (53) and separator water level control valve (31), be provided with pressure sensor and observable drain valve and close tightly to confirm water storage tank outlet shutoff valve (53); The condition that water storage tank outlet shutoff valve (53) is opened is: steam-water separator pressure is not higher than 9.0MPa; No. 1 high adds that admission stop valve (40), No. 2 are high adds that admission stop valve (41), No. 3 highly add admission stop valve (42), No. 4 high admission stop valves (43) that add are all closed tightly; No. 1 HP heater drainage control valve (48), No. 2 HP heater drainage control valves (49), No. 3 HP heater drainage control valves (50), No. 4 HP heater drainage control valves (51) are all positioned at the initial aperture region of aperture 70% to 80%; Unit DCS (dcs) enters water water heat exchanger control model; Feed pump (15) is working properly, and position left by feed pump outlet valve (14); Above condition meets simultaneously, with logic.

3. high-pressure heater according to claim 1 reclaims the method for the hydrophobic working medium of double reheat boiler startup and heat, it is characterized in that described separator water level control valve (31) is a cage spool control valve, Deng hundred parts of ratio characteristics, shell can bear supercritical pressure, and its Kv value should ensure can cross by very hot startup water-cooling wall the large flow of expansion in the time that inlet outlet pressure differential is 0.5MPa.

4. high-pressure heater according to claim 1 reclaims the method for the hydrophobic working medium of double reheat boiler startup and heat, it is characterized in that the draw gas strike plate of import of described No. 1 high-pressure heater (44) is enough to bear the hydrophobic impact of boiler startup, can not damage U-shaped pipe group; The HP heater drainage entrance flow area of the hydrophobic outlet flow area of No. 1 high-pressure heater (44), the Kv value of No. 1 HP heater drainage control valve (48) and No. 2 high-pressure heaters (45), the large flow of guaranteeing to cross expansion at very hot startup water-cooling wall by time, the shell pressure of No. 1 high-pressure heater (44) is not higher than 8MPa.

5. high-pressure heater according to claim 1 reclaims the method for the hydrophobic working medium of double reheat boiler startup and heat, it is characterized in that hydrophobic outlet flow area, the Kv value of No. 2 HP heater drainage control valves (49) and the HP heater drainage entrance flow area of No. 3 high-pressure heaters (46) of described No. 2 high-pressure heaters (45), the large flow of guaranteeing to cross expansion at very hot startup water-cooling wall by time, the shell pressure of No. 2 high-pressure heaters (45) is not higher than 5.4MPa.

6. high-pressure heater according to claim 1 reclaims the method for the hydrophobic working medium of double reheat boiler startup and heat, it is characterized in that hydrophobic outlet flow area, the Kv value of No. 3 HP heater drainage control valves (50) and the HP heater drainage entrance flow area of No. 4 high-pressure heaters (47) of described No. 3 high-pressure heaters (46), the large flow of guaranteeing to cross expansion at very hot startup water-cooling wall by time, the shell pressure of No. 3 high-pressure heaters (46) is not higher than 3.4MPa.

7. high-pressure heater according to claim 1 reclaims the method for the hydrophobic working medium of double reheat boiler startup and heat, it is characterized in that hydrophobic outlet flow area, the Kv value of No. 4 HP heater drainage control valves (51) and the HP heater drainage entrance flow area of oxygen-eliminating device (22) of described No. 4 high-pressure heaters (47), the large flow of guaranteeing to cross expansion at very hot startup water-cooling wall by time, the shell pressure of No. 4 high-pressure heaters (47) is not higher than 2.3MPa.

8. high-pressure heater according to claim 1 reclaims the method for the hydrophobic working medium of double reheat boiler startup and heat, it is characterized in that described oxygen-eliminating device (22) is built-in deaerator, the highest permission operating pressure 2.0MPa, Steam Turbine at full capacity oxygen-eliminating device operating pressure is no more than 1.3MPa, Once-through Boiler in the time of very hot startup oxygen-eliminating device pressure not higher than 1.5MPa.

9. high-pressure heater according to claim 1 reclaims the method for the hydrophobic working medium of double reheat boiler startup and heat, it is characterized in that described oxygen-eliminating device (22) is provided with oxygen-eliminating device decompression exhaust steam valve (52), open fast during higher than 1.5MPa when oxygen-eliminating device pressure, steam enters the low voltage bypass entrance of condenser (25); In the time that oxygen-eliminating device pressure returns to 1.0MPa, oxygen-eliminating device decompression exhaust steam valve (52) cuts out automatically.When oxygen-eliminating device decompression exhaust steam valve (52) is opened, oxygen-eliminating device decompression exhaust steam valve (52) outlet pressure is no more than 0.7MPa, and the built-in energy dissipator of condenser (25) can be accepted safely; The relieving capacity of oxygen-eliminating device decompression exhaust steam valve (52) in the time of inlet pressure 1.5MPa is 0.075BMCR mass flow.

10. high-pressure heater according to claim 1 reclaims the method for the hydrophobic working medium of double reheat boiler startup and heat, it is characterized in that described unit DCS dcs coordination control steam-water separator (6), steam-water separator water storage tank (7), water storage tank outlet shutoff valve (53), separator water level control valve (31), No. 1 high admission stop valve (40) that adds, No. 2 high admission stop valves (41) that add, No. 3 high admission stop valves (42) that add, No. 4 high admission stop valves (43) that add, No. 1 high-pressure heater (44), No. 2 high-pressure heaters (45), No. 3 high-pressure heaters (46), No. 4 high-pressure heaters (47), No. 1 HP heater drainage control valve (48), No. 2 HP heater drainage control valves (49), No. 3 HP heater drainage control valves (50), No. 4 HP heater drainage control valves (51), oxygen-eliminating device (22), oxygen-eliminating device decompression exhaust steam valve (52) safety, complete economically Once-through Boiler start-up course, DCS coordinates to control the aperture of No. 1 HP heater drainage control valve (48), No. 2 HP heater drainage control valves (49), No. 3 HP heater drainage control valves (50), No. 4 HP heater drainage control valves (51), and the shell pressure that makes No. 1 high-pressure heater (44), No. 2 high-pressure heaters (45), No. 3 high-pressure heaters (46), No. 4 high-pressure heaters (47) is in desired value separately, complete after start-up course, unit DCS closes water storage tank outlet shutoff valve (53) and isolates reliably steam-water separator water storage tank (7) and No. 1 high-pressure heater (44) shell-side, and unit DCS recovers high-pressure heater heat regenerative system mode and moves.