RU2448144C2 - Dry coke quenching apparatus - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: dry coke quenching apparatus has gas coolant circulation loop comprising gas conduit-connected quenching chamber 1, dust-trapping device 3, exhaust-heat boiler 4, cyclone 5, forced-draft fan 6, coolant gas recycling loop and a device 9 for continuous outlet of coke. The coolant gas recycling loop includes the bottom and top parts of the quenching chamber 1, connected by a gas conduit 7 fitted in the zone of the top annular channel 2 of the chamber 1. Safe working conditions are achieved by optimising hydraulic conditions in the device 9 for continuous outlet of coke through dust removal and degassing. Additional chemical heat from recycled gas is recycled in the exhaust-heat boiler 4.

EFFECT: stable composition of coolant gas on content of combustible components enables to keep loss of coke at a constant level.

1 dwg

Description

The invention relates to the coke industry and relates to dry quenching of coke (hereinafter CTC) with continuous unloading of quenched coke from the quenching chamber.

BACKGROUND

The CCCTs contain a fire extinguishing chamber connected in series in a closed loop with a device for unloading coke, a dust collecting bin, a waste heat boiler, dust collecting cyclones, and a blower fan. Coke quenching in the chamber is carried out by passing cooling gas through a coke layer. In the process of heat transfer, coke gives its heat to the cooling gas, which is then removed from the coke quenching chamber to the cooling gas circulation system containing a waste heat boiler with heat-exchange surfaces. (Teplitsky M.G. et al. Dry quenching of coke, M .: Metallurgy, 1971; R.I. Davidson. Master of dry quenching of coke. M: Metallurgy, 1980; US patent No. 414195, publ. 02.27.1979) .

The cooling gas is formed at the initial moment of loading the hot coke and is inert with respect to coke. It consists of the products of combustion of the combustible part of coke and atmospheric air located in the closed circuit of the CCP, and includes carbon monoxide, hydrogen, methane, carbon dioxide, nitrogen. However, during the operation of the CCP, the composition of the circulating gas changes.

Due to the fact that part of the cooling gas circulation circuit is constantly under significant vacuum, air is sucked in and mixed with gas. With repeated gas circulation through hot coke, the content of combustible components increases: carbon monoxide - up to 20-24%, hydrogen - up to 6-8%. Combustible components impede the operation of the CCCT, make the installation explosive, and the gas highly toxic. In accordance with the requirements of the rules of technical operation, the content of carbon monoxide in the gas cannot exceed 12%, and hydrogen 4%.

To reduce the content of combustible components, the so-called afterburning is applied by supplying air to the upper annular channel of the fire extinguishing chamber through inspection hatches. In this case, the amount of air supplied is controlled by the number of openable hatches. Almost uncontrolled air supply leads to an increase in coke "burnout" due to the interaction of coke carbon with carbon monoxide and incoming oxygen.

In the process of quenching of coke, a significant amount of dust is formed, which enters the cooling gas circulation system. The size of dust particles varies over a wide range - from relatively large to microscopic. The following are provided for collecting dust in the CCT cooling gas circulation system: for coarse cleaning - a dust precipitation device installed in front of the recovery boiler, for fine cleaning - a cyclone installed after the recovery boiler in front of the blower fan. The use of the named dust-cleaning equipment ensures the operation of the STCC in a given technological mode. However, dust and toxic cooling gas may be released during coke loading and unloading.

To prevent the emission of dust and toxic cooling gas in a closed cycle, the CCPP creates a certain hydraulic regime.

A pressure close to atmospheric pressure (the so-called aerodynamic zero) is maintained in the upper part of the coke quenching chamber, which prevents the release of cooling gas into the atmosphere during coke loading into the quenching chamber.

During the operation of the CCP in the lower part of the coke quenching chamber, the pressure exceeds atmospheric pressure by 200-300 mm water column. due to the high resistance of coke during the passage of cooling gas through the coke, which leads to emissions of cooling gas and dust at the time of coke unloading on a vehicle, such as a conveyor.

In order to prevent the release of cooling gas from the lower part of the quenching chamber, a pressure equal to atmospheric pressure, the so-called “aerodynamic lock”, is created in the means for continuously discharging coke. This is accomplished by a so-called cooling gas recirculation loop connected to a cooling gas circulation loop and a device for continuously discharging coke.

Analogue

Known USTK (patent RU 2111230, СВВ 39/02, publ. 20.05.19), containing a coke quenching chamber, a cooling gas circulation system, including a waste heat boiler, a device for continuous discharge of coke, a cooling gas recirculation circuit, a connecting device for continuous discharge coke with a cooling gas circulation system, specifically with a cyclone.

The disadvantages of the known USTC is the following.

To stabilize the composition of the circulating cooling gas according to the content of combustible components, an afterburning is used.

Due to the recirculation loop at the outlet of the device for continuous unloading of coke, a pressure equal to atmospheric is created, which prevents the emission of dust and gas. However, the optimal hydraulic mode in the discharge device is not achieved. Coke discharged onto the conveyor contains a significant amount of cooling gas and dust, which affects the working conditions of personnel. It is not possible to create a pressure below atmospheric pressure and thereby reduce emissions of dust and gas with coke due to the suction of additional air and its ingress into the cooling gas recirculation loop associated with the cooling gas circulation loop. Suction of air into the cooling gas circulation system increases the “burnout” of coke in the quenching chamber.

Prototype

There is a known CCP with its continuous discharge through the estrus in the lower part of the extinguishing chamber, containing two closed circuits of cooling gas circulation, one of which includes an extinguishing chamber connected by gas ducts, a recovery boiler with a dust collecting device and a blower fan, and the second - recirculation circuit - includes an unloading estrus extinguished coke, connected by gas pipelines to a dust collecting cyclone, and equipped with an automatic regulator of gas recirculation. To reduce the content of cooling gas and dust in the coke in the unloading zone, the CCGT is equipped with an additional air circulation circuit through the estrus connected to the cooling gas circulation and recirculation circuits, as well as an auxiliary fan and an additional cyclone (AS USSR 1600329, С01В 39/02, publ. 07.92.19920).

The disadvantages of the known USTC is the following.

To stabilize the composition of the circulating cooling gas according to the content of combustible components, an afterburning is used.

Due to the recirculation circuit in estrus, a pressure equal to atmospheric is created for the continuous discharge of coke. Additional purge of coke with air through the estrus for unloading improves the working conditions of the staff.

However, “aerodynamic locks” were created after coke exited the extinguishing chamber, which does not ensure the complete safety of maintenance personnel during the operation of the CCP. The installation of additional equipment (fan, cyclone) for dedusting and degassing of coke in the unloading zone leads to an increase in the accident rate of the CCP and is associated with additional capital and operating costs.

Due to the used recirculation loop, the chemical heat of the recirculation gas entering the dedusting device into the cyclone is lost.

The aim of the invention is to eliminate the above disadvantages, namely:

- stabilization of the composition of the cooling gas according to the content of combustible components without burning the combustible components with air;

- reduction of coke fumes;

- creating an optimal hydraulic mode in a continuous device for unloading coke;

- heat recovery of recirculation gas.

This goal is achieved in that in a dry coke extinguishing installation containing a cooling gas circuit, including a quenching chamber connected by gas ducts, a dust collecting device, a waste heat boiler, a cyclone, a blower fan, a cooling gas recirculation circuit and a device for continuously discharging coke, the recirculation circuit includes the lower and upper parts of the extinguishing chamber, connected by a gas duct.

The proposed CCPF does not use the afterburning of combustible components in the cooling gas by air supply. The stable composition of the cooling gas according to the content of combustible components provides the proposed circuit recirculation of the cooling gas. The constant supply of recirculation gas to the zone of the upper annular channel of the quenching chamber allows not only to optimize the content of combustible components in the cooling gas, but also to support it during the operation of the CCCT. The content of carbon monoxide in the circulating gas is not more than 2-3%, hydrogen - not more than 1-1.5%, oxygen less than 0.5%. This composition meets all the standards of operation of the USTK.

Stabilization of the composition of the cooling gas in the combustible components allows you to maintain the "coke" of coke at the level of 0.3-0.4%.

In the proposed USTK, the “aerodynamic shutter” is caused by lower than atmospheric pressure and is created in the lower part of the quenching chamber at the coke outlet into the device for continuous coke unloading. From the lower part of the quenching chamber, dust and small fractions of coke are carried away, as well as cooling gas from the coke space between the coke by recirculation gas. The air sucked into the device is mixed with the recirculated gas and fed to the afterburning in the high temperature zone in the upper part of the chamber. Effective dedusting of coke and effective degassing of coke is achieved, namely the removal of cooling gas from the pores of the coke and the inter-space, which ensures safe working conditions for the staff.

The additional chemical heat of the recycle gas is utilized in a recovery boiler.

The use of proprietary recirculation gas for the afterburning of combustible components leads to a simplified installation and cheaper process.

The invention is illustrated in the drawing.

The proposed installation consists of gas flues connected in series into a closed loop 1 with an upper annular channel 2, a dust collection bin 3, a waste heat boiler 4, a dust collection cyclone 5, a blower fan 6. A recycle gas duct 7 with an automatic gas flow regulator 8 connects the lower part of the chamber extinguishing 1 from the top in the area of the upper annular channel 2. Under the fire extinguishing chamber 1 there is a device for continuous discharge of coke 9, a conveyor for transporting coke 10.

Installation of dry quenching of coke works as follows.

In the extinguishing chamber 1 towards the moving red-hot (temperature 1000-1100 ° C) coke, a blowing fan 6 is supplied with cooling circulating gas with a temperature of 150-180 ° C. In this case, coke is cooled to a temperature of 150-200 ° C, giving its heat to the circulating gas, which is heated to a temperature of 700-800 ° C. Heated cooling gas with a temperature of 700-800 ° C enters the dust collector 3, then to the waste heat boiler 4, where it gives its heat to the heating surfaces. After the recovery boiler 4, the gas cooled to 150-180 ° C is supplied for final cleaning to the dust collecting cyclone 5 and again returned via the blower fan 6 to the extinguishing chamber 1.

Coke under the action of gravity moves to the lower part of chamber 1. A part of the cooling gas with a temperature of 150-180 ° C from the lower part of chamber 1 through the duct 7 due to rarefaction in the circulating gas circuit enters the upper part of chamber 1 into the zone of the upper annular channel 2. At a temperature of 700-800 ° C, the recirculation gas is mixed with the main stream of cooling gas. In the lower part of the chamber 1 and the device for continuous discharge 9, a vacuum of 5-10 mm of water is created. Art., which is supported by an automatic regulator of the flow of recirculation gas 8. Coke, freed from dust and gas, through an unloading funnel (not shown in the drawing) enters the device for continuous unloading 9, then to the conveyor 10.

Claims (1)

Dry coke extinguishing installation, comprising a cooling gas circulation circuit, including a quenching chamber connected by gas ducts, a dust collector, a waste heat boiler, a cyclone, a blower fan, a cooling gas recirculation circuit and a coke unloading device, characterized in that the recirculation circuit includes lower and upper extinguishing chamber parts connected by a gas duct.