JPS6191293A - Stabilized dust coal feeder - Google Patents

Abstract

PURPOSE:To feed dust coal with a high reliability under a stabilized condition, by detecting abnormality in a dust coal supply system and, once abnormality has occurred, blowing a high-pressure gas into the system to restore the original state. CONSTITUTION:Dust coal 1 is placed in a hopper 4 and fed by a feeder 5 to a coal/carrier gas confluence zone 6. The dust coal is carried by the carrier gas 2 to a coal distributor 7 through a pipe 20 and sent to a gasifying oven 9 through a pipe 21. Differential pressure gages DELTAPa:10 are attached to an outlet of the feeder 5 and an inlet of the distributor 7, differential pressure gages DELTAPb1-4:11, to the inlet and outlet of the distributor 7 and differential pressure gages DELTAPc1-4:12, to piping between the outlet of the distributor 7 and an entrance of the oven 9. A valve 13 is attached to the pipe 29, valves 14-17, to the pipe 21 and valves 18a-18d, to an outlet of a high-pressure tank 8. Signals from the differential pressure gages 10-12 are put in a control unit 30 and, when abnormality has occurred, one of the valves 18a-18d is opened momentarily to feed a high-pressure gas 3 intermittently for removal of deposits in the supply system.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a pulverized coal supply device, and particularly to a highly reliable supply device that eliminates troubles in the supply system.

[Background of the invention]

In order to expand the use of coal, coal combustion and gasification technologies are being developed. In particular, pulverized coal is reacted with oxygen or air to produce hydrogen gas, - oxidized carbon gas.

Gasification technology that generates methane gas, etc. is expected to be put to practical use because the gas can be used for a wide range of purposes, including fuel, chemical raw materials, and hydrogen sources. Gasifiers are operated under normal pressure or high pressure, but in order to fully demonstrate their performance, it is first necessary to stably supply coal to the gasifier. Coal supply methods include l) Wet supply method in which a slurry of coal and liquid is supplied using a pump, and It) Dry supply method in which coal is dropped by gravity, pushed in by a feeder, and pneumatic transport in which coal is mixed with gas. Among the methods of classical studies 11), the gravity fall method has been commercialized by the Lurgi method, but the air flow transport method is currently under development at the pilot plant stage.

The pneumatic transport device is usually composed of equipment such as a hopper for storing pulverized coal, a feeder for controlling the supply amount, a gas supply section for transporting the pulverized coal, a solid-gas two-phase flow pipe, and a coal burner. When there is one coal burner, the flow pipe and the burner are directly connected, but when there is a plurality of coal burners, the feeders are provided as many as the number of burners, or a coal distributor is provided following the feeder.

In either method, what is important in air transport is to take sufficient measures in the event that the amount of coal supplied changes or if a pipe becomes blocked somewhere. That is, it is essential to have an effective method for detecting whether the energy is evenly distributed to each burner and restoring it to the original state if the energy is distributed unevenly.

When the amount of coal supplied fluctuated and it became impossible to distribute it evenly, the gasification efficiency decreased.The length of the gasification flame from each burner became uneven, and the high-temperature flames hit the gasifier wall. Direct contact will cause damage. Also, for the amount of gasifying agent,
If the amount becomes abnormally low, the flame temperature will rise abnormally and destroy the furnace.

The method for detecting abnormalities is as seen in the development of the American Bi-Qas method (K., Young: Recen
t])eVelopeut in )(igh P
Ressure EntrairedFIOW Sla
gging Qasification of Co
a+.

8th C0GLAC, Aug, 1981)
Differential pressure in piping, sound.

Heat transfer speed, density inside piping, etc. are being considered.

If coal supply is interrupted by these devices,
Measures were taken such as stopping the gasification agent or supplying fuel gas instead of coal to maintain the temperature inside the furnace. Although this method allows for countermeasures against fluctuations in coal supply, it is not sufficient to restore the situation to its original state.

In the f3aarberg-Qtto method (W, Bro
cke, M.

Rossback, 5aarber-Otto Ga
51f 1cationprocess, 1st engineering
international Qas Re5carchC
onference, June, 1980)
, feeders are provided as many as the number of burners from the hopper, and gas is supplied to the outlet of the feeder and the flow pipe to be supplied to the gasification furnace.

Although equal distribution can be achieved by matching the supply amount of each feeder, measures against abnormalities and recovery methods are insufficient.

[Purpose of the invention]

The present invention has been made in an attempt to improve the above-mentioned drawbacks.
The purpose of this system is to monitor the supply amount, restore it to its original state if a fluctuation occurs, and stably supply pulverized coal.

[Summary of the invention]

That is, the feature of the present invention is to detect the pressure difference Lt between the coal hopper outlet and the coal distributor inlet, L2 between the coal distributor inlet and the coal distributor outlet, and L3 between the coal distributor outlet and the gasifier. and valves in sections LL and L3,
A high-pressure tank with a pressure as high as a coal hopper, and piping connecting the high-pressure tank to the inlet and outlet of the pulp, respectively, are installed, and any abnormality in the pressure difference is detected, and the pulp is transported to a predetermined place from the high-pressure tank according to a predetermined base drop. The purpose is to restore a coal supply system in an abnormal state to normal by instantaneously supplying high-pressure gas.

Abnormal conditions in the pneumatic transport system of pulverized coal are: 1) Loss of stable feedability due to coal bridging phenomenon.

11) Loss of feeder quantification due to gas movement due to pressure fluctuations between the coal hopper and gasifier.

;11) Uneven distribution due to uneven flow of gas and particles.

1■) Change in the cross-sectional area of the piping system due to foreign matter or coarse particles entering the pulverized coal.

■) Path cross-sectional area change and blockage due to slag adhesion to the tip of the coal burner.

etc. These phenomena can be detected by measuring the pressure difference in the piping.

It has been found that when the pressure measuring device t is provided as in the present invention, the relationship between the occurrence of the above-mentioned abnormal condition and the pressure difference is as follows.

Case 1)...L! + Lx r The differential pressure between Lx decreases uniformly.

Case 11)...L+, L2. The differential pressure between Lx changes uniformly.

Case 111)...The differential pressure between L+ and L2 is normal,
The differential pressure between L3 increases or decreases depending on the total amount of GjL pulverized coal.

Case 1)... The differential pressure on the upstream side where the cross-sectional area of the pipe has changed or blockage has occurred has increased, but the flow afterward is normal.

In the case of complete blockage, the differential pressure is Oo ■) Case...The differential pressure between Ls and L2 is normal, the cross-sectional area changes, and the differential pressure in the blocked burner pipe is Oo Among these, l), i White has 9 device shapes selected.

It can be avoided in advance by controlling hopper pressure, etc., but
) to +V) is difficult to predict.

In pneumatic transport, as a prerequisite for stably supplying pulverized coal, it is first important to stably supply gas. The flow of gas depends on the pressure distribution, and when this distribution is disrupted, phenomena such as changes in flow velocity and uneven flow occur.

The factor that disrupts the gas pressure distribution within the supply system is the pulverized coal itself. Coarse particles (accumulated at the bottom of straight pipes, curved pipes, and branched parts) stagnate in some parts of the pipe. Furthermore, even if the gas flow rate changes, the pressure distribution collapses. Once the balance is disrupted, development proceeds unilaterally in that direction.

Even if the pulverized coal supply system is operated as designed, it will always occur over a long period of time, and countermeasures must be taken when it occurs.

The most effective countermeasure is to instantaneously blow high-pressure gas into the area where the blockage is near or where the flow is drifting.

By doing this, the factors that disrupted the balance can be eliminated, and the original stable supply state can be restored.

The criteria for detecting the variation in differential pressure in each section and selecting a place to supply high-pressure gas are determined as shown in Table 1 based on the results of cases () to () above.

[Embodiments of the invention]

An embodiment of the present invention is shown in FIG. The embodiment includes a coal hopper 4, a coal feeder 5, a coal-carrying gas confluence section 6, a coal distributor 7, a gasifier 9, a high pressure tank 8, and a control unit 30.

Coal 1 is put into a coal hopper 4 and fed in a fixed amount by a coal feeder 5. The feeder is a screw star.

Use rotary history, table type, etc. The coal-carrier gas confluence section 6 is an ejector, and sends out pulverized coal (by the carrier gas 2). Nitrogen gas, air, oxygen gas, gasification product gas, etc. are used as the carrier gas.

It flows through the pipe 20 in a solid-gas two-phase flow and enters the coal distributor 7. As the distributor 7, for example, a fluidized bed system disclosed in Japanese Unexamined Patent Publication No. 57-205488 is used. The pulverized coal that has been multi-distributed by the distributor 7 (divided into four in the embodiment) flows through the pipes 21 and is supplied to the gasifier 9. In the gasification furnace 9, the product is gasified by a gasification agent (not shown), and the product is discharged through a pipe 19.

In this system, differential pressure gauges ΔF and 10 are installed at the outlet of the coal feeder 5 and the inlet of the distributor 7, and differential pressure gauges ΔPh1411 and 10 are installed at the inlet and the outlet of the distributor 7, respectively. Differential pressure gauges ΔP are installed on the four pipes from the outlet of the distributor 7 to the gasifier 9.
There are 14. In addition, pulp 13 is placed in the inlet side pipe 20 of the distributor 7, and valves 14 to 1 are placed in the outlet side pipe 21 of the distributor 7.
There are 7. Valve 18a-1 at high pressure tank 8 outlet
8d is provided, and the ends thereof are the inlets of pulps 13 to 17, respectively.

Connected to outlet piping. The control unit 30 receives signals from 10 to 12 differential pressure gauges. If an abnormality occurs, the first
The supply destination is determined according to the basis shown in the table, and the valve 18
Any one of a to 18d opens momentarily, and high pressure gas 3 is intermittently supplied.

By supplying high-pressure gas, the accumulation in the supply system is removed and the system returns to normal.

Coal hopper pressure is 4Kf/iG, coal supply amount is zoK
g/h, the results when using nitrogen gas as the carrier gas are shown in the second
This is shown in FIGS. The horizontal axis represents the elapsed time, and the vertical axis represents the differential pressure in the pipes in each section. FIG. 2 shows a case where one of the differential pressures ΔPh becomes higher than the other differential pressures. In this case, distributor 7
It is assumed that one of the outlet pipes is clogged with pulverized coal, so first, check the valve 17tJ of the pipe with high ΔPh.
nu, the valve 18 of the piping connected upstream of the valve 17 was opened to allow high-pressure gas to flow. As a result, the pulverized coal that had been clogged at the outlet of the distributor 7 was removed, and a stable supply state was restored. FIG. 3 shows a case where one of the differential pressures ΔP9 becomes higher than the other differential pressures. In this case, it is assumed that one pipe between the distributor 7 outlet and the gasifier 9 intake is clogged with pulverized coal, so first the pulp 1 of the pipe with a high ΔP
6 and connect the pulp 1 of the pipe downstream of the valve 16.
8 was opened and high pressure gas was allowed to flow. As a result, the pulverized coal that had been clogged at the gasifier entrance was removed, and stable supply returned. FIG. 4 shows a case where ΔP is higher than other differential pressures. In this case, it is assumed that the piping between the coal feeder 5 and the entrance of the distributor 7 is clogged with pulverized coal.
First, the pulp 13 was closed, and high pressure gas was flowed downstream and upstream of the pulp 13.

Other phenomena shown in Table 1 also occurred, but the present invention made stable supply possible.

〔Effect of the invention〕

According to the present invention, abnormal phenomena in the pulverized coal supply system can be automatically detected, countermeasures can be taken, and recovery can be performed, thereby enabling stable operation of the coal gasifier and improving reliability.

[Brief explanation of the drawing]

FIG. 1 is a system diagram showing an embodiment of the pulverized coal stable supply device of the present invention, and FIGS. 2 to 4 are diagrams showing examples of test results using the present invention supply device. 1... Coal, 2... Carrier gas, 3... High pressure gas,
4... Coal hopper, 5... Coal feeder, 7...
Distributor, 8... High pressure tank, 9... Gasifier, 10
~12...Differential pressure gauge, 13~17...Pulp, 20~
21... Piping, 30... Control unit.

Claims (1)

[Claims] 1. A coal feeder that supplies pulverized coal, a coal burner that conveys the coal together with gas to a coal distributor, which distributes the coal to the reactor, and an outlet of the coal feeder. and a differential pressure measuring device that is installed in the section of the inlet of the coal distributor, the section of the inlet and outlet of the coal distributor, and the section of the outlet of the coal distributor and the inlet of the coal burner, and measures the differential pressure in each section; Applicable depending on the on-off valve installed between the conveyance path between the outlet of the coal feeder and the inlet of the coal distributor, and between the conveyance path between the outlet of the coal distributor and the inlet of the coal burner, and the differential pressure measured in each section above. It is characterized by comprising a device for closing the on-off valve of the conveyance path, and a high-pressure tank that instantly supplies gas at a higher pressure than the pulverized coal conveyance flow to the inlet or outlet side of the on-off valve when the on-off valve is closed. A stable supply device for pulverized coal.