RU2606422C2 - Operating method of loose material gateway - Google Patents

Abstract

FIELD: gas industry.

SUBSTANCE: invention relates to gas industry. Operation of gasifier gateway with fixed bed of coal is performed by coal loading in gateway through one hole and unloading of coal from gateway through other hole into reactor under excess pressure of process gas. Both holes are equipped with self-sealing gates. Before gateway filling pressure is reduced to ambient pressure and gateway is blown-off by inert gas. After gateway filling with coal at mechanically closed hole pressure in gateway is increased with help of inert gas to such values that self-sealing gate hermetically closes hole. Prior to emptying pressure in gateway is increased by means of process gas to pressure in reactor.

EFFECT: higher efficiency and reliability, simplified operation of gateway are provided.

3 cl, 1 dwg

Description

Field of Invention

The invention relates to a method for operating a lock of bulk material, the opening for loading of which bulk material is equipped with a self-sealing shutter, this lock serves to fill process equipment that is under the pressure of the process gas, and before being emptied, the lock creates the pressure using the process gas to the existing in pressure equipment, and before filling, the pressure in it decreases to ambient pressure.

The invention also relates to the use of this method during operation of a lock of bulk material of a fixed-bed coal gasifier.

State of the art

Self-sealing valves have long been used in the art to close openings, such as container openings, in a gas or liquid impermeable manner. Usually they are equipped with a mechanism by which the shutter is placed in front of the hole, so that the sealing surfaces of the shutter and the holes are one on top of another or slightly pressed against each other. The principle of self-sealing is that a substantial part of the force necessary to press the sealing surfaces against each other in a gas or liquid impermeable manner is provided not by the shutter mechanism, but by the gas or liquid pressure existing in the corresponding technological equipment.

For example, bulk material locks for filling a fixed-bed coal gasifier are often equipped with self-sealing openings, with a round opening equipped with a sealing surface closed with a conical or cone-shaped shutter, see also Ullmann's Encyclopedia of Industrial Chemistry, Sixth Edition, Vol. 15, Gas Production, Chap. 4.4.

To fill the gas generator with coal in an empty lock of bulk material, the pressure decreases to the ambient pressure, then a loading opening opens and coal is loaded into the lock. Then, the loading opening of the airlock is closed by mechanically pressing the shutter into the round loading opening. Then the pressure in the valve is increased with the help of the process gas until a pressure corresponding to the process pressure of the gas generator is reached.

A disadvantage is that in the initial phase of the pressure increase, in which sufficient pressure has not yet been reached to completely seal the self-sealing loading hole, the process gas leaves the airlock through the loading hole. This process gas outlet is problematic in the case of coal gasification in a fixed bed, since the outgoing synthesis gas is toxic and, when mixed with atmospheric oxygen, is also explosive.

Until now, this problem has usually been solved by attempting to collect the outgoing process gas, as far as possible, and to safely utilize it, for example, in a combustion system.

This can be achieved, for example, in that the tray, which is inserted into the loading hole for loading the gateway, is equipped with a casing that is molded so that it completely covers the loading hole of the gateway and collects the exhaust gas. The casing is connected to an exhaust system that safely removes gas.

DD 239000 A1 describes another method for safely removing this gas. Upstream of the bulk material sluice, a reliably installed dosing tank, called a loading basket, is provided. Gas leaving the airlock is collected by a loading basket. By flushing with an inert gas, hazardous process gas is displaced from the loading basket and is removed through a pipeline connected to the loading basket.

The disadvantage of these methods is that they require relatively expensive equipment. Therefore, the goal was to develop a method of operating a bulk material lock that eliminates these disadvantages.

Description of the invention

This goal is solved by the method according to all the features of paragraph 1 of the claims. After the lock was filled with bulk material and the hole was mechanically closed, the pressure in the lock is first increased with inert gas until the necessary internal pressure is reached, which is necessary for the self-sealing shutter to achieve tightness. The gas outlet occurring at this moment is not dangerous, since the gas is an inert gas. Only when the tightness of the self-sealing shutter has been achieved is process gas used to further increase the pressure in the airlock, usually up to the process pressure existing in the connected equipment.

In one preferred embodiment of the invention, nitrogen is used as an inert gas. Nitrogen is non-toxic and generally affordable at a low price.

In another preferred embodiment of the invention, a sluice free of bulk material is purged with an inert gas after it has been reduced to ambient pressure and before it is again filled with bulk material. In the process, that is, during pressure reduction and during purging, the gas is released from the lock through a special pipeline connected to the lock, and not through the opening for filling the lock with bulk material. By flushing the lock with inert gas it is prevented that when filling the lock with bulk material, the process gas escapes through the loading opening of the lock into the environment.

In yet another preferred embodiment of the invention, the gas pressure in the lock after the self-sealing valve has been closed by a hermetically introduced inert gas is reduced by discharging gas to such an extent that it is possible to maintain the seal of the lock before the pressure in the lock is further increased by the process gas . Closing a self-sealing shutter usually requires a pressure higher than that necessary then to maintain shutter density, since to close the shutter body, it must be pressed into the optimal position in the shutter seat with great force. When this position is reached, the pressure can be reduced, since the shutter should only be maintained in this position. By discharging inert gas from the lock, as far as possible to maintain density, it is achieved that when bulk material is transferred from the lock to the reactor, less inert gas enters the reactor and pollutes the process gas.

To what extent the pressure in the gateway can be reduced without deteriorating the gate density can be easily determined by a specialist by conducting daily experiments.

Particularly preferably, the method according to the invention can be used in the operation of a fixed-bed coal gasifier. The process gas produced in this way is particularly toxic and explosive due to the content of carbon monoxide and hydrogen in it, so the leakage of this gas poses a particular threat to the safety of staff and the installation. Due to the large overall dimensions prevailing in this technology, valve tightness is usually only achieved at pressures above 4 bar. This means that before this pressure is reached, large quantities of process gas exit the lock.

The application of the method according to the invention prevents the escape of these hazardous gases in a simple manner, and devices that are designed to collect and discharge process gas leaving the feed opening become unnecessary.

Implementation example

Further improvements, advantages, and possible uses of the invention may be taken from the following description of exemplary embodiments and drawings. All described and / or illustrated features form the invention on their own or in any combination, regardless of their inclusion in the claims or their backlinks.

The drawing shows a lock of bulk material for a fixed-bed coal gasifier operated by the method of the invention.

The drawing shows the upper part of the reactor 1, which is filled with granular material, such as coal, through a lock 2 of granular material. Bulk material 3 is loaded into the gateway 2 bulk material through the hopper 4. The reactor 1 can be sealed relative to the gateway 2 through a self-sealing valve 5, and the gateway, in turn, can be sealed relative to the atmosphere through a self-sealing valve 6. The valves 5, 6 are equipped with a mechanical actuator shutter mechanism 5a, 6a.

The gateway 2 is filled with bulk material 3 through the hopper 4 and the open shutter 6. The shutter 5 is open. The shutter 6 is then mechanically closed by means of the device 6a. The shutter body 6b is placed in front of the shutter seat 6c. Then, the pressure in the gateway 2 is increased by inert gas through the pipeline 7, and the gas first exits the gateway through the valve 6 until the pressure increase in the gateway presses the valve body 6b against the valve seat 6c so tight that it remains open between them clearance. Inert gas can then be discharged through the line 8 from the lock so that upon subsequent emptying of the lock 2 in the reactor 1, inert gas will not be added to the gas atmosphere of the reactor to an unacceptable degree. By releasing inert gas from the lock, the pressure in the lock should be reduced only to such an extent that the density of the shutter 6 does not deteriorate. Through pipelines 7 and 8, the gateway 2 can also be purged with inert gas before the shutter 6 is open, with the release of process or purge gas through the pipe 8.

After the shutter 6 is hermetically closed, the pressure in the lock 2 is further increased through the pipeline 9 by means of the process gas from the reactor 1. After the pressure compensation between the lock 2 and the reactor 1 has been achieved in this way, the shutter 5 is mechanically opened and the bulk material flows out of the lock into the reactor.

LIST OF REFERENCE NUMBERS

1 - upper part of the reactor

2 - bulk material gateway

3 - bulk material

4 - hopper

5, 6 - self-sealing shutter

5a, 6a - mechanical shutter drive mechanism

6b - shutter housing

6s - shutter seat

7 - inert gas pipeline

8 - pipeline for the release of gas

9 - pipeline for increasing the pressure in the airlock with process gas

Claims (3)

1. A method of operating a gasifier lock with a fixed bed of coal, comprising loading coal into the lock through one opening equipped with a self-sealing shutter, discharging coal from the lock through another opening equipped with a self-sealing shutter, into a reactor under overpressure of the process gas, and before emptying the pressure in the lock, increase with the process gas to the pressure existing in the reactor, and before filling, reduce the pressure to ambient pressure and blow the lock with an inert gas, before it is again filled with coal, and after filling the lock with coal and after mechanical closing of the hole, the pressure in the lock is increased with inert gas to such a pressure until the self-sealing shutter closes the hole in an airtight manner, and only after reaching this state the pressure in the lock is further increased with using process gas. 2. The method according to p. 1, characterized in that the inert gas consists essentially of nitrogen. 3. The method according to p. 1 or 2, characterized in that after the self-sealing valve is closed in an airtight manner, the pressure in the lock is reduced to such an extent that it is possible to maintain the tightness of the shutter, and then the pressure in the lock is increased using process gas.

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