JPH0291192A - Method and device for purification of crude gas obtained by solid gasification - Google Patents

Abstract

In a process and apparatus for purifying raw gas from solids gasification, containing granular and dusty solids particles, a solution is to be found, by means of which solids particles of any size are largely removed from the raw gas before entry to downstream cooling devices. This is achieved when the raw gas is passed in a first purification stage from the gasification zone in a straight line in the direction of a gas-holding space, whereby the granular solids particles are precipitated at the bottom of the gas-holding space and then, in a second purification stage, the partially purified raw gas is laterally deflected from the gas-holding space and undergoes a change to a velocity reduced by a factor of at least 3 and, after a further gas deflection, is passed substantially in the vertical direction through a solids filter, where the dusty solids particles are removed from the raw gas. <IMAGE>

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method and an apparatus for purifying crude gases obtained from solid gasification containing solid particles in the form of granules and powders. Solid gasification
Gasung) shall in particular mean the gasification of coal or lignite. Coal is introduced into the gasification reactor as pulverized coal and as a suspension together with an oxidizing agent, such as air or oxygen-enriched air. The resulting hot crude gas is conducted through the charged coal seam or freely discharged from the gasification reactor in the opposite direction. The present invention does not require crude gas to be passed through the charged coal seam (
and the purification of the crude gas which is freely discharged therefrom.

During the latter gas introduction, it is advantageous to first solidify the liquid slurry by known means. This is because the solid slurry is easily removed from the gas stream.

Since the crude gas obtained from the solid gasification described above contains one solid, it must be subjected to solid bone separation before further processing. In that case, the solid.

In each case, it is separated from the crude gas before further processing 1, for example cooling. This demand has heretofore been either not met at all or met only in an insufficient manner.

German Patent No. 3,223,702 discloses a method for producing synthesis gas in which pulverized coal and an oxidizing gas are introduced into nine reactors. The coarse ash is collected and discharged from the lower part of the reactor, while the synthesis gas is led together with the fly ash in powder form through one conduit into a heat exchanger which is at the same time a fly ash separator.

Due to the significantly different gas velocities and the long gas paths behind the heat exchanger to the cyclones, undesirable powder deposits inevitably form within the heat exchanger. Therefore, the efficiency of the heat exchanger is severely limited or periodic cleaning is required within a short period of time.

European Patent No. 77.851 discloses a gas cooler arrangement for cooling the reaction product of a coal gasification reactor. By using this new gas cooler arrangement, there should be no segregation of ash particles onto the convection gas cooler tubes.

This is achieved in that the convective gas cooler includes at least one riser for the gas to be cooled. In order to avoid contamination of the surfaces of the gas cooler, special pipe cleaning means, such as a soot blower, must of course be incorporated.

The problem to be solved by the present invention consists in ensuring that the solid particles of the respective size produced during solid gasification are sufficiently separated from the crude gas before being introduced into the cooling device.

According to the present invention, the above-mentioned problem is solved in a method according to the characterizing part of claim 1, that is, a two-stage purification method of a crude gas obtained from solid gasification containing granular and powdery solid particles. The crude gas is introduced from the gasification zone into the first purification stage linearly in the direction of the gas retention chamber (3), whereby granular solid particles are removed from the bottom of the gas retention chamber.

The partially purified crude gas is then led laterally from the gas retention chamber (3) and subjected to a velocity change reduced by a factor of at least 3, and after the gas has been redirected, substantially in a vertical direction through a solid filter in a second purification stage.

The problem is solved by a process characterized in that powdery solid particles are separated from the crude gas.

According to one embodiment of the invention, the method includes:

This is carried out in an apparatus characterized in that the gasification reactor has a gas outlet in the lower part, to the periphery of which a gas inlet chamber is connected, which is arranged above the fixed bed filter.

The advantages obtained by the invention are that, in terms of operating technology, coarse and fine purification of crude gases from granular and powdery particles is possible.
The advantage is that it takes place immediately in time without interrupting the flow of the gas produced or without using further containers. As a further direct result of the strong gas velocity reduction after the gas redirection.

This results in a uniform flow through the next filter surface.

This is achieved according to the invention by flowing the crude gas separated from the granular solid particles and still containing powder through a surface that is at least three times larger than the circulation surface of the gas outlet pipe from the gasification reactor. achieved.

The present invention will be explained in more detail with reference to examples.

Amount of gas to be purified; 7,040m3
/h Composition; CO42% H230% CO2 11% 820 15% 2% Other gas part powder content; 46.7g/m'N breakdown;
Granular solid grain reservation 85% Powdered solid grain reservation 15% Gas temperature 500-700'C Solid filter material; Building sand Sand grain size 0.5
~3 mm Bed temperature 500-700° C. Achievable separation, 90-99% The invention will now be described in more detail with reference to the accompanying drawings.

According to FIG. 1, raw gas flows down from a gasification reactor 1 of freely selectable construction, not fully illustrated, via a funnel-shaped raw gas outlet 2 to the bottom of the reactor. A gas retention chamber 3 exists below the funnel-shaped crude gas outlet 2 . Gas comes from here.

It must escape radially laterally and upwards into the filter inlet chamber 4. Granular solid particles contained in the crude gas are not separated by gas baffles;
The ash is separated into the ash collection chamber 5 at the bottom of the gas retention chamber by centrifugal force or gravity.

From there the granular solid particles are removed via a sluice valve 6 of known construction. In addition, 0 to 200μ
The crude gas contaminated by the powder particles of I flows from the filter inlet chamber 4 into the fixed bed filter 7, flows through it and is collected in the outlet chamber 8, from where it is further transported via the outlet 9 to the heat recovery device. be led to. The temperature of the purified crude gas is still above 500°C.

According to FIG. 2, a radiant cooler 10 is installed at the bottom of the gasification reactor 1 to reduce the temperature of the crude gas to 500-700°C.
is incorporated. The crude gas flows through the radiant cooler without significant deposition of solid particles on the heat exchange surfaces. The ash collection chamber 5 can also be designed as a water bath. The fixed bed 7, which is designed as an annular surface, is preferably filled with solid filter material via individual inlet conduits 11. After the surface of the filter is covered with powder,
The top layer of the filter is collected in the ash collection chamber 5 by gas backwashing using a nozzle 12 in a sliding manner.

The purified gas flowing through the filter 7 is passed through the collection conduit 1
3 and is removed from the device. Replenishment with fresh filter sand takes place from the sand storage tank 14 via the supply conduit 11 in a known manner.

[Brief explanation of the drawing]

1 is a principle diagram illustrating the method according to the invention, and FIG. 2 is an apparatus according to the invention with a fixed bed filter. In both figures above, the main parts are shown with reference numbers as follows: 1, ..., gasification reactor 2, ...! ■Gas outlet 3, gas retention chamber 4, filter inflow chamber 5, ash collection chamber 6, sluice valve 7, fixed bed filter 8, outflow chamber 9, Outlet 10, Radiation cooler 11, Supply conduit 12, Nozzle 13, Collection conduit 14, Sand storage tank

Claims (1)

[Claims] 1. In a two-stage purification method for crude gas obtained by solid gasification containing granular and powdery solid particles, the crude gas is retained in a first purification stage from a gasification region. Room (3
), whereby granular solid particles are removed from the bottom of the gas retention chamber, and partially purified crude gas is led laterally from the gas retention chamber (3). After undergoing a velocity change reduced by a factor of at least 3 and once again being redirected, the gas is directed in a substantially vertical direction through a solid filter in a second purification stage, thereby forming a powder. A two-stage purification method for the crude gas obtained from the solid gasification, characterized in that solid particles of are separated from the crude gas. 2. The method of claim 1, wherein the solid filter is a flowable sand bed filter. 3. The method according to claim 1 or 2, wherein the second purification step is carried out at a temperature of 500°C or higher. 4. An apparatus for purifying crude gas obtained from solid gasification containing granular and powdery solid particles, in which the apparatus has a lower crude gas outlet (2) and an ash collection chamber (5). In the above purification device consisting of a gasification reactor with a vertically located cooling space, a filter inlet chamber (4) is provided around the crude gas outlet (2) with a fixed bed filter (7).
The refining device is arranged above the refining device.