Method and apparatus for discharging slag from gasification reactors

Abstract

A method and device for evacuating ash and slag from reactors for pressure gasification of fuels, said fuels including coals of various ranks, cokes or ash-containing liquids or liquid-solid suspensions, at pressures between ambient pressure and 80 bar at gasification temperatures ranging between 800 and 1,800° C. There is a water circuit for loosening the deposited slag between a gasification chamber downstream of which there is mounted a quench chamber to which there is connected a slag lock hopper. Circuit water is supplied to the upper and lower part of the quench chamber.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

Other objects and features of the present invention will become apparent from the following detailed description considered in connection with the accompanying drawings. It is to be understood, however, that the drawings are designed as an illustration only and not as a definition of the limits of the invention.

In the drawings, wherein similar reference characters denote similar elements throughout the several views:

FIG. 1 shows a solution of the invention with gasification chamber, quench chamber and slag bath; and

FIG. 2 shows a solution of the invention with quench chamber, slag bath and slag crusher.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now in detail to the drawings, FIG. 1 shows a gasification chamber 3 with fuel and gasification means supply 1, 2, nozzle equipment 4 and quench chamber 5 from which crude gas 16 is evacuated and in the lower part of which there is disposed a water bath 6. A valve 12 separates quench chamber 5 and slag lock hopper 7; in the lower part of slag lock hopper 7 there is bulk slag 8 that may be evacuated through an additional valve 13 and slag evacuation tube 11. A water supply 9 is disposed in the lower part of slag lock hopper 7. The pump with circuit lines 10 is disposed in such a manner that the water can be pumped back and forth in the lines between quench chamber 5, water bath 6 and slag lock hopper 7.

In a reactor for entrained flow gasification, 30 mg/h hard coal dust are supplied through line 1 and converted at 40 bar together with a gasification means oxygen/water vapor inflowing from line 2. The hard coal has an ash content of 10 Ma %, which corresponds to 3 Mg/h. Gasification is conducted so that the crude gasification gas leaves gasification reactor 3 together with the molten ash in the form of slag at a temperature of 1,400° C. and is cooled down to 220° C. in quench chamber 5 with quench water supplied through nozzle system 4. Crude gas 16 flowing out has the same temperature.

To lower the temperature in water bath 6 and in bulk slag 8 and to break up and cool said slag, water is supplied at a temperature of 30° C. through line 9 into the lower part of slag lock hopper 7 and circulated to quench chamber 5 through pump 10. This causes the temperature in water bath 5 and in bulk slag 8 to lower before evacuation is initiated by closing valve 12 and opening valve 13.

FIG. 2 shows the invention with a slag crusher 15. In order to allow for evacuation of slag in the form of big lumps, a slag crusher 15 is mounted in the lower part of quench chamber 5. In order to avoid deposits, mainly of fine slag, in water bath 6, water is recirculated by means of pump 10 from slag lock hopper 7 through the water circuit line and supplied above and beneath slag crusher 15. This helps in discharging fine grains. As in FIG. 1, water is additionally introduced in the lower part of slag lock hopper 7 in order to achieve both loosening of bulk slag 8 and desired cooling prior to expansion.

Accordingly, while only a few embodiments of the present invention have been shown and described, it is obvious that many changes and modifications may be made thereunto without departing from the spirit and scope of the invention.

Claims

1. A method of evacuating ash and slag from reactors for pressure gasification of fuels, said fuels including coals of various ranks, cokes or ash-containing liquids or liquid-solid suspensions, at pressures between ambient pressure and 80 bar at gasification temperatures ranging between 800 and 1,800° C., comprising the following steps: maintaining a water circuit for loosening deposited slag between a quench chamber mounted downstream of a gasification chamber and a slag lock hopper disposed downstream of the quench chamber; andsupplying circuit water to an upper and a lower part of the quench chamber.

2. The method according to claim 1, further comprising the step of supplying to a lower part of the slag lock hopper at a temperature of between 20 and 90° C. in order to cool a water bath and the slag and to avoid or minimize the formation of vapor during expansion of the lock hopper.

3. The method according to claim 1, wherein the steps of supplying the water circuit between the slag lock hopper and the quench chamber and supplying water at temperatures ranging between 20 and 90° C. to the lower part of the slag lock hopper are performed simultaneously.

4. The method as according to claim 1, wherein the steps of maintaining a water circuit between the slag lock hopper and the quench chamber and supplying water at temperatures ranging between 20 and 90° C. to the lower part of the slag lock hopper are performed alternately.

5. The method according to claim 1, wherein the steps of maintaining the water circuit between the slag lock hopper and the quench chamber and supplying water at temperatures ranging between 20 and 90° C. to the lower part of the slag lock hopper are performed continuously or discontinuously.

6. The method according to claim 1, wherein the slag is shredded in the lower part of the quench chamber.

7. A device for evacuating ash and slag from reactors for pressure gasification of fuels comprising: a gasification chamber;a quench chamber mounted downstream of the gasification chamber;a slag lock hopper mounted downstream of the quench chamber;water circuit lines connecting said quench chamber to a water bath and to said slag lock hopper; anda pump mounted between the quench chamber and the slag lock hopper.

8. The device according to claim 7, further comprising a water supply mounted in the lower part of the slag lock hopper.

9. The device according to claim 7, further comprising a slag crusher disposed in a lower part of the quench chamber.