Method and apparatus for cooling hot gases and fluidized slag in entrained flow gasification

Abstract

A method and device for cooling hot crude gas and slag from entrained flow gasification of liquid and solid combustibles at crude gas temperatures ranging from 1,200 to 1,800° C. and at pressures of up to 80 bar in a cooling chamber disposed downstream of the gasification reactor by injecting water. The cooling water is distributed, with a first portion being finely dispersed into to cooling chamber and a second portion being fed at the bottom into an annular gap provided between the pressure-carrying tank wall and an incorporated metal apron for protecting said pressure-carrying tank wall. The second portion of the cooling water flows upward in the annular gap and trickles down the inner side of the metal apron in the form of a water film.

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 drawing. It is to be understood, however, that the drawing is designed as an illustration only and not as a definition of the limits of the invention.

FIG. 1 shows an entrained flow gasification reactor for carrying out the method of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

As shown in the drawing, a gasification reactor 2 with a gross output of 500 MW. 58 t/h of carbon dust are converted to crude gas and to liquid slag by adding an oxygen-containing gasifying agent and vapor by means of autothermal partial oxidation at an operating pressure of 41 bar. An amount of 145,000 m³ N/h of produced, humid crude gas and 4.7 Mg/h of slag exit together the reactor 2 into the free space of the cooler 1. Through 12 nozzles 1.1 evenly spaced on the perimeter of the cooler 1, an amount of 220 m³/h of cooling water is injected at a temperature of 178° C. Through the cooling process, the crude gas is cooled down to an equilibrium temperature of 220° C. and saturated according to the operating pressure. The 328,000 m³ N/h of now cooled, saturated crude gas exits the cooler 1 through the lateral crude gas outlet 1.2. The slag drops into the water bath 3 at the cooler's bottom where the temperature shock causes the slag to vitrify and, as a result thereof, to solidify and form into granules. The slag is evacuated by means of a lock hopper. 15 m, 3/h of cooling water are fed into the annular gap between pressure tank wall 1.6 and the metal apron 1.3. The cooling water flows upward in annular chamber 1.8, enters cooling chamber 1 through the spillover dam 1.4 and runs down the inner wall of metal apron 1.3 in the form of a water film 1.7.

The cooling water utilized is gas condensate, partially purified wash or excess water, partially recirculated from downstream process stages and demineralised water for replenishing lost water or a mixture thereof, with the pH being adjusted between 6 and 8. This adjustment is made by adding an acid or alkaline substances.

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.

LIST OF THE REFERENCE NUMERALS USED

• 1 cooler
• 1.1 nozzles
• 1.2 crude gas outlet
• 1.3 metal apron
• 1.4 spillover dam
• 1.5 port
• 1.6 pressure tank wall
• 1.7 water film
• 1.8 annular chamber
• 1.9 port
• 2 reactor
• 3 water bath

Claims

1. A method of cooling hot crude gas and slag from entrained flow gasification of liquid and solid combustibles at crude gas temperatures ranging from 1,200 to 1,800° C. and at pressures of up to 80 bar in a cooling chamber designed to be a free space disposed downstream of a gasification reactor, the method comprising: distributing a first portion of cooling water through a nozzle into the cooling chamber so as to be finely dispersed; anddistributing a second portion of cooling water fed at a bottom of the cooling chamber into an annular gap provided between a pressure-carrying tank wall and an incorporated metal apron for protecting said pressure-carrying tank wall, said second portion of the cooling water flowing upward in the annular gap and trickling down the inner side of the metal apron in the form of a water film.

2. The method as set forth in claim 1, wherein an excess of cooling water is used such that the crude gas is water vapor-saturated at temperatures ranging between 180 and 240° C.

3. The method as set forth in claim 1, wherein the cooling water used is selected from the group consisting of gas condensate, partially purified wash, excess water partially recirculated from downstream process stages, demineralised water for replenishing lost water, and mixtures thereof, with a pH of between 6 and 8.

4. The method as set forth in claim 1, wherein the pH of the cooling water is controlled.

5. An apparatus for cooling hot crude gas and slag from entrained flow gasification of liquid and solid combustibles at crude gas temperatures ranging from 1,200 to 1,800° C. and at pressures of up to 80 bar, comprising: an entrained flow gasification reactor having a cooling chamber with a pressure jacket;a metal apron incorporated into the cooling chamber and having nozzles so that an annular space is formed between the pressure jacket and the metal apron; anda port for supplying cooling water to the annular space,wherein cooling water flows upward through said annular space, and runs down the inner side of the metal apron in the form of a water film.

6. The apparatus as set forth in claim 5, wherein the metal apron is welded in gas-tight connection with ports mounted to the pressure-carrying tank wall.

7. The apparatus as set forth in claim 5, wherein the metal apron has a spillover dam toward a top of the apron, over which the water flows.

8. The apparatus as set forth in the claims 5, wherein the metal apron is made from a material that is resistant to Cl ions and acid corrosion.

9. The apparatus as set forth in the claim 5, further comprising a fill level measuring means for controlling the operability of the metal apron, said fill level measuring means being disposed on the metal apron at a height of the spillover dam.