Apparatus for gasifying a fuel with a dripper edge and heat shield

Abstract

The invention provides an apparatus for gasifying a fuel to form synthesis gas wherein also a slag is formed. The apparatus comprises: a pressure shell; a slag bath; a gasifier wall; a free-fall trajectory for slag; and a heat shield. The gasifier wall is arranged inside the pressure shell defining a gasification chamber. It comprises a converging wall part that is provided with a slag discharge opening, located above the quench fluid in the slag bath. The heat shield is arranged above the slag bath between the free-fall trajectory and the pressure shell. The heat shield has a wall structure for allowing passage of a cooling fluid, the wall structure comprising an upper wall part and a lower wall part. The lower wall part of the heat shield is essentially refractory free.

1 . A method of gasifying a fuel to form a synthesis gas, wherein also a slag is formed, the method comprising:
 maintaining a pressure in a pressure shell higher than atmospheric pressure;   providing a slag bath in a lower part of the pressure shell, the slag bath comprising a quench fluid;   forming the synthesis gas and slag in a gasification chamber inside the pressure shell, a lower part of the gasification chamber comprising a converging wall part that is provided with a slag discharge opening, located above the quench fluid;   allowing the slag to fall freely from the discharge opening into the slag bath through a heat shield comprising a wall structure, the wall structure comprising an upper wall part and an essentially retractory-free lower wall part, the upper wall part being located closer to the slag discharge opening than the lower wall part and the lower wall part being located closer to the slag bath than the upper wall part; and   passing a cooling fluid through the heat shield wall structure.   
     
     
         2 . The method of  claim 1 , comprising preventing synthesis gas to pass through an opening between the heat shield and the gasifier wall. 
     
     
         3 . The method of  claim 1 , comprising covering at least a part of the upper wall part of the heat shield with a layer of retractory material. 
     
     
         4 . The method of  claim 1 , wherein forming the synthesis gas comprises partially oxidizing a fuel. 
     
     
         5 . The method of  claim 1 , wherein the slag is allowed to drip down to a converging wall part that at a lower end thereof is provided with the slag discharge opening. 
     
     
         6 . The method of  claim 1 , comprising allowing covering of the heat shield with a layer of solidified slag. 
     
     
         7 . The method of  claim 1 , comprising monitoring the inflow and outflow of the cooling fluid in and from the heat shield wall structure.