Gasifier Throat Cooling

Abstract

A gasifier for converting a carbonaceous feedstock to produce syngas comprising a cone section and a throat section; wherein the throat section comprises a throat refractory material having an inside surface and a substantially cylindrical cooling element having an inner face and an outer face in a radial direction, and a top face and a bottom face in the vertical direction, wherein the inner, outer, top, and bottom faces define a cooling cavity; and wherein the cooling element is in thermal contact with the throat refractory material on the inner face, the top face, and the outer face.

1 . A gasifier for converting a carbonaceous feedstock to produce syngas comprising a cone section and a throat section;
 wherein the throat section comprises a throat refractory material and a substantially cylindrical cooling element having an inner face and an outer face in a radial direction, and a top face and a bottom face in a vertical direction, wherein the inner, outer, top, and bottom faces define a cooling cavity; and   wherein the cooling element is in thermal contact with the throat refractory material on the inner face, the top face, and the outer face.   
     
     
         2 . The gasifier of  claim 1 , comprising a coolant inlet conduit in fluid flow communication with the cooling element and a coolant outlet conduit in fluid flow communication with the cooling element;
 wherein the coolant inlet conduit is in fluid flow communication with a coolant source external to the gasifier; and   wherein the coolant outlet conduit is in fluid flow communication with a coolant sink external to the gasifier.   
     
     
         3 . The gasifier of  claim 2 , wherein the coolant inlet conduit and the coolant outlet conduit comprise a section oriented in the radial direction perpendicular to the centerline of the gasifier. 
     
     
         4 . The gasifier of  claim 1 , wherein the throat refractory material comprises refractory bricks. 
     
     
         5 . The gasifier of  claim 1 , wherein the throat section has an inside surface and an inner radius defined as the distance from the centerline of the gasifier to the inside surface of the throat section;
 wherein the minimum value of the inner radius of the throat section is within 2% of the maximum value of the inner radius of the throat section.   
     
     
         6 . The gasifier of  claim 1 , wherein the throat section has an inner radius that increases stepwise with increasing depth. 
     
     
         7 . The gasifier of  claim 1 , further comprising a refractory support floor attached to the bottom face of the cooling element. 
     
     
         8 . A method of operating a gasifier comprising:
 indirectly transferring heat from a refractory material having a refractory temperature to a coolant having a coolant temperature and a liquid stability limit;   wherein the method comprises a dryout mode characterized by increasing the refractory temperature from ambient temperature to about 100° C. and a heating mode characterized by increasing the refractory temperature from about 100° C. to the liquid stability limit of the coolant;   wherein during the dryout mode the coolant temperature is maintained between a dryout mode lower temperature limit and a dryout mode upper temperature limit;   wherein during the heating mode the coolant temperature is maintained between a heating mode lower temperature limit and a heating mode upper temperature limit.   
     
     
         9 . The method of  claim 8 , wherein the dryout mode lower temperature limit is less than or equal to 5° C. lower than the refractory temperature and wherein the dryout mode upper temperature limit is less than or equal to 5° C. greater than the refractory temperature. 
     
     
         10 . The method of  claim 8 , wherein the heating mode lower temperature limit is less than or equal to 5° C. lower than the refractory temperature and wherein the heating mode upper temperature limit is less than or equal to 10° C. lower than the liquid stability limit of the coolant. 
     
     
         11 . The method of  claim 8 , wherein the coolant has a coolant pressure; wherein the coolant pressure is kept constant at a value greater than the vapor pressure of the coolant at the liquid stability limit. 
     
     
         12 . The method of  claim 8 , wherein the coolant has a coolant pressure; wherein the coolant pressure is maintained at a value greater than the vapor pressure of the coolant at the temperature of the coolant. 
     
     
         13 . The method of  claim 8 , further comprising a cooling mode characterized by decreasing the refractory temperature from the operating temperature of the gasifier to a value equal to ambient temperature;
 wherein during the cooling mode the coolant temperature is maintained between a cooling mode lower temperature limit and a cooling mode upper temperature limit.   
     
     
         14 . The method of  claim 13 , wherein the cooling mode lower temperature limit is less than or equal to 5° C. lower than the refractory temperature and wherein the cooling mode upper temperature limit is less than or equal to the lesser of 10° C. lower than the liquid stability limit of the coolant and 5° C. greater than the refractory temperature. 
     
     
         15 . The method of  claim 8 , wherein the coolant temperature is controlled by exchanging heat with a quench bath prior to indirectly transferring heat from the refractory material. 
     
     
         15 . The method of  claim 8 , wherein the coolant temperature is controlled by heating with at least one of resistive heating, steam, and a heated heat transfer fluid prior to indirectly transferring heat from the refractory material. 
     
     
         16 . A gasifier for converting a carbonaceous feedstock to produce syngas comprising a reactor section configured to react the carbonaceous feedstock with an oxidant to produce syngas, a quench section configured to contact the syngas with a quench bath, and a throat section configured to convey the syngas from the reactor section to the quench section:
 wherein the throat section comprises a throat refractory material and a cooling element in thermal contact with the throat refractory material;   wherein the quench section comprises a dip tube having an inlet in fluid flow communication with the throat section and an outlet in fluid flow communication with the quench bath;   wherein the quench section further comprises a low liquid level located above the outlet of the dip tube;   wherein the quench bath has a level at or above the low liquid level;   wherein the quench section further comprises a quench heat exchanger in thermal contact with the quench bath;   wherein the cooling element comprises an inlet in fluid flow communication with the outlet of the quench heat exchanger; and   wherein at least a portion of the quench heat exchanger is located above the outlet of the dip tube and below the low liquid level.   
     
     
         17 . The gasifier of  claim 16  wherein at least a portion of the quench heat exchanger is configured to reduce level and flow instabilities in the quench bath. 
     
     
         18 . The gasifier of  claim 17 , wherein the at least a portion of the quench heat exchanger configured to reduce level and flow instabilities in the quench bath forms a conical frustrum surface.