Gasifier system and method

Abstract

An energy conversion system which comprises a solid fuel fed combustor system having a first chamber portion with an inlet feed for feeding a metered amount of a solid fuel thereto, a first burner stage having a first traveling conveyor firebelt, a metered amount of air introduced in progressively increasing proportions along the length of the first traveling conveyor. A second burner stage having a second traveling conveyor firebelt with air introduced in a progressively decreasing amount along the length of said second traveling conveyor firebelt and a controller for controlling air introduced to the system. The chamber has a sloped common roof section common to the burner stages and is made of radiative energy reflective fire brick and angled to reflect radiative energy generated from fuel traveling on the traveling conveyor firebelts and directing the radiative energy on fuel traveling on the first firebelt. The air introduced is controlled in amounts so as to automatically minimize excess air to the firebelt conveyors to minimize the quantity of carbon monoxide and nitrogen oxides and other pollutants.

What is claimed is:  
     
         1 . A solid fuel fed combustor system comprising: 
 a first chamber portion having an inlet feed for feeding a metered amount of a solid fuel thereto,    a first burner stage having a first traveling conveyor firebelt with a first air introducing means for introducing a metered amount of air in progressively increasing proportion along the length of said first traveling conveyor to cause endothermic decomposition of said solid fuel,    a second burner stage having a second traveling conveyor firebelt with a second air introducing means for introducing air in a progressively decreasing amount along the length of said second traveling conveyor firebelt. and to cause exothermic decomposition of solid fuel received from said burner stage, and    means for controlling air introduced to said burners.    
     
     
         2 . The solid fuel combustor system defined in    claim 1    wherein said first chamber portion has a sloped common roof section common to said burner stages and made of radiative energy reflective fire brick and angled to reflect radiative energy generated from fuel traveling on said traveling conveyor firebelts and directing said radiative energy on fuel traveling on said first firebelt.  
     
     
         3 . The solid fuel combustor system defined in    claim 1    wherein said means for controlling is adapted to automatically minimize excess air to said firebelts to minimize the quantity of carbon monoxide and nitrogen oxides produced in combusting said solid fuel.  
     
     
         4 . A solid fuel fed gasification system comprising: 
 a first chamber portion having an inlet feed for feeding a metered amount of a solid fuel thereto,    a first burner stage having a first traveling conveyor firebelt with a first air introducing means for introducing a metered amount of air progressively increasing proportion along the length of said first traveling conveyor,    a further burner stage having a further traveling conveyor firebelt with a second air introducing means for introducing air in a progressively decreasing amount along the length of said further traveling conveyor firebelt,    said first chamber portion having a sloped roof section common to said burner stage and made of radiative energy reflective fire brick for reflecting radiative energy generated from fuel traveling on said traveling conveyor firebelts and directing said radiative energy on fuel traveling on said first firebelt.    
     
     
         5 . An energy conversion system comprising in combination: 
 an inlet solid fuel feed conveyor and solid fuel metering unit for controlling the solid fuel flow through said system,    a gasifier for extracting combustible gaseous products from solid fuel,    a boiler for converting thermal energy to steam,    a gasifier fire tube for coupling various combustible gaseous products produced in said gasifier to said boiler at said gasifier fire tube coupling to said boiler, including means for feeding outside ambient air in preheated condition and at a controlled rate and gaseous products from said gasifier fire tube to said boiler,    cyclone device for removing particulate from the discharge unit of said boiler,    a baghouse for removing of particulate from said cyclone,    a scrubber for cleaning noxious gases from the air stream before discharge to the atmosphere, and    a control system for controlling the speed of conveyors in said gasifier.    
     
     
         6 . The system defined in    claim 5    including sensor means at each of said inlet feed conveyor and metering unit, gasifier, gasifier fire tube and connection to boiler, boiler, cyclone, bag house, and scrubber, computer means connected to a said sensors for making control adjustments for different types of fuel without changing the equipment in the gasifier system.  
     
     
         7 . A solid fuel gasification and energy system comprising in combination: 
 an inlet feed conveyor and fuel metering unit for controlling the fuel flow through said system,    a gasifier,    a boiler for converting thermal energy to steam,    a gasifier fire tube for coupling various gaseous products produced in said gasifier to said boiler at said gasifier fire tube coupling to said boiler, including means for feeding outside ambient air in preheated condition and at a controlled rate, and feeding gaseous products from said gasifier fire tube to said boiler,    cyclone device for removing particulate from the discharge unit of said boiler,    a baghouse for removing of particulate from said cyclone,    a scrubber for cleaning noxious gases from the air stream before discharge to the atmosphere,    a control system for controlling the speed of conveyors in said gasifier, and    sensor means at each of said inlet feed conveyor and metering unit, gasifier, gasifier fire tube and connection to boiler, boiler, cyclone, baghouse, and scrubber, computer means connected to said sensors for making control adjustments for different types of solid fuel without changing the equipment in the gasifier system.    
     
     
         8 . The invention defined in    claim 7    wherein said inlet solid fuel feed conveyor and solid fuel metering unit is controlled as a function of thermal conditions at the output of said boiler.  
     
     
         9 . The invention defined in    claim 7    wherein said control system is adapted to minimize excess air to said conveyors to minimize the quantity of carbon monoxide produced.  
     
     
         10 . The invention defined in    claim 7    wherein said control system is adapted to minimize the excess air and oxygen therein to said conveyors so as to minimize the quantity of nitrogen oxides produced.  
     
     
         11 . The invention defined in    claim 7    wherein said control system is adapted to minimize the excess oxygen to said conveyors and said firetube and the oxygen therein to minimize the quantities of carbon monoxide and nitrogen oxides produced.  
     
     
         12 . In a solid fuel fed combustor having an inlet feed for solid fuel and a combustion chamber including a first burner stage having a traveling conveyor firebelt with means to introduced air along the length of aid conveyor from below solid fuel on said first conveyor firebelt and a second burner stage having a second traveling conveyor firebelt and means to introduce air along the length of said second traveling conveyor firebelt from below solid fuel on said second traveling conveyor firebelt, the method of minimizing production of carbon monoxide and nitrogen oxide pollutants comprising controlling the amount of air introduced in said first and second burner stage and the speed of said conveyors such that endothermic decomposition of fuel takes place in said first burner stage and exothermic combustion and decomposition of fuel takes place in said second burner stage.  
     
     
         13 . The method defined in    claim 11    wherein gaseous products from said second burner stage are mixed and combusted with a controlled amount of heated air from ambient in a firetube and the released thermal energy converted to steam in a boiler coupled to said firetube.  
     
     
         14 . The method defined in    claim 13    wherein gaseous products and particulate from said boiler are filtered in a cyclone and baghouse to remove particulates, and a scrubber for cleaning noxious gases from the air stream before discharge to the atmosphere.