Advanced sequential batch gasification process

Abstract

The invention relates to a two stage process for the thermal treatment of wastes consisting of a batch gasification process followed by a syngas combustion process. A system and method are provided comprising of one or more first process stage batch gasification chambers ( 1 ) which are connected to a common second process stage chamber, the syngas combustion chamber, or alternatively a syngas conditioning chamber ( 13 ) and afterwards a combustion of the syngas in either a combustion chamber, reciprocating engine, boiler, gas turbine or an internal combustion device. The process can also be used to process biomass and fuels by gasification. The gasification chamber ( 1 ) has separated nozzle areas corresponding to plenum sections of the bottom where a mixture of air and recirculated flue-gas ( 8 ) is blown under the combustible material. Flue gas flow is regulated by varying the production of syngas in the gasification chambers ( 1 ) by a feedback signal from devices such as draught sensors, thermocouples, fan speeds indicators, steam flow meters, oxygen concentration meters and power production indicators.

1 . A process for thermal oxidation of combustible materials comprising the steps of:
 a) gasification of combustible materials in one or more gasification chambers,   b) transferring syngas from the one or more gasification chambers to a combustion unit, and   c) combustion of syngas from the gasification chamber in the combustion unit,   wherein external air, recirculated flue-gas from the combustion unit or a mixture thereof is blown under the combustible material in separated nozzle areas of the bottom of each gasification chamber, said nozzle areas corresponding to plenum sections of the bottom of each gasification chamber, at different times of a gasification cycle.   
     
     
         2 . The process according to  claim 1 , wherein the combustible materials comprise waste, fuel or biomass. 
     
     
         3 . The process according to  claim 1 , wherein the combustion unit is a combustion chamber, reciprocating engine, boiler, gas turbine or an internal combustion device. 
     
     
         4 . The process according to  claim 1 , wherein a flow of fully combusted flue gas from the combustion unit is regulated by varying the production of syngas in the one or more gasification chambers by a feedback signal. 
     
     
         5 . The process according to  claim 3 , wherein the combustion unit is a combustion chamber. 
     
     
         6 . The process according to  claim 5 , wherein the feedback signal is a signal from a steam flow meter, power output measure meter, speed indicator from an ID fan, flow signal from the outlet of the combustion unit or a combination thereof. 
     
     
         7 . The process according to  claim 1 , wherein the combustion unit is a reciprocating engine, boiler, gas turbine or an internal combustion device. 
     
     
         8 . The process according to  claim 7 , wherein the feedback signal is
 power output of the reciprocating engine generator set,   power output of the gas turbine generator set, or   steam flow output from the boiler that the syngas is combusted in,   where the output is proportional to the flow of syngas to the respective combustion unit.   
     
     
         9 . The process according to  claim 8 , wherein a syngas conditioning chamber is used as a part of the second process stage to mix the syngas from the multiple gasification chambers before it is routed to the combustion unit. 
     
     
         10 . The process according to  claim 1 , wherein the oxygen concentration of the external air and the recirculated flue-gas in each plenum section area is regulated independently. 
     
     
         11 . The process according to  claim 1 , wherein the flow of the external air and the recirculated flue-gas in each plenum section area is regulated independently. 
     
     
         12 . The process according to  claim 1 , wherein the overall flow of air and recirculated flue-gas to the hearth sections collectively is regulated. 
     
     
         13 . The process according to  claim 1 , wherein the one or more gasification chambers are surrounded by a cooling compartment for cooling the gasification chamber. 
     
     
         14 . The process according to  claim 12 , wherein air is used as cooling media in the cooling chamber. 
     
     
         15 . The process according to  claim 12 , wherein water is used as cooling media in the cooling chamber. 
     
     
         16 . The process according to  claim 12 , wherein thermal oil or other fluid is used as cooling media in the cooling chamber 
     
     
         17 . The process according to  claim 13 , wherein two or more gasification chambers are connected to the same combustion unit to provide a constant flow of syngas for combustion. 
     
     
         18 . The process according to  claim 1 , wherein the mixture of external air flow and recirculated flue-gas is mixed in any ratio and introduced into the combustion unit for the combustion of syngas. 
     
     
         19 . The process according to  claim 17 , wherein the external air flow introduced into the combustion chamber is heated air from the cooling compartment of the gasification chamber. 
     
     
         20 . The process according to  claim 4 , wherein the flow of fully combusted flue gas is regulated by varying the production of syngas in the one or more gasification chambers by a feedback signal from devices such as, but not limited to draught sensors, thermocouples, fan speeds indicators, steam flow meters, oxygen concentration meters and power production indicators. 
     
     
         21 . An apparatus for thermal oxidation of combustible materials, the apparatus comprising:
 one or more gasification chambers for gasification of combustible materials, the one or more gasification chambers further comprising:
 a plurality inlets at the bottom of the chamber, 
 one or more burners, 
   a combustion unit for combustion of syngas from the first chamber, the second combustion unit further comprising;
 a gas inlet for receiving syngas from the one or more gasification chambers, 
 a burner, and 
 an outlet for disposing of flue-gas from the combustion unit, 
   a duct to transfer syngas from each of the gasification chambers to the combustion unit, the duct further comprising a valve to isolate each of the gasification chambers from the combustion unit,   a duct for re-directing flue-gas from the outlet of the combustion unit into the one or more gasification chambers,   an industrial computer,   wherein plenums under the bottom hearth form plenum sections,   wherein a plurality of nozzles penetrating the bottom hearth of each gasification chamber form the plurality of openings into the gasification chamber, said nozzles forming separated nozzle areas corresponding to the plenum sections, and   wherein external air, recirculated flue-gas from the combustion unit or a mixture thereof is blown under the combustible material through the nozzles of the separated nozzle areas at different times of a gasification cycle.   
     
     
         22 . The apparatus according to  claim 21 , wherein the gasification chamber is surrounded by a cooling compartment for cooling the gasification chamber. 
     
     
         23 . The apparatus according to  claim 21 , wherein a syngas conditioning chamber is placed between the one or more gasification chambers and the combustion unit connected with ducts to mix the syngas from the one or more gasification chambers before it is routed to the combustion unit. 
     
     
         24 . The apparatus according to  claim 21 , wherein the combustion unit is a combustion chamber, reciprocating engine, boiler, gas turbine or an internal combustion device.