Staged Opposed Multi Burner (OMB) for Modular Gasifier/Burner

The main objective is to develop emerging gasification technology through modularized small scale gasifier for the requirement of distributed system with cost reduction, where the gasifier is highly capable of wide load and fuel flexible by use of so proposed herein a gasifier with staged OMB (opposed multi-burners) based on the existing advanced OMB entrained flow high temperature gasification technology for syngas production and/or for electric power generation for a distributed small scale. To satisfy the application of modularization concept and the cost reduction, the keys of modularized gasifier are in: 1) OMB – To use the advanced horizontal opposed multi-burners in compared with one lumped vertical burner to modify the gas/solid flow pattern inside a gasifier and so to reach a more even flow and residence time distribution. As it has been recognized, the drawbacks of one vertical burner gasifier is in that it forms a jet spray type down-flow with high momentum and uneven flow distribution, where the gas/solids residence time in the center of the jet is short and the flame zone temperature is high. All of these are eventually caused by a big jet formed from all of fuel fed to one vertical burner and thus a concentrated combustion/flame zone. In contrast, the OMB provides essentially a more even flow distribution with distributed flame zones due to multi-burners applied and fuel distributed, as well as a better flow pattern established without a big and fast down-flow jet. As a result, a better mixing and fuel conversion can be obtained, over 98% in comparison with 94-95% from the one vertical burner gasifier. Better gasification efficiency and reduced UBC (unburn carbon) can be obtained too. 2) Staged OMB – For high temperature process, to avoid hot spot the staged operation has been widely applied as a method to reduce flame temperature, either by staged fuel or by staged oxidant or both. A typical example is the pulverized coal furnace for advanced high temperature high pressure steam generation, where multi-burners by multi-rows are generally designed. Due to the distributed firing along the pathway of gas flow, the extended flame zone with more even temperature distribution is obtained, resulted with more even heat flux and wall temperature as desired. It also helps to effectively avoid the flame and feed particles in touching to the opposed wall. This is a desired approach for modularization of a gasifier to avoid hot spot under different load with different fuel, simply by number of burners fired and by varying the load of each burner. By this way, one refractory wall can be used for both load and fuel change tuning. 3) Modularized Burner – As has been recognized, the burner is a key equipment for modularization of gasification technology. The same as the refractory wall, an advanced long life modularized burner is required. The staged OMB with more burners arranged can provide such a possibility for burner modularization, where the burner will be designed and structured with suitable velocity and momentum, better mixing, low flame zone temperature, which in turn to protect the burner and refractory wall to get a long life. The modularized burner will be used for load control, reached by less burners firing, which provides a wide range of load following since each burner can be operated at near design condition to maintain its better burner performance for different fuel and blend of fuels. This helps not only for the load control, but also for the fuel flexibility, such as co-firing or firing with biomass. The proposed staged OMB becomes highly flexible and so that with modularized burner can function as a modularized gasifier. It is clear that modularized burner can provide such an approach for the concept of modularized gasifier by use of the staged OMB.