Gasifier feed system

The CFB gasifier test facility is an atmospheric air-blown installation and consists of four main parts (1) Feeding system (2) Primary and secondary air supply (3) Gasifier vessel equipped with a cyclone and a particle recirculation system (4) Gas analysis equipment. 

The VUB pilot plant consists of a feeding system (a hopper equipped with a rotary valve and a conveyor screw), the fluidized bed reactor, preheating burner, cyclone and a control system. The bubbling fluidized bed gasifier has a capacity of 400 kg/h and consists of a bed (0.8 m diameter/0.6 m height) with an extended freeboard section (1.2 m diameter/2 m height). More technical details about the gasifier can be found in [16]. 

Due to the dry feeding of the Shell gasifier, the 02 consumption is reduced, and the efficiency is increased by -2% compared with the CWS feeding system. However, the maximum gasification pressure is limited to about 5 MPa due to the dry-feeding system, as opposed to 8 MPa for some CWS feeding systems. 

The dry-feeding system of the Shell gasifier requires the water content in the bituminous coal to be less than -2 wt %. For high-moisture, low-rank coal, the required water content could be less than 10wt%. 

The reliability of the dry-feeding gasifier is not as good as the matured CWS feeding system and the initial investment is much higher.39... 

The feed system is an important choice for entrained-flow gasifiers. GE and E-Gas use a coal-water slurry compared with the dry-feed systems of Shell and Future Energy, which require lock hoppering. 

The various gasifiers dififer in method of feeding and in waste heat recovery [230], The GE (Texaco) gasifier feeds coal in a waste slurry (paste) which means that oxygen is used for evaporation of water. However, the slurry feed system allows a much higher pressure (up to 70-80 bar) than possible for gasifiers with dry feeding systems. 

The gasifier must interface with the pressurized oxidant delivery system (air or oxygen-blown gasifiers being feasible for coals) with the pressurized coal and sorbent preparation and feed systems with the raw fuel gas pressurized processing system and with the pressurized ash processing system. Coals may be... 

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