Biomass gasification power plant technology is to convert various solid biomass raw materials (such as agricultural and forestry waste, domestic organic waste, etc.) into combustible gas (mixed gas containing hydrogen, methane, carbon monoxide, etc.) through pyrolysis and gasification, and then provide it to Gas user’s technology.
Biomass gasification can be used for heating in two ways: the first is that the biomass gas enters the gas tank after cooling and purification, and then the gas tank is passed to the user for use. This solution requires gas tanks and cooling water. The second option is that the biomass gas does not need to be cooled and enters the boiler to burn to produce steam, and the steam drives the steam turbine to generate electricity. This solution does not require gas storage tanks and cooling water, has low maintenance and operating costs, and is suitable for continuous operation and production. This project adopts the second scheme. Compared with traditional biomass direct combustion power generation, our company's biomass gasification heating technology focuses on polygeneration. Biomass gasification polygeneration technology is a combination of carbon production and heat supply. The biomass carbon produced can be used as civil carbon, metallurgical carbon and industrial carbon. Compared with simple biomass gasification and heating, polygeneration technology products are diversified, which can improve the profitability of biomass heating projects and the ability to adapt to the market.
The general layout of the 1.6mw biomass gasification power station is composed of the main plant, raw material storage, biomass gasification furnace workshop, gas boiler, and steam turbine generator set main plant. The specific data of the space occupied by each host device is determined by the preliminary design):
(1) Finished product raw material warehouse
(2) Biomass gasification furnace workshop (plant shed or shed above the equipment)
(3) Gas boiler workshop
(4) Steam turbine generator set workshop
(5) Chemical water room
(6) Circulating cooling tower
(7) Production water pump room
(8) The raw water settles in the clear pool
on the top of gasifier is the dryer layer and fuel will be delivered to this area from upside.
The moisture inside fuel will evaporate by heat exchange with hot air coming from the below three reaction area and temperature of this layer is 100-200°C.
Output is the dried material and vapor.
Vapor will go outside together with the waste heat from below reaction layers.
The dried material will go down to pyrolysis layer.
the dried material go down to pyrolysis layer and heat the biomass material for pyrolysis reaction.
Most volatile component will be separated from solid & charcoal left behind when the temperature is 200-500°C
Output of pyrolysis layer is carbon, H2, vapor, CO, CO2, CH4, tar and other material.
the remaining charcoal will make strong reaction with air and release lots of heat. At the same time, the incomplete combustion will produce CO and heat, owing to anaerobic combustion and insufficiency O2.
In Oxidation layer, the temperature can reach 800-1000°C, and the reaction equation: C+O2=CO2+∆H, ∆H=408.8KJ
It is combustion reaction in this Oxidation area and release heat energy, that supply energy to reduction area for reduction reaction, material pyrolysis and drying. The hot air (CO & CO2) from Oxidation area will enter into reduction area, and ash will drop into the bottom room.
there is no O2 in reduction area and the CO2 from Oxidation area will have reduction with charcoal and vapor to produce CO and H2. The temperature will drop down to 600-800°C, owing to the reduction is endothermic reaction. The main output of reduction layer is CO, CO2 and H2.
Gasification always come with material drying and pyrolysis. In actual operation, there is no clear border during the described four area, that is interpenetrating and interlocking, so the main gas output is CO, CO2, H2, CH4, tar, small amount alkanes, vapor and little dust.