Method and apparatus for preparing fuel gas or synthetic gas through biomass fluidized bed gasification

Abstract

The invention belongs to the technical field of preparation of fuel gas or synthetic gas, and particularly relates to a method and an apparatus for preparing fuel gas or synthetic gas through biomassfluidized bed gasification. The apparatus comprises a feeding device, a fluidized bed, a dust removal device, a waste heat recovery device and a water washing tower, wherein a bed material star-shapedfeeder and a biomass spiral feeder are connected with the lower section of a gasification furnace through a feeding pipe, a vibrating screen is connected with a bed material receiving hopper througha conveying system, the upper section of the gasification furnace is connected with an inlet of a first-stage cyclone separator through a high-temperature pipe section, and a powder outlet of the first-stage cyclone separator is connected with the lower section of the gasification furnace. A bed material and a biomass raw material are respectively metered and respectively blown to the lower section of the gasification furnace, so that the problem that the bed material and the biomass raw material are automatically layered in the stock bin after being mixed due to different particle sizes and different densities of the bed material and the biomass raw material is solved, and stable metering and stable conveying of the bed material and the biomass raw material can be realized.

Description

technical field [0001] The invention belongs to the technical field of preparation of fuel gas or synthesis gas, and in particular relates to a method and device for preparing fuel gas or synthesis gas by biomass fluidized bed gasification. Background technique [0002] With the increasing demand for energy in the society, the fossil fuels as the main energy source are decreasing, and it has also brought serious environmental problems. Therefore, seeking renewable alternative energy sources has become the direction of future energy development. Biomass energy is an ideal renewable energy and is the fourth largest energy in the world. The use of biomass energy has two advantages: one is that biomass can be used as a renewable energy source, which enables human beings to get rid of dependence on fossil energy; 2 amount equal to the CO absorbed during its formation 2 Therefore, the replacement of fossil energy by biomass can help reduce the greenhouse effect, and the low cont...

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Problems solved by technology

Therefore, the patent CN1557919A proposes an intermittent operation process flow of coal and biomass fluidized bed air supply combustion and steam supply gasification. In the air supply combustion stage, coal and air are introduced to make the coal burn in a fluidized state to generate heat; In the steam supply stage, water vapor and biomass are fed into the gasifier to obtain fuel gas with high calorific value without tar production. This process adopts intermittent operation of air supply combustion and steam supply gasification, and coal combustion produces The high-temperature material layer is used to gasify coal and biomass, which increases the calorific value of fuel gas and avoids the production of tar, but reduces production efficiency and increases the complexity of operation, and intermittent operation makes frequent switching of valves at high temperatures. High requirements on materials increase the difficulty of industrial application. Therefore, in order to overcome the shortcomings of intermittent operation, the patent CN1865408A proposed a method of continuous gasification of air-steam fluidized bed. Although this process improves production efficiency, it also has obvious shortcomings. : Biomass and coal are fed after mixing. In the same storage bin, even if they are mixed evenly, due to the difference in density and flow, the materials in the bin will slowly stratify during the feeding process. Coal particles will gather in the lower part of the silo, while biomass particles with light density will gradually gather in the upper part of the coal silo, resulting in uneven feeding, or even continuous feeding, which affects the continuity of production; the amount of fine powder brought out by the gas is large , the carbon content is high, the total carbon conversion rate of the process is low, and the application of the process has limitations

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