Method for preparing flue gas by using high-temperature cracking biomass

Abstract

The invention discloses a method for preparing flue gas by using high-temperature cracking biomass. A cracking gasification furnace is divided into an upper section and a lower section, wherein a heat exchanger used for cracking biomass is arranged in an upper-section furnace hearth; a heater and a catalyst which are used for performing catalytic cracking on tar are arranged in a lower-section furnace hearth; the upper-section furnace hearth is communicated with the lower-section furnace hearth; raw materials are continuously or intermittently fed from a furnace feeding port; because high-temperature cracking gas exists in a heat exchanger array tube in a furnace from bottom to top, the raw materials fed into the furnace are dried and cracked from top to bottom to generate cracking gas, biomass carbon and the tar; the generated cracking gas carries the biomass carbon and the tar to enter a lower-section tar cracking section; in the section, the cracking gas, the biomass carbon and the tar are heated to reach the tar catalytic cracking temperature by virtue of a heating device, wherein 99.5% of tar in the cracking gas is cracked into the flue gas and the biomass carbon; the biomass carbon and ash slag are separated from the cracking gas subjected to tar cracking, and then the cracking gas is introduced into an upper-section heat exchanger array tube pass, and is used for transferring the heat to the materials outside a tube for cracking. The flue gas prepared by the method disclosed by the invention is high in calorific value, and does not contain the tar.

Description

technical field [0001] The invention relates to a method for producing gas by pyrolyzing biomass at high temperature. Background technique [0002] Whether the current fixed-bed biomass pyrolysis furnace is an updraft or downdraft furnace, the gas outlet temperature is relatively low, and the outlet gas contains bio-oil and tar. The oil and gas separation process is complicated, and it is difficult to separate completely; some use water washing or filtration, but the actual tar will be transferred into the water, seriously polluting the environment, and it is difficult for practical application. At the same time, the current fixed-bed cracking furnace uses oxygen in the air and biomass to burn in the furnace to provide the heat energy required for cracking, and the combustion products are carbon dioxide and water. However, the content of oxygen in the biomass is relatively high, so the content of carbon dioxide in the pyrolysis gas produced by such cracking is high, but the...

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Problems solved by technology

However, the content of oxygen in the biomass is high, so the content of carbon dioxide in the pyrolysis gas produced by such cracking is high, but the content of active ingredients is low, and the calorific value of the pyrolysis gas is low, so the application is limited.

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