Two-stage low-temperature gasification device and method based on low-order fuel autocatalysis

Abstract

The invention relates to a two-stage low temperature gasification device based on low-order fuel autocatalysis, and a two-stage low temperature gasification method based on low-order fuel autocatalysis, belonging to the field of clean energy utilization of low-order fuel. A pyrolysis reactor is communicated with a fluidized-bed gasifier and a cyclone separator, and the cyclone separator is sequentially communicated with a primary back feeding pipe, a spiral back feeder, a secondary back feeding pipe and the pyrolysis reactor. A moving bed pyrolysis system is replenished with non-carrier gas, high alkaline metal low-order fuel and alkaline earth metal low-order fuel are pyrolyzed by being heated together with a heat carrier in a mixing way, and part of pyrolysis products are gasified and reformed; the pyrolysis products are directly conveyed into a fluidized-bed gasifying system so as to be subjected to in situ low temperature gasification, and most coke and all tar are involved in the reaction; the heat carrier at an outlet of the fluidized-bed gasifying system is separated from synthesis gas by means of a cyclone separation system, the heat carrier enters to the moving bed pyrolysis system, and the synthesis gas discharged outside. The device and the method which are provided by the invention utilize pyrolysis coke to carry out in situ catalytic pyrolysis on part of tar and utilize reabsorption alkali metal and alkali earth metal to catalyze coke gasification at low temperature, thus realizing high efficient low temperature autocatalytic gasification of the low-order fuel.

Description

technical field [0001] The invention belongs to the field of clean energy utilization of low-order fuels, and in particular relates to a two-stage low-temperature gasification device and method for in-situ catalytic cracking of tar and reabsorbed alkali metals and alkaline earth metals to catalyze coke low-temperature gasification. Background technique [0002] Gasification is one of the main ways to convert carbon-containing fuels and an important technical means to realize their clean and efficient utilization. Low-rank fuels (low-rank coal, biomass, and kitchen waste) have low deterioration, high volatile content, and high gasification activity; low-rank fuels are rich in alkali metals and alkaline earth metals (low-rank coal is rich in sodium, calcium and Magnesium, biomass is rich in potassium, calcium, and magnesium, while kitchen waste mainly contains sodium) has a good catalytic effect on gasification, which can significantly improve the reactivity and carbon convers...

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Problems solved by technology

However, there is a carrier gas passing through the pyrolysis fuel bed, which is not conducive to the in-situ catalytic decomposition of tar and the retention of alkali metals and alkaline earth metals in the coke, so that the tar content in the pyrolysis gas entering the gasifier increases, and the pyrolysis The content of catalyst in the coke is reduced

[0007] The two-stage gasification technology developed at home and abroad increases the reaction rate of coke by increasing the temperature of the gasification stage, and at the same time promotes the cracking of tar, but the higher gasification temperature will inevitably lead to lower cold gasification efficiency

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