Bottom feed type gas method and equipment for preparing gas with no tar products through oxygendeficient fluid bed combustion

Abstract

This invention relates to downdraft gasification method and equipment for preparing tar-free product gas by oxygen-deficient fluidized burning. The equipment comprised a front fluidized bed burner, a downdraft fixed bed gasifier set lower than the burner, a transporting pipe for carbocoal and semi-finished gas connecting the burner and the gasifying furnace, a fuel inlet and an oxidant inlet. The method comprised: (1) adding fuel through the fuel inlet of the fluidized bed burner, and performing oxygen-deficient fluidized burning with oxidant added through the oxidant inlet at the bottom of the fluidized bed burner to obtain carbocoal and semi-finished gas containing tar, and (2) sending the unseparated carbooal and semi-finished gas containing tar to a down-draft fixed bed gasifier at a high temperature to gasify the carbocoal, and modifying and cracking the tar introduced by the semi-finished gas by the catalytic activity of high-temperature carbocoal to obtain the product gas with tar. The equipment has such advantages as simple structure, easy operation and high gasifying efficiency, and is suitable for a wide variety of fuels and can produce product gas without tar.

Description

technical field [0001] The invention belongs to the technical field of clean energy, and particularly relates to a pre-oxygen-poor fluidized combustion downdraft gasification method and device for preparing tar-free product gas. The fuel includes coal, biomass, urban waste, and high-water solid waste substances (such as sludge), a mixture of one or more of these solid fuels and other gaseous and liquid fuels or waste. Background technique [0002] The research and development of coal gasification technology has a history of nearly a hundred years, and the gasification technology of biomass and organic solid waste has also developed rapidly since the 1980s. However, the gas conversion efficiency achieved by various existing gasification technologies is seldom higher than 70% (efficiency is defined as the percentage of the calorific value of gas products to the sum of the calorific value of the fuel used and the energy consumed in the gasification process), However, the tar c...

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Problems solved by technology

[0008] However, the DTU two-stage gasification technology using the Winkler furnace will be difficult to apply to large-scale processes and systems, and the use of the Winkler furnace itself may lead to relatively high equipment costs and operating costs

The gasification process disclosed in Chinese patent 94190559.4 does not send the low-temperature (450-600°C) pyrolysis gas to the post-gasification section for further refinement, and the tar content in the final product gas must be high

This may not only cause high tar content in the product gas (produced by the pyrolysis of newly added fuel), but also lead to incomplete gasification of newly added fuel and affect the improvement of the overall gasification efficiency

At the same time, the gasification process of the three Chinese patents is obviously more complex in system configuration than the DTU gasification technology, so it may have relatively high equipment and operating costs

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