Oxygen-enriched combustion device and method of solid fuel circulating fluidized bed

Abstract

The invention discloses an oxygen-enriched combustion device and method of a solid fuel circulating fluidized bed and belongs to the field of clean utilization of solid fuel. The device mainly comprises an air chamber, an air distribution device, a furnace hearth, a high-temperature cyclone separator, a return feeder, a heat exchanger, a coal economizer, a medium-temperature cyclone separator and a secondary air distribution pipe, wherein the furnace hearth is composed of a lower dense-phase bubble or turbulence strongly mixing area with a large sectional area and an upper dilute-phase quick or pneumatic conveyed quasi plug-flow area with a small sectional area. According to the method, combustion of solid fuel is achieved by adopting oxygen-enriched combustion zone control and regulation and multi-stage air distribution in the oxygen-enriched combustion device of the circulating fluidized bed, wherein the primary air is oxygen and recycled exhaust gas mixed air, the secondary air is oxygen, and the recycled exhaust gas includes fuel spreading air and vibrating air. The oxygen-enriched combustion device and method can overcome the defects of the prior art; the CO2 concentration of exhaust gas generated after combustion of solid fuel is made to be above 80%, so that storage or utilization after combustion is facilitated; and meanwhile, emission of nitric oxide and sulfur oxide is reduced, and accordingly the oxygen-enriched combustion device and method have the broad application prospect.

Description

technical field [0001] The invention belongs to the field of clean utilization of coal and biomass, and in particular relates to a solid fuel circulating fluidized bed oxygen-enriched combustion device and method. Background technique [0002] The resource endowment of rich coal, lack of oil and little gas determines that coal will remain the most important basic energy in my country in the foreseeable future. Clean, efficient and low-carbon coal-fired power generation is a major strategic demand to ensure the sustainable development of the country. According to statistics from the China Coal Industry Association, the national coal production in 2013 was about 3.7 billion tons, and the consumption was about 3.61 billion tons. According to the statistics of the National Energy Administration, the total national energy consumption in 2013 was 3.76 billion tons of standard coal, of which coal accounted for 65.7%. As of the end of 2013, the total installed capacity of power gene...

AI Technical Summary

Problems solved by technology

[0005] The traditional oxy-fuel combustion fluidized bed boiler has the same cross-sectional area of ​​the furnace body in the dense-phase zone and the dilute-phase zone, and must go through a long transition section to achieve gas-solid separation; due to the increase in oxygen concentration and the decrease in circulating flue gas concentration, the boiler volume The corresponding reduction, especially the reduction in the volume of the tail flue, has brought great difficulties to the layout of the heating surface of the boiler, thus affecting the absorption of heat in the furnace and reducing the combustion efficiency of coal

In the oxyfuel combustion circulating fluidized bed, how to mix high-purity oxygen with recirculated flue gas and how to inject it into the furnace is a technical problem that needs to be solved mainly. Since there are particles with a particle size below 0.5 μm in the recirculated flue gas, it is different from high Concentration of oxygen (50% or more) mixing is very prone to deflagration and other safety accidents

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