Pulverized coal combustion process in annular lime kiln and application thereof

Abstract

The invention relates to a pulverized coal combustion process in an annular lime kiln and application thereof. The process comprises the following steps: (1) anoxic ignition combustion of pulverized coal in a volute; (2) combustion of pulverized coal volatile matters in a combustion chamber; and (3) combustion of pulverized coal fixed carbon in a material bed. The process provided by the invention is used for calcining limestone. The process has the advantages that because of oxygen debt, the combustion temperature level and the combustion speed level are low, the combustion process is delayed, the NOx reaction rate is reduced in a reducing atmosphere, and the NOx yield in the area is inhibited; the circulating gas in the step (2) has large overall weight and high flow rate, the heat generated by combustion of volatile matters can be diluted and quickly transferred into a limestone material bed, the decreasing amplitude of the temperature of the combustion chamber is relatively large, and thus coal ash fusion nodulation and refractory material damage caused by accumulation of the heat in the combustion zone are avoided; and the burn-off rate of fixed carbon in the step (3) is improved, the content of CO in the tail gas is reduced to be 100-150mg / Nm<3>, and when the process provided by the invention is used for calcining limestone, the heat loss is reduced to 860kCal / kg from 930kCal / kg.

Description

technical field [0001] The invention relates to a fuel combustion process in an annular sleeve kiln, in particular to a pulverized coal combustion process in an annular sleeve kiln and its application, and the technical field of annular sleeve kiln combustion. Background technique [0002] As one of the industrial furnaces for calcining limestone with high efficiency, annular sleeve kiln usually uses gas fuel (such as blast furnace gas, converter gas, coke oven gas, natural gas, etc.) to burn to provide heat energy, and the combustion of these fuels is easy to control the temperature in the kiln. At present, coal resources account for about 60% of my country's primary energy consumption, and experts predict that coal will still account for about 50% in 2050. Not much will change. The annular sleeve kiln was originally introduced from Germany, and the fuel of foreign annular sleeve kilns has always been gas fuel. Due to the abundant coal fuel resources in China, it is necess...

AI Technical Summary

Problems solved by technology

Therefore, after 2010, through the research and development of technicians, pulverized coal began to be applied to the annular sleeve kiln, but engineering practice shows that when pulverized coal is used as the fuel of the sleeve kiln, once the melting point of pulverized coal ash is low, the pulverized coal will burn The generated coal ash is very easy to slagging in the combustion chamber, and the molten coal slag is highly corrosive to the refractory materials in the combustion chamber; after the pulverized coal is completely burned, a high-temperature zone is formed in the arch bridge part of the annular sleeve kiln, and the excessively high temperature causes The collapse of the arch bridge has caused the sleeve kiln to be unable to continue production. If it is not discovered in time, it will lead to a major safety accident.

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