Double-hearth kiln for calcining lime by using low-calorific-value fuel and calcining method

Abstract

The invention relates to a double-hearth kiln for calcining lime by using low-calorific-value fuel and a calcining method. The double-hearth kiln comprises a double-hearth kiln body, a fuel pipeline and an exhaust emission system. The double-hearth kiln body comprises a kiln hearth A and a kiln hearth B, a calcining zone is provided with an inserted burner, the lower part of the kiln hearth is provided with a fuel nozzle, and a fuel pipeline is respectively connected to the inserted burner and the fuel nozzle. The calcining method comprises the steps that the plug-in combustor sprays out fuel, combustion-supporting air enters the kiln hearth through the air inlet and outlet for combustion-supporting combustion, and limestone materials are calcined. The fuel and flue gas sprayed out of the fuel nozzles enter the kiln chamber on the other side through the flue gas channel and combust in a combustion-supporting mode on the lower portion of the calcining zone together with air obtained after lime is cooled in the cooling zone, and the limestone is further calcined. By arranging the fuel nozzles, secondary combustion is carried out on the lower portion of the kiln chamber on the other side, undecomposed limestone is continuously calcined, the fuel supply mode and the limestone calcining method are optimized, the calcining effect is improved, low-calorific-value fuel is fully utilized, and the quality of calcined products is improved.

Description

technical field [0001] The invention belongs to the technical field of chemical building material production, and relates to an industrial furnace, in particular to a double-chamber kiln and a calcination method for calcining lime as fuel with a low calorific value. Background technique [0002] Double-chamber kiln is also called double-chamber parallel-flow regenerative lime kiln. The fuel enters from the upper end of the calcination belt and flows in parallel with the raw materials. Since the fuel is injected from the upper part of the calcination zone, the raw material can absorb most of the heat released by the fuel here. Another important feature of double-chamber kiln is heat storage, which uses heat storage to preheat part of the combustion air. The thermal characteristics of co-current calcination and counter-current heat storage determine that the double-chamber kiln has high thermal efficiency, and its thermal energy consumption is the lowest among all types of li...

AI Technical Summary

Problems solved by technology

Limestone cannot be decomposed if the combustion of low calorific value fuel cannot reach the required temperature; or if the temperature is low, the decomposition of limestone will not be complete, resulting in problems such as raw burning and poor quality of lime products

In the production process of metallurgical enterprises, a large amount of blast furnace gas is produced, which is a valuable fuel resource. The calorific value of blast furnace gas is 3000~3400kJ / Nm 3 . Due to its low calorific value, it cannot be directly used for calcining limestone, so that a large amount of low calorific value fuel cannot be used fully utilized

However, the production of lime also requires the purchase of fuels with high calorific value, resulting in waste of resources and affecting economic benefits

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