Grate-rotary kiln pellet low NOx production process and system

Abstract

The invention provides a grate-rotary kiln pellet low NOx production process. The process comprises the following steps that flue gas exhausted from an air draft drying section (DDD) and a first preheating section (TPH) is used as cooling wind and conveyed to an air inlet of a ring-cooling second section (C2), a reducing agent is sprayed into the position of an air box at the bottom of the ring-cooling second section (C2), the reducing agent reacts with NOx in the flue gas exhausted from the air draft drying section (DDD) and the first preheating section (TPH), so that SNCR denitration is realized. The production process and system have the characteristics that the investment is saved, the operation cost is low, and the NOx emission reduction effect is remarkable.

Description

technical field [0001] The invention relates to a chain grate-rotary kiln pellet production technology, in particular to a chain grate-rotary kiln pellet low NO x (Nitrogen oxide) production process and production system, belonging to the technical fields of pellet production and environmental protection. Background technique [0002] Pellets are the main iron-containing charge for blast furnace ironmaking in my country. In 2015, the output of pellets in my country was 128 million tons. Compared with sinter, due to the low energy consumption and relatively friendly environment of the pellet production process, and the product has the advantages of good strength, high grade, and good metallurgical properties, it can increase production and save coke when applied to blast furnace smelting, and improve ironmaking technology and economy Indicators, reducing the cost of pig iron, and improving economic benefits, so pellets have been vigorously developed in my country in recent ye...

AI Technical Summary

Problems solved by technology

[0010] In view of the existing problems in the prior art, in order to solve the NO x Disadvantages of emissions and the high cost of adding denitrification devices at the end are unacceptable to enterprises. This patent proposes to circulate all or part (10% to 70%) of the desulfurized flue gas back to the second ring cooling section as cooling air. Gas has low dust content, low sulfur content, NO x The characteristic of higher content, using the high temperature (800-1000°C) characteristics of the ring-cooled second-stage oxidation pellets, by spraying the ammonia reducing agent at a suitable position at the bottom of the bellows, to achieve NO x high temperature selective reduction of

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