Method and plant for mfg. cement clinker

Abstract

A description is given of a method as well as a plant for manufacturing cement clinker by which method cement raw meal is preheated in a preheater (1), calcined in a calciner (3) comprising an upper end (3a) and a lower end (3b), burned into clinker in a kiln (5) and cooled in a subsequent clinker cooler (7). The invention is peculiar in that exhaust gases from the kiln (5) are introduced into the upper end (3a) of the calciner, in that fuel is likewise introduced into the upper end (3a) of the calciner, in that the exhaust gas / fuel suspension is directed down through the calciner (3), in that preheated air from the clinker cooler (7) and preheated raw meal from the preheater (1) in combination or separately are fed into the calciner (3) at a location under the zone where exhaust gases from the kiln and fuel are introduced, in that the preheated air is directed down through the caliciner (3), being gradually mixed with the exhaust gas / fuel suspension, in that the raw meal under the action of gravity is directed down through the calciner (3) along its wall, being suspended in the exhaust gases at the lower end (3b) of the calciner, and in that the exhaust gas / raw meal suspension is extracted from the lower end (3b) of the calciner and conveyed to a separating means (4) for separating the raw meal which is subsequently directed to the kiln (5). Hereby is obtained a significant reduction of the NOx which is led to the calciner together with the kiln exhaust gases, a high degree of fuel burn out even when using fuels with a low content of volatile constituents, and a low degree of conversion into NOx of the nitrogen which is led to the calciner together with the fuel.

Description

technical field [0001] The present invention relates to a method of producing cement clinker, by which raw meal is preheated in a preheating furnace, calcined in a calciner comprising an upper end and a lower end, clinker is fired in a kiln and subsequently Cool in a cooler. The invention also relates to a device for carrying out the method. Background technique [0002] The above-mentioned plants for the manufacture of cement are well known in the literature. In some plants, calciners are specially designed to use fuels with low volatile content, such as petroleum coke (petrocoke), while in other plants, calciners are specially designed to obtain low NO x designed for emission levels. Obviously, in the future, the acceptable NO x Emission levels will impose more stringent requirements, and there will continue to be benefits to using fuels with low levels of volatile components. Accordingly, there is a need for a method and apparatus for making cement that can exhibit t...

AI Technical Summary

Problems solved by technology

In addition, NO in the calciner x very low yield

However, a disadvantage of this type of kiln is that it may be necessary to add a proportion of the uncalcined raw meal directly to the exhaust gas from the kiln, thus preventing the formation of Overlay

As a result, the exhaust gas / fuel suspension is overcooled, leading to reduced NO generation in the kiln when fuels with low volatile content are used x Possibilities are limited

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