Energy-saving emission-reducing partial oxygen-increasing combustion-supporting device used for cement kiln

Abstract

An energy-saving emission-reducing partial oxygen-increasing combustion-supporting device used for a cement kiln is placed beside the cement kiln. A VPSA oxygen enrichment generation device of the energy-saving emission-reducing partial oxygen-increasing combustion-supporting device is connected with an oxygen enrichment control device. The oxygen enrichment control device is connected with an air blower and connected with an oxygen enrichment preheater through an oxygen conveying pipeline. An oxygen enrichment pressure transmitter, an oxygen enrichment concentration transmitter, an oxygen enrichment flow rate transmitter and a control valve are respectively arranged on the oxygen conveying pipeline. A smoke inlet of the oxygen enrichment preheater is connected with high-temperature waste gas of the cement kiln, and an oxygen enrichment gas outlet is connected with an oxygen enrichment jet nozzle. The oxygen enrichment jet nozzle is arranged on the lower half portion of a rotary kiln combustion device. According to the energy-saving emission-reducing partial oxygen-increasing combustion-supporting device used for the cement kiln, not only can materials absorb more effective heat energy as much as possible, but also the temperature in the upper portion of the cement kiln can be reduced effectively and fuel can be burnt fully, timely and completely with less combustion air. Moreover, performance of high-quality fuel can be fully developed so that usage of poor-quality fuel becomes possible. Smoke dust, dust, CO, CO2, NOX and the like are reduced. The energy-saving emission-reducing partial oxygen-increasing combustion-supporting device used for the cement kiln has remarkable comprehensive energy-saving emission-reducing benefit.

Description

technical field [0001] The invention relates to an oxygen-enriched combustion-supporting device for a cement kiln. Background technique [0002] At present, the general cement kiln uses ordinary air combustion or overall oxygen-increased combustion. The former, because the air only contains less than 21% oxygen, and the rest is inert gas, not only does not participate in combustion, but absorbs a lot of heat, thereby reducing cement The performance and efficiency of the kiln, etc., while the latter generally has a very large investment and many side effects such as a significant decrease in furnace life, NO X Significantly improved etc. For example, in the scheme of Chinese utility model patent 201120253557.8 (CN202177298U), "a blower and a pre-mixer are provided at the lower part of the grid cooler, which are used to mix the normal air of the secondary air and the oxygen-enriched air of the secondary air and send them to the cement rotary kiln. "Middle", if according to t...

AI Technical Summary

Problems solved by technology

For cement kiln application of partial oxygen-increasing combustion-supporting technology, although mentioned in the following patent applications or patents, including Chinese invention patent application 200810233560.6 (CN101407381A), Chinese invention patent application 200910010412.2 (CN101487593A), Chinese utility model patent 200920010534.7 (CN201344555Y) and 201120436379.2 (CN202390203U), but these patents have the following disadvantages: the "effect description" as mentioned in CN101407381A is completely taken for granted and is very unrealistic: if the kiln head is added with a pure oxygen flow rate of 6m 3 / h, the temperature can be increased by 150°C, the amount of coal input is reduced from 6.15 t / h to 5.9 t / h, and the low calorific value of coal is 17200 KJ / Kg. Based on these data, it is calculated that 6.15 t / h coal consumption requires at least 28240 m3 of air 3 / h, if the oxygen-enriched concentration only increases by 0.02 percentage points after mixing, it is impossible to increase the temperature of the kiln head by 150°C! In addition, this patent designs a variety of oxygen-enriched nozzles, all of which have little practical significance. Especially "as shown in Figure 6", the oxygen-enriched nozzles are inserted on the "side or top of the kiln head cover", because the inside of the kiln head cover is from the grate cooler. There is a large amount of secondary air, so adding oxygen to the kiln hood is equivalent to increasing oxygen as a whole! In this way, the temperature of the cooling zone close to the kiln hood will be significantly increased, and the technological task of the cooling zone is to cool the clinker rapidly, and increasing the temperature will not be worth the loss! It is mentioned in CN101487593A and CN201344555Y that "when used in a cement rotary kiln, the proprietary oxygen-enriched nozzle can be replaced by the central tube used for the central ignition gun of the four-channel burner of the cement rotary kiln

"Because there are many factors affecting the cement rotary kiln, the kiln is often shut down, so it is inconvenient to use the central tube, and the angle cannot be adjusted. The center (firing zone) moves forward to the cooling zone (shortening), which seriously affects the cooling of the clinker and the normal operation of the rotary kiln; CN202390203U has more prominent problems in terms of practical effects: the inventor's research on the separation and application of oxygen-enriched membranes Practice and research can prove that the above-mentioned patents have relatively high energy consumption in oxygen production, especially the second-stage membrane separator, which has higher energy consumption, and the energy consumption cost is more expensive than the equipment cost; for example, according to the 3000Nm 3 / h as an example, the annual operating energy consumption cost of the first-stage membrane separator is at least 1 / 2 of the equipment cost, while using VPSA, the equipment cost is more than 10% lower than that of the membrane method, and the energy consumption cost is only 1 / 2 of the membrane method About 65%; In addition, this patent "sends oxygen-enriched gas into the multi-channel burner", which is the same as the technical solution described in CN201344555Y or CN101487593A. It is used as primary air without oxygen-enriched nozzles, and the best energy-saving and emission-reduction effects cannot be achieved , cannot give full play to the advantages of local oxygen-increasing combustion-supporting technology

In addition, the above-mentioned technologies all use membrane method oxygen source, and adopt water ring vacuum pump and gas-water separation, dehumidification and voltage stabilizing device. Affect the quality of oxygen enrichment and the effect of energy saving and emission reduction

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