CN1554609A - Cement clinker calcining cycle pre-calcination process and device - Google Patents

Abstract

The invention relates to a cement clinker calcination cycle pre-calcination process and device. The lower part of the calciner body is connected to the pre-calcination furnace, and the upper side is connected to the cyclone cylinder. The tertiary air duct is respectively connected with the calciner body and the pre-burning furnace through the tertiary air volume regulating valve, and the upper cyclone is respectively connected with the calciner body and the pre-calciner through the raw material pipe. This process integrates the advantages of precalcining kiln and fluidized bed process, so that the process with the largest heat transfer in the rotary kiln is completed in the pre-firing furnace. At the same time, a small amount of rotary kiln is reserved for firing in the high-temperature reaction zone, which can increase the output by 50% %, the harmful gases of nitrogen oxides and sulfides are greatly reduced, the adaptability to coal is wide, and the combustion efficiency is high.

Description

Cement clinker calcining cycle pre-calcination process and device

Technical field

The invention relates to a cement clinker calcining cycle pre-calcination process and device.

Background technique

The current pre-decomposition cement calcination technology has put 90% of the calcium carbonate decomposition process with the largest heat absorption in the cement clinker calcination process in the gas-solid suspension decomposition furnace outside the kiln, so the output is high and the efficiency is high. However, there are still some calcium carbonate and the heating process of materials are completed in the rotary kiln. Studies have shown that in the precalcined rotary kiln, the temperature range of 850-1100°C still occupies nearly half of the space of the rotary kiln, and in this range, 90% of the heat exchange capacity of the rotary kiln is concentrated. However, due to the low temperature difference between gas and solid in the rotary kiln in this range, the weak heat radiation capability, and the extremely low efficiency of convective heat transfer due to the small contact area between the material and the air flow, there is still a large heat transfer demand and heat transfer in the rotary kiln. The paradox of extremely low thermal efficiency. In response to this problem, Japanese scholars proposed a solution to completely replace rotary kiln calcination with fluidized bed calcination technology with high heat transfer rate, and passed the 200t/d level pilot test research. However, practice has proved that fluidized bed calcination has the problems of poor uniformity and stability, the calcination system is difficult to control, and the clinker sintering temperature of 1450 ° C is seriously clogged and clogged, so it is difficult to apply on a large scale. Theoretically speaking, cement clinker calcination has a large amount of exothermic solid-phase reaction in the high-temperature zone (1100-1450°C), and the actual heat exchange required is extremely small, so the use of fluidized bed has no practical significance in this range. .

Contents of the invention

The purpose of the present invention is to provide a cement clinker calcination cycle pre-calcination process and device, which is to further improve its efficiency, output, quality and ecological environmental protection performance on the basis of the current new dry process cement technology (ie pre-decomposition technology) Advanced technology, wide adaptability to coal, high combustion efficiency.

The object of the present invention is achieved in this way: in this cement clinker calcining cycle pre-calcination device, the lower part of the decomposition furnace body is connected with the pre-calcination furnace, the upper side of the decomposition furnace body is connected with the cyclone, and the lower part of the cyclone has a regulating valve through the feeding pipe. They are respectively connected to the pre-burning furnace and the entrance of the kiln. The three air ducts are respectively connected to the calciner body and the pre-burning furnace through the three air volume regulating valves. A raw material regulating valve is connected with the decomposition furnace body and the pre-burning furnace respectively through the raw material pipe.

A cement clinker calcination cycle pre-burning process, equipped with three kinds of regulating valves, the pre-decomposed raw meal regulating valve, the hot raw meal regulating valve and the third air volume regulating valve, the coal powder is fed from the coal injection pipe at the bottom of the pre-calcination furnace, Mix with kiln tail flue gas, raise the temperature to 900°C~1000°C, and combust the pulverized coal and part of the tertiary air in the pre-calcination furnace 4, and further calcinate and completely decompose the raw meal from the cyclone; the raw meal in the pre-calcination furnace After pre-burning at high temperature, part of the raw material is sintered into granules, and enters the kiln directly from the nozzle at the end of the kiln, and the rest of the raw material enters the calciner together with the airflow and some unburned coal powder. In the calciner, the coal powder is combined with the remaining three The air is mixed and burned completely, and at the same time mixed with the raw meal from the upper cyclone to complete the pre-decomposition process; then the raw meal is separated from gas and solid by the cyclone, and fed into the kiln and pre-burning furnace through the regulating valve to form a cycle.

The present invention has the following effects: combining the advantages of the precalcining kiln and the fluidized bed process, an intensified pre-sintering furnace is added between the rotary kiln and the calcining furnace, so that the process of the largest heat transfer in the rotary kiln is completed in the pre-sintering furnace, and at the same time, Reserve a small amount of rotary kiln for firing in the high-temperature reaction zone, so as to achieve the high-efficiency effect of the fluidized bed and avoid the two-dimensional effect that the fluidized bed is difficult to produce on a large scale; the output can be increased by more than 50%, and the nitrogen oxides and vulcanization Harmful gases are greatly reduced, the adaptability to coal is wide, and the combustion efficiency is high.

Description of drawings

Fig. 1 is a schematic structural view of the device of the present invention.

Detailed ways

In Fig. 1, the lower part of the calciner body 9 is connected with the pre-burning furnace 4, the upper side of the calciner body 9 is connected with the cyclone 11, and the lower part of the cyclone 11 has a pre-decomposed raw meal regulating valve 8 respectively connected to the pre-calcined furnace through the feeding pipe 6. The furnace 4 is connected to the entrance of the kiln 1, and the tertiary air pipe 5 is respectively connected to the calciner body 9 and the pre-burning furnace 4 through the tertiary air volume regulating valve 13. The lower part is connected to the kiln 1, and the lower part of the upper cyclone 12 has a hot raw material regulating valve 10, which is connected to the calciner body 9 and the pre-burning furnace 4 through the raw material pipe 7 respectively.

In this process, there are three regulating valves, pre-decomposed raw meal regulating valve 8, hot raw meal regulating valve 10 and tertiary air volume regulating valve 13, to adapt to different calcination conditions. The pulverized coal is fed from the coal injection pipe 3 at the bottom of the pre-combustion furnace 4, mixed with the flue gas at the kiln tail, and the temperature is raised to 900 ° C ~ 1000 ° C in the state of unburned or a small amount of combustion. The mixed combustion of wind makes the raw material from the cyclone 11 further calcined and completely decomposed. In order to prevent the temperature in the calciner 4 from being too high, a raw meal pipe 7 from a hot raw meal regulating valve 10 is provided to introduce part of the raw meal to control the temperature within 1100°C. After the raw meal is pre-fired at high temperature in the pre-burning furnace 4, some of the raw meal is sintered and granulated, and enters the kiln 1 directly from the kiln tail nozzle 2, and the rest of the raw meal enters the calciner 9 together with the air flow and some unburned coal powder. In the calciner 9, the pulverized coal is mixed with the rest of the tertiary air and burned completely, and simultaneously mixed with the raw material from the upper cyclone 12 to complete the pre-decomposition process. Then the raw meal is separated from the gas and solid by the cyclone 11, and fed into the kiln 1 and the pre-burning furnace 4 through the regulating valve 8 to form a cycle. When the amount of raw material entering the pre-burning furnace 4 is large, the amount of raw material sintered into granules and directly fed into the kiln will increase, so that the amount of material entering and leaving reaches a balance.

Claims (3)

1. A cement clinker calcining cycle pre-burning device, characterized in that: the lower part of the calciner body 9 is connected to the pre-calcined furnace 4, the upper side of the calciner body 9 is connected to the cyclone 11, and the lower part of the cyclone 11 has pre-decomposed raw materials. The material regulating valve 8 is connected to the pre-burning furnace 4 and the entrance of the kiln 1 respectively through the feeding pipe 6, and the tertiary air pipe 5 is respectively connected to the calciner body 9 and the pre-calcining furnace 4 through the tertiary air volume regulating valve 13, and the lower part of the pre-burning furnace 4 is connected. The nozzle 2, the lower part of the nozzle 2 is connected to the kiln 1, and the lower part of the superior cyclone 12 has a hot raw material regulating valve 10, which is connected to the calciner body 9 and the pre-burning furnace 4 through the raw material pipe 7 respectively. 2. A cement clinker calcination cycle pre-burning process, characterized in that: there are three kinds of regulating valves, the pre-decomposed raw meal regulating valve 8, the hot raw meal regulating valve 10, the third air volume regulating valve 13, and the pulverized coal from the pre-burning The coal injection pipe 3 at the bottom of the furnace 4 feeds, mixes with the kiln tail flue gas, and heats up to 900°C-1000°C. In the pre-burning furnace 4, the coal powder and part of the tertiary air are mixed and burned, and the raw meal from the cyclone 11 is further processed. Calcination, complete decomposition; after the raw material is pre-calcined at high temperature in the pre-calcination furnace 4, part of the raw material is sintered into granules, and directly enters the kiln 1 from the nozzle 2 at the kiln tail, and the rest of the raw material is mixed with the air flow and part of the unburned coal powder. Enter the calciner 9, where the pulverized coal is mixed with the rest of the tertiary air and burned completely, and at the same time mixed with the raw meal from the upper cyclone 12 to complete the pre-decomposition process; then the raw meal is separated from gas to solid by the cyclone 11, and It is fed into the kiln 1 and the pre-fired furnace 4 through the regulating valve 8 to form a cycle. 3. According to claim 2, the cement clinker calcination cycle pre-combustion process is characterized in that: the pulverized coal is fed from the coal injection pipe 3 at the bottom of the pre-combustion furnace 4 and the temperature should be raised to 900°C in an unburned or a small amount of combustion state ~1000°C, another raw meal pipe 7 from the hot raw meal regulating valve 10 is set at the cyclone 12 to introduce part of the raw meal, so as to control the temperature not to exceed 1100°C.