CN1146546A - External decomposition technology for waste heat generating technology of cement kiln - Google Patents

Abstract

The rotary kiln with a precalcinator for power generation process by using waste heat of cement kiln is characterized by that all the kiln smoke and raw material are passed through said process system and a suction operation process is used so as to implement external circulating process of partial material. Said invention can raise kiln yield by above 80%, and the generated output is raised by 30-40%, and can implement large-scale production.

Description

The precal cination technique that is used for cement kiln residual heat generating technology

The present invention belongs to pre-burning manufacturing cement in fluid bed, utilizes a kind of improvement of kiln fume afterheat electricity-generating method simultaneously.

Precal cination technique is a kind of burning clinker of cement new technology that grows up the seventies, this method is to have set up a dore furnace between suspended preheater and rotary kiln, the fuel of adding about 60% in stove, make the exothermic process of fuel combustion and the endothermic process of raw material carbonate decomposition, make it promptly carry out heat exchange with suspended state or fluidisation attitude form, thereby the resolution ratio that makes the kiln raw material is brought up to more than 75%, has reduced the thermic load of rotary kiln thus, has improved the productivity ratio of kiln again.

Utilize the cement kiln residual heat generating technology, prior art all adopts the technology pattern of traditional hollow kiln band waste heat boiler, and this technological process kiln output is little, efficient is low, hear rate is high, generating production line small scale.Though the patent 85100898 of my institute's earlier application adopts the fluidization principle that cold wind, cold burden are directly sent into dore furnace, save 4 to 5 grades of preheaters, but its technological process is not perfect, the kiln flue gas of this patent is not by decomposition furnace system, and raw material are gone into kiln after partly decomposing through dore furnace, and the remainder raw material are directly into kiln, this patent adopts positive pressure operation, the used combustion air of dore furnace is the normal temperature air that blower fan blasts, and hear rate is still high, and system scale is again little.

The objective of the invention is: improve technological process, make full use of the kiln fume afterheat, improve raw material resolution ratio and kiln output, cut down the consumption of energy simultaneously, increase economic efficiency.

Feature of the present invention is:

(1) the kiln flue gas is all by this process system, and its flow process is that the kiln discharge flue gas is gone into fluidized bed calciner earlier, through 1-3 level rotoclone collector, goes into waste heat boiler and cottrell then;

Raw material can all feed fluidized bed calciner, also can partly feed dore furnace, and preheating, decomposition are after go into kiln behind the 1-3 level rotoclone collector;

(2) fluidized bed calciner and supporting 1-3 level rotoclone collector;

(3) under the one-level dust-precipitator, be provided with high temperature ratio tripper, make part or all of material go into fluidized bed calciner again according to running situation, realize part decomposition material stove external circulation process;

(4) total system moves under negative-pressure operation, and raw material, coal dust directly enter fluidized bed calciner, goes into fluidized bed calciner from the hot blast that kiln hood extracts through tertiary-air pipe.

Technological process of the present invention is expressed in accompanying drawing 1.

Among the figure: 1. rotary kiln 2. roots blowers 3. fluidized bed calciners 4. one-level rotoclone collectors 5. secondary rotoclone collectors 6. waste heat boilers 7. Turbo-generator Set 8. air-introduced machines 9. cottrells 10. high temperature ratio trippers

Fig. 2 is the dore furnace schematic diagram.

Advantage of the present invention:

1. fluidized bed calciner moves under negative-pressure operation, and raw material preheating and decomposition under 850 ℃ of-900 ℃ of temperature reaches more than 75% calcium carbonate decomposition rate, and kiln output improves 80%.

2. existing hollow kiln dust contained flue gas is big, and system leaks out greatly, and dust stratification is many, influence waste heat boiler efficient and scale, efficient cyclone dust-precipitator gross efficiency reaches about 95% in the system of the present invention, so Gas Parameters is stable, flow height, EGT can improve generated energy 30-40% up to 850 ℃.The present invention can be supporting with horizontal or vertical waste heat boiler, and scale and benefit are arranged, and improved the cogeneration integral level.

3. save 4-5 level pre-heating device, saved equipment investment.

The embodiment of the invention:

Technological process shown in the accompanying drawing 1 is promptly implemented at cement plant, Huhehaote City 2# kiln at present.Raw material directly feed fluidized bed calciner without preheater, the coal dust of burning usefulness directly feeds the dore furnace bottom by delivery pump from kiln hood, required combustion air major part extracts hot blast by tertiary-air pipe from kiln hood and provides, the fluidized wind of dore furnace is blasted from the bottom by roots blower, go out kiln exit gas and enter the dore furnace middle part, raw material preheating in dore furnace is also decomposed the back and is accepted into kiln by the secondary rotoclone collector, this system can make the raw material resolution ratio reach more than 75%, for the thermal efficiency and the operational stability that improves dore furnace, again return dore furnace by the partial material that the one-level rotoclone collector is accepted by the control of high temperature ratio tripper, form the stove outer circulation with this, go into the usefulness of waste heat boiler for generating by the high-temperature flue gas (about about 850 ℃) of secondary rotoclone collector.

Claims (1)

1. precal cination technique that is used for cement kiln residual heat generating technology is characterized in that:

(1) the kiln flue gas is all by this process system, and its flow process is that the kiln discharge flue gas is gone into fluidized bed calciner earlier, through 1-3 level rotoclone collector, goes into waste heat boiler and cottrell then;

Raw material can all feed fluidized bed calciner, also can partly feed dore furnace, and preheating, decomposition are after go into kiln behind the 1-3 level rotoclone collector;

(2) fluidized bed calciner and supporting 1-3 level rotoclone collector thereof;

(3) under the one-level dust-precipitator, be provided with high temperature ratio tripper, make part or all of material go into fluidized bed calciner again according to running situation, realize part decomposition material stove external circulation process;

(4) total system moves under negative-pressure operation, and raw material, coal dust directly enter fluidized bed calciner, goes into fluidized bed calciner from the hot blast that kiln hood extracts through tertiary-air pipe.