CN202350556U - An air intake system for waste heat power generation of flue gas discharged from cement kiln bypass - Google Patents

Abstract

A wind intake system for power generation from waste heat of flue gas from bypass ventilation of cement kiln, comprising a rotary kiln, a kiln tail smoke chamber, an ascending flue, a preheater and a kiln tail bypass ventilation waste heat boiler, an air intake port is provided on the side wall of the kiln tail smoke chamber or the top of the kiln tail smoke chamber or the side wall of the ascending flue, and the air intake port and the smoke inlet of the kiln tail bypass ventilation waste heat boiler are connected by an air intake pipe; the air intake pipe is composed of three sections of pipe bodies, namely, air intake pipe I, air intake pipe II and air intake pipe III; air intake pipe I is installed upwardly with its bottom end connected to the air intake port and its top end connected to the vertical air intake pipe II; the top end of air intake pipe II is closed, and its top side wall is connected to an air intake pipe III inclined downward, and the bottom end of air intake pipe III is connected to the smoke inlet of the kiln tail bypass ventilation waste heat boiler. The utility model can effectively solve the problem of ash blockage of bypass ventilation and air intake pipelines, and has the advantages of reasonable structure, convenient disassembly and assembly, high efficiency, high safety, easy cleaning, and not easy to be blocked by ash.

Description

An air intake system for waste heat power generation of flue gas discharged from cement kiln bypass

technical field

The utility model relates to a cement kiln bypass air release and air intake device, in particular to a flue gas air intake device used in the process of cement kiln bypass air release and waste heat power generation. the

Background technique

In the cement production process, potassium, sodium, chlorine, and sulfur elements in raw materials and fuels are the interference factors that can stabilize the production of the new dry process cement kiln and affect the quality of cement products. Excessive presence of them may easily cause the kiln tail or preheater, smoke There are problems such as crusting and clogging in the road, and in severe cases, it will cause clogging, affect the normal operation of the cement firing system, and also reduce the quality of cement. the

It is known that the bypass ventilation technology has been widely used at home and abroad, and the bypass ventilation technology is mainly used in the cement production process to solve the problem of circulating harmful components and reducing the content of harmful components in clinker. The current bypass ventilation system is as follows: the high-temperature kiln gas entering the system is quenched first, and the volatile components are condensed and attached to the material powder as much as possible, and then separated and removed from the air flow by a dust collector. The currently used quenching method is "air cooling", that is, the kiln gas is passed into a "quick cooling chamber", and at the same time, cold air is blown in to cool it sharply and then collect dust. However, although the bypass ventilation process is commonly used internationally, it is quite expensive from an economic point of view. The reason lies in three aspects: 1) The influx of a large amount of cold air makes the processing air volume of the bypass ventilation system far greater than the initial kiln gas volume (up to 2-4 times). In actual production, bypass air release can often be performed intermittently, and the air release volume fluctuates within a certain range. The specifications of the bypass ventilation system must be adapted to the instantaneous maximum air volume, which means that even for a small amount of ventilation, a relatively large and efficient dust collection system must be added, and the specifications of the main dust collection system will not be reduced accordingly. The total processing capacity of the two sets of kiln gas purification systems will greatly exceed the original kiln gas volume, and a huge price will be paid in terms of infrastructure investment, floor area, power consumption, operation and maintenance costs. 2) Due to the high viscosity of the exhaust gas dust in the kiln tail smoke chamber, it is easy to cause the blockage of the exhaust gas pipeline and the exhaust gas cooling equipment of the bypass exhaust, which seriously affects the normal operation of the bypass exhaust system. 3) The kiln gas heat recovery utilization rate in the bypass ventilation system is low, which not only pollutes the environment but also wastes heat energy. To sum up, it has become an unavoidable technical topic to improve the dust removal effect of the existing bypass ventilation technology and make full use of the flue gas heat energy of the bypass ventilation. the

For example: the patent No. 201120438574.9 that our company applied for in advance on the process of waste heat power generation at the tail of a cement kiln is "A waste heat power generation device for bypassing air at the tail of a cement kiln". The main structure is: another part of the tail smoke chamber of the rotary kiln The flue gas outlet is connected to the smoke inlet of the bypass waste heat boiler shell through the high-temperature waste gas pipe, and its smoke outlet is connected to the chimney through the dust collector and induced draft fan. The water outlet of the oxygen generator is connected, the water outlet of the economizer is connected with the steam drum, and the steam drum forms a cycle with the evaporation section through the riser and the downcomer respectively, and the steam outlet of the steam drum is connected with the steam inlet of the superheater, and the superheater The steam outlet is connected to the steam inlet of the steam turbine. Its function is to use the heat in the high-temperature flue gas of the bypass at the end of the cement kiln to generate steam for power generation. However, during an industrial experiment in a domestic cement plant, it was found that due to the high temperature of the flue gas in the kiln exhaust chamber and the high viscosity of the flue gas dust, problems such as skinning and blockage of the bypass air intake pipeline are prone to occur, so the waste heat of the bypass air release The boiler could not be put into use, which caused the waste heat power generation technology of bypass ventilation to be unable to be implemented smoothly. Therefore, in order to ensure the normal use of the waste heat boiler for bypass ventilation and make the power generation of the whole set of technology more considerable, it is necessary to improve the air intake process and device for bypass ventilation. the

Contents of the invention

The purpose of this utility model is to provide an air intake system for cement kiln bypass exhaust flue gas waste heat power generation which avoids clogging ash, facilitates cleaning and improves utilization rate during the process of generating electricity by utilizing high temperature flue gas bypass in cement kiln . the

The main technical scheme adopted by the utility model is: including a rotary kiln, a kiln tail smoke chamber, an ascending flue, a preheater, and a kiln tail bypass exhaust heat waste heat boiler. The top of the chamber or the side wall of the ascending flue is provided with an air intake, and the air intake is connected with the smoke inlet of the kiln tail bypass waste heat boiler through an air intake; the air intake is composed of the air intake pipe I, the air intake Pipe II and air intake pipe III are composed of at least two sections of pipe body; air intake pipe I is installed obliquely upwards, the bottom end is connected to the air intake port, and the top is connected to the vertical air intake pipe II; the top end of air intake pipe II is closed, and the top side The wall is connected with a slanted downward air intake pipe III, and the bottom end of the air intake pipe III is connected with the smoke inlet of the kiln tail bypass waste heat boiler. the

The air intake is set on the top of the kiln tail smoke chamber, and the air intake pipe II and the air intake pipe III are used to form a two-stage air intake pipe. The air intake is directly connected with the bottom end of the air intake pipe II; Air duct III is connected. the

The air intake is set on the side wall of the kiln tail smoke chamber or the ascending flue, and the three-stage air intake duct is composed of the air intake pipe I, the air intake pipe II and the air intake pipe III. The air intake is connected with the air intake pipe I, and the air intake pipe Ⅰ is connected to the air intake pipe II and the air intake pipe III in sequence, and the air intake pipe III is connected to the smoke inlet of the kiln tail bypass exhaust heat recovery boiler. the

A flexible ash-retaining device and ash-cleaning device are installed at the air intake; the flexible ash-retaining device is a chain curtain or a spring curtain or a reed shutter. the

The inner diameter of the air intake pipe II is larger than that of the air intake pipe III; the flue gas flow rate in the air intake pipe II is 2-15m/s; the smoke flow rate in the air intake pipe III is 8-45m/s. the

Lay the insulation layer and pouring material on the inner wall of the air intake pipe. Install a dust blocking device in the air intake pipe II, and the dust blocking device is a louver type baffle or a "∽" shaped baffle or a shrinking baffle. the

Expansion devices are installed at the joints of the air intake pipe, the air intake, and the smoke inlet of the kiln tail bypass waste heat boiler.

The air-taking pipe I is a square pipe or a round pipe of equal diameter, or a trumpet-shaped non-equal-diameter square pipe or a round pipe, and the connection with the air-taking pipe II is connected by a streamline. the

An air cannon is provided on the air intake pipe I. the

Install a smoke damper on the air intake pipe. the

The working process of the utility model is: open the smoke damper to ensure the smooth flow of the air pipe. The bypass flue gas from the kiln tail smoke chamber enters the air intake pipe through the air intake, and flows through the air intake pipe I, air intake II, and air intake pipe III step by step in turn (when the air intake is opened on the top of the kiln tail smoke chamber , the flue gas directly flows through the air intake pipe II and air intake pipe III) and then enters the kiln tail bypass waste heat boiler, and finally the flue gas exchanges heat with water and generates superheated steam, which is used to generate electricity. Among them, the flexible dust blocking device at the air intake can stick sticky dust on its surface, and then use the dust cleaning device to regularly remove the dust stuck on the flexible dust blocking device to keep the air intake unblocked. The inner diameter of the air intake pipe II is larger than that of the air intake pipe I and the air intake pipe III, which helps to change the flow velocity of the flue gas in it, and makes the large particles of dust settle in this section, further reducing the risk of blockage. The air intake pipe III adopts a smaller pipe diameter, so that the flue gas flow rate in it is greatly increased, and the dust on the inner wall of the pipe is carried into the bypass exhaust waste heat boiler, preventing the blockage problem in the air intake pipe III. A dust-blocking device can also be set in the air-taking pipe II, and the dust-blocking device can further block dust. In addition, the air cannon can be used to blow up the dust inside the air intake pipe I to avoid the blockage of this section of pipe body. the

The beneficial effects of the utility model are:

1. A flexible ash-retaining device is installed at the air intake of the kiln tail smoke chamber, which can be used in conjunction with the ash cleaning device to effectively prevent some cohesive particles from entering the next-level air intake pipe, and at the same time, it can also solve the problem of easy crusting and blockage of the air intake The problem.

2. Several air cannons are installed on the air intake pipe Ⅰ, which can quickly and smoothly remove the smoke and dust settled on the inner wall of the air intake pipe Ⅱ, and prevent the pipeline from being blocked. the

3. The air intake pipe II adopts a vertical large-section structure, so that the high-temperature flue gas will slow down significantly after entering, so that some large particles of dust will settle down due to the action of gravity, and avoid entering the next-level air intake pipe to cause wall surface The problem of dust accumulation and clogging. the

4. The inner diameter of the air intake pipe III is smaller than that of the air intake pipe II, so that the flue gas flow rate increases when the flue gas enters the air intake pipe III, and the dust in the air intake pipe III is carried to the kiln tail bypass waste heat boiler by the high-speed airflow In order to prevent the blockage of the air pipe. the

5. Contribute to the smooth discharge of alkaline gas in the rotary kiln and improve the quality of cement products. the

6. It can increase the power generation of the waste heat power station, effectively utilize the high-temperature flue gas discharged, and make this part of the high-temperature flue gas enter the kiln tail bypass waste heat boiler to generate steam for power generation. Taking the 4500t/d cement production line as an example, in Under the condition of 10% bypass air release, the power generation can be greatly increased, and the heat consumption of clinker can also be reduced. the

7. It has the advantages of reasonable structure, convenient disassembly and assembly, high efficiency, high safety, easy cleaning, and not easy to block ash. the

Description of drawings

Fig. 1 is a schematic diagram of the structure of the utility model adopting the opening of the side wall of the kiln tail smoke chamber to take the wind.

Fig. 2 is a schematic diagram of the structure of the utility model adopting the opening of the side wall of the ascending flue to take the wind. the

Fig. 3 is a schematic diagram of the structure of the utility model using the top opening of the kiln tail smoke chamber to take the wind. the

Explanation of symbols in the figure:

1: Rotary kiln, 2: Kiln tail smoke chamber, 3: Air intake, 4: Preheater, 5: Air intake pipe I, 6: Air intake pipe II, 7: Air intake pipe III, 8: Expansion device, 9 : kiln tail bypass waste heat boiler, 10: insulation layer, 11: castable, 12: flexible ash retaining device, 13: smoke damper, 14: ash cleaning device, 15: air cannon, 16: ascending flue, 17 : Dust blocking device.

Detailed ways

Process and device:

The utility model includes a rotary kiln 1, a kiln tail smoke chamber 2, an ascending flue 16, a preheater 4 and a kiln tail bypass waste heat boiler 9. The air intake 3 is set on the side wall of the duct, and the air intake is connected with the smoke inlet of the kiln tail bypass waste heat boiler through the air intake pipe; the air intake pipe is composed of the air intake pipe I5, the air intake pipe II6, the air intake Pipe III7 consists of at least two sections of pipe body; the air intake pipe I is installed obliquely upwards, the bottom end is connected with the air intake port, and the top is connected with the vertical air intake pipe II; the top end of the air intake pipe II is closed, and the top side wall is connected to an inclined direction The lower one is connected with the air pipe III, and the bottom end of the air pipe III is connected with the smoke inlet of the kiln tail bypass waste heat boiler. A flexible ash-retaining device 12 and ash-cleaning device 14 are installed at the air intake; the flexible ash-retaining device is a chain curtain or a spring curtain or a reed shutter. The inner diameter of the air intake pipe II is larger than that of the air intake pipe III; the flue gas flow rate in the air intake pipe II is 2-15m/s; the smoke flow rate in the air intake pipe III is 8-45m/s. The insulation layer 10 and castable 11 are laid on the inner wall of the air intake pipe. A dust blocking device 17 is installed in the air-taking pipe II, and the dust blocking device is a louver type baffle or a "∽" shaped baffle or a shrinking baffle. Expansion devices 8 are arranged at the joints of the air intake pipe, the air intake, and the smoke inlet of the kiln tail bypass waste heat boiler. The air-taking pipe I is a square pipe or a round pipe of equal diameter, or a trumpet-shaped non-equal-diameter square pipe or a round pipe, and the connection with the air-taking pipe II is connected by a streamline. An air cannon 15 is provided on the air taking pipe I. Smoke air valve 13 is installed on the air taking pipe.

The utility model is described in detail below in conjunction with accompanying drawing and specific embodiment. the

Embodiment one

As shown in Figure 1, an air intake is provided on the side wall of the kiln tail smoke chamber, and a flexible ash retaining device is arranged at the air intake. The flexible ash retaining device is a chain curtain or a spring curtain or a reed shutter. When the flue gas passes through the flexible ash retaining device at the air intake, part of the viscous dust sticks on the flexible ash retaining device. The dust removal device arranged here can regularly remove the dust bonded to the flexible dust retaining device. A flue air valve is also set on the air taking pipe I to open the bypass flue gas. Multiple groups of air cannons are installed along the length direction of the wall surface of the air intake pipe I, which can remove the dust settled on the wall surface of the air intake pipe I, and make the dust fall into the rotary kiln. The top of the air pipe I is connected to the air pipe II, and the air pipe II is placed vertically. The flow velocity of the flue gas in the air pipe II is 7m/s. Subsidence in the second section, and finally return to the kiln tail smoke chamber through the air pipe I, and the top of the air pipe II is closed. The opening on the side wall surface of the air intake pipe II near the top is connected to the air intake pipe III, and the other end of the air intake pipe III is connected to the smoke inlet of the kiln tail bypass waste heat boiler. The flow rate of the flue gas in the air intake pipe III is 30m/ s. Since the diameter of the air intake pipe III is smaller than that of the air intake pipe II, when the flue gas flows through the air intake pipe III, the flow velocity of the flue gas increases, and the dust particles in the air intake pipe III can be carried into the kiln tail Bypass venting waste heat boilers to prevent blockage of air intake pipes. In order to recover the waste heat in the flue gas released by the bypass to the greatest extent, all the inner walls of the air intake pipes are laid with insulation layers and castables. In addition, for the sake of safety, an expansion device is installed between the air intake pipe I and the air intake port, and an expansion device is also installed at the air intake pipe III and the smoke inlet of the kiln tail bypass exhaust heat recovery boiler. The expansion device can prevent the pipe Road expansion caused damage. Finally, the high-temperature flue gas enters the bypass waste heat boiler at the end of the kiln to generate steam and use the steam to generate electricity.

Example two

As shown in Figure 2, an air intake is set on the side wall of the ascending flue, and a flexible device is installed at the air intake. When the high-temperature flue gas from the bypass vent passes through the flexible device at the air intake, part of the sticky dust will stick to the flexible device. The dust removal device arranged here can regularly remove the dust adhered to the flexible device. The flue gas passes through the air intake pipe I connected to the air intake, and an expansion device is installed between the air intake pipe I and the air intake of the bypass air outlet, and a smoke damper is also installed on the air intake pipe I to perform bypass air release The opening of the smoke. A plurality of groups of air cannons are arranged in the length direction of the wall surface of the air intake pipe I to remove the settled dust on the wall surface of the air intake pipe I. The other end of the air pipe I is connected to the air pipe II, and the air pipe II is placed vertically. The flow velocity of the flue gas in the air pipe II is 7m/s, and the large-sized particles in the flue gas settle in it and pass through it. The air intake pipe I returns to the kiln tail smoke chamber, and a dust blocking device is also installed in the air intake pipe II to improve the separation efficiency of dust particles in the flue gas, and the top of the air intake pipe II is closed. The opening on the side wall surface of the air intake pipe II near the top is connected to the air intake pipe III, and the other end of the air intake pipe III is connected to the smoke inlet of the kiln tail bypass waste heat boiler. The flow rate of the flue gas in the air intake pipe III is 30m/ s, when the flue gas flows through the air intake pipe III, the flow rate increases, and the dust particles in the air intake pipe III can be carried into the kiln tail bypass waste heat boiler to prevent pipeline blockage. In order to recover the waste heat in the flue gas released by the bypass to the greatest extent, all the inner walls of the air intake pipes are laid with insulation layers and castables. An expansion device is installed at the flue gas inlet of the air intake pipe III and the bypass waste heat boiler to prevent damage caused by pipe expansion. Finally, the high-temperature flue gas enters the bypass waste heat boiler at the end of the kiln to generate steam and use the steam to generate electricity.

Embodiment three

As shown in Figure 3, an air intake is set on the top of the kiln tail smoke chamber, and a flexible device is installed at the air intake. When the bypass high-temperature flue gas passes through the flexible device at the air intake, part of the sticky dust sticks on the flexible device. The dust removal device arranged here can regularly remove the dust adhered to the flexible device. The flue gas passes through the air intake pipe II vertically connected to the air intake port. The average flow velocity of the flue gas in the air intake pipe II is 7m/s, and the large-sized particles in the flue gas settle here and fall directly to the kiln tail smoke chamber Among them, the top of the air intake pipe II is closed, and an expansion device is set between the air intake pipe II and the air intake to prevent damage caused by the expansion of the pipeline. Open on the side wall near the top of the air intake pipe II and communicate with the air intake pipe III, and the bottom end of the air intake pipe III is connected with the smoke inlet of the kiln tail bypass waste heat boiler, wherein the flue gas is in the air intake pipe III The flow velocity is 30m/s. When the flue gas flows through the air intake pipe III, the flow velocity increases, and the dust particles in the air intake pipe III can be carried into the bypass waste heat boiler to prevent the pipeline from being blocked. In order to recover the waste heat in the flue gas released by the bypass to the greatest extent, all the inner walls of the air intake pipes are laid with insulation layers and castables. An expansion device is installed at the flue gas inlet of the air intake pipe III and the bypass waste heat boiler to prevent damage caused by pipe expansion. A flue air valve is also set in the air taking pipe III for opening the bypass flue gas.

Claims (9)

1. A wind intake system for cement kiln bypass exhaust flue gas waste heat power generation, comprising a rotary kiln, a kiln tail smoke chamber, an ascending flue, a preheater and a kiln tail bypass exhaust heat waste heat boiler, characterized in that: The side wall of the kiln tail smoke chamber or the top of the kiln tail smoke chamber or the side wall of the ascending flue is provided with an air intake, and the air intake is connected with the smoke inlet of the kiln tail bypass exhaust heat recovery boiler through an air intake pipe; The air duct is composed of at least two sections of air intake pipe I, air intake pipe II, and air intake pipe III; the air intake duct I is installed obliquely upward, the bottom end is connected to the air intake port, and the top is connected to the vertical air intake pipe II The top of the air intake pipe II is closed, and the top side wall is connected with an inclined downward air intake pipe III, and the bottom end of the air intake pipe III is connected with the smoke inlet of the kiln tail bypass waste heat boiler. 2. A kind of wind taking system for cement kiln bypass flue gas waste heat power generation according to claim 1, it is characterized in that: a flexible ash-retaining device and ash-cleaning device are installed at the air-taking port; the flexible ash-retaining device The installation is chain curtain or spring curtain or reed shutter. 3. A wind extraction system for cement kiln bypass flue gas waste heat power generation according to claim 1, characterized in that: the inner diameter of the air extraction pipe II is larger than that of the air extraction pipe III; the flue gas in the air extraction pipe II The flow velocity is 2-15m/s; the flow velocity of the flue gas in the duct III is 8-45m/s. 4. An air extraction system for generating waste heat from flue gas in the bypass of a cement kiln according to claim 1, characterized in that: an insulating layer and castables are laid on the inner wall of the air extraction pipe. 5. A wind extraction system for cement kiln bypass exhaust flue gas waste heat power generation according to claim 1, characterized in that: a dust blocking device is installed in the air extraction pipe II, and the dust blocking device is a louver type baffle Or "∽" shaped baffle or shrinking baffle. 6. The air intake system for cement kiln bypass exhaust flue gas waste heat power generation according to claim 1, characterized in that: the air intake pipe is connected with the air intake, the smoke inlet of the kiln tail bypass exhaust waste heat boiler Expansion devices are installed at the joints of the mouth and mouth respectively. 7. A wind extraction system for generating waste heat from flue gas in the cement kiln bypass according to claim 1, characterized in that: said air extraction pipe I is a square pipe or a round pipe of equal diameter, and can also be a horn Square pipe or round pipe with non-equal diameter, and the connection with the air pipe II is connected by a streamline. 8. An air extraction system for generating waste heat from waste heat of flue gas released from cement kiln bypass according to claim 1, characterized in that an air cannon is provided on the air extraction pipe I. 9. An air extraction system for power generation with waste heat of flue gas released from cement kiln bypass according to claim 1, characterized in that: a smoke air valve is installed on the air extraction pipe.

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