Cement kiln waste heat multi-stage heat energy utilization system

Abstract

The utility model discloses a cement kiln waste heat multi-stage heat energy utilization system which comprises waste heat generation equipment, the waste heat generation equipment is a preheater and / or a grate cooler, the waste heat generation equipment is communicated with steam generation equipment, and the steam generation equipment is a steam generator and / or a waste heat boiler of a waste heat power generation system. The steam generating device is in communication with a cement product associated device. The method has the beneficial effects that the cement plant has diversified economic benefits; the production cost is reduced; the building material industry is integrated, energy-saving and environment-friendly; the process arrangement flexibility is improved; multi-stage utilization of waste heat of the cement kiln; energy can be fully utilized, and meanwhile economic benefits are improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of cement kiln waste heat utilization, and particularly relates to a cement kiln waste heat multi-stage heat energy utilization system. BACKGROUND

[0002] Cement, as a typical high energy consumption and high emission key industry, has always been concerned. At present, the main technical breakthrough directions of energy saving and emission reduction in the cement industry in the waste heat power generation system include: 1. Upgrading and upgrading of existing processes and equipment mainly aiming at energy efficiency improvement; 2. Raw material substitution mainly aiming at the emission problem in the calcination process; 3. Fuel substitution mainly aiming at the coal emission problem in the calcination process; 4. Carbon capture, utilization and storage (CCUS) aiming at end-of-pipe disposal. According to the current situation of the cement industry, the development of technology and market preparation conditions, the four technical breakthrough directions play different roles in different periods. In the near future, the energy saving and emission reduction of cement kiln waste heat technology expects the upgrading and upgrading of existing processes and equipment.

[0003] The cement kiln waste heat mainly comes from the kiln tail flue gas and the grate cooler for clinker cooling. With the improvement of energy utilization technology, cement enterprises gradually adopt new type high efficiency low pressure loss six-stage preheating and pre-decomposition system. Despite this, the temperature at the outlet of the preheater C1 is still about 280℃. At the same time, the grate cooler has developed to the fourth generation, and the recovery efficiency, cooling efficiency and operation efficiency of the grate cooler have been greatly improved. At present, the cement kiln waste heat is mainly used for power generation, and the economic benefit of heat energy for power generation is not high: the cost of waste heat power generation system is high, 5000 yuan to 7000 yuan per kilowatt; the investment comprehensive return period is long, about 5 years; and professional technology and equipment are needed. Therefore, the diversified utilization of cement kiln waste heat will become a future trend.

[0004] The downstream industries of cement, such as aerated concrete block (ACC), aerated concrete board (ALC), pipe pile product (PC), concrete prefabricated component and calcium silicate board, mainly use cement as raw material in the manufacturing process, and need steam and temperature maintenance in the production process. Therefore, increasing the manufacturing of cement products in the cement plant can not only increase the energy utilization efficiency, but also increase the economic benefit of the cement plant. CONTENT OF THE INVENTION

[0005] The cement industry has become a key field of energy saving and carbon reduction due to its high carbon emissions and energy consumption, especially the energy structure dominated by coal process emissions. At present, all carbon reduction measures are aimed at: 1. low-carbon cement; 2. alternative fuels; 3. process and equipment modification to improve energy efficiency; 4. carbon capture, utilization and storage technology (CCUS). Among these measures, low-carbon cement and fuel substitution are relatively mature, while CCUS is still in the exploratory application stage. Most cement companies do not have the ability to experiment and error, so they need to find a smooth development path before the carbon reduction technology matures. This path must meet the requirements of energy saving and emission reduction, while also meeting the economic benefits of enterprises.

[0006] From the current problems faced by the cement industry: 1. The clinker utilization rate continues to decline, which means that cement companies will intensify peak production and industry elimination; 2. Energy saving and carbon reduction targets are constantly updated, and most companies face upgrading or consolidation; 3. Most cement companies lack the ability to innovate; 4. There is still room for waste heat utilization in cement plants.

[0007] The breakthrough direction for most cement plant waste heat power generation systems to save energy and reduce emissions is to upgrade equipment and processes. Cement plant equipment has been upgraded for several generations from research and development to the present, and the improvement space of future equipment is not proportional to the economic investment. In view of the current situation faced by cement companies, the present application provides a cement kiln waste heat multi-stage heat energy utilization system for the first time from the perspective of economic benefits, solving the above problems.

[0008] The purpose of the present application is achieved by the following technical solutions:

[0009] A cement kiln waste heat multi-stage heat energy utilization system, comprising a waste heat generating device, the waste heat generating device being a preheater and / or a grate cooler, the waste heat generating device being in communication with a steam generating device, the steam generating device being a steam generator and / or a waste heat boiler of a waste heat power generation system, the steam generating device being in communication with cement product related equipment.

[0010] Further, the waste heat generating device is a preheater and a grate cooler, and the steam generating device is a steam generator or a waste heat boiler of a waste heat power generation system.

[0011] Further, the C1 outlet of the preheater is in communication with the steam generating device.

[0012] Further, when the waste heat power generation system is present, the middle part of the grate cooler is in communication with the steam generating device, and when the waste heat power generation system is not present, the tail part of the grate cooler is in communication with the steam generating device.

[0013] Further, the waste heat boiler of the waste heat power generation system is an SP boiler or an AQC boiler.

[0014] Further, the steam generator is a boiler or a steam heat source machine.

[0015] Further, the steam generating device is in communication with a gas distribution cylinder, which is in communication with a plurality of cement product related devices.

[0016] Further, at least one of a heat accumulator, a temperature and pressure reducer, a stop valve, a cold air valve, and a pressure relief valve is arranged on a pipeline between the gas distribution cylinder and the cement product related device.

[0017] Further, the cement product related device includes at least one of an aerated concrete product related device, a pipe pile product related device, a concrete precast product related device, and a calcium silicate board related device.

[0018] Further, the cement product related device includes at least one of a steam autoclave, a mixer, and a curing chamber.

[0019] The beneficial effects of the present application are as follows:

[0020] 1. Diversified economic benefits of a cement plant, the excess heat of the cement plant is used for power generation, and compared with the production of high value-added cement products, the economic benefits of the production of cement products will be greatly increased.

[0021] 2. Reducing production costs, the main raw materials for cement products are mainly cement, and auxiliary materials are sandstone, fly ash, gypsum, sandstone, aggregate, etc. The use of steam generated by the waste heat of cement can not only solve the temperature and steam required for equipment and maintenance during the production process of cement products, but also reduce the transportation cost of raw materials and the fuel cost of steam combustion. The production of cement products in the cement plant can reduce the transportation cost of raw materials and the fuel cost of steam combustion.

[0022] 3. Integrated energy-saving and environment-friendly building materials industry, the integrated production plan of cement and cement products is formulated according to local conditions to promote resource sharing and complementary ability of the industry, form positive feedback, improve production efficiency, and achieve the purpose of reducing comprehensive cost, and enhance the market competitiveness of the company. At the same time, the integrated industry shares the sewage and waste gas treatment system to achieve the purpose of energy saving and environmental protection. For example, there are great defects in the steam curing of concrete precast components, which consumes a large amount of steam and produces a large amount of waste water and waste gas. Sharing the cement plant flue gas and waste water treatment system can effectively improve the utilization rate.

[0023] 4. The flexibility of process arrangement is improved, in order to improve the efficiency of waste heat power generation, waste heat power generation needs to be built in a location close to the heat source. Now a new arrangement scheme can be provided for waste heat utilization of the cement plant to improve the flexibility of process arrangement.

[0024] 5. Multi-stage utilization of cement kiln waste heat. The cement kiln waste heat comes from the outlet of the preheater C1 and the grate cooler, wherein the waste gas temperature of the grate cooler is 0-1200℃, the waste gas is sent into the kiln and the decomposing furnace by the secondary and tertiary air pipes respectively; the waste gas temperature of 0-800℃ enters the waste heat power generation system; the waste gas temperature of 0-500℃ can enter the coal mill, raw material drying system and steam generator; the waste gas temperature of 0-300℃ can enter the cement product curing room. The waste gas temperature of the outlet of the preheater C1 is 260-350℃, which can enter the waste heat power generation system, steam generator and cement product curing room.

[0025] 6. Cement plant modification. For the cement plant with a production capacity of less than 5000 tons per day and without a waste heat power generation system in the cement line, the energy can be fully utilized and the economic benefit can be improved.

[0026] The foregoing main scheme and each further selected scheme of the present application can be freely combined to form multiple schemes, which are all the schemes that can be adopted and claimed by the present application; and the present application can also be freely combined between each non-conflicting selection and between other selections. A person skilled in the art can understand that there are multiple combinations according to the prior art and common knowledge after understanding the present scheme, which are all the technical schemes claimed by the present application and will not be listed here. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 is a schematic diagram of the system structure of the present application.

[0028] Figure 2 is a schematic diagram of the logic flow of the present application.

[0029] In the figure: 1-preheater, 2-grate cooler, 3-waste heat power generation system, 4-waste heat boiler, 5-steam generator, 6-gas distribution cylinder, 7-aerated concrete product related equipment, 8-pipe pile product related equipment, 9-concrete precast product related equipment, 10-silicon calcium board related equipment, 11-autoclave, 12-curing room. DETAILED DESCRIPTION

[0030] The present application will be further described below in combination with specific embodiments and the accompanying drawings.

[0031] Embodiment 1

[0032] Reference Figure 1 and Figure 2 As shown in the figure, a multi-stage thermal energy utilization system of cement kiln waste heat includes waste heat generating equipment, steam generating equipment and cement product related equipment.

[0033] The waste heat generating equipment is in communication with the steam generating equipment, the waste heat generating equipment is the preheater 1 and / or the grate cooler 2, the steam generating equipment is the steam generator 5 and / or the waste heat boiler 4 of the waste heat power generation system 3, and the steam generating equipment is in communication with the cement product related equipment.

[0034] The flue gas from the power generation boiler or steam generator is heated by the waste heat of the preheater 1 and / or the waste heat of the grate cooler 2. The power generation boiler generates steam for direct power generation. The steam generator generates steam for auxiliary production of cement products.

[0035] When the waste heat generation devices are the preheater 1 and the grate cooler 2, the waste heat of both devices is utilized to ensure sufficient heating. When the steam generation device is the steam generator 5 or the waste heat boiler 4 of the waste heat power generation system 3, one of the two steam generation devices is selected. The waste heat boiler 4 has the functions of power generation and auxiliary production. The steam generator 5 has only the function of auxiliary production.

[0036] The C1 outlet of the preheater 1 is connected to the steam generation device. The temperature of the C1 outlet of the preheater of the cement kiln is generally 260-350℃. The waste heat of this part can be used to heat the waste heat boiler of the waste heat power generation system 3 or the steam generator.

[0037] The temperature of different parts of the head grate cooler of the cement kiln is different. The position of the head grate cooler where the waste heat is taken is selected according to the demand. When the waste heat power generation system 3 exists, the middle part of the grate cooler 2 is connected to the steam generation device. The temperature of the flue gas in the middle part of the grate cooler is 400-500℃. When the waste heat power generation system 3 does not exist, the tail part of the grate cooler 2 is connected to the steam generation device. The temperature of the flue gas in the middle and tail parts of the grate cooler is 240-400℃.

[0038] The waste heat boiler 4 of the waste heat power generation system 3 is an SP boiler or an AQC boiler. Other boiler forms can also be used. The steam generator 5 is a boiler or a steam heat source machine. Other steam generation devices can also be used.

[0039] The steam generation device is connected to the distribution cylinder 6. The distribution cylinder 6 is connected to a plurality of cement product related devices. The distribution cylinder 6 is used to control the distribution of steam. At least one of the heat accumulator, the temperature and pressure reducer, the stop valve, the cold air valve, and the pressure relief valve is arranged on the pipeline between the distribution cylinder 6 and the cement product related device. The heat accumulator is used to store the heat of the steam. The temperature and pressure reducer is used to ensure that the steam meets the production requirements. The stop valve is used to control the opening and closing of the pipeline and emergency discharge. The cold air valve is used to control the amount of cold air mixed into the pipeline. The pressure relief valve is used to prevent overpressure in the pipeline.

[0040] The cement product related devices include at least one of the aerated concrete product related device 7, the pipe pile product related device 8, the concrete precast product related device 9, and the calcium silicate board related device 10. Other cement product related devices can also be included.

[0041] The cement product related equipment includes at least one of an autoclave 11, a mixer and a curing chamber 12. The autoclave and the curing chamber are included in the aerated concrete product related equipment 7, the curing chamber is included in the pipe pile product related equipment 8, the curing chamber is included in the concrete precast product related equipment 9, and the autoclave and the curing chamber are included in the calcium silicate board related equipment 10.

[0042] Example 2

[0043] Referring to Figure 1 and Figure 2 As shown in the figure, a cement kiln waste heat multi-stage heat energy utilization system, a new cement plant has waste heat power generation. From the C1 outlet of the preheater and the grate cooler outlet, the induced draft enters the SP boiler / AQC boiler. The superheated steam generated by the boiler enters the steam turbine room for waste heat power generation, and part of it is sent to the aerated concrete production, to the autoclave, slurry mixer, curing chamber and other places where hot steam is needed.

[0044] Among them, in order to achieve the production conditions of the autoclave, temperature and pressure reducing valves, pressure relief valves, control valves, gas distribution cylinders and other control and display equipment and instruments need to be added on the pipeline. To the slurry mixer and the curing chamber, temperature and pressure reducing valves, pressure relief valves, control valves, gas distribution cylinders, cold air valves and other control equipment need to be added.

[0045] The hot air from the preheater and the grate cooler outlet contains dust, so the dust after heat exchange in the boiler is transported by chain conveyors and other transportation equipment to the kiln dust and other places for treatment. The SP boiler / AQC boiler and the waste water in the aerated concrete production are uniformly sent to the cement plant waste water treatment system. The waste gas in the aerated concrete production process is uniformly sent to the cement waste gas treatment workshop for treatment.

[0046] Example 3

[0047] Referring to Figure 1 and Figure 2 As shown in the figure, a cement kiln waste heat multi-stage heat energy utilization system, a new cement plant has waste heat power generation. From the C1 outlet of the preheater and the grate cooler outlet, the induced draft enters the steam generator, and the superheated steam generated by the steam generator is sent to the aerated concrete production, to the autoclave, slurry mixer, curing chamber and other places where hot steam is needed.

[0048] Among them, in order to achieve the production conditions of the autoclave, temperature and pressure reducing valves, pressure relief valves, control valves, gas distribution cylinders and other control and display equipment and instruments need to be added on the pipeline. To the slurry mixer and the curing chamber, temperature and pressure reducing valves, pressure relief valves, control valves, gas distribution cylinders, cold air valves and other control equipment need to be added.

[0049] The hot air containing dust at the outlet of the preheater and the grate cooler is transported by a chain conveyor and other conveying equipment to the kiln dust for treatment. The waste water in the production of the SP boiler / AQC boiler and the aerated concrete is uniformly sent to the sewage treatment system of the cement plant. The waste gas in the production of the aerated concrete is uniformly sent to the cement waste gas treatment workshop for treatment.

[0050] Example 4

[0051] Reference Figure 1 and Figure 2 As shown in FIG. 1, a multi-stage heat energy utilization system of cement kiln waste heat is provided. In the case of waste heat power generation in a newly built cement plant, the induced draft at the C1 outlet of the preheater and the outlet of the grate cooler is sent to the SP boiler / AQC boiler. The superheated steam generated by the boiler is partially sent to the steam turbine room for waste heat power generation, and partially sent to the production of aerated concrete, the production of pipe pile products, and the production of calcium silicate board, to the autoclave, the slurry mixer, the curing room, and other places where hot steam is needed.

[0052] In order to achieve the production conditions of the autoclave, a temperature and pressure reducing valve, a pressure relief valve, a control valve, a gas distribution cylinder, and other control and display devices and instruments are added to the pipeline. To the slurry mixer and the curing room, a temperature and pressure reducing valve, a pressure relief valve, a control valve, a gas distribution cylinder, and a cold air valve are added.

[0053] The hot air containing dust at the outlet of the preheater and the grate cooler is transported by a chain conveyor and other conveying equipment to the kiln dust for treatment. The waste water in the production of the SP boiler / AQC boiler and the aerated concrete is uniformly sent to the sewage treatment system of the cement plant. The waste gas in the production of the aerated concrete, the production of pipe pile products, and the production of calcium silicate board is uniformly sent to the cement waste gas treatment workshop for treatment.

[0054] The foregoing basic examples and each further selected example of the present application can be freely combined to form a plurality of embodiments, all of which are embodiments that can be used and claimed by the present application. In the present application, each selected example can be arbitrarily combined with any basic example and selected example.

[0055] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. Any modifications, equivalent replacements, and improvements made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A multi-stage waste heat utilization system for cement kilns, comprising waste heat generation equipment, characterized in that: The waste heat generating equipment is a preheater (1) and / or a grate cooler (2). The waste heat generating equipment is connected to a steam generating equipment, which is a steam generator (5) and / or a waste heat boiler (4) of a waste heat power generation system (3). The steam generating equipment is connected to cement product-related equipment.

2. The multi-stage thermal energy utilization system for waste heat from cement kilns according to claim 1, characterized in that: The waste heat generating equipment is a preheater (1) and a grate cooler (2), and the steam generating equipment is a steam generator (5) or a waste heat boiler (4) of a waste heat power generation system (3).

3. The multi-stage thermal energy utilization system for waste heat from cement kilns according to claim 1, characterized in that: The C1 outlet of the preheater (1) is connected to the steam generating equipment.

4. The multi-stage thermal energy utilization system for waste heat from cement kilns according to claim 1 or 3, characterized in that: When a waste heat power generation system (3) is present, the middle part of the grate cooler (2) is connected to the steam generating equipment; when a waste heat power generation system (3) is not present, the tail part of the grate cooler (2) is connected to the steam generating equipment.

5. The multi-stage thermal energy utilization system for waste heat from cement kilns according to claim 1, characterized in that: The waste heat boiler (4) of the waste heat power generation system (3) is an SP boiler or an AQC boiler.

6. The multi-stage thermal energy utilization system for waste heat from cement kilns according to claim 1 or 5, characterized in that: The steam generator (5) is a boiler or a steam heat source.

7. The multi-stage thermal energy utilization system for waste heat from cement kilns according to claim 1, characterized in that: The steam generating equipment is connected to the gas distribution cylinder (6), and the gas distribution cylinder (6) is connected to several cement product-related equipment.

8. The multi-stage thermal energy utilization system for waste heat from cement kilns according to claim 7, characterized in that: The pipeline between the gas cylinder (6) and the cement product related equipment is equipped with at least one of the following: a heat accumulator, a de-heating and pressure reducing device, a shut-off valve, a cold air valve, and a pressure relief valve.

9. The multi-stage thermal energy utilization system for waste heat from cement kilns according to claim 1, characterized in that: The cement product related equipment includes at least one of the following: aerated concrete product related equipment (7), pipe pile product related equipment (8), precast concrete component related equipment (9), and calcium silicate board related equipment (10).

10. The multi-stage thermal energy utilization system for waste heat from cement kilns according to claim 1 or 9, characterized in that: The cement product-related equipment includes at least one of an autoclave (11), a mixer, and a curing chamber (12).

Images