Cement hot raw material desulfurization process and desulfurization device

Abstract

The invention discloses a cement hot raw material desulfurization process and a desulfurization device. The desulfurization process comprises the following steps: (1) taking out a high-temperature solid hot raw material from a C5-grade cyclone blanking pipe; (2) mixing the taken-out high-temperature solid hot raw material with air flow for primary cooling; (3) carrying out gas-solid separation on the hot raw material mixed with the gas, and carrying out secondary cooling by using atomized water to obtain a low-temperature hot raw material; (4) metering the obtained low-temperature hot raw material, adding the low-temperature hot raw material into a digester, and carrying out digestion reaction on the low-temperature hot raw material and digestion water in the digester to generate calcium hydroxide; (5) conveying the digested material into a powder bin for temporary storage; and (6) metering the material temporarily stored in the powder bin, adding the material into a first air pipe from the C2 cyclone separator to the C1 cyclone separator, and carrying out desulfurization treatment. The process method provided by the invention has the advantages of small influence on a preheater system, low energy consumption, high desulfurization efficiency, small use amount of a desulfurizing agent and stable desulfurization effect, and can adapt to a working condition with relatively large SO2 concentration fluctuation.

Description

Technical Field

[0001] The invention relates to the technical field of desulfurization, and in particular to a cement hot raw meal desulfurization process and a desulfurization device. Background Art

[0002] SO2 produced by cement production 2 Pollutants mainly come from two parts, one from raw materials and the other from fuel. Sulfur in raw materials mainly exists in the form of organic sulfides, sulfides or sulfates; sulfates in raw materials usually do not form SO in the preheater system. 2 , most of which enter the kiln system. Sulfide and organic sulfur in the raw material generate SO at 400℃-600℃ 2 Exhausted with the exhaust gas. Traditional cement kiln flue gas desulfurization technologies mainly include wet desulfurization, dry desulfurization and semi-dry desulfurization. Wet desulfurization technology, such as limestone-gypsum wet desulfurization, has a high desulfurization efficiency of more than 90%, but this method has the disadvantages of large equipment, high investment cost, large consumption of water resources during operation and easy secondary pollution of wastewater. At the same time, the flue gas temperature after wet desulfurization is low, and usually needs to be reheated to meet the chimney emission requirements, which further increases energy consumption and operating costs.

[0003] Dry desulfurization technology, such as the circulating fluidized bed dry desulfurization process with calcium-based desulfurizer, has the advantages of simple system, small footprint, no wastewater discharge, etc., but its desulfurization efficiency is relatively low, generally around 80-85%, which is difficult to meet the current increasingly high environmental emission standards. Moreover, the contact time between the desulfurizer and the flue gas during the dry desulfurization process is limited, and the reaction is not sufficient, resulting in low utilization of the desulfurizer, requiring a large amount of desulfurizer to be added, which increases the operating cost.

[0004] Semi-dry desulfurization technology is between the wet and dry methods. For example, rotary spray semi-dry desulfurization has overcome some of the shortcomings of wet desulfurization to a certain extent, but there are still problems such as equipment scaling and clogging, and poor adaptability to changes in flue gas flow and composition. This poses a challenge to the stable operation of the system, requiring frequent equipment maintenance and overhaul, affecting the normal production of the cement plant.

[0005] In addition, the existing desulfurization technology has different SO 2 The adaptability is insufficient when the concentration fluctuates greatly. When cement plants produce different types of cement or adjust the production process, the SO in the exhaust gas at the kiln tail is 2 The concentration may vary in a large range, and it is difficult for traditional desulfurization processes to quickly and effectively adjust the desulfurization operating parameters, resulting in unstable desulfurization effects and sometimes SO 2 Excessive emission phenomenon.

[0006] In summary, the existing cement plant desulfurization technology still has the problem of being difficult to simultaneously meet multiple requirements such as efficient desulfurization, low-cost operation, stability and reliability, and adaptability to complex working conditions. Summary of the invention

[0007] In order to solve the above technical problems, the present invention provides a cement hot raw meal desulfurization process and a desulfurization device.

[0008] The technical solution adopted by the present invention is:

[0009] A cement hot raw meal desulfurization process comprises the following steps:

[0010] (1) taking out the high-temperature solid hot raw material from the discharge pipe of the C5-level cyclone;

[0011] (2) mixing the taken-out high-temperature solid hot raw material with the airflow to cool it down once;

[0012] (3) performing gas-solid separation on the hot raw meal mixed with gas and performing secondary cooling using atomized water to obtain low-temperature hot raw meal;

[0013] (4) adding the obtained low-temperature hot raw meal to a digester after metering, and the calcium oxide in the hot raw meal reacts with the digestion water in the digester to generate calcium hydroxide;

[0014] (5) The digested material is transported to the powder silo for temporary storage;

[0015] (6) The material temporarily stored in the powder silo is added into the first air duct from the C2 cyclone separator to the C1 cyclone separator after being measured for desulfurization treatment.

[0016] Furthermore, part of the gas separated from the top of the cyclone separator is transported to step (2) through a circulating fan to be mixed with the high-temperature hot raw material for cooling, and the other part is filtered by a dust collector and discharged from the desulfurization system through a tail exhaust fan.

[0017] Furthermore, the water vapor generated during the digestion reaction is extracted by the digestion fan, filtered through the filter in the digester, and then discharged from the desulfurization system.

[0018] A desulfurization device for any of the above-mentioned cement hot raw meal desulfurization processes, comprising a material taking device, a disperser, a cyclone separator, a circulating fan, a first spiral metering scale, a digester, a first conveying device, a powder silo, a second spiral metering scale and a second conveying device;

[0019] The discharge pipe of the C5-level cyclone is connected to the disperser through the material taking device, and the disperser has a feed port, an air inlet and a discharge port; the feed port of the disperser is connected to the material taking device through a pipeline, the discharge port of the disperser is connected to the cyclone separator through a pipeline, the air outlet at the top of the cyclone separator is connected to the circulating fan through an air duct, and the circulating fan is connected to the air inlet of the disperser through the air duct; the discharge port of the cyclone separator is connected to the digester through the first spiral metering scale, the outlet of the digester is connected to the powder bin through the first conveying device, and the discharge port of the powder bin is connected to the first air duct through the second spiral metering scale and the second conveying device in sequence.

[0020] Furthermore, it also includes a dust collector and a tail exhaust fan, the dust collector inlet is connected to the circulation fan outlet through the air duct, and the tail exhaust fan inlet is connected to the dust collector outlet.

[0021] Furthermore, it also includes a digestion fan, which is connected to the filter outlet in the digester.

[0022] Furthermore, the feeding device includes a three-way feeding pipe and a rotary feeding valve, the inlet of the three-way feeding pipe is connected to the C5-level cyclone discharge pipe, the first outlet of the three-way feeding pipe is connected to the smoke chamber, and the second outlet is connected to the inlet of the rotary feeding valve.

[0023] Furthermore, the disperser includes a straight cylinder with a neck in the middle, a discharge port formed at the top of the straight cylinder, and an air inlet formed at the bottom; a feed pipe is provided at the upper part of the straight cylinder, a feed port is formed at the top of the feed pipe, and a spreading plate is provided on the inner surface of the lower end of the feed pipe, and the spreading plate is radially distributed on the lower side of the inner surface of the feed pipe.

[0024] Furthermore, the cyclone separator is connected to the first spiral metering scale via a double-layer air lock valve.

[0025] Furthermore, a spray gun is arranged in the middle ring of the cyclone separator, and the spray gun is used to spray atomized water into the cyclone separator.

[0026] Beneficial effects of the present invention:

[0027] 1. The material is taken from the C5-level cyclone discharge pipe for cooling, which reduces the heat loss of the system and has little impact on the preheater system.

[0028] 2. The material is dispersed into the circulating air flow for a primary cooling process. The circulating air volume is small and the energy consumption of the dispersed air flow is low.

[0029] 3. The gas-solid mixture is separated and cooled twice using atomized water, making full use of the heat absorption of water's evaporation phase change. Compared with the method of collecting the hot raw material first and then cooling it with cooling water, it can effectively reduce the use of cooling water and greatly reduce the heat load of the circulating cooling water pool, greatly saving energy consumption and reducing the cooling load of the circulating water.

[0030] 4. The digested CaO generates Ca(OH)2， and SO 2 Better reactivity, easier to achieve SO 2 Solidification absorption, high desulfurization efficiency and small amount of desulfurizer used.

[0031] 5. The desulfurization device of the present invention can adapt to SO 2 Under conditions with large concentration fluctuations, the desulfurization effect is stable. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 The present invention discloses a cement hot raw meal desulfurization process flow chart.

[0033] Figure 2 It is a structural diagram of the disperser of the present invention.

[0034] Figure 3 yes Figure 2 BB section view.

[0035] In the figure: 1. three-way feeding pipe; 2. plug-in valve; 3. compressed air ring blowing; 4. rotary feeding valve; 5. disperser; 6. cyclone separator; 7. double-layer air lock valve; 8. first spiral metering scale; 9. digester; 10. screw conveyor; 11. air lock discharger; 12. FU chain conveyor; 13. circulating fan; 14. dust collector; 15. tail exhaust fan; 16. digestion fan; 17. bucket elevator; 18. powder silo; 19. second spiral metering scale; 20. kiln bucket elevator; 51. cylinder; 52. feed pipe; 53. spreading plate; 501. feed port; 502. discharge port; 503. air inlet; 511. upper straight cylinder; 512 necking; 513. lower straight cylinder. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical solution and advantages of the present invention more clear, the technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings and a preferred implementation manner.

[0037] See also Figure 1-Figure 3 The present invention provides a desulfurization device, including a three-way feeding pipe 1, a gate valve 2, a rotary feeding valve 4, a disperser 5, a cyclone separator 6, a first spiral metering scale 8, a digester 9, a screw conveyor 10, a wind-locking feeder 11, an FU chain conveyor 12, a circulating fan 13, a dust collector 14, a tail exhaust fan 15, a digestion fan 16, a bucket elevator 17, a powder bin 18, a second spiral metering scale 19 and a kiln bucket elevator 20.

[0038] The three-way feeding pipe 1, the gate valve 2, and the rotary feeding valve 4 are connected in sequence to form a feeding device. The three-way feeding pipe 1 is installed below the C5-level cyclone discharge pipe. The inlet of the three-way feeding pipe is connected to the C5-level cyclone discharge pipe. The first outlet of the three-way feeding pipe is connected to the smoke chamber, and the second outlet is connected to the inlet of the gate valve 2. The outlet of the gate valve 2 is connected to the inlet of the rotary feeding valve 4. The solid hot raw material in the C5-level cyclone discharge pipe flows into the rotary feeding valve 4 through the three-way feeding pipe 1 under the action of gravity, and the amount of material taken out is controlled by the rotary feeding valve 4. The inlet end of the rotary feeding valve 4 is provided with a compressed air ring blowing 3, which uses compressed air to assist the flow of the material pipe above the rotary feeding valve 4 to promote material flow and avoid blockage.

[0039] The disperser 5 comprises a straight tube 51 with a neck in the middle, that is, the straight tube 51 is composed of an upper straight tube part 511, a middle neck 512 and a lower straight tube part 513, the top of the straight tube forms a discharge port 502, and the bottom forms an air inlet 503; the upper straight tube part 511 is obliquely connected to a feed pipe 52, the top of the feed pipe forms a feed port 501, and a spreading plate 53 is provided on the inner surface of the lower end of the feed pipe, and the spreading plate 53 is radially distributed on the lower side of the inner surface of the feed pipe. The setting of the middle neck 512 can increase the flow rate of the gas, improve the dispersion effect of the hot raw material, and prevent the hot raw material from slipping.

[0040] The feed port 501 of the disperser 5 is connected to the outlet of the rotary feed valve 4 via a pipeline, the discharge port 502 is connected to the feed port of the cyclone separator 6 via a pipeline, and the air outlet at the top of the cyclone separator is connected to the circulation fan 13 via an air duct.

[0041] A spray gun is arranged in the middle of the cyclone separator 6, and the spray gun is used to spray atomized cooling water into the separator.

[0042] The outlet of the circulating fan 13 is divided into two paths, one of which is connected to the disperser 5 to provide dispersed airflow for the disperser 5. The temperature of this airflow is the outlet temperature of the separator, which is much lower than the temperature of the hot raw material, and the gas composition is a mixture of air and water vapor. This airflow has a high flow rate in the disperser 5. When it contacts the hot raw material dispersed by the disperser 6, it can accelerate the hot raw material in a very short time and realize heat exchange at the same time. Due to the efficient dispersion performance of the disperser 5, the amount of gas required by the disperser 5 can be minimized, thereby reducing the power consumption of the circulating fan 13 and reducing the operating energy consumption of the system.

[0043] Another outlet of the circulating fan 13 is connected to the dust collector 14, and the outlet of the dust collector 14 is connected to the tail exhaust fan 15. The tail exhaust fan 15 discharges the gas containing moisture from the desulfurization system as needed. The volume of the gas discharged from the system is the leakage volume of the system and the volume of water vapor generated by the vaporization of the atomized water sprayed by the cyclone separator 6, which can be judged by the pressure balance in the system, that is: a pressure gauge is set at the outlet of the circulating fan 13 for pressure detection. When the outlet pressure of the circulating fan 13 is high, it means that the amount of circulating gas in the system is too large. The frequency of the tail exhaust fan 15 can be increased, and the exhaust volume can be increased until the outlet pressure of the circulating fan 13 reaches the set value; when the outlet pressure of the circulating fan 13 is low, it means that the amount of circulating gas in the system is low. The frequency of the tail exhaust fan 15 can be reduced, and the exhaust volume can be reduced until the outlet pressure of the circulating fan 13 reaches the set value.

[0044] The lower discharge port of the cyclone separator 6 is connected to the double-layer air lock valve 7 through a pipeline, the outlet of the double-layer air lock valve 7 is connected to the first spiral metering scale 8 through a pipeline, the outlet of the first spiral metering scale 8 is connected to the digester 9 through a pipeline, and the digester 9 is provided with a dust collector and a digestion water injection unit, and the dust collector outlet is connected to the digestion fan 16 through an air duct. The digestion water injection unit is used to inject digestion water into the digester.

[0045] The outlet of the digester 9 is connected to the screw conveyor 10 through a pipeline. The outlet of the screw conveyor 10 is provided with an air-locking discharger 11. The air-locking discharger 11 is connected to the FU chain conveyor 12 through a pipeline. The outlet of the FU chain conveyor 12 is connected to the bucket elevator 17. The outlet of the bucket elevator 17 is connected to the powder silo 18. The outlet of the powder silo 18 is connected to the second spiral metering scale 19. The outlet of the second spiral metering scale 19 is connected to the kiln bucket elevator 20 through a pipeline. The outlet of the kiln bucket elevator is connected to the first air duct.

[0046] The screw conveyor 10, the air-locking feeder 11, the FU chain conveyor 12 and the bucket elevator 17 constitute the first conveying device; the kiln bucket elevator 20 serves as the second conveying device.

[0047] The following is an explanation of the hot raw cement meal desulfurization process of the present invention. The desulfurization process is carried out using the above-mentioned desulfurization device and specifically comprises the following steps:

[0048] (1) Using a material taking device to take out the high-temperature solid hot raw material from the C5-level cyclone discharge pipe;

[0049] (2) The high-temperature hot raw material extracted by the material taking device enters the disperser 5 through the feed pipe 52, and enters the airflow entering from the air inlet 503 in a dispersed state under the action of the spreading plate 53, is fully mixed with the airflow and moves with the airflow, and is discharged from the discharge port 502; during the mixing process, the high-temperature hot raw material and the airflow exchange heat, the temperature drops, and a cooling process is completed;

[0050] (3) After the primary cooling, the hot raw meal flows into the cyclone separator 6 at a high speed together with the airflow, and is fully mixed with the atomized cooling water in the cyclone separator 6 and undergoes heat exchange, thereby achieving secondary cooling of the hot raw meal. The cooled hot raw meal is separated from the airflow by the separator and discharged from the discharge port at the bottom of the separator; the atomized water absorbs heat and vaporizes into water vapor, which is discharged from the air outlet at the top of the separator with the gas that has completed the heat exchange, and enters the circulating fan 13;

[0051] The circulating fan 13 conveys part of the gas to step (2) to mix with the high-temperature hot raw material for cooling, and conveys the other part of the gas to the dust collector, where it is filtered and then discharged from the desulfurization system through the tail exhaust fan;

[0052] (4) The hot raw meal discharged from the lower discharge port of the cyclone separator 6 is discharged into the first spiral metering scale 8 through the double-layer air lock valve 7, and then discharged into the digester 9 after being measured in the spiral metering scale 8. The calcium oxide in the hot raw meal fully reacts with the sprayed water to generate calcium hydroxide; the water vapor generated during the reaction is extracted by the digestion fan 16, filtered by the dust collector provided in the digester 9, and then discharged from the desulfurization system; the amount of the sprayed water is quantitatively determined according to the weight of the hot raw meal measured by the spiral metering scale;

[0053] (5) The hot raw material after digestion is fed into the powder silo 18 by the first conveying device for temporary storage;

[0054] (6) The material stored in the powder bin 18 is fed into the raw material feeding hopper at the end of the kiln after being weighed by the second screw feeder 19, that is, the kiln feeding hopper 20. The material is transported to the first air duct C2-C1 together with the raw material in the kiln feeding hopper. Under the action of the high-speed airflow in the air duct, the material is quickly dispersed and fully mixed with the airflow, and the SO in the airflow is 2 The reaction will SO 2 absorb;

[0055] The metering value of the second spiral metering scale 19 is dynamically controlled by the sulfur value detected by the sulfide detection device in the preheater system. When the sulfur value increases, the amount of digested hot raw material fed is increased, and when the sulfur value decreases, the amount of digested hot raw material fed is reduced to keep the sulfur content discharged by the system within the required range.

[0056] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications are also within the protection scope of the present invention.

Claims

1. A cement hot raw meal desulfurization process, characterized in that: The following steps are involved: (1) taking out the high-temperature solid hot raw material from the discharge pipe of the C5-level cyclone; (2) mixing the taken-out high-temperature solid hot raw material with the airflow to cool it down once; (3) performing gas-solid separation on the hot raw meal mixed with gas and performing secondary cooling using atomized water to obtain low-temperature hot raw meal; (4) adding the obtained low-temperature hot raw meal to a digester after metering, and the calcium oxide in the hot raw meal reacts with the digestion water in the digester to generate calcium hydroxide; (5) The digested material is transported to the powder silo for temporary storage; (6) The material temporarily stored in the powder silo is added into the first air duct from the C2 cyclone separator to the C1 cyclone separator after being measured for desulfurization treatment.

2. A cement hot raw meal desulfurization process according to claim 1, characterized in that: A portion of the gas separated from the top of the cyclone separator is transported to step (2) through a circulating fan to be mixed with the high-temperature hot raw material for cooling, and the other portion is filtered by a dust collector and discharged from the desulfurization system through a tail exhaust fan.

3. A cement hot raw meal desulfurization process according to claim 1, characterized in that: The water vapor generated during the digestion reaction is extracted by the digestion fan, filtered through the filter in the digester, and then discharged from the desulfurization system.

4. A desulfurization device for a cement hot raw meal desulfurization process according to any one of claims 1 to 3, characterized in that: It includes a material taking device, a disperser, a cyclone separator, a circulating fan, a first spiral metering scale, a digester, a first conveying device, a powder silo, a second spiral metering scale and a second conveying device; The C5-level cyclone discharge pipe is connected to the disperser through the material taking device, and the disperser has a feed inlet, an air inlet and a discharge port; The feed inlet of the disperser is connected to the material taking device through a pipeline, the discharge port of the disperser is connected to the cyclone separator through a pipeline, the air outlet on the top of the cyclone separator is connected to the circulating fan through an air duct, and the circulating fan is connected to the air inlet of the disperser through the air duct; the discharge port of the cyclone separator is connected to the digester through the first spiral metering scale, the outlet of the digester is connected to the powder bin through the first conveying device, and the discharge port of the powder bin is connected to the first air duct through the second spiral metering scale and the second conveying device in sequence.

5. The desulfurization device according to claim 4, characterized in that: It also includes a dust collector and a tail exhaust fan. The dust collector inlet is connected to the circulation fan outlet through an air duct, and the tail exhaust fan inlet is connected to the dust collector outlet.

6. The desulfurization device according to claim 4, characterized in that: It also includes a digestion fan, which is connected to the filter outlet in the digester.

7. The desulfurization device according to claim 4, characterized in that: The feeding device comprises a three-way feeding pipe and a rotary feeding valve, the inlet of the three-way feeding pipe is connected with the C5-level cyclone discharge pipe, the first outlet of the three-way feeding pipe is connected with the smoke chamber, and the second outlet is connected with the inlet of the rotary feeding valve.

8. The desulfurization device according to claim 4, characterized in that: The disperser includes a straight cylinder with a neck in the middle, a discharge port formed at the top of the straight cylinder, and an air inlet formed at the bottom; a feed pipe is arranged at the upper part of the straight cylinder, a feed port is formed at the top of the feed pipe, and a spreading plate is arranged on the inner surface of the lower end of the feed pipe, and the spreading plate is radially distributed on the lower side of the inner surface of the feed pipe.

9. The desulfurization device according to claim 8, characterized in that: The cyclone separator is connected to the first spiral metering scale through a double-layer air lock valve.

10. The desulfurization device according to claim 4, characterized in that: A spray gun is arranged in the middle ring of the cyclone separator, and the spray gun is used for spraying atomized water into the cyclone separator.

Images