Accurate pulverized coal and gas mixing regulation and control device

Abstract

The invention discloses a pulverized coal and gas precise mixing regulation and control device which comprises a pulverized coal bin, an air compressor, a spiral conveyor, a premixing bin and a mixer. A spiral conveyor is connected below the pulverized coal bunker, an outlet is communicated with the premixing bunker, the air compressor is communicated with the premixing bunker through a pipeline, the premixing bunker is connected with the mixer through a feeding pipe, and the mixer is further connected with a ventilation air methane pipeline and a mixed gas pipeline. Pulverized coal is conveyed to the premixing bin through the spiral conveyor, is premixed with compressed air, then is mixed with ventilation air methane in the mixer, and is discharged from a mixed gas pipeline. The device further comprises a control system and a pulverized coal concentration meter, the pulverized coal concentration meter is arranged on the mixed gas pipeline and used for monitoring the pulverized coal concentration and feeding back the pulverized coal concentration to the control system, and the speed of the spiral conveyor is adjusted. Pulverized coal is used for supporting combustion to destroy ventilation air methane, the spiral conveyor accurately measures the pulverized coal, the premixing bin and the mixer improve the mixing uniformity, the control system dynamically adjusts the concentration, and the problem of ultra-low concentration methane oxidation is solved.

Description

Technical Field

[0001] The invention belongs to the technical field of coal mine gas utilization and relates to a device for accurately mixing and controlling coal powder and gas. Background Art

[0002] As an important gas resource associated with coal mining, the rational use and safe treatment of coal mine gas has always been a key topic of concern in the industry. In particular, air-deficient gas (i.e. ultra-low concentration gas), which usually has a methane concentration of less than 0.3%, accounts for an important proportion in my country's coal mining. Due to the extremely low methane content in air-deficient gas, the heat generated by its oxidation reaction under normal conditions is not enough to maintain continuous combustion, resulting in the vast majority of air-deficient gas being unable to be effectively utilized and can only be directly discharged into the atmosphere through the mine ventilation system.

[0003] At present, the treatment technologies for exhaust gas mainly include high-concentration gas mixed combustion and thermal storage oxidation technology. However, the methane concentration of exhaust gas is usually less than 0.3%, which is much lower than the self-heating equilibrium concentration required by traditional thermal storage oxidation technology (generally 0.3%-0.5%). In the absence of sufficient heat support, exhaust gas is difficult to achieve its own sustained and stable oxidation reaction. To make up for this deficiency, diesel is often used as an auxiliary fuel in the existing technology to increase the calorific value of the mixed gas by injecting diesel, thereby achieving the combustion and destruction of exhaust gas. However, this method has significant limitations: first, the use of diesel significantly increases the operating cost, making it difficult to widely promote the destruction of exhaust gas in terms of economy, especially in small and medium-sized coal mines or remote areas; second, diesel combustion itself will produce additional pollutants, such as nitrogen oxides and particulate matter, which is contrary to the current green and low-carbon development concept. In addition, in some mining areas lacking high-concentration gas resources, the scheme of mixed combustion of high-concentration gas and exhaust gas cannot be implemented due to conditions, resulting in the applicability of exhaust gas treatment technology being greatly restricted.

[0004] In recent years, with the increasing demand for comprehensive coal mine gas management, researchers have begun to explore more economical and efficient ventilation gas utilization technologies. For example, some technologies attempt to improve the oxidation efficiency of ventilation gas by adding external heat sources or improving the structure of combustion equipment, but these methods often require complex equipment support, which increases construction and maintenance costs. In addition, there are technologies that propose the use of catalytic oxidation or plasma technology to treat ultra-low concentration gas. Although certain results have been achieved under laboratory conditions, in actual industrial applications, it is difficult to achieve large-scale promotion due to high equipment investment, high energy consumption, and insufficient operational stability. In general, existing technologies generally face the dilemma of balancing economy and efficiency when treating ventilation gas, especially under conditions of extremely low methane concentrations. How to achieve continuous and stable oxidative combustion is still an unresolved problem.

[0005] At the same time, the environmental significance and economic value of ventilation gas treatment are becoming increasingly prominent. If a low-cost, high-efficiency treatment technology can be developed, it will not only reduce greenhouse gas emissions, but also convert ventilation gas into usable heat or electricity, bringing additional economic benefits to coal mining companies. Therefore, in view of the low concentration of methane in ventilation gas and the difficulty of oxidation, it is urgent to develop a technical solution with strong adaptability and stable operation to achieve its economic destruction and resource utilization, and at the same time promote the green transformation of the coal mining industry. Summary of the invention

[0006] In view of this, the purpose of the present invention is to solve the above-mentioned shortcomings and provide a device for precise mixing and controlling of pulverized coal and gas to achieve economical destruction and resource utilization of air-lack gas.

[0007] In order to achieve the above object, the present invention provides the following technical solutions:

[0008] A device for precise mixing and controlling of pulverized coal and gas, comprising a pulverized coal bin, an air compressor, a screw conveyor, a premixing bin, and a mixer;

[0009] The screw conveyor is connected below the pulverized coal bin, the outlet of the screw conveyor is connected to the premixing bin, the outlet of the air compressor is connected to the premixing bin through a pipeline, and the premixing bin is connected to the mixer through a feed pipe; the mixer is also connected to a ventilation gas pipeline and a mixed gas pipeline;

[0010] The pulverized coal in the pulverized coal bin is transported to the premixing bin through a screw conveyor, premixed with compressed air, and then mixed with exhaust gas in the mixer and discharged from the mixed gas pipeline.

[0011] Furthermore, it also includes a control system and a coal powder concentration meter. The coal powder concentration meter is arranged in the mixed gas pipeline to monitor the concentration of the mixed coal powder; the coal powder concentration meter and the screw conveyor are both connected to the control system, and the control system adjusts the conveying speed of the screw conveyor according to the coal powder concentration feedback from the coal powder concentration meter.

[0012] Furthermore, a pressure balance pipe is provided on the pulverized coal bin, one end of the pressure balance pipe is connected to the pulverized coal bin, and the other end is connected to the outlet of the air compressor.

[0013] Furthermore, the pressure balance pipe and the pipeline connecting the air compressor and the premixing bin are both provided with regulating valves.

[0014] Further, the gas pressure in the pressure balance pipe is greater than the gas pressure in the premixing chamber.

[0015] Furthermore, the screw conveyor is provided with a hopper, and the bottom of the pulverized coal bin is connected to the hopper via a regulating valve.

[0016] Furthermore, it is used for the destruction of exhaust gas; the coal powder is transported to the premixing bin by a screw conveyor and premixed with compressed air to form a gas-solid mixture. The gas-solid mixture enters the mixer under the push of compressed air and gravity, and is mixed with exhaust gas in the mixer according to the set ratio. After being evenly mixed, it is transported to the outside for oxidation combustion.

[0017] Furthermore, the control system monitors the concentration of the mixed coal powder through a coal powder concentration meter, and adjusts the conveying speed of the conveyor in real time to control the coal powder concentration to meet the standard.

[0018] The beneficial effects of the present invention are:

[0019] Compared with the prior art, the present invention has significant technical advantages and application value, which are specifically reflected in the following aspects:

[0020] 1. Significant improvement in economy and environmental protection: The present invention uses coal powder as a combustion aid to replace diesel commonly used in traditional technologies, effectively reducing the operating cost of the destruction of air-deficient methane. Coal powder, as a by-product of coal mining, is widely available and inexpensive, and its use cost is greatly reduced compared to diesel. At the same time, the pollutants produced by the combustion of coal powder are easier to handle than diesel, avoiding the additional carbon emissions and volatile organic compound pollution caused by diesel combustion, and meeting the development requirements of green environmental protection. This method not only achieves the economic destruction of air-deficient methane, but also reduces greenhouse gas emissions through resource utilization, providing a new path for the sustainable development of the coal mining industry.

[0021] 2. Breakthrough in accurate metering of coal powder: The present invention realizes the replenishment of coal powder through a screw conveyor, whose screw diameter is small and the speed can be adjusted steplessly, and can accurately control the delivery amount of trace coal powder. Traditional weighing-type coal powder conveying devices often lack accuracy when measuring ultra-low concentration coal powder, and it is difficult to adapt to the dynamic needs of fluctuating methane concentration in exhaust gas. The screw conveyor of the present invention can achieve accurate replenishment of coal powder from several grams to tens of grams per minute by adjusting the speed, ensuring that the coal powder concentration in the mixed gas is always in the optimal range, thereby significantly improving the stability and adaptability of the system.

[0022] 3. Optimization of mixing uniformity: Under the dual effects of the premixing bin and the mixer, the present invention significantly improves the mixing uniformity of coal powder and gas. The premixing bin initially mixes the compressed air and coal powder into a high-concentration gas-solid mixture, which is convenient for pipeline transportation and avoids coal powder sedimentation; the mixer further realizes the full fusion of the gas-solid mixture and the exhaust gas, ensuring that the coal powder particles in the mixed gas are evenly distributed. This uniformity is crucial to the stability of subsequent oxidative combustion, and can effectively avoid the problem of local insufficient combustion or reduced efficiency caused by uneven distribution of coal powder.

[0023] 4. Enhanced dynamic control capability: By setting up a coal powder concentration meter and a control system, the present invention realizes real-time monitoring and dynamic adjustment of coal powder concentration. The coal powder concentration meter can accurately detect the coal powder content in the mixed gas and feed back the data to the control system. The control system adjusts the speed of the screw conveyor in real time according to the feedback results, so that the coal powder supply is synchronized with the fluctuation of the methane content in the exhaust gas. This dynamic control mechanism not only overcomes the problem that the coal powder concentration is difficult to adjust with the gas changes in traditional technology, but also ensures the combustion performance of the mixed gas under different working conditions, significantly improving the operating efficiency and reliability of the device.

[0024] 5. Expansion of application scope: The present invention is particularly suitable for mining areas with scarce high-concentration gas resources. It can independently process exhaust gas with a methane concentration of less than 0.3%, filling the gap in the field of ultra-low concentration gas destruction with traditional technology. At the same time, the device has a compact structure and is easy to operate. It can be flexibly deployed at various coal mine sites and has strong promotion value and application prospects. The continuous and stable oxidation of exhaust gas through coal powder combustion not only reduces resource waste, but also provides an innovative solution for the comprehensive management of coal mine gas in my country.

[0025] Other advantages, objectives and features of the present invention will be described in the following description to some extent, and to some extent, will be obvious to those skilled in the art based on the following examination and study, or can be taught from the practice of the present invention. The objectives and other advantages of the present invention can be realized and obtained through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention will be described in detail below in conjunction with the accompanying drawings, wherein:

[0027] Figure 1 It is a schematic diagram of the precise mixing control device of pulverized coal and gas in the present invention.

[0028] Figure markings: 1-coal powder bin; 2-air compressor; 3-screw conveyor; 4-premixing bin; 5-mixer; 6-coal powder concentration machine; 7-PLC control system; 8-pressure balance pipe; 9-feed pipe; 10-first regulating valve; 11-second regulating valve; 12-third regulating valve; 13-hopper. DETAILED DESCRIPTION

[0029] The following describes the embodiments of the present invention by specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments only illustrate the basic concept of the present invention in a schematic manner, and the following embodiments and features in the embodiments can be combined with each other without conflict.

[0030] Among them, the drawings are only used for illustrative explanations, and they only represent schematic diagrams rather than actual pictures, and should not be understood as limitations on the present invention. In order to better illustrate the embodiments of the present invention, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the size of actual products. For those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted.

[0031] The same or similar numbers in the drawings of the embodiments of the present invention correspond to the same or similar parts; in the description of the present invention, it should be understood that if the terms "upper", "lower", "left", "right", "front", "rear", etc. indicate the orientation or position relationship, they are based on the orientation or position relationship shown in the drawings, which is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, the terms describing the position relationship in the drawings are only used for illustrative purposes and cannot be understood as limiting the present invention. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0032] See also Figure 1 , please refer to Figure 1 , which is a schematic diagram of a precise mixing and control device for pulverized coal and gas, including a pulverized coal bin 1, an air compressor 2, a screw conveyor 3, a premixing bin 4, a mixer 5, a pulverized coal concentration meter 6, a PLC control system 7, a pressure balance pipe 8, a feed pipe 9, a first regulating valve 10, a second regulating valve 11, a third regulating valve 12 and a hopper 13.

[0033] A screw conveyor 3 is connected below the pulverized coal bin 1, and the outlet of the screw conveyor 3 is connected to the premixing bin 4. The outlet of the air compressor 2 is connected to the premixing bin 4 through a pipeline, and the premixing bin 4 is connected to the mixer 5 through a feed pipe 9; the mixer 5 is also connected to a fatigue gas pipeline and a mixed gas pipeline; the pulverized coal in the pulverized coal bin 1 is transported to the premixing bin 4 through the screw conveyor 3, and after being premixed with compressed air, it is mixed with the fatigue gas in the mixer 5 and discharged from the mixed gas pipeline.

[0034] The coal powder concentration meter 6 is installed in the mixed gas pipeline to monitor the concentration of the mixed coal powder; the coal powder concentration meter 6 and the screw conveyor 3 are both electrically connected to the PLC control system 7, and the PLC control system 7 adjusts the conveying speed of the screw conveyor 3 according to the coal powder concentration fed back by the coal powder concentration meter 6. A pressure balance pipe 8 is installed on the coal powder bin 1, one end of the pressure balance pipe 8 is connected to the coal powder bin 1, and the other end is connected to the outlet end of the air compressor 2. The pressure balance pipe 8 and the pipeline connecting the air compressor 2 and the premixing bin 4 are respectively provided with a first regulating valve 10 and a second regulating valve 11. The PLC control system 7 can control the air flow and pressure of the first regulating valve and the second regulating valve, so that the gas pressure in the pressure balance pipe 8 is greater than the gas pressure in the premixing bin 4, so that the coal powder can enter the premixing bin smoothly and prevent the coal powder from being blown back to the coal powder bin by air. A hopper 13 is provided on the screw conveyor 3, and the bottom of the coal powder bin 1 is connected to the hopper 13 through a third regulating valve 12.

[0035] The device is used for the destruction of exhaust gas; the coal powder is transported to the premixing bin 4 by the screw conveyor 3 to be premixed with compressed air to form a gas-solid mixture. The gas-solid mixture enters the mixer 5 under the push of compressed air and gravity, and is mixed with exhaust gas in the mixer 5 according to the set ratio. After being evenly mixed, it is transported to the outside for oxidation combustion. The PLC control system 7 monitors the concentration of the mixed coal powder through the coal powder concentration meter 6, and adjusts the conveying speed of the screw conveyor 3 in real time. If the coal powder concentration is too high, the PLC control system 7 reduces the speed of the speed regulating motor to reduce the coal powder entering the premixing bin. On the contrary, the speed of the speed regulating motor is increased to control the coal powder concentration to meet the standard.

[0036] Example 1

[0037] In this embodiment, the coal powder and gas precise mixing control device is used to treat the ventilation gas with a methane concentration of 0.25%. The specific operating parameters are as follows:

[0038] Device startup: Start the air compressor 2, set its output pressure to 0.2MPa, and the compressed air enters the coal powder bin 1 through the first regulating valve 10, with the air flow rate controlled at 50L / min. At the same time, the compressed air is delivered to the premixing bin 4 through the second regulating valve 11, with a flow rate of 30L / min. The coal powder bin 1 is loaded with coal powder with a particle size of 50-100μm, and the first regulating valve 10 and the third regulating valve 12 are coordinated to adjust the coal powder to enter the hopper 13 at a rate of 8000g / h under the action of gravity and air pressure.

[0039] Coal powder conveying and premixing: After the hopper 13 receives the coal powder, the screw conveyor 3 uses a screw with a diameter of 20mm and an initial speed of 50rpm to continuously squeeze the coal powder into the premixing bin 4 through the rotation of the screw. In the premixing bin 4, the coal powder is initially mixed with compressed air to form a concentration of about 10g / m 3The gas-solid mixture enters the mixer 5 through the feed pipe 9 under the push of compressed air.

[0040] Mixing and regulation: spiral blades are set in the mixer 5, and the exhaust gas is mixed with 1000m 3 The flow rate of / h enters the mixer 5 through the exhaust gas pipeline and mixes with the gas-solid mixture. The mixed gas is discharged through the mixed gas pipeline. The coal powder concentration meter 6 detects the coal powder concentration in the mixed gas in real time. The target concentration is set to 8g / m 3 If the detected concentration is higher than the set value, the PLC control system 7 reduces the speed of the screw conveyor 3 to 40 rpm; if it is lower than the set value, it is increased to 60 rpm.

[0041] Operation results: After testing, the coal powder concentration in the mixed gas stabilized at 8±0.5g / m after the device was operated for 30 minutes. 3 After being transported to the external oxidation furnace, it can achieve continuous and stable combustion, the exhaust gas destruction rate is over 98%, and the operating cost is reduced by about 35% compared with diesel combustion.

[0042] Example 2

[0043] In this embodiment, the device is used to treat ventilation gas with a methane concentration fluctuating between 0.15% and 0.3%, and the operating parameters are dynamically adjusted as follows:

[0044] Device startup: the output pressure of the air compressor 2 is 0.25 MPa, the first regulating valve 10 adjusts the air flow rate to 60 L / min to enter the coal powder bin 1, and the second regulating valve 11 adjusts the flow rate to 40 L / min to enter the premixing bin 4. The coal powder bin 1 is loaded with coal powder with a particle size of 30 to 80 μm, the initial opening of the third regulating valve 12 is 50%, and the coal powder enters the hopper 13 at a rate of 8000 g / h.

[0045] Coal powder conveying and premixing: After the hopper 13 receives the coal powder, the screw conveyor 3 has a screw diameter of 25mm and an initial speed of 60rpm, and conveys the coal powder to the premixing bin 4. The concentration in the premixing bin 4 is about 12g / m 3 The gas-solid mixture enters the mixer 5 through the feed pipe 9. The pressure balance pipe 8 maintains the pressure in the coal powder bin 1 at 0.22MPa, which is higher than the 0.18MPa of the premixing bin 4 to prevent the gas-solid mixture from flowing back.

[0046] Mixing and regulation: the flow rate of exhaust gas is 1000m 3 / h. The coal powder concentration meter 6 monitors the concentration of the mixed gas, and the target value is 10g / m 3The PLC control system 7 dynamically adjusts the speed of the screw conveyor 3 according to the fluctuation of the methane concentration in the exhaust gas (provided by an external sensor): when the methane concentration drops to 0.15%, the speed drops to 50rpm; when it rises to 0.3%, the speed rises to 70rpm. At the same time, the first regulating valve 10 and the second regulating valve 11 fine-tune the air flow according to the pressure feedback to keep the system stable.

[0047] Operation results: After the device was operated for 1 hour, the concentration of coal powder in the mixed gas was stabilized at 10±0.6g / m 3 It has a strong ability to adapt to fluctuations in methane concentration, the destruction rate of exhaust gas reaches 99%, and the operating energy consumption is reduced by about 20% compared with traditional thermal storage oxidation technology.

[0048] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution, which should be included in the scope of the claims of the present invention.

Claims

1. A device for precise mixing and controlling of pulverized coal and gas, characterized in that: It includes coal powder bin, air compressor, screw conveyor, premixing bin and mixer; The screw conveyor is connected below the pulverized coal bin, the outlet of the screw conveyor is connected to the premixing bin, the outlet of the air compressor is connected to the premixing bin through a pipeline, and the premixing bin is connected to the mixer through a feed pipe; the mixer is also connected to a ventilation gas pipeline and a mixed gas pipeline; The pulverized coal in the pulverized coal bin is transported to the premixing bin through a screw conveyor, premixed with compressed air, and then mixed with exhaust gas in the mixer and discharged from the mixed gas pipeline.

2. The device for precise mixing and controlling of pulverized coal and gas according to claim 1, characterized in that: It also includes a control system and a coal powder concentration meter. The coal powder concentration meter is arranged in the mixed gas pipeline and is used to monitor the concentration of the mixed coal powder. The coal powder concentration meter and the screw conveyor are both connected to the control system. The control system adjusts the conveying speed of the screw conveyor according to the coal powder concentration fed back by the coal powder concentration meter.

3. The device for precise mixing and controlling of pulverized coal and gas according to claim 1 is characterized in that: The pulverized coal bin is also provided with a pressure balance pipe, one end of the pressure balance pipe is connected to the pulverized coal bin, and the other end is connected to the outlet end of the air compressor.

4. The device for precise mixing and controlling of pulverized coal and gas according to claim 3 is characterized in that: The pressure balance pipe and the pipeline connecting the air compressor and the premixing bin are both provided with regulating valves.

5. The device for precise mixing and controlling of pulverized coal and gas according to claim 4 is characterized in that: The gas pressure in the pressure balance pipe is greater than the gas pressure in the premixing chamber.

6. The device for precise mixing and controlling of pulverized coal and gas according to claim 1, characterized in that: The screw conveyor is provided with a hopper, and the bottom of the pulverized coal bin is connected to the hopper via a regulating valve.

7. The device for precise mixing and controlling of pulverized coal and gas according to claim 1 is characterized in that: Used for the destruction of exhaust gas; coal powder is transported to the premixing bin through a screw conveyor and premixed with compressed air to form a gas-solid mixture. The gas-solid mixture enters the mixer under the push of compressed air and gravity, and is mixed with exhaust gas in the mixer according to the set ratio. After being evenly mixed, it is transported to the outside for oxidation combustion.

8. The device for precise mixing and controlling of pulverized coal and gas according to claim 7 is characterized in that: The control system monitors the concentration of the mixed coal powder through a coal powder concentration meter and adjusts the conveying speed of the conveyor in real time to control the coal powder concentration to meet the standard.

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