Waste heat recovery device for vacuum flue gas heat exchange

Abstract

The utility model discloses a waste heat recovery device for vacuum flue gas heat exchange, which comprises a vacuum heat exchange chamber, a vacuum cavity is formed between the inner layer and the outer layer of the vacuum heat exchange chamber, the inner wall of the vacuum cavity is coated with a high-radiance coating, and a flue gas channel is arranged in the vacuum heat exchange chamber and is used for increasing the contact time and the contact area of flue gas and a heat exchange surface. A heat exchange medium circulating system is arranged on one side of the vacuum heat exchange chamber, the upper end and the lower end of the flue gas channel penetrate through the vacuum heat exchange chamber and are provided with a gas outlet pipe and a gas inlet pipe, and a flow adjusting valve is arranged on the outer wall of the gas inlet pipe and used for accurately controlling the flue gas flow; the heat exchange efficiency is remarkably improved by utilizing a convection heat exchange mechanism in a vacuum environment and combining a special coating and a spiral flue gas channel design, meanwhile, the existence of the vacuum cavity effectively reduces the loss of heat in a convection mode, the heat loss is greatly reduced, the corrosion and oxidation effects of flue gas on equipment are reduced in the vacuum environment, and the service life of the equipment is prolonged. And the service life of the equipment is prolonged.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of methane oxidizing bacteria culture, specifically to a waste heat recovery device for vacuum flue gas heat exchange. BACKGROUND

[0002] With the rapid development of global economy, energy consumption is increasing, and the problem of energy shortage is becoming increasingly serious. In the industrial production process, a large amount of energy is consumed, and a considerable part of it is lost in the form of waste heat to the environment. According to statistics, waste heat resources in the industrial field account for about 15%-60% of the total fuel consumption, and if these waste heat can be effectively recovered and utilized, it will have important significance for improving energy utilization efficiency, reducing energy consumption and alleviating energy shortage, and improving energy utilization efficiency is also a key measure to realize environmental protection and sustainable development.

[0003] At present, the traditional flue gas waste heat recovery method has many limitations, direct heat exchange has large heat loss and high equipment requirements, indirect heat exchange has low heat transfer efficiency and is easy to accumulate dust and scale, although vacuum technology has advantages in heat exchange field, but in actual application, the construction and maintenance cost is also high, and the structure of the traditional vacuum preheating recovery device is complex, which is not convenient for actual use.

[0004] Therefore, a waste heat recovery device for vacuum flue gas heat exchange is proposed. UTILITY MODEL CONTENT

[0005] The utility model aims at providing a waste heat recovery device for vacuum flue gas heat exchange to solve the problems in the background art.

[0006] To achieve the above purpose, the utility model provides the following technical scheme: a waste heat recovery device for vacuum flue gas heat exchange, comprising a vacuum heat exchange chamber, a vacuum cavity is formed between the inner and outer layers of the vacuum heat exchange chamber, the inner wall of the vacuum cavity is coated with a high emissivity coating, the inside of the vacuum heat exchange chamber is provided with a flue gas passage for increasing the contact time and area of flue gas and heat exchange surface, one side of the vacuum heat exchange chamber is provided with a heat exchange medium circulation system, the upper end and the lower end of the flue gas passage penetrate through the vacuum heat exchange chamber and are provided with an air outlet pipe 6 and an air inlet pipe, the outer wall of the air inlet pipe is provided with a flow regulating valve for accurately controlling the flue gas flow, and the top of the vacuum heat exchange chamber is provided with a vacuum pumping assembly.

[0007] Preferably, the flue gas passage is made of high-temperature-resistant ceramic material, and the flue gas passage is spirally wound in the vacuum heat exchange chamber.

[0008] Preferably, the heat exchange medium circulation system comprises a medium input pipe connected with the inside of the vacuum heat exchange chamber, a liquid inlet pipe is installed at the lower end of the medium input pipe, a circulating pump is arranged on the outer wall of the liquid inlet pipe, a medium storage tank is installed at the other end of the liquid inlet pipe, a circulating pipe is installed at the top of the medium storage tank, a temperature sensor is arranged on the outer wall of the circulating pipe, a medium output pipe is installed at the other end of the circulating pipe, and the lower end of the medium output pipe is connected with the inside of the vacuum heat exchange chamber.

[0009] Preferably, the vacuum pump is installed at the top of the vacuum heat exchange chamber, an output pipe is installed at the input end of the vacuum pump, a vacuum electromagnetic valve is arranged on the outer wall of the output pipe, the other end of the output pipe penetrates through the vacuum heat exchange chamber and extends into the inside of the vacuum heat exchange chamber, and a vacuum gauge is installed on one side of the vacuum heat exchange chamber.

[0010] Preferably, the vacuum degree of the vacuum cavity can be maintained between 0.01-0.1 Pa.

[0011] Preferably, a control box is installed on one side of the vacuum heat exchange chamber, a PLC controller is arranged in the inside of the control box, a sealing door is rotatably installed in the inside of the control box, and a control panel is installed in the inside of the sealing door.

[0012] Preferably, the bottom of the vacuum heat exchange chamber and the medium storage tank are jointly provided with a mounting table, and the mounting table is made of stainless steel.

[0013] Compared with the prior art, the utility model has the advantages that:

[0014] 1. The utility model utilizes the convection heat exchange mechanism in the vacuum environment, combines the special coating and the spiral flue gas passage design, significantly improves the heat exchange efficiency, simultaneously, the existence of the vacuum cavity effectively reduces the heat loss through the convection mode, the heat loss is greatly reduced, secondly, the vacuum environment reduces the corrosion and oxidation effect of the flue gas on the equipment, prolongs the service life of the equipment. BRIEF DESCRIPTION OF DRAWINGS

[0015] Fig. 1 It is the main structure schematic diagram of the utility model;

[0016] Fig. 2 It is the main body cross section structure schematic diagram of the utility model;

[0017] Fig. 3 It is the system control structure schematic diagram of the utility model.

[0018] In the figure: 1, vacuum heat exchange chamber; 2, vacuum cavity; 3, high emissivity coating; 4, flue gas passage; 5, air inlet pipe; 6, air outlet pipe 6; 7, flow regulating valve; 8, medium storage tank; 9, liquid inlet pipe; 10, medium input pipe; 11, circulating pump; 12, medium output pipe; 13, circulating pipe; 14, temperature sensor; 15, vacuum pump; 16, vacuum gauge; 17, output pipe; 18, vacuum electromagnetic valve; 19, control box; 20, PLC controller; 21, sealing door; 22, control panel; 23, mounting table. DETAILED DESCRIPTION

[0019] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0020] Embodiment 1: Please refer to Figs. 1-3 The present application provides a technical solution: a waste heat recovery device for vacuum flue gas heat exchange, comprising a vacuum heat exchange chamber 1, in use, the inner and outer layers of the vacuum heat exchange chamber 1 are welded and assembled with stainless steel plates, and are mounted on the mounting table 23, to ensure the welding quality and have no leakage. The inner wall of the vacuum cavity 2 is uniformly coated with a high emissivity coating 3, the coating thickness is controlled to be between 0.1-0.3mm, and processes such as spraying or sintering are used to ensure firm adhesion of the coating. The flue gas passage 4 is installed to be spirally coiled in the vacuum heat exchange chamber 1, to ensure that there is a proper gap between the flue gas passage 4 and the inner wall of the vacuum heat exchange chamber 1, generally 10-20mm, facilitating heat transfer. The air inlet pipe 5 and the air outlet pipe 6 connected with the flue gas passage 4 are connected with the external flue gas pipeline, the flow regulating valve 7 is installed and adjusted, so that the flue gas flow can be accurately controlled, and the flow regulating range is between 100-1000m³ / h.

[0021] Secondly, install the heat exchange medium circulating system, firmly connect the medium storage tank 8, the liquid inlet pipe 9, the circulating pump 11, the circulating pipe 13 and other components, to ensure no leakage. Install the temperature sensor 14 on the circulating pipe 13, calibrate the measurement accuracy, and the error is not more than ±1℃. Install the vacuum maintenance and monitoring system, connect the vacuum pump 15, the vacuum gauge 16 and the vacuum electromagnetic valve 18, check the air pumping performance of the vacuum pump 15, ensure the measurement accuracy of the vacuum gauge 16, and the action of the vacuum electromagnetic valve 18 is reliable. Install the automatic control system, install the PLC controller 20 in the control box 19, operate or maintain the internal components through the sealing door 21, connect the control lines of various sensors and execution devices, write the control program, and debug the control panel 22, so that it can normally display and operate various parameters.

[0022] Before starting, check whether each part of the device is normal, such as whether the rotation of the circulating pump 11 is flexible, whether the oil level of the vacuum pump 15 is appropriate, whether the opening and closing state of each valve is correct, etc. Set the initial parameters on the control panel 22, such as the target heat exchange temperature, the flue gas flow setting value, the vacuum degree setting value, etc. Then start the vacuum pump 15, and the vacuum degree in the vacuum cavity 2 is extracted to the preset value. Then start the circulating pump 11, so that the heat exchange medium starts to circulate. Open the valve on the flue gas pipeline to let the flue gas enter the flue gas passage 4, and start the waste heat recovery process.

[0023] During operation, the running parameters of the device are observed in real time through the control panel 22, such as if the temperature of the heat exchange medium is too high or too low, the vacuum degree is abnormal, the flue gas flow is unstable, etc. Adjust the corresponding parameters in time, for example, if the temperature of the heat exchange medium is too high, the rotating speed of the circulating pump 11 can be appropriately reduced or the flue gas flow can be increased;

[0024] If the vacuum degree decreases, check whether there is a leakage point, and if necessary, start the vacuum pump 15 to supplement the air extraction through the output pipe 17. Record the running data of the device regularly, including the running time, the change of each parameter, etc. so as to analyze the running performance of the device and carry out maintenance.

[0025] At the same time, the sealing performance of the vacuum heat exchange chamber 1 is checked regularly. Helium mass spectrometry leak detector and other equipment can be used for detection. If leakage is found, it is repaired in time. Every time the device is operated, check whether the high-emissivity coating 3 has peeling or damage phenomenon. If necessary, re-coat the coating. Clean the flue gas passage 4 regularly to prevent dust accumulation and fouling from affecting the heat exchange efficiency. High-pressure gas purging or chemical cleaning method can be used. The cleaning frequency is determined according to the dust content and composition of the flue gas;

[0026] Check the mechanical seal and bearing wear of the circulating pump 11. Regularly maintain the vacuum pump 15, including replacing the vacuum pump 15, checking the pump body seal, etc. Check whether the electrical connection of the automatic control system is loose. Update the PLC controller 20 program regularly to ensure stable operation of the system. Calibrate the temperature sensor 14, vacuum gauge 16 and other sensors regularly to ensure measurement accuracy.

[0027] Working principle: in use, high-temperature flue gas enters from the flue gas passage 4 inlet pipe 5, and flows in the spiral flue gas passage 4 at a stable flow rate under the control of the flow regulating valve 7. Since the vacuum cavity 2 is in a vacuum environment, the flue gas mainly transfers heat to the high-emissivity coating 3 on the inner wall of the vacuum cavity 2 by heat exchange, reduces heat loss through the high-emissivity coating 3, and is discharged from the outlet pipe 6 at a lower temperature. For example, when the flue gas temperature of the inlet pipe 5 is 800 DEG C, the flue gas temperature of the outlet pipe 6 can be reduced to below 200 DEG C after heat exchange;

[0028] After the circulation pump 11 is started, the heat exchange medium is transported from the medium storage tank 8 to the medium input pipe 10 at the bottom of the vacuum heat exchange chamber 1 through the liquid inlet pipe 9, in the vacuum heat exchange chamber 1, the temperature is increased, the heat exchange medium flows back to the medium storage tank 8 through the circulation pipe 13 from the medium output pipe 12, forming a circulation, the temperature sensor 14 monitors the temperature of the outlet pipe 6 of the heat exchange medium in real time and transmits a signal to the PLC controller 20, the PLC controller 20 adjusts the flow of the heat exchange medium by controlling the rotating speed of the circulation pump 11 according to the preset target heat exchange temperature, so as to realize accurate control of the heat exchange temperature, when the target heat exchange temperature is 80 DEG C, if the temperature of the outlet pipe 6 is higher than 80 DEG C, the PLC controller 20 reduces the rotating speed of the circulation pump 11 to reduce the flow of the heat exchange medium, if the temperature of the outlet pipe 6 is lower than 80 DEG C, the rotating speed of the circulation pump 11 is increased to increase the flow of the heat exchange medium;

[0029] The vacuum pump 15 is initially started to extract the gas in the vacuum cavity 2, so that the vacuum degree reaches a preset value such as 0.05Pa, the vacuum gauge 16 monitors the vacuum degree in real time, when the vacuum degree drops below a set lower limit value such as 0.04Pa, the vacuum electromagnetic valve 18 is opened, the vacuum pump 15 is started to extract the gas again, so that the vacuum degree rises to the set value range, when the vacuum degree is higher than a set upper limit value such as 0.06Pa, the vacuum pump 15 stops working, in this way, the stable vacuum environment in the vacuum cavity 2 is ensured, the efficient convection heat exchange is ensured, and the automatic control system coordinates the work of each device according to the sensor signal and the preset program, so that the whole waste heat recovery device is stably operated.

[0030] Although the embodiments of the utility model have been shown and described, it can be understood by those skilled in the art that various changes, modifications, replacements and variations can be made to these embodiments without departing from the principles and spirits of the utility model, the scope of the utility model is defined by the appended claims and their equivalents.

Claims

1. A waste heat recovery device for vacuum flue gas heat exchange, comprising a vacuum heat exchange chamber (1), characterized in that: A vacuum chamber (2) is formed between the inner and outer layers of the vacuum heat exchange chamber (1). The inner wall of the vacuum chamber (2) is coated with a high emissivity coating (3). The interior of the vacuum heat exchange chamber (1) is provided with a flue gas channel (4) to increase the contact time and area between the flue gas and the heat exchange surface. A heat exchange medium circulation system is provided on one side of the vacuum heat exchange chamber (1). The upper and lower ends of the flue gas channel (4) both penetrate the vacuum heat exchange chamber (1) and are equipped with an outlet pipe 6 (6) and an inlet pipe (5). A flow regulating valve (7) is provided on the outer wall of the inlet pipe (5) to precisely control the flue gas flow rate. A vacuum pumping assembly is provided on the top of the vacuum heat exchange chamber (1).

2. The waste heat recovery device for vacuum flue gas heat exchange according to claim 1, characterized in that: The flue gas passage (4) is made of high-temperature resistant ceramic material and is spirally coiled inside the vacuum heat exchange chamber (1).

3. The waste heat recovery device for vacuum flue gas heat exchange according to claim 1, characterized in that: The heat exchange medium circulation system includes a medium input pipe (10) that is connected to the interior of the vacuum heat exchange chamber (1). A liquid inlet pipe (9) is installed at the lower end of the medium input pipe (10). A circulation pump (11) is provided on the outer wall of the liquid inlet pipe (9). A medium storage tank (8) is installed at the other end of the liquid inlet pipe (9). A circulation pipe (13) is installed at the top of the medium storage tank (8). A temperature sensor (14) is provided on the outer wall of the circulation pipe (13). A medium output pipe (12) is installed at the other end of the circulation pipe (13). The lower end of the medium output pipe (12) is connected to the interior of the vacuum heat exchange chamber (1).

4. The waste heat recovery device for vacuum flue gas heat exchange according to claim 1, characterized in that: The vacuum pump assembly includes a vacuum pump (15) installed on the top of the vacuum heat exchange chamber (1). The input end of the vacuum pump (15) is equipped with an output pipe (17). The outer wall of the output pipe (17) is provided with a vacuum solenoid valve (18). The other end of the output pipe (17) passes through the vacuum heat exchange chamber (1) and extends into its interior. A vacuum gauge (16) is installed on one side of the vacuum heat exchange chamber (1).

5. A waste heat recovery device for vacuum flue gas heat exchange according to any one of claims 1-4, characterized in that: The vacuum level of the vacuum chamber (2) can be maintained between 0.01 and 0.1 Pa.

6. The waste heat recovery device for vacuum flue gas heat exchange according to claim 1, characterized in that: A control box (19) is installed on one side of the vacuum heat exchange chamber (1). A PLC controller (20) is installed inside the control box (19). A sealing door (21) is rotatably installed inside the control box (19). A control panel (22) is installed inside the sealing door (21).

7. A waste heat recovery device for vacuum flue gas heat exchange according to claim 3, characterized in that: The vacuum heat exchange chamber (1) and the medium storage tank (8) are both equipped with a mounting platform (23) at their bottoms, which is made of stainless steel.

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