Inlet air heating system for chemical production

Abstract

The utility model belongs to the technical field of chemical industry production, and discloses an air inlet heating system for chemical industry production, which comprises an air inlet preheater, an air inlet heating device and an air outlet heating device, the air heating device is provided with a second air flow channel communicating with the outlet end of the first air flow channel and further provided with a steam flow channel, and air in the second air flow channel can exchange heat with steam in the steam flow channel to be heated; and the outlet end of the steam flow channel is communicated with the air inlet preheater. According to the utility model, steam passes through the steam flow channel of the air heating device and exchanges heat with air for cooling, condensate water with higher temperature is discharged from the outlet end of the steam flow channel, and the outlet end of the steam flow channel is communicated with the inlet air preheater, so that the condensate water with higher temperature can be conveyed to the inlet air preheater for preheating inlet air; the temperature of the air before entering the air heating device is increased, and the use amount of steam needed by the air heating device for heating the air is reduced.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the field of chemical production, concretely relates to a kind of air intake heating system for chemical production. BACKGROUND

[0002] In the polymer production process, the polymer produced needs to be dried in the later stage of the process. The existing drying method is mostly achieved by passing in relatively dry hot air. The source of the hot air is often the air in the production site, which is cleaned and heated to obtain clean and high-temperature drying air. The hot air used for material drying generally needs to reach a temperature range of 130-160℃. In the existing production process, the ambient air in the production site is used as the source of the hot air, which is purified and heated to obtain hot air for drying materials. Specifically, a heat exchanger can be provided at the position of the primary, intermediate and high-efficiency three-stage filter for filtering air. When the air passes through the heat exchanger, it exchanges heat with the medium-pressure steam introduced into the heat exchanger to heat the air to the target temperature range for material drying. Since the initial air temperature is basically ambient temperature, a large amount of medium-pressure steam needs to be consumed to heat it to the target temperature range.

[0003] By increasing the inlet air temperature, the amount of subsequent medium-pressure steam used can be saved. One method of increasing the inlet air temperature is to install a shell-and-tube heat exchanger at the air inlet. Fresh low-pressure steam is used to pass through the shell-and-tube heat exchanger and exchange heat with the incoming atmospheric air to achieve the preheating effect of the fresh air. Then the air with a certain temperature rise is delivered to the primary, intermediate and high-efficiency three-stage filter and exchanges heat with the medium-pressure steam to further increase the temperature, thereby saving the amount of medium-pressure steam used.

[0004] In the above scheme, although the use of medium-pressure steam is reduced, a certain amount of low-pressure steam is additionally consumed. At the primary, intermediate and high-efficiency three-stage filter, the condensate after the medium-pressure steam in the heat exchanger exchanges heat with the air usually has a relatively high temperature, about 90-95℃. The heat in this part of the condensate is not fully utilized and is discharged, resulting in low energy utilization rate and a large amount of energy waste.

[0005] Therefore, the utility model is proposed. UTILITY MODEL CONTENT

[0006] The technical problem to be solved by the utility model is to overcome the shortcomings of the prior art and provide an air intake heating system for chemical production, which can recover the waste heat energy in the steam condensate and reduce energy waste.

[0007] To solve the above technical problems, the basic idea of the technical solution of the utility model is:

[0008] The application discloses an air inlet heating system for chemical production, which comprises:

[0009] an air inlet preheater having a first air flow channel;

[0010] an air heating device having a second air flow channel communicated with an outlet end of the first air flow channel, and further having a steam flow channel;

[0011] an outlet end of the steam flow channel is communicated with the air inlet preheater.

[0012] Further, the first air flow channel has a first air inlet and a first air outlet, and the air inlet preheater further has a heat exchange medium inlet and a heat exchange medium outlet;

[0013] the second air flow channel has a second air inlet and a second air outlet, and the steam flow channel has a steam inlet and a condensed water outlet;

[0014] the first air outlet is communicated with the second air inlet, and the condensed water outlet is communicated with the heat exchange medium inlet.

[0015] Further, the air inlet heating system is provided with a condensed water storage tank for storing condensed water, the condensed water outlet is communicated with the condensed water storage tank, and a water outlet of the condensed water storage tank is communicated with the heat exchange medium inlet through a pipeline provided with a delivery pump for delivering condensed water.

[0016] Further, the condensed water outlet is connected with a first condensed water drain pipe, and the other end of the first condensed water drain pipe is connected with the condensed water storage tank.

[0017] Further, the air inlet heating system is provided with a desalted water heater, and the desalted water heater has:

[0018] a low-pressure steam inlet for receiving external steam;

[0019] a condensed water discharge outlet for discharging condensed water formed after steam is exchanged with desalted water;

[0020] a desalted water inlet for receiving desalted water to be heated;

[0021] a desalted water outlet for discharging heated desalted water;

[0022] the condensed water discharge outlet is communicated with the condensed water storage tank.

[0023] Further, the condensed water storage tank is connected with a backwater pipe for conveying warm backwater and / or steam condensed water to the condensed water storage tank along the backwater pipe.

[0024] Further, an adjustable regulating valve is arranged on the backwater pipe.

[0025] And / or, the condensed water storage tank is provided with a temperature detection device for detecting the temperature of the condensed water stored therein.

[0026] Furthermore, the air intake heating system has a controller electrically connected to the regulating valve and the temperature detection device respectively.

[0027] Furthermore, the heat exchange medium inlet is connected to a three-way structure, and the three-way structure has:

[0028] a first inlet for connecting to an external steam source;

[0029] a second inlet, connected to the condensed water storage tank through a pipeline;

[0030] an outlet connected to the heat exchange medium inlet;

[0031] The first inlet is connected to an external steam source through a steam delivery pipe, and a first control valve is provided on the steam delivery pipe; the second inlet is connected to a condensate delivery pipe connected to the condensate storage tank, and a second control valve is provided on the condensate delivery pipe.

[0032] Furthermore, the heat exchange medium outlet is connected to a third condensed water drain pipe, the other end of which is connected to the condensed water storage tank; the water outlet of the condensed water storage tank is connected to a drain pipe for discharging condensed water;

[0033] The third condensate drain pipe is provided with a third control valve; the air inlet heating system is provided with a waste water pipe, the water inlet end of the waste water pipe is connected to the third condensate drain pipe, and is located between the water inlet end of the third condensate drain pipe and the third control valve, and the water outlet end of the waste water pipe is connected to the discharge pipe;

[0034] The discharge pipe is connected to a condensate delivery pipe that is in communication with the heat exchange medium inlet; a fourth control valve is provided on the discharge pipe, and the fourth control valve is located between the water inlet end of the condensate delivery pipe and the water outlet end of the waste water pipe.

[0035] After adopting the above technical solution, the utility model has the following beneficial effects compared with the prior art.

[0036] In the present invention, the incoming air passes through the air inlet preheater and the air heating device in sequence to achieve a double heating effect. The air heating device heats the air by introducing steam to exchange heat with the air. The condensed water discharged after the steam heat exchange has a higher temperature. This part of the condensed water is transported to the air inlet preheater, and the residual heat in the condensed water is used to preheat the incoming air, thereby increasing the temperature of the air entering the air heating device, and saving the steam usage required for heating the air by the air heating device without increasing additional consumption.

[0037] The condensate storage tank is arranged between the condensate outlet of the air heating device and the heat exchange medium inlet of the air preheater, on the one hand, continuous supply of high-temperature condensate to the air preheater is easily realized, and the preheating effect of the air preheater on air is ensured.

[0038] In the utility model, the air inlet heating system can be formed by reforming on the basis of the existing structure, specifically, the high-temperature condensate in the condensate storage tank is guided to the air preheater by adding pipelines and control valves, the high-temperature condensate exchanges heat with air in the air preheater, and the obtained low-temperature condensate is guided to the original discharge path and directly discharged.

[0039] The specific embodiments of the utility model will be described in further detail below with reference to the drawings. BRIEF DESCRIPTION OF DRAWINGS

[0040] The drawings are part of the utility model and serve to provide further understanding of the utility model, the illustrative embodiments of the utility model and the description thereof serve to explain the utility model, but do not constitute improper limitation on the utility model. Obviously, the drawings described below are only some embodiments, and other drawings can be obtained according to the drawings without creative labor for those skilled in the art. In the drawings,

[0041] Figure 1 It is a structure schematic view of the air inlet heating system in the embodiment one of the utility model;

[0042] Figure 2 It is a structure schematic view of the air inlet heating system in the embodiment one of the utility model;

[0043] Figure 3 It is a structure schematic view of the air inlet heating system in the embodiment two of the utility model.

[0044] In the figure: 100, air preheater; 101, first air inlet; 102, first air outlet; 103, heat exchange medium inlet; 104, heat exchange medium outlet; 200, air heating device; 201, second air inlet; 202, second air outlet; 203, steam inlet; 204, condensate outlet; 300, condensate storage tank; 400, desalted water heater; 401, desalted water inlet; 402, desalted water outlet; 403, low-pressure steam inlet; 404, condensate discharge outlet; 501, first condensate drain pipe; 502, second condensate drain pipe; 503, third condensate drain pipe; 504, backwater pipe; 505, discharge pipe; 506, waste water pipe; 507, condensate conveying pipe; 508, steam conveying pipe; 509, air supply pipe; 601, first control valve; 602, second control valve; 603, third control valve; 604, fourth control valve; 605, fifth control valve; 700, conveying pump.

[0045] It should be noted that the drawings and the written description are not intended to limit the scope of the present application in any way. DETAILED DESCRIPTION

[0046] In order to make the purpose, technical scheme and advantages of the embodiments of the present application more clear, the technical scheme in the embodiments will be described clearly and completely below with reference to the drawings in the embodiments of the present application. The following embodiments are used to illustrate the present application, but not to limit the scope of the present application.

[0047] In the description of the present application, it should be noted that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0048] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connection" should be understood broadly, for example, it can be fixed connection, or detachable connection, or integrally connected; it can be mechanical connection, or electrical connection; it can be directly connected, or indirectly connected through an intermediate medium. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0049] As Figure 2 and Figure 3The embodiment of the utility model provides a kind of air heating system for chemical production.

[0050] As a specific embodiment, the air heating system provided by the embodiment of the utility model is used for polymerization production process, and the heated air is used for drying polymer. The polymer can be polyacrylonitrile, polyamide, polyester, polyethylene, etc.

[0051] In the embodiment of the utility model, the air source of the air heating system is atmospheric air in the production site, which is heated to a certain temperature by the air heating system and then delivered to the drying device for drying polymer. In addition, to prevent dust or other impurities carried in the atmospheric air from polluting the production materials, the air heating system also filters the atmospheric air.

[0052] Figure 1 It is a specific structure of the existing air heating system in the production site, which includes air preheater 100 and air heating device 200 that heat air in sequence. The atmospheric air in the production site first enters the air preheater 100, and is preheated by heat exchange with low-pressure steam introduced into the air preheater 100 to increase the temperature. The preheated air is then heated again by heat exchange with medium-pressure steam introduced into the air heating device 200, and reaches the required target temperature range.

[0053] Specifically, the air preheater 100 is provided with a heat exchange medium inlet 103 and a heat exchange medium outlet 104 connected in communication, and the heat exchange medium inlet 103 is connected with a steam delivery pipe 508. The low-pressure steam outside is delivered to the heat exchange medium inlet 103 of the air preheater 100 along the steam delivery pipe 508 and exchanges heat with the air passing through the air preheater 100. The condensed water formed by the low-pressure steam after heat exchange and cooling is discharged from the heat exchange medium outlet 104.

[0054] The air heating device 200 is provided with a steam inlet 203 and a condensed water outlet 204 connected in communication, and the medium-pressure steam is introduced into the air heating device 200 through the steam inlet 203 and exchanges heat with the passing air, and the condensed water formed after heat exchange is discharged from the condensed water outlet 204.

[0055] The air preheater 100 is provided with a first air inlet 101 and a first air outlet 102 connected in communication, and the air heating device 200 is provided with a second air inlet 201 and a second air outlet 202 connected in communication, and the first air outlet 102 and the second air inlet 201 are connected in communication through an air supply pipe 509. The atmospheric air enters the air preheater 100 through the first air inlet 101, is preheated and discharged from the first air outlet 102, is delivered to the second air inlet 201 of the air heating device 200 along the air supply pipe 509, and is heated again in the air heating device 200 and discharged from the second air outlet 202.

[0056] Furthermore, the air intake heating system further includes a condensate storage tank 300 for storing condensate. The heat exchange medium outlet 104 is connected to a third condensate drain pipe 503, and the condensate outlet 204 is connected to a first condensate drain pipe 501. The third condensate drain pipe 503 and the first condensate drain pipe 501 are each connected to the condensate storage tank 300, and the discharged condensate is sent to the condensate storage tank 300.

[0057] The water outlet of the condensed water storage tank 300 is connected to the discharge pipe 505 , on which a delivery pump 700 is provided. The delivery pump 700 can discharge the condensed water stored in the condensed water storage tank 300 when it is running.

[0058] In the aforementioned inlet air heating system, the inlet air preheater 100 and the air heating device 200 consume large amounts of low-pressure steam and medium-pressure steam, respectively, to heat the inlet air. However, the condensed water that is ultimately discharged still has a relatively high temperature, approximately above 90°C. The heat carried by this condensed water is directly discharged with the condensed water, leaving it unused and resulting in energy waste.

[0059] Example 1

[0060] This embodiment provides an air inlet heating system for chemical production, which is used to solve the problem that the heat in the condensed water is not fully utilized, and can save the amount of steam required for air inlet heating.

[0061] Specifically, if Figure 2 As shown, the air intake heating system in this embodiment includes an air intake preheater 100 and an air heating device 200. The air intake preheater 100 has a first air flow channel, and the air heating device 200 has a second air flow channel, which is connected to the outlet of the first air flow channel. The air heating device 200 also has a steam flow channel, and the air in the second air flow channel can exchange heat with the steam in the steam flow channel to increase its temperature.

[0062] Normal temperature air at the production site enters the first air flow channel of the air inlet preheater 100, is preheated to a certain temperature, and then enters the second air flow channel of the air heating device 200 to further heat up through heat exchange with the steam in the steam flow channel.

[0063] In this embodiment, the outlet end of the steam flow channel is connected to the air inlet preheater 100. The condensed water with a higher temperature discharged from the outlet end of the steam flow channel can be transported to the air inlet preheater 100 to preheat the air passing through the air inlet preheater 100. Without providing an additional heat source, the temperature of the air before entering the air heating device 200 can be increased. Compared with the solution of using the air heater 200 alone to directly heat the incoming air, the amount of steam required for the air heating device 200 to heat the air can be saved. At the same time,Figure 1 Compared with the prior art, the air inlet preheater 100 does not consume low-pressure steam, and the use amount of low-pressure steam is saved.

[0064] In a specific structure of the embodiment, the first air flow channel has a first air inlet 101 and a first air outlet 102, and the air inlet preheater 100 further has a heat exchange medium inlet 103 and a heat exchange medium outlet 104 connected in communication. The second air flow channel has a second air inlet 201 and a second air outlet 202, and the steam flow channel has a steam inlet 203 and a condensed water outlet 204. The first air outlet 102 is in communication with the second air inlet 201, and the condensed water outlet 204 is in communication with the heat exchange medium inlet 103.

[0065] The normal-temperature air in the production site enters the air inlet preheater 100 through the first air inlet 101, exchanges heat with the heat exchange medium flowing from the heat exchange medium inlet 103 to the heat exchange medium outlet 104, and is heated to be discharged from the first air outlet 102. The first air outlet 102 is in communication with the second air inlet 201, and the air preheated by the air inlet preheater 100 is sent into the air heating device 200 for reheating.

[0066] The steam inlet 203 of the air heating device 200 is connected to medium-pressure steam, the air is further heated by absorbing the heat of the medium-pressure steam in the air heating device 200, and is discharged from the second air outlet 202 to be sent to a drying device for drying polymers. The condensed water formed by the condensation of the medium-pressure steam in the steam flow channel of the air heating device 200 is discharged from the condensed water outlet 204, enters the air inlet preheater 100 through the heat exchange medium inlet 103, and serves as the heat exchange medium for exchanging heat with the air in the air inlet preheater 100.

[0067] As a specific embodiment, the air inlet preheater 100 is a tube heat exchanger, which is arranged close to the air inlet of the air inlet heating system.

[0068] In the embodiment, the air needs to be filtered to remove dust and other impurities before being used for drying polymers, so as to avoid contaminating the materials. As a specific embodiment, the air is filtered during the process of being reheated by the air heating device 200.

[0069] As a specific embodiment, the air heating device 200 includes a primary, medium and high efficiency three-stage filter and a heat exchanger. The air passes through the primary, medium and high efficiency three-stage filter, and can be filtered step by step to remove dust and other impurities, so as to ensure the cleanliness of the air outlet. Meanwhile, the air exchanges heat with the medium-pressure steam flowing in the heat exchanger, so as to be heated to the required temperature.

[0070] In this embodiment, the temperature of the medium-pressure steam is reduced to a certain degree after passing through the air heating device 200, and the condensed water is discharged from the condensed water outlet 204. Specifically, the high-temperature condensed water discharged from the condensed water outlet 204 of the air heating device 200 is generally about 90°C, and can even reach a high temperature of about 95°C, and a large amount of heat is carried in the condensed water. The temperature of the incoming air is basically equal to the ambient temperature of the production site, which varies from -30 to 30°C according to the season, which is obviously lower than the temperature of the high-temperature condensed water. Therefore, the high-temperature condensed water discharged from the air heating device 200 is sufficient to preheat the air passing through the air preheater 100.

[0071] The high-temperature condensed water discharged from the air heating device 200 is transported to the air preheater 100 to preheat the incoming air, instead of the low-pressure steam used in the prior art, so that the heat in the high-temperature condensed water is fully utilized, and the production cost is reduced without the need for additional use of low-pressure steam.

[0072] Further, the temperature of the high-temperature condensed water is further reduced after passing through the air preheater 100, and the low-temperature condensed water is discharged from the heat exchange medium outlet 104, which can be directly discharged.

[0073] In a specific structure, the heat exchange medium outlet 104 is connected with a waste water pipe 506, and the low-temperature condensed water discharged from the air preheater 100 is discharged along the waste water pipe 506.

[0074] In a further scheme of the embodiment, the air heating system is provided with a condensed water storage tank 300 for storing the condensed water, and the condensed water outlet 204 is communicated with the heat exchange medium inlet 103 through the condensed water storage tank 300.

[0075] In a specific structure, the condensed water outlet 204 is connected with a first condensed water discharge pipe 501, and the other end of the first condensed water discharge pipe 501 is connected to the condensed water storage tank 300. The water outlet of the condensed water storage tank 300 is communicated with the heat exchange medium inlet 103 through a condensed water conveying pipe 507, and a conveying pump 700 is arranged on the condensed water conveying pipe 507 to convey the condensed water in the condensed water storage tank 300 into the air preheater 100.

[0076] In the above scheme, the high-temperature condensed water discharged from the air heating device 200 is transferred and conveyed into the air preheater 100 from the condensed water storage tank 300, which can ensure the continuous supply of high-temperature condensed water at the air preheater 100, and further ensure the stable air preheating effect.

[0077] In a further aspect, the air inlet heating system is further provided with a desalted water heater 400. In the desalted water heater 400, the cool desalted water is heated by exchanging heat with external steam to form hot desalted water, which can be sent to other devices participating in the polymer production process. After the steam exchanges heat with the cool desalted water in the desalted water heater 400, the temperature of the steam is reduced to form condensed water, which is also high-temperature condensed water with a temperature of about 90°C or higher.

[0078] In a specific aspect, the hot desalted water discharged from the desalted water heater 400 is sent to another heater for secondary heating to reduce the use of low-pressure steam in the desalted water heater 400. The desalted water after secondary heating can be used for cleaning the stripping tower, or used as filter flushing water, spray water, etc.

[0079] In a specific structure, the desalted water heater 400 is provided with a low-pressure steam inlet 403 and a condensed water discharge outlet 404 connected in communication, and a desalted water inlet 401 and a desalted water outlet 402 connected in communication. The desalted water inlet 401 is used to receive cool desalted water to be heated. The cool desalted water enters the desalted water heater 400 from the desalted water inlet 401 and is discharged from the desalted water outlet 402. The low-pressure steam inlet 403 receives external steam to exchange heat with the cool desalted water, thereby heating the cool desalted water to hot desalted water.

[0080] More specifically, the steam entering the desalted water heater 400 is low-pressure steam. The low-pressure steam enters the desalted water heater 400 through the low-pressure steam inlet 403, exchanges heat with the cool desalted water passing through the desalted water heater 400, and forms high-temperature condensed water discharged from the condensed water discharge outlet 404.

[0081] In this embodiment, the condensed water discharge outlet 404 is connected with a second condensed water drain pipe 502, and the other end of the second condensed water drain pipe 502 is connected with the condensed water storage tank 300. In this way, the high-temperature condensed water generated by the desalted water heater 400 also flows into the condensed water storage tank 300, and can be transported to the air inlet preheater 100, so that the heat carried by this part of the condensed water is also fully utilized, further improving the energy utilization rate of the overall production process.

[0082] Further, the condensed water storage tank 300 is also connected with a backwater pipe 504 for transporting warm backwater and / or steam condensed water generated by other devices in the production site to the condensed water storage tank 300. Generally, the warm backwater and steam condensed water is about 90-95°C.

[0083] Specifically, all the warm return water in the production site, and high-temperature condensate water generated by other equipment, especially heat exchange equipment using steam, are respectively collected into the return water pipe 504, and then enter the condensate water storage tank 300 along the return water pipe 504. That is, all the high-temperature water that is no longer used in the production site is sent to the condensate water storage tank 300, so as to be used for heat exchange with air in the air preheater 100 instead of being directly discharged.

[0084] By using the above scheme, all the high-temperature water carrying more heat in the production site is collected and provided to the air preheater 100, so as to fully utilize the waste heat in the water and avoid energy waste. At the same time, more heat can be provided to the air preheater 100, which helps to heat the air to a higher temperature in the air preheater 100, thereby saving the use amount of medium-pressure steam in the subsequent air heating device 200.

[0085] The condensate water storage tank 300 is arranged to facilitate the collection of high-temperature condensate water generated by different equipment in the production site and the delivery of the high-temperature condensate water to the air preheater 100, so as to be more easily controlled. At the same time, the structure of the heat exchange medium inlet 103 of the air preheater 100 can be avoided to be complicated due to the collection of multiple pipes, thereby avoiding the problem of pipe connection.

[0086] In a further scheme of the embodiment, an adjustable regulating valve (not shown in the figure) is arranged on the return water pipe 504, and the flow of the return water pipe 504 into the condensate water storage tank 300 can be adjusted through the regulating valve. The condensate water storage tank 300 is provided with a temperature detection device, such as a temperature sensor, which can detect the temperature of the condensate water stored in the condensate water storage tank 300.

[0087] Furthermore, the air heating system is provided with a controller, and the controller is electrically connected with the temperature detection device and the regulating valve, respectively. Specifically, the controller can receive temperature information fed back by the temperature detection device, and control the opening degree of the regulating valve according to the temperature information.

[0088] In a specific implementation, the required condensate water temperature at the air preheater 100 is a preset temperature T0, and the temperature of the water in the return water pipe 504 is higher than the preset temperature T0. When the temperature information fed back by the temperature detection device is lower than the preset temperature T0, the controller controls the opening degree of the regulating valve to increase, so as to increase the flow in the return water pipe 504. If the temperature information fed back by the temperature detection device is higher than the preset temperature T0, the controller controls the opening degree of the regulating valve to decrease, so as to decrease the flow in the return water pipe 504.

[0089] In another specific embodiment, the temperature of the water in the return water pipe 504 is lower than the preset temperature T0. When the temperature information fed back by the temperature detecting device is lower than the preset temperature T0, the controller controls the opening of the regulating valve to decrease, so as to decrease the flow rate in the return water pipe 504. If the temperature information fed back by the temperature detecting device is higher than the preset temperature T0, the controller controls the opening of the regulating valve to increase, so as to increase the flow rate in the return water pipe 504.

[0090] In the embodiment, the temperature of the condensate water received at the heat exchange medium inlet 103 affects the temperature of the air after the air is preheated by the air preheater 100. In order to ensure that the air heating device 200 has a relatively stable outlet air temperature, so as to ensure the drying effect of the subsequent material drying, the temperature of the preheated air also needs to be kept stable, and thus the temperature of the condensate water entering the air preheater 100 from the heat exchange medium inlet 103 needs to be controlled in a stable range. The temperature of the condensate water in the condensate water storage tank 300 detected by the temperature detecting device is basically the temperature of the condensate water entering the air preheater 100, and thus the temperature of the condensate water in the condensate water storage tank 300 needs to be controlled to be basically stable.

[0091] In the above scheme, the temperature of the water in the first condensate water drain pipe 501, the second condensate water drain pipe 502 and the return water pipe 504 can reach 90-95℃ in general cases, but the temperatures of the water in the three pipes are usually not completely consistent. Once the flow rate of the water in the pipes changes, the temperature of the water finally collected in the condensate water storage tank 300 will fluctuate. By setting the controller, the regulating valve and the temperature detecting device, the flow rate of the water from the return water pipe 504 to the condensate water storage tank 300 can be adjusted according to the real-time temperature of the condensate water in the condensate water storage tank 300, so as to adjust the real-time temperature and ensure that the temperature of the condensate water in the condensate water storage tank 300 is basically stable.

[0092] On the other hand, in the embodiment, the hot air output by the air heating device 200 can be used to dry various polymers, and the drying air temperature required for different types of polymers can be different, that is, the outlet air temperature of the corresponding air heating device 200 is different. It can be understood that when different types of polymers are dried, the required temperature of the condensate water at the air preheater 100 also has certain differences.

[0093] By setting the regulating valve and the temperature detecting device which are electrically connected with the controller, the controller can control the opening of the regulating valve to change according to the current required water temperature and the detected real-time temperature, so as to adjust the real-time temperature of the condensate water in the condensate water storage tank 300 to a temperature matching the material to be dried by using the flow rate change of the water in the return water pipe 504. In this way, the final outlet air temperature at the air heating device 200 can be ensured to match the drying air temperature required by the material to be dried.

[0094] In this embodiment, the condensate outlet 204 of the air heating device 200 is communicated with the heat exchange medium inlet 103 of the air preheater 100, and the high-temperature condensate discharged from the air heating device 200 can be used to replace the low-pressure steam provided to the air preheater 100 in the prior art, so that the residual heat in the condensate is fully utilized. Further, the condensate formed by condensation of the medium-pressure steam and the low-pressure steam in the plurality of heat exchange devices in the production site is collected into the condensate storage tank 300, and then is delivered to the air preheater 100, so that the residual heat in the condensate is fully utilized, the energy utilization rate is improved, and the steam usage of the entire system is saved.

[0095] Embodiment Two

[0096] The embodiment further provides an air inlet heating system for chemical production based on the above-mentioned embodiment one.

[0097] As shown in Figure 3 In this embodiment, the heat exchange medium inlet 103 of the air preheater 100 is connected with a three-way structure, and the three-way structure is communicated with the external low-pressure steam source and the condensate storage tank 300 respectively through the three-way structure.

[0098] Specifically, the three-way structure has a first inlet, a second inlet and an outlet. The first inlet is used to connect with the external low-pressure steam source, the second inlet is communicated with the condensate storage tank 300 through a pipeline, and the outlet is connected to the heat exchange medium inlet 103.

[0099] Further, the first inlet of the three-way structure is connected with the external low-pressure steam source through a steam delivery pipe 508, and a first control valve 601 which can be opened and closed is arranged on the steam delivery pipe 508. The second inlet of the three-way structure is connected with a condensate delivery pipe 507, the condensate delivery pipe 507 is communicated with the condensate storage tank 300, and a second control valve 602 which can be opened and closed is arranged on the condensate delivery pipe 507.

[0100] When the high-temperature condensate in the condensate storage tank 300 is used normally, the first control valve 601 is kept closed, the second control valve 602 is kept open, and the delivery pump 700 is operated to pump the high-temperature condensate to the heat exchange medium inlet 103 of the air preheater 100. When the low-pressure steam needs to be used in a special case, the second control valve 602 can be closed and the first control valve 601 can be opened, so that the low-pressure steam can be provided to the air preheater 100 to preheat the air.

[0101] In a specific scheme of the embodiment, the existing air inlet heating system in the production site as shown in Figure 1 can be modified to obtain the air inlet heating system provided in the embodiment.

[0102] Specifically, a three-way structure is installed between the steam delivery pipe 508 and the heat exchange medium inlet 103, through which the condensate delivery pipe 507 with a second control valve 602 is connected. A first control valve 601 is also installed on the steam delivery pipe 508. The outlet of the condensate storage tank 300 is connected to the discharge pipe 505 with a delivery pump 700. The water inlet of the condensate delivery pipe 507 is connected to the discharge pipe 505, specifically to the downstream area of ​​the delivery pump 700. A fourth control valve 604 is added to the discharge pipe 505 downstream of the water inlet of the condensate delivery pipe 507.

[0103] When the above-described inlet air heating system is operating, the first control valve 601 is closed, and low-pressure steam is no longer supplied to the inlet air preheater 100. The fourth control valve 604 is closed, and the second control valve 602 is opened. At this time, the delivery pump 700 operates, and the high-temperature condensate in the condensate storage tank 300 is delivered to the inlet air preheater 100 along the discharge pipe 505 and the condensate delivery pipe 507, thereby eliminating the waste of heat caused by the high-temperature condensate being directly discharged.

[0104] It is understandable that if some special circumstances occur where the condensed water cannot be used, the second control valve 602 can be closed, and the first control valve 601 and the fourth control valve 604 can be opened. At this time, low-pressure steam can still be used normally to provide heat for the air inlet preheater 100.

[0105] Furthermore, the temperature of the low-pressure steam delivered to the inlet air preheater 100 along the steam delivery pipe 508 is generally between 160°C and 180°C. When high-temperature condensed water is used instead of the original low-pressure steam to provide heat for preheating the inlet air, the heat exchange efficiency in the inlet air preheater 100 decreases because the temperature of the high-temperature condensed water is 90°C to 95°C lower than that of the original low-pressure steam.

[0106] As a specific implementation method, the flow rate of high-temperature condensed water can be controlled to be greater than the flow rate of the original low-pressure steam, so that the temperature of the air after preheating at the air inlet preheater 100 is basically the same as before the modification, thereby achieving the purpose of saving steam usage as a whole.

[0107] As another specific embodiment, the outlet air temperature of the inlet air preheater 100 may not be specifically controlled to remain consistent with that before the modification. In this case, the outlet air temperature of the inlet air preheater 100 may be lower than before the modification, especially in winter when the ambient temperature is high. However, it is understandable that since low-pressure steam is no longer consumed at the inlet air preheater 100, the usage of low-pressure steam is significantly reduced. At the same time, the heat carried by the medium-pressure steam is transferred to the air through two heat exchange processes, thereby achieving a higher heat utilization rate. Therefore, from the perspective of the entire system, as long as the required outlet air temperature of the air heating device 200 remains unchanged, the goal of saving steam usage can still be achieved.

[0108] In a further aspect, the high-temperature condensate is exchanged with the incoming air through the air inlet preheater 100, and the low-temperature condensate formed after the temperature reduction is discharged through the waste water pipe 506.

[0109] As a specific embodiment, the waste water pipe 506 is connected to the pipe structure of the existing air inlet heating system, so that the final discharge path of the condensate can not be changed, the modification to the existing structure is reduced, and the modification cost is reduced.

[0110] Specifically, in the existing structure, the heat exchange medium outlet 104 is connected to the third condensate drain pipe 503, and the other end of the third condensate drain pipe 503 is connected to the condensate storage tank 300. The water outlet of the condensate storage tank 300 is connected to the discharge pipe 505, which leads to the outlet for the final discharge of the condensate in the entire system.

[0111] On the basis of the above, in the present embodiment, a third controllable valve 603 is additionally arranged on the third condensate drain pipe 503, and the water inlet end of the waste water pipe 506 is connected to the third condensate drain pipe 503 between the water inlet end of the third condensate drain pipe 503 and the third controllable valve 603. When the air inlet heating system is working, the third controllable valve 603 is closed, so that the low-temperature condensate discharged from the heat exchange medium outlet 104 can enter the waste water pipe 506 through the third condensate drain pipe 503, and will not enter the condensate storage tank 300.

[0112] The water outlet end of the waste water pipe 506 is connected to the downstream region of the discharge pipe 505, so that the low-temperature condensate is transported to the downstream region of the existing discharge pipe 505, and the condensate is finally discharged from the water outlet end of the discharge pipe 505. In this way, the subsequent pipe structure of the discharge pipe 505 does not need to be modified.

[0113] The fifth controllable valve 605 is arranged on the waste water pipe 506, and in the special case that the air inlet preheater 100 needs to use low-pressure steam, the third controllable valve 603 and the fourth controllable valve 604 can be opened, and the fifth controllable valve 605 is closed. At this time, the condensate discharged from the heat exchange medium outlet 104 can enter the condensate storage tank 300 through the third condensate drain pipe 503, and then be discharged through the discharge pipe 505.

[0114] In the present embodiment, the water inlet end of the condensate delivery pipe 507 is connected to the discharge pipe 505, so that the high-temperature condensate in the condensate storage tank 300 is delivered to the air inlet preheater 100.

[0115] Further, to avoid interference between the delivery of the high-temperature condensate and the discharge of the low-temperature condensate, the water outlet end of the waste water pipe 506 is connected to the discharge pipe 505 on the side away from the water inlet end of the condensate delivery pipe 507.

[0116] In the above scheme, when the air inlet heating system is working, the fourth control valve 604 is closed, and the area of the discharge pipe 505 between the water inlet end of the condensate water delivery pipe 507 and the water outlet end of the waste water pipe 506 is cut off. At the same time, the second control valve 602 and the fifth control valve 605 are opened, and the first control valve 601 and the third control valve 603 are closed. After the delivery pump 700 is started, the high-temperature condensate water in the condensate water storage tank 300 can be sent to the air inlet preheater 100 along the discharge pipe 505 and the condensate water delivery pipe 507. The high-temperature condensate water exchanges heat with the air in the air inlet preheater 100 and becomes low-temperature condensate water, which can enter the downstream area of the discharge pipe 505 along the third condensate water discharge pipe 503 and the waste water pipe 506, and finally be discharged along the discharge pipe 505.

[0117] The air inlet heating system provided by the embodiment can be transformed by adding pipelines and control valves to the existing structure. The delivery of the condensate water utilizes part of the existing pipelines, and the final discharge position of the condensate water is still the water outlet end of the discharge pipe 505. Therefore, the structure that needs to be transformed can be minimized, and the transformation cost can be reduced. After the transformation is completed, the high-temperature condensate water generated by multiple devices in the system can be collected and sent to the air inlet preheater 100 for preheating of the air inlet. The waste heat energy in the high-temperature condensate water is fully utilized, and the use amount of steam is saved.

[0118] The above only describes the preferred embodiments of the present application, and does not limit the present application in any form. Although the preferred embodiments of the present application have been described above, the present application is not limited thereto. Any person skilled in the art can make some changes or modifications to the above-mentioned technical content without departing from the technical solution of the present application, and equivalent embodiments with equivalent changes are obtained. Any simple modification, equivalent change and modification of the above embodiments based on the technical essence of the present application are still within the scope of the present application.

Claims

1. An air inlet heating system for chemical production, characterized by, The application relates to an air preheating system. The air preheating system comprises: an air preheater (100) having a first air flow channel; an air heating device (200) having a second air flow channel communicated with an outlet end of the first air flow channel, and further having a steam flow channel, air in the second air flow channel can be heated by steam in the steam flow channel; 2. The air inlet heating system for chemical production according to claim 1, characterized in that, an outlet end of the steam flow channel is communicated with the air preheater (100). The first air flow channel has a first air inlet (101) and a first air outlet (102), and the air preheater (100) further has a heat exchange medium inlet (103) and a heat exchange medium outlet (104); the second air flow channel has a second air inlet (201) and a second air outlet (202), and the steam flow channel has a steam inlet (203) and a condensed water outlet (204); 3. The air inlet heating system for chemical production according to claim 2, characterized in that, the first air outlet (102) is communicated with the second air inlet (201), and the condensed water outlet (204) is communicated with the heat exchange medium inlet (103).

4. The air inlet heating system for chemical production according to claim 3, characterized in that, The air preheating system is provided with a condensed water storage tank (300) for storing condensed water, the condensed water outlet (204) is communicated with the condensed water storage tank (300), and a water outlet of the condensed water storage tank (300) is communicated with the heat exchange medium inlet (103) through a pipeline, and a conveying pump (700) for conveying condensed water is arranged on the pipeline.

5. The air inlet heating system for chemical production according to claim 3, characterized in that, The condensed water outlet (204) is connected with a first condensed water drain pipe (501), and the other end of the first condensed water drain pipe (501) is connected with the condensed water storage tank (300). The air preheating system is provided with a desalted water heater (400), and the desalted water heater (400) has: a low-pressure steam inlet (403) for receiving external steam; a condensed water discharge outlet (404) for discharging condensed water formed after steam is exchanged with desalted water; a desalted water inlet (401) for receiving desalted water to be heated; a desalted water outlet (402) for discharging heated desalted water; 6. The air inlet heating system for chemical production according to claim 4, characterized in that, the condensed water discharge outlet (404) is communicated with the condensed water storage tank (300).

7. The air inlet heating system for chemical production according to claim 6, characterized in that, The condensed water storage tank (300) is connected with a backwater pipe (504), and warm backwater and / or steam condensed water is conveyed to the condensed water storage tank (300) along the backwater pipe (504). An adjustable regulating valve is arranged on the backwater pipe (504); 8. The air inlet heating system for chemical production according to claim 7, characterized in that, and / or, the condensed water storage tank (300) is provided with a temperature detection device for detecting the temperature of the stored condensed water.

9. The air inlet heating system for chemical production according to claim 3, characterized in that, The air preheating system is provided with a controller electrically connected with the regulating valve and the temperature detection device respectively. The heat exchange medium inlet (103) is connected with a tee structure, and the tee structure has: a first inlet for connecting with an external steam source; a second inlet communicated with the condensed water storage tank (300) through a pipeline; an outlet connected with the heat exchange medium inlet (103). The first inlet is connected with an external steam source through a steam delivery pipe (508) provided with a first control valve (601); the second inlet is connected with a condensate delivery pipe (507) in communication with the condensate storage tank (300), and the condensate delivery pipe (507) is provided with a second control valve (602).

10. The air inlet heating system for chemical production according to any one of claims 3-9, characterized in that, The heat exchange medium outlet (104) is connected with a third condensate drainage pipe (503) having the other end connected with the condensate storage tank (300); the water outlet of the condensate storage tank (300) is connected with a discharge pipe (505) for discharging condensate; The third condensate drainage pipe (503) is provided with a third control valve (603); the air inlet heating system is provided with a waste water pipe (506) having the water inlet end connected on the third condensate drainage pipe (503) between the water inlet end of the third condensate drainage pipe (503) and the third control valve (603), and the water outlet end connected on the discharge pipe (505); The discharge pipe (505) is connected with a condensate delivery pipe (507) in communication with the heat exchange medium inlet (103); the discharge pipe (505) is provided with a fourth control valve (604) between the water inlet end of the condensate delivery pipe (507) and the water outlet end of the waste water pipe (506).

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