A heat exchange system and method based on hot air energy recovery

Abstract

The present application relates to hot air energy recovery technical field, especially based on a kind of heat exchange system and method of hot air energy recovery, comprising, heat exchanger;First heat exchange passage, to receive heated gas, the inlet end of first heat exchange passage is provided with first inlet to receive heated gas, the outlet end of first heat exchange passage is provided with first outlet to discharge low-temperature gas after heat exchange;Second heat exchange passage, to provide preheating space for regeneration gas, the inlet end of second heat exchange passage is provided with second inlet to receive the regeneration gas to be preheated, and the outlet end of second heat exchange passage is provided with second outlet to discharge the preheated regeneration gas;Wherein, heat exchanger carries out heat exchange between the heated gas input by first heat exchange passage and the regeneration gas input by second heat exchange passage.The present application avoids impurity suction by using clean process regeneration gas, and reduces heating energy consumption by preheating regeneration gas.

Description

Technical Field

[0001] This invention relates to the field of hot air energy recovery technology, and in particular to a heat exchange system and method based on hot air energy recovery. Background Technology

[0002] During high-temperature regeneration of the distillation column, an electric heater is used to directly heat the ambient-temperature regeneration gas. In the initial heating phase, due to the low temperature of the regeneration gas, the electric heater's startup power is excessive, easily leading to overcurrent and fuse blowout, impacting the power grid and equipment. Throughout the heating period, the electric heater needs to operate at high power continuously, resulting in high electricity consumption. The expander uses a blower brake, directly drawing in dusty air, causing rapid clogging and severe wear of the air filter, requiring frequent replacement. The hot air generated after braking is directly exhausted, resulting in heat waste and low system thermal efficiency. Existing heat exchange systems lack adaptability to different regeneration conditions. If the regeneration gas is still preheated by the heat exchanger during the cold blowing phase, it affects the cooling effect of the molecular sieve bed, reducing regeneration efficiency. Therefore, there is an urgent need for a heat exchanger and its control method that can switch heat exchange paths according to regeneration conditions and achieve efficient hot air energy recovery. Summary of the Invention

[0003] In this section, as well as in the abstract and title of this application, some simplifications or omissions may be made to avoid obscuring the purpose of this section, the abstract, and the title of this application, and such simplifications or omissions shall not be used to limit the scope of the invention.

[0004] To address the shortcomings of existing technologies, one objective of this invention is to provide a heat exchange system and method based on hot air energy recovery.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: a heat exchange system based on hot air energy recovery, comprising: a heat exchanger for preheating regeneration gas; a first heat exchange channel connected to the heat exchanger for receiving heated gas, wherein the inlet end of the first heat exchange channel is provided with a first inlet for receiving heated gas, and the outlet end of the first heat exchange channel is provided with a first outlet for discharging low-temperature gas after heat exchange; and a second heat exchange channel connected to the heat exchanger for providing preheating space for the regeneration gas, wherein the inlet end of the second heat exchange channel is provided with a second inlet for receiving regeneration gas to be preheated, and the outlet end of the second heat exchange channel is provided with a second outlet for discharging preheated regeneration gas; wherein the heat exchanger exchanges heat between the heated gas input into the first heat exchange channel and the regeneration gas input into the second heat exchange channel.

[0006] As a preferred embodiment of the heat exchange system based on hot air energy recovery according to the present invention, it further includes: a regeneration gas pipeline assembly connected to the second heat exchange channel for providing clean process gas as regeneration gas to the second heat exchange channel; and an expander connected to the first heat exchange channel for providing heating gas to the first heat exchange channel.

[0007] As a preferred embodiment of the heat exchange system based on hot air energy recovery described in this invention, the regenerated gas pipeline assembly includes: a regenerated gas heating pipeline connected to the expander, used to introduce the output regenerated gas into the expander to do work and then discharge heated gas; and a regenerated gas preheating pipeline connected to the second heat exchange channel, used to transport the output ambient temperature regenerated gas to the second heat exchange channel.

[0008] As a preferred embodiment of the heat exchange system based on hot air energy recovery according to the present invention, the expander includes: an inlet valve connected to the regenerated gas heating pipeline for introducing regenerated gas as a braking gas source; an outlet valve connected to the first inlet for controlling the opening and closing of the heating gas of the expander into the first heat exchange channel; and an atmospheric inlet connected to the expander for introducing atmospheric air as a supplementary gas source for the expander.

[0009] As a preferred embodiment of the heat exchange system based on hot air energy recovery according to the present invention, it further includes: a first shut-off valve connected to the second inlet for controlling the on / off flow of regenerated gas into the heat exchanger; a heater connected to the second outlet for supplementing heating of the preheated regenerated gas; a bypass pipeline connected at both ends to the regenerated gas preheating pipeline and the heater, respectively; and a second shut-off valve connected to the bypass pipeline for controlling the on / off flow of ambient temperature regenerated gas through the bypass pipeline.

[0010] As a preferred embodiment of the heat exchange system based on hot air energy recovery according to the present invention, it further includes: a control mechanism, which is connected to the first shut-off valve and the second shut-off valve respectively. The control mechanism controls the opening of the first shut-off valve and the closing of the second shut-off valve under a heating command, so that the regenerated gas enters the heat exchanger through the second heat exchange channel for preheating; and controls the closing of the first shut-off valve and the opening of the second shut-off valve under a cold blowing command, so that the regenerated gas is transported to the heater through the bypass pipeline.

[0011] As a preferred embodiment of the heat exchange system based on hot air energy recovery described in this invention, the outlet end of the first heat exchange channel is provided with a silencing element for silencing the heated gas after heat exchange before it is discharged.

[0012] As a preferred embodiment of the heat exchange system based on hot air energy recovery described in this invention, an inlet filter for filtering the regenerated gas is provided between the regenerated gas heating pipeline and the expander.

[0013] As a preferred embodiment of the heat exchange system based on hot air energy recovery described in this invention, the gas flow directions in the first heat exchange channel and the second heat exchange channel of the heat exchanger are countercurrent.

[0014] The beneficial effects of the heat exchange system based on hot air energy recovery of the present invention are as follows: By coordinating the regeneration gas pipeline assembly, expander, and heat exchanger, the brake gas source can be changed from dusty atmospheric air to clean process gas, fundamentally eliminating the intake of dust and impurities and solving the problem of filter wear. At the same time, the waste heat generated by braking is used to preheat the main regeneration gas, realizing internal energy recovery. The heater only needs to provide supplementary heat to reach the temperature required for regeneration, and its starting current and operating power are significantly reduced. This solves the technical problems of large inrush current and continuous high-power operation of electric heating furnaces, making the system a high-efficiency, low-consumption closed-loop energy recovery system, which facilitates the long-term stable operation of the air separation unit. By switching the regeneration gas delivery path, the waste heat generated by the expander braking is fully recovered in the heating stage to preheat the regeneration gas, and the bypass pipeline is quickly switched to deliver room temperature regeneration gas in the cold blowing stage. This realizes the adaptability and switching between the heating regeneration process and the cold blowing process, improving energy utilization efficiency and operational stability.

[0015] To address the shortcomings of existing technologies, another objective of this invention is to provide a heat exchange method based on hot air energy recovery.

[0016] To achieve the above objectives, the present invention adopts the following technical solution: a heat exchange method based on hot air energy recovery, employing the aforementioned heat exchange system based on hot air energy recovery, and operating according to the following steps: heating regenerated gas using an expander to form heated gas; introducing the heated gas into a first heat exchange channel; introducing the regenerated gas into a second heat exchange channel or a bypass pipeline; exchanging heat between the heated gas in the first heat exchange channel and the regenerated gas in the second heat exchange channel to preheat the regenerated gas in the second heat exchange channel; introducing the preheated regenerated gas into a heater for supplementary heating; under a heating command, opening the second heat exchange channel and closing the bypass pipeline; the regenerated gas preheated through the second heat exchange channel entering the heater for supplementary heating to a set temperature; under a cold blowing command, closing the second heat exchange channel and opening the bypass pipeline; venting the heated gas that has undergone heat exchange in the first heat exchange channel.

[0017] The beneficial effects of the heat exchange method based on hot air energy recovery of the present invention are the same as those of the heat exchange system based on hot air energy recovery, and will not be repeated here. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the connection structure of the heat exchanger, the first heat exchange channel, and the second heat exchange channel in the heat exchange system based on hot air energy recovery according to the present invention.

[0020] Figure 2 This is a schematic diagram of the expander, regeneration gas pipeline assembly, and heat exchanger connection structure of the heat exchange system based on hot air energy recovery according to the present invention.

[0021] Figure 3 This is a schematic diagram of the overall structure of the heat exchange system based on hot air energy recovery according to the present invention.

[0022] Figure 4 This is a schematic diagram of the connection structure of the control mechanism of the heat exchange system based on hot air energy recovery according to the present invention.

[0023] Explanation of reference numerals in the attached drawings: 100, expander; 101, inlet valve; 102, outlet valve; 103, atmospheric inlet; 200, regenerated gas pipeline assembly; 201, regenerated gas heating pipeline; 202, regenerated gas preheating pipeline; 300, heat exchanger; 301, first heat exchange channel; 301-1, first inlet; 301-2, first outlet; 302, second heat exchange channel; 302-1, second inlet; 302-2, second outlet; 400, first shut-off valve; 500, second shut-off valve; 600, bypass pipeline; 700, heater; 800, distillation column; 900, silencer element; 1000, inlet filter; 1100, temperature sensor; 1200, control mechanism. Detailed Implementation

[0024] To make the objectives, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0025] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0026] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0027] Example 1

[0028] Reference Figure 1 This is the first embodiment of the present invention. This embodiment provides a hot air energy recovery system for an expander 100, which can realize the effect of recovering the hot air energy discharged from the expander 100 for preheating regeneration gas. It includes: a heat exchanger 300, a first heat exchange channel 301, and a second heat exchange channel.

[0029] Specifically, the system includes a heat exchanger 300 for preheating the regeneration gas; a first heat exchange channel 301 connected to the heat exchanger 300 for receiving heated gas, with a first inlet 301-1 at the inlet end for receiving heated gas and a first outlet 301-2 at the outlet end for discharging the cooled gas after heat exchange; and a second heat exchange channel 302 connected to the heat exchanger 300 for providing preheating space for the regeneration gas, with a second inlet 302-1 at the inlet end for receiving the regeneration gas to be preheated and a second outlet 302-2 at the outlet end for discharging the preheated regeneration gas; wherein the heat exchanger 300 exchanges heat between the heated gas input into the first heat exchange channel 301 and the regeneration gas input into the second heat exchange channel 302.

[0030] Working principle: Heating gas enters the first heat exchange channel 301 through the first inlet 301-1, and regeneration gas enters the second heat exchange channel 302 through the second inlet 302-1. The media on both sides exchange heat in the heat exchanger 300. The room temperature regeneration gas is preheated and discharged from the second outlet 302-2, and enters the downstream electric heater for supplementary heating. The low temperature gas after heat exchange is discharged from the first outlet 301-2.

[0031] In summary, by setting up heat exchanger 300, first heat exchange channel 301 and second heat exchange channel 302, the waste heat generated by the braking of expander 100 can be recovered and used to preheat regeneration gas, thus realizing the internal recovery and utilization of energy.

[0032] Specifically, heat exchanger 300 adopts a plate heat exchanger with a heat exchange area of ​​45-60 m² and a hot end exhaust temperature of 369 K (96 °C is selected). The medium in the first heat exchange channel 301 and the second heat exchange channel 302 is the same clean regeneration gas. Since the regeneration gas pipeline assembly 200 receives the clean process gas discharged from the distillation column 800, the problem of dust and impurities being drawn into the expander 100 is reduced, and the problem of filter wear is solved. Since the medium on both sides is the same clean regeneration gas, the risk of contamination in heat exchanger 300 is eliminated.

[0033] This embodiment provides measured data. The measured conditions include: a rated regeneration gas flow rate of 1150 Nm³ / h for distillation column 800, and a silane impurity content of 0.32% vol in the regeneration gas feedstock; a brake gas source flow rate of 372 Nm³ / h and a pressure of 0.15 MPa (G) for expander 100; an ambient temperature of 25°C; and an annual operating time of 8000 hours for the hot air energy recovery system of expander 100. Without the hot air energy recovery system of expander 100, the average hourly heating power consumption is 35 kWh. With an average hourly heating power consumption of 45.3 kWh / h and a total hourly power consumption of 27.55 kWh / h, the average hourly heating power consumption of the expander 100 with and without the hot air energy recovery system is 19.95 kWh / h, and the total hourly power consumption is 27.55 kWh / h. Therefore, the annual savings corresponding to the average hourly heating power consumption with and without the expander 100 with the hot air energy recovery system is 122,800 kWh / year, and the annual savings corresponding to the total hourly power consumption is 142,000 kWh / year.

[0034] Example 2

[0035] Reference Figure 2 This is the second embodiment of the present invention. Unlike the previous embodiment, this embodiment provides a distillation column 800 connection structure, which solves the problem of the cleanliness of the regeneration gas source.

[0036] Specifically, it also includes a regeneration gas pipeline assembly 200, which is connected to the second heat exchange channel 302 to provide clean process gas as regeneration gas to the second heat exchange channel 302; and an expander 100, which is connected to the first heat exchange channel 301 to provide heating gas to the first heat exchange channel 301.

[0037] Specifically, the inlet end of the regenerated gas pipeline assembly 200 is connected to the distillation column 800.

[0038] Specifically, the regenerated gas pipeline assembly 200 includes a regenerated gas heating pipeline 201, which is connected to the expander 100 and is used to introduce the output regenerated gas into the expander 100 to do work and then discharge heated gas; and a regenerated gas preheating pipeline 202, which is connected to the second heat exchange channel 302 and is used to transport the output room temperature regenerated gas to the second heat exchange channel 302.

[0039] Specifically, a temperature sensor 1100 is installed on the regenerated gas heating pipeline 201 and the regenerated gas preheating pipeline 202 respectively to detect the temperature of the output regenerated gas.

[0040] Furthermore, the regeneration gas heating pipeline 201 draws a stream of clean regeneration gas from the main regeneration gas pipeline of the distillation column 800, with a gas source flow rate of 372 Nm³ / h and a gas source pressure of approximately 0.15 MPa. The regeneration gas in the regeneration gas heating pipeline 201 is pressurized and heated by the expander 100 brake fan to form a heated gas at 80~120℃. The regeneration gas preheating pipeline 202 draws another stream of ambient temperature regeneration gas from the main regeneration gas pipeline of the distillation column 800. The ambient temperature regeneration gas has a temperature below 40℃ and a flow rate of 1000~1300 Nm³ / h. The ambient temperature regeneration gas enters the second heat exchange channel 302 of the heat exchanger 300 as a cold side medium.

[0041] Specifically, the expander 100 adopts a blower braking method, which drives the brake blower through the brake air source. The gas after braking rises in temperature due to the work done, forming heated gas with a temperature range of 80~120℃.

[0042] Furthermore, the regenerated gas pipeline assembly 200 delivers a clean source of regenerated gas for supplying regenerated gas to the expander 100 and the heat exchanger 300, respectively.

[0043] The rest of the structure is the same as in Example 1.

[0044] Working principle: The regenerated gas discharged from the distillation column 800 enters the regenerated gas pipeline assembly 200. The regenerated gas is divided into two paths within the regenerated gas pipeline assembly 200. One path is transported to the expander 100 through the regenerated gas heating pipeline 201, where it is introduced as a braking gas source to perform work. After the temperature rises, it becomes heated gas and enters the first heat exchange channel 301 of the heat exchanger 300. The other path is transported to the second heat exchange channel 302 of the heat exchanger 300 through the regenerated gas preheating pipeline, where it serves as the gas to be preheated. Within the heat exchanger 300, the heated gas in the first heat exchange channel 301 exchanges heat with the room temperature regenerated gas in the second heat exchange channel 302 to preheat the regenerated gas. The preheated regenerated gas is discharged from the second heat exchange channel 302 and enters the subsequent heating process.

[0045] In summary, by setting up regenerated gas heating pipeline 201 and regenerated gas preheating pipeline 202, the regenerated gas is diverted and transported. One pipeline is introduced into the expander 100 as a braking gas source to perform work heating, while the other pipeline is introduced into the heat exchanger 300 as gas to be preheated to recover heat, thus forming a complete energy recovery loop. By setting up regenerated gas pipeline assembly 200 to connect with distillation column 800, clean process gas is received as regenerated gas, thereby reducing the intake of dust and impurities, ensuring the cleanliness of the media on both sides of the heat exchanger 300, and reducing the risk of contamination.

[0046] Example 3

[0047] Reference Figure 3 This is the third embodiment of the present invention. Unlike the previous embodiment, this embodiment provides a specific structure for the expander 100, including an inlet valve 101, an outlet valve 102, and an atmospheric inlet 103, which solves the problems of brake air source introduction control and supplementary air source.

[0048] Specifically, the expander 100 includes an inlet valve 101, which is connected to the regenerated gas heating pipeline 201 to introduce regenerated gas as a braking gas source; an outlet valve 102, which is connected to the first inlet 301-1 to control the opening and closing of the heating gas of the expander 100 into the first heat exchange channel 301; and an atmospheric inlet 103, which is connected to the expander 100 to introduce atmospheric air as a supplementary gas source for the expander 100.

[0049] Furthermore, the inlet valve 101 is located between the regeneration gas heating pipeline 201 and the brake fan inlet of the expander 100. When the inlet valve 101 is open, clean regeneration gas is introduced into the expander 100 from the regeneration gas heating pipeline 201. The outlet valve 102 is located between the exhaust end of the expander 100 and the inlet of the first heat exchange channel 301 of the heat exchanger 300. When the outlet valve 102 is open, the heated gas discharged from the expander 100 enters the first heat exchange channel 301. When the outlet valve 102 is closed, the heated gas cannot enter the heat exchanger 300. The atmospheric inlet 103 is located on the brake fan inlet side of the expander 100 and is connected in parallel with the inlet valve 101.

[0050] The rest of the structure is the same as in Example 2.

[0051] Working principle: During normal operation, inlet valve 101 is open and atmospheric inlet 103 is closed. Clean regenerated gas is introduced into expander 100 from regenerated gas heating pipeline 201 through inlet valve 101, serving as a brake gas source to drive brake fan operation. After the regenerated gas does work in expander 100, its temperature rises, forming heated gas. Outlet valve 102 is opened, and heated gas enters the first heat exchange channel 301 of heat exchanger 300 from the exhaust end of expander 100 through outlet valve 102. In the initial stage of air separation unit start-up or when brake gas source is insufficient, inlet valve 101 is closed and atmospheric inlet 103 is opened, with atmospheric gas supplied as a supplementary gas source to expander 100.

[0052] In summary, by setting inlet valve 101, outlet valve 102 and atmospheric inlet 103, the introduction and switching of the brake air source and the supplementary air source are realized, ensuring the normal operation of the expander 100 under various working conditions and realizing the orderly discharge of heating gas and heat recovery.

[0053] Example 4

[0054] Reference Figure 3 This is the fourth embodiment of the present invention. Unlike the previous embodiment, this embodiment provides a first shut-off valve 400, a heater 700, a bypass pipeline 600, and a second shut-off valve 500, which solves the problem of switching the regeneration gas preheating path and supplementary heating.

[0055] Specifically, it also includes: a first shut-off valve 400, which is connected to the second inlet 302-1, for controlling the on / off of regeneration gas entering the heat exchanger 300; a heater 700, which is connected to the second outlet 302-2, for supplementing heating of the preheated regeneration gas; a bypass pipeline 600, whose two ends are connected to the regeneration gas preheating pipeline 202 and the heater 700 respectively; and a second shut-off valve 500, which is connected to the bypass pipeline 600, for controlling the on / off of the regeneration gas at room temperature through the bypass pipeline 600.

[0056] Specifically, the first shut-off valve 400 is located between the regeneration gas preheating pipeline 202 and the inlet end of the second heat exchange channel 302 of the heat exchanger 300. When the first shut-off valve 400 is open, the regeneration gas enters the heat exchanger 300 through the second heat exchange channel 302 for preheating; when the first shut-off valve 400 is closed, the regeneration gas cannot enter the heat exchanger 300. The heater 700 is an electric heater. The temperature range of the regeneration gas after preheating by the heat exchanger 300 is 32~48℃. The heater 700 heats the regeneration gas to the required regeneration temperature of 180~220℃. The steady-state power of heater 700 is 50% to 70% of the rated power. One end of the bypass pipeline 600 is connected to the section of the regenerated gas preheating pipeline 202 before the first shut-off valve 400, and the other end is connected to the inlet end of heater 700. During the cold blowing stage, room temperature regenerated gas bypasses heat exchanger 300 and is directly delivered to heater 700. When the second shut-off valve 500 is opened, room temperature regenerated gas is directly delivered to heater 700 through bypass pipeline 600. When the second shut-off valve 500 is closed, bypass pipeline 600 is cut off, and regenerated gas cannot pass through bypass pipeline 600.

[0057] The remaining structure is the same as in Example 3.

[0058] In summary, by setting up a first shut-off valve 400, a heater 700, a bypass pipeline 600, and a second shut-off valve 500, the preheating path of the regenerated gas is switched. During the heating stage, waste heat is used to preheat the regenerated gas to reduce the energy consumption of the electric heater. During the cold blowing stage, the heat exchanger 300 is bypassed to ensure the cooling effect. At the same time, the heater 700 only needs to provide supplementary heat to reach the temperature required for regeneration, thus reducing the operating power.

[0059] Example 5

[0060] Reference Figure 4 This is the fifth embodiment of the present invention. Unlike the previous embodiment, this embodiment provides a control mechanism 1200, which solves the problem of automatic control of the first shut-off valve 400 and the second shut-off valve 500.

[0061] Specifically, it also includes a control mechanism 1200, which is connected to the first shut-off valve 400 and the second shut-off valve 500 respectively. Under the heating command, it controls the first shut-off valve 400 to open and the second shut-off valve 500 to close, so that the regenerated gas enters the heat exchanger 300 through the second heat exchange channel 302 for preheating. Under the cold blowing command, it controls the first shut-off valve 400 to close and the second shut-off valve 500 to open, so that the regenerated gas is delivered to the heater 700 through the bypass pipeline 600.

[0062] Furthermore, the control mechanism 1200 controls the opening of the first shut-off valve 400 and the closing of the second shut-off valve 500 respectively under the heating command, so that the regenerated gas enters the heat exchanger 300 through the second heat exchange channel 302 for preheating; the heating command corresponds to the heating and regeneration stage of the distillation column 800, at which time high-temperature regenerated gas is required to heat the molecular sieve bed; the control mechanism 1200 issues a heating command, the first shut-off valve 400 opens, the second shut-off valve 500 closes, the regenerated gas enters the heat exchanger 300 through the second heat exchange channel 302 for preheating, and the preheated regenerated gas enters the heater 700 for supplementary heating to the set temperature.

[0063] Furthermore, the control mechanism 1200 also controls the first shut-off valve 400 to close and the second shut-off valve 500 to open under the cold blowing command, so that the regenerated gas is delivered to the heater 700 through the bypass pipeline 600. The cold blowing command corresponds to the cold blowing stage of the distillation column 800. The heated high-temperature molecular sieve bed is gradually cooled by ambient temperature waste nitrogen. When the control mechanism 1200 issues the cold blowing command, the first shut-off valve 400 closes and the second shut-off valve 500 opens. The regenerated gas is directly delivered to the heater 700 through the bypass pipeline 600 without passing through the heat exchanger 300, so as to avoid the regenerated gas being heated and affecting the cooling effect.

[0064] Preferably, the control mechanism 1200 is also connected to a temperature detection element located at the outlet of the second heat exchange channel 302 of the heat exchanger 300, for detecting the temperature of the preheated regeneration gas.

[0065] The remaining structure is the same as in Example 4.

[0066] During the 240 minutes of a complete cycle of the hot air energy recovery system in expander 100, the control timing of control mechanism 1200 is shown in Table 1, which is suitable for high-flow-rate regeneration gas conditions of 1000~1300 Nm³ / h.

[0067] Table 1

[0068] Furthermore, during the cold blowing command stage, the first shut-off valve 400 is closed and the second shut-off valve 500 is opened. The regeneration gas at room temperature is directly sent to the subsequent process through the bypass pipeline 600 to cool the adsorption bed in reverse, thus avoiding the residual heat of the heat exchanger 300 from affecting the cold blowing cooling effect.

[0069] Working principle: According to the regeneration program of the distillation column 800, the control mechanism 1200 issues a heating command during the heating stage, controlling the first shut-off valve 400 to open and the second shut-off valve 500 to close. The regeneration gas is preheated by the heat exchanger 300 and then enters the heater 700 for supplementary heating, which is used for the regeneration of the distillation column 800. During the cold blowing stage, the control mechanism 1200 issues a cold blowing command, controlling the first shut-off valve 400 to close and the second shut-off valve 500 to open. The regeneration gas is directly delivered to the heater 700 through the bypass pipeline 600 without passing through the heat exchanger 300.

[0070] In summary, by setting the control mechanism 1200 to control the opening and closing of the first shut-off valve 400 and the second shut-off valve 500, the preheating path of the regenerated gas can be controlled, the heating and cold blowing modes can be switched, and the operational reliability of the system can be improved.

[0071] Example 6

[0072] Reference Figure 3 and Figure 4 This is the sixth embodiment of the present invention. Unlike the previous embodiment, this embodiment provides a noise reduction element 900, which solves the problem of noise emitted by the heated gas after heat exchange.

[0073] Specifically, the outlet end of the first heat exchange channel 301 is provided with a silencer element 900 for silencing the heated gas after heat exchange before it is discharged; an inlet filter 1000 for filtering the regenerated gas is provided between the regenerated gas heating pipeline 201 and the expander 100.

[0074] Furthermore, the silencing element 900 is a venting silencer, installed between the outlet end of the first heat exchange channel 301 and the atmospheric discharge port, used to silence the heated gas after heat exchange before discharge. The heated gas discharged from the expander 100 enters the first heat exchange channel 301 of the heat exchanger 300, and after heat exchange with the regeneration gas in the second heat exchange channel 302, the temperature decreases. The heated gas after heat exchange is discharged from the outlet end of the first heat exchange channel 301 and enters the silencing element 900. The silencing element 900 silences the discharged gas, reducing the noise during gas discharge, and then discharges the silenced gas into the atmosphere. Since the regeneration system already has excess gas venting for controlling the pressure inside the tower, and venting is still required during the cold blowing stage, the heated gas after heat exchange is directly discharged after silencing treatment and does not return to the regeneration system. The silencing volume of the silencing element 900 is determined according to the site noise requirements.

[0075] Furthermore, the inlet filter 1000 is an air filter, and the filtration area of ​​the inlet filter 1000 is determined according to the gas source flow rate of the regeneration gas heating pipeline 201.

[0076] The remaining structure is the same as in Example 5.

[0077] Working principle: Regenerated gas is transported from the distillation column 800 to the inlet filter 1000 via the regenerated gas heating pipeline 201. The inlet filter 1000 filters the regenerated gas to remove any possible minute impurities. The filtered regenerated gas enters the expander 100 through the inlet valve 101, serving as a brake gas source to drive the brake fan. After the expander 100 heats the regenerated gas, the heated gas enters the first heat exchange channel 301 of the heat exchanger 300, where it exchanges heat with the regenerated gas in the second heat exchange channel 302. The heated gas, after heat exchange, has a lower temperature and is discharged from the outlet of the first heat exchange channel 301, entering the silencer element 900. The silencer element 900 silences the discharged gas, reducing emission noise, and then the silenced gas is released into the atmosphere.

[0078] In summary, by setting the silencing element 900, the system operating noise is reduced, and by setting the inlet filter 1000, the regeneration gas entering the expander 100 is further filtered, thereby protecting the brake fan of the expander 100.

[0079] Example 7

[0080] Reference Figure 1 , Figure 2 , Figure 3 as well as Figure 4 This is the seventh embodiment of the present invention. Unlike the previous embodiment, this embodiment provides that the gas flow directions in the first heat exchange channel 301 and the second heat exchange channel 302 of the heat exchanger 300 are countercurrent, which solves the problem of improving heat exchange efficiency.

[0081] Specifically, the gas flows in countercurrent directions within the first heat exchange channel 301 and the second heat exchange channel 302 of the heat exchanger 300. In the first heat exchange channel 301, the heating gas flows from the inlet end to the outlet end; in the second heat exchange channel 302, the regenerated gas flows from the inlet end to the outlet end. The inlet end of the first heat exchange channel 301 and the outlet end of the second heat exchange channel 302 are located on the same side of the heat exchanger 300, while the outlet end of the first heat exchange channel 301 and the inlet end of the second heat exchange channel 302 are located on the other side of the heat exchanger 300, forming a countercurrent heat exchange structure.

[0082] Furthermore, in the counter-current heat exchange structure, the high-temperature heating gas enters from the inlet end of the first heat exchange channel 301 and exits from the outlet end; the room-temperature regeneration gas enters from the inlet end of the second heat exchange channel 302 and exits from the outlet end. The heating gas and the regeneration gas flow in opposite directions within the heat exchanger 300, creating a temperature difference and improving heat exchange efficiency; moreover, since the media on both sides are the same clean regeneration gas, the risk of contamination is eliminated.

[0083] The rest of the structure is the same as in Example 6.

[0084] Working principle: High-temperature heated gas enters the inlet of the first heat exchange channel 301 of the heat exchanger 300 from the exhaust end of the expander 100 and flows to the outlet end. Room temperature regenerated gas enters the inlet of the second heat exchange channel 302 of the heat exchanger 300 from the regenerated gas preheating pipe 202 and flows to the outlet end. Since the gas flows in the first heat exchange channel 301 and the second heat exchange channel 302 are countercurrent, the heated gas and the regenerated gas flow towards each other in the heat exchanger 300, forming a temperature difference and realizing countercurrent heat exchange. The preheated regenerated gas is discharged from the outlet end of the second heat exchange channel 302 and enters the heater 700 for supplementary heating.

[0085] Example 8

[0086] Reference Figure 4 This is the eighth embodiment of the present invention. Unlike the previous embodiment, this embodiment provides a heat exchange method based on hot air energy recovery.

[0087] Specifically, it includes the following steps: Step S1: The regeneration gas is heated using expander 100 to form heated gas. Clean regeneration gas from distillation column 800 is introduced into expander 100 through regeneration gas heating pipeline 201 and used as a brake gas source to drive brake fan. After the regeneration gas does work in expander 100, its temperature rises to 80~120℃, forming heated gas.

[0088] Step S2: The heating gas from the expander 100 is introduced into the first heat exchange channel 301.

[0089] Step S3: Introduce regenerated gas into the second heat exchange channel 302 or the bypass line 600. Under the heating command, the first shut-off valve 400 opens and the second shut-off valve 500 closes, and the regenerated gas enters the second heat exchange channel 302 of the heat exchanger 300 via the regenerated gas preheating line 202 and the first shut-off valve 400; under the cold blowing command, the first shut-off valve 400 closes and the second shut-off valve 500 opens, and the regenerated gas is directly delivered to the heater 700 via the regenerated gas preheating line 202, the bypass line 600, and the second shut-off valve 500.

[0090] Step S4 involves exchanging heat between the heating gas in the first heat exchange channel 301 and the regeneration gas in the second heat exchange channel 302 to preheat the regeneration gas in the second heat exchange channel 302. Within the heat exchanger 300, the gas flows in countercurrent directions in the first heat exchange channel 301 and the second heat exchange channel 302, with the high-temperature heating gas and the room-temperature regeneration gas exchanging heat in a countercurrent manner.

[0091] Step S5: The preheated regeneration gas is introduced into the heater 700 for supplementary heating. The heater 700 provides supplementary heating to the preheated regeneration gas, and only supplementary heat is needed to heat the regeneration gas to the required regeneration temperature.

[0092] In step S6, under the condition of the heating command, the second heat exchange channel 302 is opened and the bypass pipe 600 is closed.

[0093] In step S7, the regenerated gas, after being preheated through the second heat exchange channel 302, enters the heater 700 for supplementary heating to the set temperature.

[0094] In step S8, under the condition of the cold blowing command, the second heat exchange channel 302 is closed and the bypass pipeline 600 is opened.

[0095] Step S9: Vent the heated gas that has undergone heat exchange in the first heat exchange channel 301.

[0096] The remaining structure is the same as in Example 7.

[0097] This embodiment provides measured data. The measured conditions include: the rated flow rate of regeneration gas in distillation column 800 is 1150 Nm³ / h, the silane impurity content in the regeneration gas feedstock is 0.32% vol; the flow rate of brake gas source in expander 100 is 372 Nm³ / h, and the pressure is 0.15 MPa (G); the ambient temperature is 25℃.

[0098] The cold blowing cooling stage lasts for 90 minutes. After the hot blowing regeneration is completed, the control mechanism 1200 issues a cold blowing command. The ambient temperature regeneration gas flows through the bypass pipeline 600. The ambient temperature regeneration gas cools the adsorption bed in the reverse direction. The brake fan air source is continuously maintained at 372 Nm³ / h and 0.15 MPa (G). The specific cold blowing process parameters are shown in Table 1.

[0099] Table 2

[0100] As shown in Table 2, after 90 minutes of cold blowing, the temperature at the inlet of distillation column 800 dropped to 25.8℃ and the temperature at the bottom of the column dropped to 27.1℃, which is close to room temperature and meets the cooling process requirements after the regeneration of distillation column 800. The impurity content in the gas exiting the column dropped to 0.076%vol, which meets the impurity removal requirements for the regeneration of distillation column 800, and the regeneration effect is qualified.

[0101] Working principle: By using the waste heat generated at the braking end of the expander 100 to preheat the regeneration gas, the purpose of replacing electric heating with waste heat and braking with clean gas source is achieved. In the heating stage, the regeneration gas is preheated by the heat exchanger 300 and then enters the electric heater. The electric heater only needs to provide supplementary heat to reach the temperature required for regeneration, which greatly reduces the operating power. In the cold blowing stage, the regeneration gas enters the electric heater directly through the bypass pipeline 600 without passing through the heat exchanger 300, which ensures the cooling effect.

[0102] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A heat exchange system based on hot air energy recovery, characterized in that: include, A heat exchanger (300) is used to preheat the regeneration gas; The first heat exchange channel (301) is connected to the heat exchanger (300) and is used to receive heating gas. The inlet end of the first heat exchange channel (301) is provided with a first inlet (301-1) for receiving heating gas, and the outlet end of the first heat exchange channel (301) is provided with a first outlet (301-2) for discharging the low-temperature gas after heat exchange. The second heat exchange channel (302) is connected to the heat exchanger (300) and is used to provide a preheating space for the regeneration gas. The inlet end of the second heat exchange channel (302) is provided with a second inlet (302-1) for receiving the regeneration gas to be preheated, and the outlet end of the second heat exchange channel (302) is provided with a second outlet (302-2) for discharging the preheated regeneration gas. The heat exchanger (300) exchanges heat between the heating gas input into the first heat exchange channel (301) and the regeneration gas input into the second heat exchange channel (302); A regeneration gas pipeline assembly (200) is connected to the second heat exchange channel (302) to provide clean process gas as regeneration gas to the second heat exchange channel (302); An expander (100) is connected to the first heat exchange channel (301) to provide heating gas to the first heat exchange channel (301); The regenerated gas pipeline assembly (200) includes a regenerated gas heating pipeline (201), which is connected to the expander (100) to introduce the output regenerated gas into the expander (100) to do work and then discharge heated gas; and a regenerated gas preheating pipeline (202), which is connected to the second heat exchange channel (302) to transport the output room temperature regenerated gas to the second heat exchange channel (302). The expander (100) includes an inlet valve (101) connected to the regenerated gas heating pipeline (201) for introducing regenerated gas as a braking gas source; The first shut-off valve (400), which is connected to the second inlet (302-1), is used to control the on / off of regeneration gas entering the heat exchanger (300); A heater (700), which is connected to the second outlet (302-2), is used to supplement the heating of the preheated regeneration gas; A bypass pipeline (600) is connected at both ends to a regeneration gas preheating pipeline (202) and the heater (700), respectively; The second shut-off valve (500), which is connected to the bypass line (600), is used to control the on / off of regeneration gas at room temperature through the bypass line (600).

2. The heat exchange system based on hot air energy recovery as described in claim 1, characterized in that: The expander (100) also includes, The outlet valve (102) is connected to the first inlet (301-1) and is used to control the opening and closing of the heating gas from the expander (100) into the first heat exchange channel (301); An atmospheric inlet (103) is connected to the expander (100) to allow air to flow in as a supplementary air source for the expander (100).

3. The heat exchange system based on hot air energy recovery as described in claim 1 or 2, characterized in that: It also includes a control mechanism (1200), which is connected to the first shut-off valve (400) and the second shut-off valve (500) respectively. By controlling the opening of the first shut-off valve (400) and the closing of the second shut-off valve (500) under the heating command, the regenerated gas enters the heat exchanger (300) through the second heat exchange channel (302) for preheating. Furthermore, by controlling the first shut-off valve (400) to close and the second shut-off valve (500) to open under the cold blowing command, the regenerated gas is delivered to the heater (700) through the bypass pipeline (600).

4. The heat exchange system based on hot air energy recovery as described in claim 1, characterized in that: The outlet end of the first heat exchange channel (301) is provided with a silencing element (900) for silencing the heated gas after heat exchange before it is discharged.

5. The heat exchange system based on hot air energy recovery as described in claim 1, characterized in that: An inlet filter (1000) for filtering regenerated gas is provided between the regenerated gas heating pipeline (201) and the expander (100).

6. The heat exchange system based on hot air energy recovery as described in any one of claims 1, 2, 4 or 5, characterized in that: The gas flows in the first heat exchange channel (301) and the second heat exchange channel (302) of the heat exchanger (300) in opposite directions.

7. A heat exchange method based on hot air energy recovery, characterized in that, The heat exchange system based on hot air energy recovery as described in any one of claims 3 to 6 includes: The regenerated gas is heated using an expander (100) to form heated gas; The heating gas is introduced into the first heat exchange channel (301); The regenerated gas is introduced into the second heat exchange channel (302) or the bypass pipeline (600). The heating gas in the first heat exchange channel (301) is exchanged with the regeneration gas in the second heat exchange channel (302) to preheat the regeneration gas in the second heat exchange channel (302); The preheated regenerated gas is introduced into the heater (700) for supplementary heating; Under the condition of the heating command, the second heat exchange channel (302) is opened and the bypass pipeline (600) is closed. The regenerated gas, after being preheated through the second heat exchange channel (302), enters the heater (700) for supplementary heating to the set temperature; Under the condition of the cold blowing command, the second heat exchange channel (302) is closed and the bypass pipeline (600) is opened; The heated gas that has undergone heat exchange in the first heat exchange channel (301) is vented.

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