Olefin separation device dryer regeneration nitrogen self-circulation system

Abstract

This application discloses a self-circulating nitrogen regeneration system for an olefin separation unit dryer, comprising a recovery unit connected to the dryer's regeneration waste gas outlet; a heat exchange unit for cooling the regeneration waste gas; a purification unit connected to the heat exchange unit's outlet for removing impurities from the cooled regeneration waste gas; a compression unit connected to the purification unit for pressurizing the purified nitrogen; and an electric heating unit for heating the pressurized nitrogen. The inlet of the electric heating unit is connected to the outlet of the compression unit, and the outlet of the electric heating unit is connected to the dryer's regeneration gas inlet, forming a closed-loop nitrogen circulation system. This application's solution achieves nitrogen recycling and waste heat utilization through a closed loop formed between the recovery unit, heat exchange unit, purification unit, compression unit, electric heating unit, and dryer, thereby significantly reducing energy consumption and meeting the environmental protection requirements of the chemical industry for green, low-carbon, and resource recycling.

Description

Technical Field

[0001] This application generally relates to the field of coal chemical olefin separation production technology. More specifically, this application relates to a self-circulating nitrogen regeneration system for an olefin separation unit dryer. Background Technology

[0002] In methanol-to-olefins (MTO) plants, the dryer is a crucial piece of equipment for removing moisture from the olefin reaction gas. This prevents moisture from affecting the purity of the olefin product and from poisoning the subsequent polymerization catalyst. After the molecular sieve adsorbent in the dryer becomes saturated, high-temperature, high-purity nitrogen gas is introduced as a regeneration gas to purge and heat the adsorption bed, removing the adsorbed moisture and impurities, restoring the adsorbent's activity, and completing the regeneration process.

[0003] Currently, the industry-standard dryer regeneration process uses a single-use direct nitrogen discharge mode: purchased high-purity nitrogen is heated before being introduced into the dryer, and the regenerated waste gas, carrying moisture, dust, solvents, and other impurities, is directly discharged into the flare system or the atmosphere. This mode has the following drawbacks: First, it results in significant nitrogen resource waste and high operating costs. The direct discharge of high-purity nitrogen after a single use necessitates continuous large-scale external purchases of nitrogen, leading to high procurement, transportation, and storage costs. Second, it suffers from low energy efficiency. The regenerated waste gas temperature reaches 200-300℃, carrying a large amount of waste heat, resulting in wasted thermal energy. Furthermore, new nitrogen requires additional energy to heat to the regeneration temperature, leading to high overall energy consumption. Third, existing processes lack efficient methods for removing impurities from the waste gas. Simply recycling the waste gas for direct reuse will result in residual moisture, dust, and solvents contaminating the adsorbent or damaging the equipment, leading to incomplete waste gas purification and hindering recycling. Finally, the direct discharge of large amounts of waste nitrogen does not meet the requirements of green and environmentally friendly production, contradicting the chemical industry's production philosophy of low-carbon energy conservation and resource recycling.

[0004] In view of this, there is an urgent need to provide a self-circulating nitrogen regeneration system for dryers in olefin separation units, so as to recover the waste gas from dryer regeneration, realize the recycling of nitrogen, reduce nitrogen consumption and operating energy consumption, and meet environmental protection requirements. Summary of the Invention

[0005] In order to at least solve one or more of the technical problems mentioned above, this application proposes a scheme for a self-circulating nitrogen regeneration system for an olefin separation unit dryer in several aspects.

[0006] This application provides a self-circulating nitrogen regeneration system for an olefin separation device dryer, comprising: a recovery unit connected to the regeneration waste gas outlet of the dryer and used to collect the regeneration waste gas discharged from the dryer; a heat exchange unit used to cool the regeneration waste gas; a purification unit connected to the outlet of the heat exchange unit and used to remove impurities from the cooled regeneration waste gas; a compression unit connected to the outlet of the purification unit and used to pressurize the purified nitrogen; and an electric heating unit used to heat the pressurized nitrogen; the inlet of the electric heating unit is connected to the outlet of the compression unit, and the outlet of the electric heating unit is connected to the regeneration gas inlet of the dryer, forming a closed-loop nitrogen circulation circuit.

[0007] In some embodiments, the heat exchange unit is disposed inside the recovery unit or connected in series to the outlet or inlet of the recovery unit.

[0008] In some embodiments, the purification unit includes a filter assembly, a condensation assembly, and a coalescing separation assembly connected in sequence, for removing dust, solvents, and moisture from the exhaust gas.

[0009] In some embodiments, the compression unit is a nitrogen compressor, and its outlet is provided with a pressure regulating valve and a check valve.

[0010] In some embodiments, the electric heating unit is an electric heater, and its outlet is equipped with a temperature sensor to control the temperature of the heated nitrogen gas between 200°C and 300°C.

[0011] In some embodiments, an automated control system is also included. The automated control system is a PLC system or a DCS system, which is communicatively connected to different types of sensors in the recovery unit, heat exchange unit, purification unit, compression unit, electric heating unit, and pipeline. It is used to automatically adjust the operating frequency of the compression unit, the heating power of the electric heating unit, and the opening and closing of pipeline valves according to the monitoring signals of each sensor, and has a safety interlock function.

[0012] In some embodiments, the automated control system is further provided with a safety interlock module, which automatically cuts off the compression unit and the electric heating unit and opens the discharge valve when the nitrogen oxygen content exceeds a set threshold or the outlet temperature of the electric heating unit exceeds the limit.

[0013] In some embodiments, a fresh nitrogen replenishment line is also included, which is connected to the air inlet of the compression unit or the air inlet of the electric heating unit, and is provided with a replenishment regulating valve.

[0014] In some embodiments, a discharge line is also included, which is connected to the outlet of the purification unit or the compression unit and is provided with a discharge valve for discharging part of the gas when the system pressure is too high or the nitrogen purity is insufficient.

[0015] In some embodiments, the recovery unit is a gas-liquid separator or a cyclone separator, used to initially remove liquid water and dust entrained in the regenerated waste gas.

[0016] The nitrogen regeneration self-circulation system for the dryer in the olefin separation unit, as described above, in this embodiment, comprises a recovery unit, a heat exchange unit, a purification unit, a compression unit, and an electric heating unit, which are sequentially connected to form a closed-loop nitrogen circulation circuit. The recovery unit captures the regeneration waste gas, avoiding resource waste caused by direct nitrogen emission, significantly reducing the amount of purchased high-purity nitrogen and lowering operating costs. The heat exchange unit cools the high-temperature regeneration waste gas, facilitating efficient removal of moisture and impurities by the subsequent purification unit, while also recovering some waste heat. The purification unit removes dust, solvents, and moisture from the waste gas, restoring the purity of the circulating nitrogen to a reusable standard and preventing impurities from contaminating the adsorbent or damaging the equipment. The compression unit and the electric heating unit pressurize and heat the purified nitrogen to the required regeneration temperature, ensuring stable regeneration performance of the dryer. Attached Figure Description

[0017] The above and other objects, features, and advantages of exemplary embodiments of this application will become readily understood by reading the following detailed description with reference to the accompanying drawings. In the drawings, several embodiments of this application are illustrated by way of example and not limitation, and the same or corresponding reference numerals denote the same or corresponding parts, wherein:

[0018] Figure 1 A schematic diagram of the regenerated nitrogen self-circulation system of the dryer in the olefin separation device according to an embodiment of this application is shown; Figure 2 A schematic diagram of a specific embodiment of the self-circulating nitrogen regeneration system of the dryer in the olefin separation device according to an embodiment of this application is shown.

[0019] In the diagram: 100, Olefin Separation Unit Dryer Regeneration Nitrogen Self-Circulation System; 101. Dryer; 102. Heat exchange unit; 103. Purification unit; 104. Compression unit; 105. Electric heating unit; 106. Automated control system. Detailed Implementation

[0020] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0021] It should be understood that the terms "comprising" and "including" used in the specification and claims of this application indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0022] It should also be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application. As used in this specification and claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used in this specification and claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes such combinations.

[0023] As used in this specification and claims, the term "if" may be interpreted, depending on the context, as "when," "once," "in response to determination," or "in response to detection." Similarly, the phrase "if determined" or "if [described condition or event] is detected" may be interpreted, depending on the context, as "once determined," "in response to determination," "once [described condition or event] is detected," or "in response to detection of [described condition or event]."

[0024] The specific embodiments of this application will now be described in detail with reference to the accompanying drawings.

[0025] like Figure 1 As shown, in some embodiments, this application provides a nitrogen regeneration self-circulation system 100 for an olefin separation device dryer 101, comprising: a recovery unit connected to the regeneration waste gas outlet of the dryer 101 and used to collect the regeneration waste gas discharged from the dryer 101; a heat exchange unit 102 used to cool the regeneration waste gas; a purification unit 103 connected to the outlet of the heat exchange unit 102 and used to remove impurities from the cooled regeneration waste gas; a compression unit 104 connected to the outlet of the purification unit 103 and used to pressurize the purified nitrogen; and an electric heating unit 105 used to heat the pressurized nitrogen; the inlet of the electric heating unit 105 is connected to the outlet of the compression unit 104, and the outlet of the electric heating unit 105 is connected to the regeneration gas inlet of the dryer 101, forming a closed-loop nitrogen circulation circuit.

[0026] In this application, the regenerated nitrogen self-circulation system 100 of the olefin separation unit dryer 101 includes a recovery unit, a heat exchange unit 102, a purification unit 103, a compression unit 104, and an electric heating unit 105. Specifically, the recovery unit is connected to the regeneration waste gas outlet of the dryer 101 to collect the regeneration waste gas discharged from the dryer 101. The inlet of the heat exchange unit 102 is connected to the outlet of the recovery unit to cool the high-temperature waste gas. The inlet of the purification unit 103 is connected to the outlet of the heat exchange unit 102 to remove impurities such as moisture, dust, and solvents from the cooled regeneration waste gas, so that the nitrogen reaches the purity requirement for recyclability.

[0027] The inlet of the compression unit 104 is connected to the outlet of the purification unit 103, and is used to pressurize the purified nitrogen to the pressure level required for regeneration. The inlet of the electric heating unit 105 is connected to the outlet of the compression unit 104, and is used to heat the pressurized nitrogen to the temperature required for regeneration of the dryer 101. The outlet of the electric heating unit 105 is connected to the regeneration gas inlet of the dryer 101.

[0028] In the scheme of this application, the exhaust gas discharged from the regeneration stage of the dryer 101 flows sequentially through the recovery unit, heat exchange unit 102, purification unit 103, compression unit 104 and electric heating unit 105, and then returns to the dryer 101 as regeneration gas, forming a closed loop of nitrogen gas, thereby realizing the recycling of nitrogen gas, reducing the amount of purchased nitrogen gas, reducing operating costs, and recovering waste heat while meeting environmental protection requirements.

[0029] In some implementations, the heat exchange unit 102 is disposed inside the recovery unit or connected in series to the outlet or inlet of the recovery unit.

[0030] In this application, the heat exchange unit 102 can be connected in various ways according to actual layout requirements. Specifically, the heat exchange unit 102 can be installed inside the recovery unit, i.e., using an integrated structure, so that the regenerated waste gas is captured and cooled simultaneously within the recovery unit, thereby saving equipment space and reducing pipeline connections. Furthermore, the heat exchange unit 102 can also be connected in series to the outlet or inlet of the recovery unit: when the heat exchange unit 102 is connected in series to the inlet of the recovery unit, the regenerated waste gas is cooled by the heat exchange unit 102 before entering the recovery unit, which helps to precipitate some liquid impurities during the cooling process and reduces the separation load on the recovery unit; when the heat exchange unit 102 is connected in series to the outlet of the recovery unit, the regenerated waste gas is captured by the recovery unit before entering the heat exchange unit 102 for cooling, which avoids large dust particles entrained in the waste gas directly entering the heat exchange unit 102 and causing blockage. Both of these arrangement methods can achieve effective cooperation between the recovery unit and the heat exchange unit 102, ensuring that the regenerated waste gas is adequately cooled before entering the purification unit 103.

[0031] It is worth noting that this application does not limit the specific form of the heat exchange unit 102. The heat exchange unit 102 is used to cool the regenerated waste gas and can be a shell-and-tube heat exchanger, a plate heat exchanger, a finned tube heat exchanger, or a spiral plate heat exchanger. Shell-and-tube heat exchangers are resistant to high temperature and high pressure and are the preferred structure of this application; plate heat exchangers have high heat transfer efficiency and a compact structure; finned tube heat exchangers are suitable for gas-liquid heat exchange; spiral plate heat exchangers have strong self-cleaning ability and are suitable for fluids containing suspended solids or with high viscosity.

[0032] In one specific implementation, the purification unit 103 includes a filter assembly, a condensation assembly, and a coalescing separation assembly connected in sequence, for removing dust, solvents, and moisture from the exhaust gas.

[0033] In this application, the purification unit 103 includes a filter assembly, a condensation assembly, and a coalescing separation assembly connected in sequence, used to remove dust, solvents, and moisture from the exhaust gas. Specifically, the cooled regenerated exhaust gas from the heat exchange unit 102 first enters the filter assembly, which traps solid dust and some larger droplets entrained in the exhaust gas. The exhaust gas then enters the condensation assembly, which lowers the exhaust gas temperature, condensing gaseous moisture and solvents into liquids. Finally, the exhaust gas enters the coalescing separation assembly, which contains a coalescing filter element. Tiny droplets coalesce and grow as they pass through the filter element, and then settle and separate under gravity, further removing residual liquid moisture and solvents. Through this three-stage combined process of filtration, condensation, and coalescing, various impurities in the regenerated exhaust gas are gradually removed, restoring the nitrogen purity to a recyclable standard and preventing impurities from contaminating or damaging subsequent equipment and the adsorbent in the dryer 101.

[0034] As a specific implementation of the purification unit 103, the filtration component can be a gas filter with an internal sintered metal filter element or fiber filter element to trap solid dust and some large-diameter liquid droplets; the condensation component can be a shell-and-tube condenser or a plate condenser, using circulating water or chilled water as the cooling medium to lower the exhaust gas temperature below the dew point of water vapor and solvent, causing gaseous moisture and solvent to condense into liquid; the coalescing and separation component can be a coalescing separator with an internal coalescing filter element and a separation filter element. The exhaust gas first passes through the coalescing filter element to cause the tiny liquid droplets to coalesce and grow, and then passes through the separation filter element to achieve gas-liquid separation. Liquid moisture and solvent are discharged from the bottom of the separator, and clean nitrogen flows out from the top. In addition, the purification unit 103 can also adopt an integrated purification device, integrating the three-stage functions of filtration, condensation, and coalescing and separation into the same housing, with a filtration section, a condensation section, and a coalescing and separation section arranged sequentially. The exhaust gas flows through each functional section to complete the step-by-step purification. This structure is compact, occupies less space, and is suitable for space-constrained renovation projects.

[0035] In one specific implementation, the compression unit 104 is a nitrogen compressor, and its outlet is equipped with a pressure regulating valve and a check valve.

[0036] In this application, the compression unit 104 is a nitrogen compressor, used to pressurize the purified nitrogen to the pressure required for the regeneration of the dryer 101. The outlet of the nitrogen compressor is equipped with a pressure regulating valve and a check valve. The pressure regulating valve is used to regulate the output nitrogen pressure, stabilizing it within the range required by the regeneration process. The check valve is used to prevent high-temperature gas from the dryer 101 side or pressure fluctuations within the system from causing gas to flow back into the compressor, thereby protecting the compression unit 104 and maintaining stable system pressure. By setting the pressure regulating valve and the check valve, it can be ensured that the nitrogen pressure output by the compression unit 104 is constant and the flow direction is unique, providing a guarantee for the stable operation of the subsequent electric heating unit 105 and the dryer 101.

[0037] In one specific implementation, the electric heating unit 105 is an electric heater, and its outlet is equipped with a temperature sensor to control the temperature of the heated nitrogen gas between 200°C and 300°C.

[0038] In this application, the electric heating unit 105 is an electric heater used to heat the pressurized nitrogen gas from the compression unit 104 to the temperature required for regeneration of the dryer 101. A temperature sensor is installed at the outlet of the electric heater. The temperature sensor detects the temperature of the heated nitrogen gas in real time and feeds the temperature signal back to the control system. The control system then controls the heating power of the electric heater to stabilize the temperature of the heated nitrogen gas between 200℃ and 300℃. Those skilled in the art will understand that this temperature range can effectively remove the moisture and impurities adsorbed by the molecular sieve adsorbent in the dryer 101, ensuring regeneration efficiency. Simultaneously, the temperature sensor enables closed-loop control, preventing damage to the adsorbent due to excessively high temperatures or incomplete regeneration due to excessively low temperatures, thereby ensuring the safe, stable, and efficient operation of the dryer 101 during the regeneration process.

[0039] like Figure 2 As shown, in a specific implementation, it also includes an automated control system 106, which is a PLC system or a DCS system. It is communicatively connected to the recovery unit, heat exchange unit 102, purification unit 103, compression unit 104, electric heating unit 105, and different types of sensors in the pipeline. It is used to automatically adjust the operating frequency of the compression unit 104, the heating power of the electric heating unit 105, and the opening and closing of the pipeline valves according to the monitoring signals of each sensor, and has a safety interlock function.

[0040] In this application, the automated control system 106 is a PLC system or a DCS system, which is communicatively connected to the recovery unit, heat exchange unit 102, purification unit 103, compression unit 104, electric heating unit 105, and pressure sensors, temperature sensors, flow sensors, nitrogen purity sensors, and oxygen content sensors installed in the pipeline. Specifically, the pressure sensor monitors the pressure of the circulating nitrogen, the temperature sensor monitors the temperature at key locations, the flow sensor monitors the flow rate of the circulating nitrogen, the nitrogen purity sensor monitors the purity of the nitrogen, and the oxygen content sensor monitors the oxygen content in the circulating nitrogen.

[0041] The automated control system 106 automatically adjusts the operating frequency of the compression unit 104 to control the circulating gas volume and pressure based on the monitoring signals from various sensors, automatically adjusts the heating power of the electric heating unit 105 to control the regeneration gas temperature, and automatically adjusts the opening and closing of pipeline valves to control the gas flow direction and on / off. Simultaneously, the automated control system 106 acquires the real-time operating status of the recovery unit, heat exchange unit 102, purification unit 103, compression unit 104, and electric heating unit 105 via communication connections, and sends control commands as needed. Furthermore, the automated control system 106 has a safety interlock function: when the oxygen content exceeds a set threshold, the outlet temperature of the electric heating unit 105 exceeds the limit, or the system pressure is abnormal, the system automatically triggers the safety interlock, cutting off the operation of the compression unit 104 and the electric heating unit 105, and opening the discharge valve to discharge substandard gas, ensuring the safe and stable operation of the system.

[0042] Through the above-mentioned automated control and safety interlock design, the system can continuously and reliably complete the self-circulation operation of regenerated nitrogen in dryer 101 without human intervention or with minimal intervention.

[0043] In one specific implementation, the automated control system 106 is further provided with a safety interlock module, which automatically cuts off the compression unit 104 and the electric heating unit 105 and opens the discharge valve when the nitrogen oxygen content exceeds the set threshold or the outlet temperature of the electric heating unit 105 exceeds the limit.

[0044] In the scheme of this application, the automated control system 106 is equipped with a safety interlock module. The safety interlock module includes an interlock controller (integrated in a PLC or DCS), an oxygen content analyzer, an outlet thermocouple of the electric heating unit 105, a circuit breaker of the compression unit 104, a contactor of the electric heating unit 105, and a pneumatic discharge valve.

[0045] Specifically, the oxygen analyzer monitors the oxygen content in the circulating nitrogen in real time. For example, a threshold of 0.5% (volume fraction) can be set. This value is only an example and can be adjusted according to process safety requirements in actual applications. The thermocouple at the outlet of the electric heating unit 105 monitors the temperature of the heated nitrogen in real time. For example, a safety upper limit can be set to 320℃. Again, this is only an example, and the specific value depends on the temperature resistance of the adsorbent and process conditions.

[0046] During operation, when the oxygen content reaches the set threshold or the outlet temperature of the electric heating unit 105 reaches the safety upper limit, the interlock controller immediately outputs two signals: one signal cuts off the circuit breaker of the compressor unit 104 motor and the contactor of the electric heating unit 105 via hard wiring, stopping the operation of the compressor unit 104 and the electric heating unit 105; the other signal sends an opening signal to the solenoid valve of the pneumatic discharge valve, for example, the discharge valve fully opens within 2 seconds (this time is only an example and can be adjusted according to the valve selection), venting the gas in the system to the flare or safety venting main. Simultaneously, the interlock controller issues an audible and visual alarm and displays the interlock triggering reason on the DCS operator station. After the fault is cleared and the parameters return to normal, the operator must manually reset the interlock signal on the DCS before restarting the system. The response time of this safety interlock module is, for example, no more than 500 milliseconds (this is only an example; the actual response time depends on the hardware configuration), ensuring reliable operation before hazardous conditions occur.

[0047] The solution proposed in this application, through the aforementioned safety interlock design, can effectively prevent the risk of combustion and explosion caused by excessive oxygen content, or avoid damage to the molecular sieve adsorbent and system equipment inside the dryer 101 due to excessive temperature, ensuring that the system can safely shut down and release dangerous gases under abnormal operating conditions, thus protecting the safety of production equipment and operators.

[0048] In one specific implementation, a fresh nitrogen replenishment pipeline is also included, which is connected to the air inlet of the compression unit 104 or the air inlet of the electric heating unit 105, and is equipped with a replenishment regulating valve.

[0049] In this application, the system also includes a fresh nitrogen replenishment pipeline. The fresh nitrogen replenishment pipeline is connected to the inlet of the compression unit 104 or the inlet of the electric heating unit 105, and is equipped with a replenishment regulating valve. When the circulating nitrogen volume decreases or its quality deteriorates due to leakage or insufficient nitrogen purity, an appropriate amount of external fresh nitrogen can be introduced through the replenishment regulating valve to maintain the total nitrogen volume and purity within the system to meet the regeneration requirements of the dryer 101.

[0050] The solution in this application connects the fresh nitrogen replenishment pipeline to the inlet of the compression unit 104, allowing the replenished nitrogen to be compressed and heated along with the circulating airflow before entering the dryer 101. Connecting it to the inlet of the electric heating unit 105 avoids the replenished nitrogen affecting the load on the compression unit 104. The replenishment regulating valve can automatically adjust its opening based on the pressure or purity signal detected by the automatic control system 106, achieving on-demand replenishment and ensuring long-term stable operation of the system.

[0051] In one specific implementation, a discharge pipeline is also included, which is connected to the outlet of the purification unit 103 or the compression unit 104 and is equipped with a discharge valve for discharging part of the gas when the system pressure is too high or the nitrogen purity is insufficient.

[0052] In this application, the system also includes an exhaust pipeline. The exhaust pipeline is connected to the outlet of the purification unit 103 or the outlet of the compression unit 104, and is equipped with an exhaust valve. When the pressure in the system is too high or the purity of the circulating nitrogen is insufficient, the exhaust valve opens, and some of the substandard gas is discharged from the system through the exhaust pipeline to maintain stable system pressure and ensure the quality of the circulating nitrogen.

[0053] The proposed solution, by setting up an emission pipeline, enables the system to promptly release excessive gases under abnormal operating conditions, ensuring the safe and stable operation of the system. At the same time, in conjunction with the fresh nitrogen replenishment pipeline, it achieves a dynamic balance between the total amount and quality of nitrogen in the system.

[0054] In one specific implementation, the recovery unit is a gas-liquid separator or a cyclone separator, used to initially remove liquid water and dust entrained in the regenerated waste gas.

[0055] In this application, the recovery unit can employ a gas-liquid separator or a cyclone separator to initially remove liquid water and dust entrained in the regeneration waste gas. The gas-liquid separator is a horizontal or vertical pressure vessel. After the regeneration waste gas enters the tank, its flow velocity decreases, and gas-liquid separation is achieved through gravity settling. Liquid water accumulates at the bottom of the tank and is discharged, while gas flows out from the top. This type of separator is suitable for handling large volumes of gas with high liquid content. The cyclone separator utilizes the principle of centrifugal force separation. After the regeneration waste gas enters tangentially, it rotates at high speed. Denser droplets and dust are thrown against the wall and fall down the wall, while the purified gas is discharged from the top. This type of separator features a simple structure, no moving parts, and moderate pressure drop, making it suitable for applications with high dust content or limited space.

[0056] The solution proposed in this application uses a recovery unit to perform preliminary treatment on the regenerated waste gas, which can effectively remove a large amount of liquid water and coarse dust entrained in it, reduce the load on the subsequent purification unit 103, and extend the service life of the filter components and coalescing separation components.

[0057] While numerous embodiments of this application have been shown and described herein, it will be apparent to those skilled in the art that such embodiments are provided by way of example only. Many modifications, alterations, and alternatives will arise for those skilled in the art without departing from the spirit and intent of this application. It should be understood that various alternatives to the embodiments of this application described herein may be employed in the practice of this application. The appended claims are intended to define the scope of protection of this application and therefore cover equivalents or alternatives within the scope of these claims.

Claims

1. A self-circulating nitrogen regeneration system for an olefin separation unit dryer, characterized in that, include: The recovery unit is connected to the regeneration exhaust gas outlet of the dryer and is used to capture the regeneration exhaust gas discharged from the dryer. A heat exchange unit is used to cool the regeneration waste gas; A purification unit is connected to the outlet of the heat exchange unit and is used to remove impurities from the cooled regenerated waste gas. A compression unit is connected to the outlet of the purification unit and is used to pressurize the purified nitrogen. as well as An electric heating unit is used to heat the pressurized nitrogen gas; the inlet of the electric heating unit is connected to the outlet of the compression unit, and the outlet of the electric heating unit is connected to the regeneration gas inlet of the dryer, forming a closed nitrogen gas circulation loop.

2. The self-circulating nitrogen regeneration system for the dryer of the olefin separation unit according to claim 1, characterized in that, The heat exchange unit is located inside the recovery unit, or connected in series to the outlet or inlet of the recovery unit.

3. The self-circulating nitrogen regeneration system for the dryer of the olefin separation unit according to claim 1, characterized in that, The purification unit includes a filter assembly, a condenser assembly, and a coalescing and separating assembly connected in sequence, used to remove dust, solvents, and moisture from the exhaust gas.

4. The self-circulating nitrogen regeneration system for the dryer of the olefin separation unit according to claim 3, characterized in that, The compression unit is a nitrogen compressor, and its outlet is equipped with a pressure regulating valve and a check valve.

5. The self-circulating nitrogen regeneration system for the dryer of the olefin separation unit according to claim 1, characterized in that, The electric heating unit is an electric heater, and its outlet is equipped with a temperature sensor to control the temperature of the nitrogen gas after heating between 200℃ and 300℃.

6. The self-circulating nitrogen regeneration system for the dryer of the olefin separation unit according to any one of claims 1-5, characterized in that, It also includes an automated control system, which is a PLC system or a DCS system, and is communicatively connected to different types of sensors in the recovery unit, heat exchange unit, purification unit, compression unit, electric heating unit and pipeline. It is used to automatically adjust the operating frequency of the compression unit, the heating power of the electric heating unit and the opening and closing of pipeline valves according to the monitoring signals of each sensor, and has a safety interlock function.

7. The self-circulating nitrogen regeneration system for the dryer of the olefin separation unit according to claim 6, characterized in that, The automated control system is also equipped with a safety interlock module. When the oxygen content of nitrogen exceeds the set threshold or the outlet temperature of the electric heating unit exceeds the limit, the compression unit and the electric heating unit are automatically cut off and the discharge valve is opened.

8. The self-circulating nitrogen regeneration system for the dryer of the olefin separation unit according to claim 6, characterized in that, It also includes a fresh nitrogen replenishment pipeline, which is connected to the air inlet of the compression unit or the air inlet of the electric heating unit, and is equipped with a replenishment regulating valve.

9. The self-circulating nitrogen regeneration system for the dryer of the olefin separation unit according to claim 8, characterized in that, It also includes an exhaust pipe connected to the outlet of the purification unit or the compression unit, and is equipped with an exhaust valve for discharging part of the gas when the system pressure is too high or the nitrogen purity is insufficient.

10. The self-circulating nitrogen regeneration system for the dryer of the olefin separation unit according to claim 1, characterized in that, The recovery unit is a gas-liquid separator or a cyclone separator, used to initially remove liquid water and dust entrained in the regenerated waste gas.

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