A system for generating power using methanol vapor back pressure

Abstract

The utility model discloses a system of methanol steam back pressure power generation, including methanol pressurizing pump, heating furnace, power mechanism, methanol reactor, generator and control unit, control unit is electric respectively connected with pressure sensor A, pressure sensor B and flow sensor, methanol pressurizing pump, heating furnace, power mechanism and methanol reactor are communicated gradually through methanol transmission pipeline between, form closed methanol circulation passageway, power mechanism is transmission connection with generator to drive its power generation, the utility model energy efficient utilization, realizes energy cascade recovery, system constructs the closed methanol circulation passageway of " pressurization - heating - work - back pressure utilization", need not extra adjustment to participate in the reaction, avoid the heat energy waste of back pressure steam, realize power generation and chemical production energy cascade utilization, improve overall energy utilization rate greatly.

Description

Technical Field

[0001] This utility model relates to the field of power generation technology, specifically a system for generating electricity using methanol vapor back pressure. Background Technology

[0002] In the current power generation sector, steam remains the dominant traditional power generation medium. However, the mainstream steam condensation power generation model, limited by its thermodynamic cycle characteristics, maintains a relatively low energy conversion efficiency, typically only between 30% and 45%. Although steam back-pressure power generation technology can improve efficiency to a higher level of 85%-90% through energy cascade utilization, its application scenarios have significant limitations—it is highly dependent on stable low-pressure steam users. Fluctuations in downstream low-pressure steam demand (such as changes in industrial steam load) or insufficient user numbers will directly disrupt the system's thermodynamic balance, affecting not only the stability of power generation output but potentially forcing units to reduce load or shut down. Meanwhile, in the coal-to-olefins chemical industry, up to 50 million tons of methanol are gasified annually before being transported to reactors at low pressure for production. In traditional processes, this portion of methanol is used solely as a heat source for stripping steam and a basic chemical raw material. Its inherent chemical and thermal energy is not utilized synergistically, resulting in idle and wasted energy resources. Therefore, the market urgently needs a methanol steam back-pressure power generation system to improve energy efficiency, reduce power generation costs, and achieve the goals of energy conservation and emission reduction. Utility Model Content

[0003] The technical problem to be solved by this utility model is to overcome the existing defects and provide a system for generating electricity using methanol vapor back pressure, thereby improving energy utilization, reducing power generation costs and achieving the goal of energy conservation and emission reduction, which can effectively solve the problems in the background technology.

[0004] To achieve the above objectives, this utility model provides the following technical solution: A system for generating electricity using methanol vapor back pressure includes a methanol pressurization pump, a heating furnace, a power mechanism, a methanol reactor, a generator, and a control unit; The control unit is electrically connected to pressure sensor A, pressure sensor B and flow sensor respectively; The methanol pressurizing pump, heating furnace, power unit, and methanol reactor are sequentially connected via methanol transmission pipelines to form a closed methanol circulation path of "pressurization-heating-work-back pressure utilization". The power unit is connected to the generator to drive it to generate electricity.

[0005] Preferably, the power mechanism is an expander or a steam turbine.

[0006] Preferably, the flow sensor is located at the outlet end of the power mechanism, and the inlet end of the power mechanism is provided with an inlet regulating valve. The flow sensor and the inlet regulating valve are respectively electrically connected to the control unit.

[0007] Preferably, the pressure sensor A is also provided at the inlet end of the power mechanism, and the pressure sensor B is provided at the outlet end of the methanol pressurizing pump.

[0008] Preferably, the methanol transmission pipe in the heating furnace is arranged in an S-shaped meandering pattern, and the outer wall of the methanol transmission pipe is provided with heat exchange fins, which extends the methanol heating path and increases the heat exchange area.

[0009] Preferably, a thermocouple for monitoring the temperature of methanol after heating is installed on the methanol outlet pipe of the heating furnace, and the thermocouple is electrically connected to the control unit.

[0010] Preferably, the top of the heating furnace is provided with a flue gas emission channel, and the bottom of the heating furnace is provided with a fuel input channel and an air inlet pipe, the outlet ends of the fuel input channel and the air inlet pipe both extending into the combustion chamber of the heating furnace.

[0011] Preferably, the output shaft of the power mechanism is connected to the input shaft of the generator via a rigid coupling.

[0012] Compared with the prior art, the beneficial effects of this utility model are: 1. High-efficiency energy utilization and cascade energy recovery: The system constructs a closed methanol cycle pathway of "pressurization-heating-work-back pressure utilization", which can participate in the reaction without additional adjustment, avoids the waste of thermal energy of back pressure steam, realizes the cascade utilization of energy in power generation and chemical production, and greatly improves the overall energy utilization rate. 2. Multi-dimensional precise control ensures stable system operation. The pressure sensor A (power mechanism inlet) and pressure sensor B (methanol pressurization pump outlet) are linked to maintain stable inlet pressure of the power mechanism; the flow sensor monitors the back pressure steam flow at the outlet of the power mechanism in real time, and the control unit responds within 5 seconds to adjust the electric inlet regulating valve to ensure that the flow is adapted to the reactor load; the thermocouple monitors the methanol temperature after heating, and the combustion system maintains stable temperature by adjusting fuel and air volume; the speed sensor works with the control unit to correct the speed to ensure the generator operates at its rated speed. The overall control is highly accurate and has a fast response. 3. The optimized structure has strong adaptability and reduces operating costs. The methanol transmission pipeline with S-shaped meandering inside the heating furnace, combined with heat exchange fins, extends the heating path and increases the heat exchange area, ensuring that methanol is heated to 350-450℃ to match the power mechanism requirements and reduce heating energy consumption. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the system of this utility model.

[0014] Figure 2 This is a schematic diagram of the electrical connections of the control unit of this utility model.

[0015] In the diagram: 1. Methanol pressurization pump; 2. Heating furnace; 3. Power unit; 4. Generator; 5. Methanol reactor. Detailed Implementation

[0016] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0017] Please see Figure 1-2 This utility model provides a technical solution: A system for generating electricity using methanol vapor back pressure includes a methanol pressurization pump 1, a heating furnace 2, a power unit 3, a methanol reactor 5, a generator 4, and a control unit; The control unit is electrically connected to pressure sensor A, pressure sensor B, and flow sensor respectively; the control unit uses an existing CPU control unit.

[0018] The methanol pressurizing pump 1, heating furnace 2, power unit 3 and methanol reactor 5 are connected in sequence through methanol transmission pipelines to form a closed methanol circulation path of "pressurization-heating-work-back pressure utilization". The power unit 3 is connected to the generator 4 to drive it to generate electricity.

[0019] The power unit 3 is specifically an expander or a steam turbine, preferably an expander.

[0020] The flow sensor is located at the outlet end of the power mechanism 3, and the inlet end of the power mechanism 3 is equipped with an inlet regulating valve. The flow sensor and the inlet regulating valve are electrically connected to the control unit respectively.

[0021] A flow sensor is installed at the outlet end of the power unit 3 to monitor the back pressure methanol vapor flow rate and match the load of the methanol reactor 5. An inlet regulating valve is installed at the inlet end of the power unit 3. The flow sensor and the inlet regulating valve are electrically connected to the control unit. The control unit adjusts the opening of the inlet regulating valve in real time according to the outlet flow monitored by the flow sensor so that the outlet flow rate is adapted to the load requirements of the methanol reactor 5.

[0022] The inlet end of the power mechanism 3 is also equipped with a pressure sensor A, and the pressure sensor B is located at the outlet end of the methanol pressurizing pump 1. The methanol pressurizing pump 1 is preferably a variable frequency pump. The control system automatically adjusts the speed of the variable frequency motor of the methanol pressurizing pump 1 or the opening of the pump outlet valve according to the inlet pressure feedback of the pressure sensor A, so as to maintain the stability of the inlet pressure of the power mechanism 3.

[0023] The back-pressure methanol vapor discharged from the power unit 3 is directly fed into the methanol reactor 5. The methanol reactor 5 is a chemical process reactor that uses low-pressure methanol vapor, specifically a methanol-to-olefins (MTO) reactor or a methanol-to-dimethyl ether (MTD) reactor. The back-pressure methanol vapor has a pressure of 1-5 MPa and a temperature of 250-400℃. The deviation from the process steam parameters of the methanol reactor 5 is ≤±0.5 MPa pressure and ≤±20℃ temperature, so it can directly participate in the reaction without additional adjustment.

[0024] The methanol pressurizing pump 1 is equipped with a PLC controller, which can set a threshold of 10-20MPa based on the real-time pressure value of pressure sensor A. The controller can also adjust the speed of the variable frequency motor (1000-2000rpm) or the opening of the pump outlet valve (30%-100%) through a PID algorithm, so that the deviation between the monitored value of pressure sensor B and the set value of pressure sensor A is ≤±0.3MPa.

[0025] The control unit is an embedded control module. The flow sensor has a monitoring range of 500-1500 kg / h, and the inlet regulating valve is an electric regulating valve with an adjustment range of 20%-100%. When the flow sensor reading is lower than the required flow rate corresponding to the load of methanol reactor 5 (e.g., when the MTO reactor load is 80%, the required flow rate is 700 kg / h), the control unit controls the inlet regulating valve to increase its opening. When the reading is higher than the required flow rate, the control unit controls the inlet regulating valve to decrease its opening. The flow regulation response time is ≤5s.

[0026] The methanol transmission pipeline inside the heating furnace 2 is arranged in an S-shape, and the outer wall of the methanol transmission pipeline is equipped with heat exchange fins with a fin spacing of 5-10mm. This extends the methanol heating path and increases the heat exchange area, ensuring that the methanol is heated to 350-450℃ to match the inlet temperature requirements of the power unit 3.

[0027] A thermocouple is installed on the methanol outlet pipe of the heating furnace 2 to monitor the temperature of methanol after heating. The thermocouple is electrically connected to the control unit. The combustion control system adjusts the fuel input range of 20-80 m³ / h according to the thermocouple monitoring value. The fuel is natural gas or coal chemical by-product gas and the air volume of the air inlet pipe is adjusted range of 100-400 m³ / h to maintain a stable methanol outlet temperature.

[0028] The top of the heating furnace 2 is provided with a flue gas emission channel, and the bottom of the heating furnace 2 is provided with a fuel input channel and an air inlet pipe. The outlet ends of the fuel input channel and the air inlet pipe both extend into the combustion chamber of the heating furnace 2.

[0029] The output shaft of the power mechanism 3 is connected to the input shaft of the generator 4 via a rigid coupling. A speed sensor with a monitoring range of 2500-3500 r / min is installed at the coupling. The speed sensor is connected to the control unit. When the speed deviates from the rated speed of the generator 4, such as 3000 r / min, the control unit can assist in adjusting the opening of the inlet regulating valve to correct the speed.

[0030] Working principle: In the methanol circulation start-up and pretreatment stage, after the system is started, the methanol feedstock first enters the methanol pressurization pump 1 (preferably a variable frequency pump). The control unit adjusts the speed of the variable frequency motor of the pump (1000-2000 rpm) or the opening of the pump outlet valve (30%-100%) according to the set threshold (10-20MPa) of the pressure sensor A (inlet of power mechanism 3) through the PID algorithm of the PLC controller to pressurize the methanol to the target pressure. The pressure sensor B monitors the pump outlet pressure in real time to ensure that its deviation from the set value of the pressure sensor A is ≤±0.3MPa, providing a stable pressure basis for subsequent heating and power generation.

[0031] In the methanol heating and power output stage, pressurized methanol enters the heating furnace 2 through a transmission pipeline. The pipeline is arranged in an S-shape and has heat exchange fins spaced 5-10mm apart on its outer wall to extend the heating path and increase the heat exchange area. The fuel input channel at the bottom of the heating furnace 2 (the heating furnace 2 can select coal, biomass or urban combustible waste as the heat source according to the actual situation, with an input of 20-80m³ / h) and the air inlet pipeline (air volume 100-400m³ / h) supply energy to the combustion chamber, heating the methanol to 350-450℃ (matching the inlet temperature requirements of the power mechanism).

[0032] Thermocouples on the outlet pipe of heater 2 monitor methanol temperature in real time and transmit the signal to the control unit. The combustion control system dynamically adjusts the fuel input and air volume according to the monitoring value to maintain a stable methanol outlet temperature. High-temperature and high-pressure methanol vapor that meets the standard enters the power mechanism 3 (expander or steam turbine, preferably an expander) to drive the power mechanism to operate. Its output shaft drives the generator 4 to rotate through a rigid coupling to generate electricity.

[0033] In the back pressure utilization and parameter dynamic control stage, the 1-5MPa, 250-400℃ back pressure methanol vapor discharged after the power unit 3 performs work is directly fed into the methanol reactor 5 (MTO or MTD reactor). Since the steam parameters deviate from the process steam of the methanol reactor 5 by ≤±0.5MPa (pressure) and ≤±20℃ (temperature), no additional adjustment is required to participate in the chemical reaction and complete the recovery and utilization of back pressure heat energy.

[0034] During this process, the flow sensor (located at the outlet of power unit 3, with a monitoring range of 500-1500 kg / h) monitors the back pressure steam flow in real time. If the flow rate is lower than the required flow rate corresponding to the load of methanol reactor 5 (e.g., 700 kg / h is required for 80% load of MTO reactor), the control unit controls the inlet regulating valve of power unit 3 to increase the opening. If the flow rate is higher than the required value, the opening is reduced, with an adjustment response time of ≤5s, to ensure that the flow rate matches the load of methanol reactor 5. At the same time, the speed sensor (located at the coupling, with a monitoring range of 2500-3500 r / min) monitors the speed of generator 4. If it deviates from the rated speed (e.g., 3000 r / min), the control unit can assist in adjusting the opening of the inlet regulating valve to correct the speed, ensuring stable operation of the system throughout the process and forming a closed-loop workflow of "circulation-power generation-recovery".

[0035] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A system for generating electricity using methanol vapor back pressure, characterized in that: It includes a methanol pressurization pump (1), a heating furnace (2), a power unit (3), a methanol reactor (5), a generator (4), and a control unit; The control unit is electrically connected to pressure sensor A, pressure sensor B and flow sensor respectively; The methanol pressurizing pump (1), heating furnace (2), power unit (3) and methanol reactor (5) are connected in sequence through methanol transmission pipeline to form a closed methanol circulation path. The power unit (3) is connected to the generator (4) to drive it to generate electricity.

2. The system for generating electricity using methanol vapor back pressure according to claim 1, characterized in that: The power mechanism (3) is specifically an expander or a steam turbine.

3. The system for generating electricity using methanol vapor back pressure according to claim 1, characterized in that: The flow sensor is located at the outlet end of the power mechanism (3), and the inlet end of the power mechanism (3) is provided with an inlet regulating valve. The flow sensor and the inlet regulating valve are electrically connected to the control unit respectively.

4. The system for generating electricity using methanol vapor back pressure according to claim 1, characterized in that: The pressure sensor A is also provided at the inlet end of the power mechanism (3), and the pressure sensor B is provided at the outlet end of the methanol pressurizing pump (1).

5. The system for generating electricity using methanol vapor back pressure according to claim 1, characterized in that: The methanol transmission pipeline inside the heating furnace (2) is arranged in an S-shaped meandering pattern, and the outer wall of the methanol transmission pipeline is provided with heat exchange fins.

6. The system for generating electricity using methanol vapor back pressure according to claim 1, characterized in that: A thermocouple for monitoring the temperature of methanol after heating is installed on the methanol outlet pipe of the heating furnace (2), and the thermocouple is electrically connected to the control unit.

7. The system for generating electricity using methanol vapor back pressure according to claim 1, characterized in that: The top of the heating furnace (2) is provided with a flue gas emission channel, and the bottom of the heating furnace (2) is provided with a fuel input channel and an air inlet pipe. The outlet ends of the fuel input channel and the air inlet pipe both extend into the combustion chamber of the heating furnace (2).

8. The system for generating electricity using methanol vapor back pressure according to claim 1, characterized in that: The output shaft of the power mechanism (3) is connected to the input shaft of the generator (4) via a rigid coupling.

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