Sealing system capable of recycling organic working medium and lubricating oil for organic Rankine cycle system

Abstract

The invention relates to a sealing system capable of recycling organic working medium and lubricating oil for an organic Rankine cycle system, which comprises an expansion machine, the first inlet of the expansion machine is connected with a working medium pipeline, and the second inlet of the expansion machine is connected with a lubricating oil conveying pipeline; a gas working medium sealing channel and a lubricating oil channel are arranged at the end of the expansion machine, and the position, in the expansion machine, of the lubricating oil channel is closer to the end of the expansion machine than the gas working medium sealing channel. A first inlet of the heating separator is connected with a recovery pipeline of the expansion machine, and an outlet of the heating separator is connected with a working medium pipeline through a working medium pump. The system can recover the organic working medium and the lubricating oil of the organic Rankine cycle system, online monitoring is carried out, the use efficiency of the working medium and the lubricating oil is improved, and the sealing effect is achieved.

Description

Technical Field

[0001] The invention relates to a sealing system for recovering organic working fluid and lubricating oil in an organic Rankine cycle system, belonging to the technical field of industrial waste heat utilization. Background Art

[0002] The organic Rankine cycle power generation system is a power generation technology based on the recycling of organic working fluids. It realizes the conversion of waste heat into electrical energy through key equipment such as expanders, heat exchangers, and working fluid pumps, which can improve energy utilization efficiency and achieve cost reduction and efficiency improvement. However, in actual operation, due to the high internal pressure of the expander, a large amount of organic working fluids and lubricating oils will leak through the gap between the rotor end and the cylinder, causing working fluid waste and safety hazards. There is an urgent need for a sealing system that can recover gaseous working fluids and lubricating oils. At present, the methods for recovering organic working fluids and lubricating oils include the use of liquid and gaseous working fluids for separate recovery, the method of separating organic working fluids and lubricating oils through an oil-gas separator, the method of recovering organic working fluids through a liquid reservoir, and the method of recovering vacuum by a vacuum pump. The expansion machine sealing methods include mechanical seals, dry gas seals, shaft end steam seals, etc. Overall, there is currently a lack of sealing systems suitable for recovering organic working fluids and lubricating oils in organic Rankine cycle systems.

[0003] The current challenges faced by the sealing system of the organic Rankine cycle system that can recycle organic working fluids and lubricants are: (1) The organic working fluids and lubricants place requirements on the chemical stability of the sealing materials, requiring them to be able to resist corrosion and expansion and adapt to high temperature conditions. (2) There may be a high degree of miscibility between the organic working fluid and the lubricant, making it difficult to effectively separate and recycle them after mixing. (3) The addition of an organic working fluid and lubricant recovery system will increase the complexity of the organic Rankine cycle system, and corresponding monitoring tools need to be configured to ensure its normal operation. Summary of the invention

[0004] In response to the above technical problems, the present invention provides a sealing system for an organic Rankine cycle system that can recover organic working fluid and lubricating oil. The system can recover the organic working fluid and lubricating oil in the organic Rankine cycle system, perform online monitoring, improve the use efficiency of the working fluid and lubricating oil, and play a sealing role.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] A sealing system for recovering organic working fluid and lubricating oil in an organic Rankine cycle system, comprising:

[0007] An expander, wherein a first inlet of the expander is connected to a working medium pipeline, a second inlet of the expander is connected to a lubricating oil delivery pipeline, a gas working medium sealing channel and a lubricating oil channel are provided at an end of the expander, and a position of the lubricating oil channel inside the expander is closer to the end of the expander than the gas working medium sealing channel;

[0008] A heating separator, wherein a first inlet of the heating separator is connected to a recovery pipeline of the expander, and an outlet of the heating separator is connected to a working fluid pipeline via a working fluid pump.

[0009] The sealing system for recovering organic working fluid and lubricating oil in an organic Rankine cycle system preferably further includes an air-cooled cooler, wherein the outlet of the heating separator is connected to the inlet of the air-cooled cooler via a lubricating oil recovery pipeline, and the outlet of the air-cooled cooler is connected to the lubricating oil delivery pipeline.

[0010] The sealing system for recovering organic working fluid and lubricating oil in an organic Rankine cycle system is preferably provided with temperature sensors at both the inlet and the outlet of the air-cooled cooler.

[0011] The sealing system for recovering organic working fluid and lubricating oil in an organic Rankine cycle system, preferably, the temperature sensor is also provided on the heating separator and the expander.

[0012] The sealing system for recovering organic working fluid and lubricating oil in an organic Rankine cycle system, preferably, the temperatures of the heating separator and the air-cooled cooler are both controlled by a central control system.

[0013] The sealing system for recovering organic working fluid and lubricating oil in an organic Rankine cycle system, preferably, the temperature sensor has a monitoring and early warning function.

[0014] The sealing system for recovering organic working fluid and lubricating oil in an organic Rankine cycle system is preferably made of perfluoroether rubber.

[0015] The present invention adopts the above technical solution, which has the following advantages:

[0016] 1. Aiming at high temperature working conditions, the present invention adopts high temperature materials and high temperature seals, and selects perfluoroether rubber materials to make O-rings, which ensures the reliability and efficiency of the sealing equipment and improves the stability and safety of the entire system in high temperature environments.

[0017] 2. The present invention is provided with temperature sensors before and after the expander housing and the cooler, which can be monitored in real time by the central control system, ensuring that the temperature of each link of the organic working fluid and lubricating oil is normal during operation, and improving the system operation and maintenance efficiency and stability.

[0018] 3. The present invention separates the organic working fluid and the lubricating oil by heating the separator and the cooler, thus solving the problem that the organic working fluid and the lubricating oil are highly miscible and difficult to effectively recycle. According to the physical and chemical properties of the organic working fluid and the lubricating oil, further improvements can be made by adding liquid storage tanks, condensers, working fluid collection tanks and other equipment, which has strong universality.

[0019] 4. The present invention combines the sealing system with the organic working fluid and lubricating oil recovery system, which simplifies the complexity of the system, reduces equipment investment and operating costs, and reduces the risk of leakage. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 A schematic diagram of a sealing system for recovering organic working fluid and lubricating oil in an organic Rankine cycle system provided by an embodiment of the present invention;

[0021] The reference numerals in the figures are as follows:

[0022] 1- expander; 2- air-cooled cooler; 3- stop valve; 4- temperature sensor; 5- heating separator; 6- working fluid pump. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention is described clearly and completely below. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary persons in the art without creative work are within the scope of protection of the present invention.

[0024] Unless otherwise defined, the technical or scientific terms used in the present invention shall have the usual meanings understood by persons with ordinary skills in the field to which the present invention belongs. The words "first", "second", "third", "fourth" and similar terms used in the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. Words such as "include" or "comprise" and the like mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Words such as "connect" or "connected" and the like are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect.

[0025] For ease of description, spatially relative terms may be used herein to describe the relationship of one element or feature relative to another element or feature as shown in the figures, such as "inside", "outside", "inner side", "outer side", "below", "above", etc. Such spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation depicted in the figures.

[0026] The current challenges faced by the sealing system of the organic Rankine cycle system that can recycle organic working fluids and lubricants are: (1) The organic working fluids and lubricants place requirements on the chemical stability of the sealing materials, requiring them to be able to resist corrosion and expansion and adapt to high temperature conditions. (2) There may be a high degree of miscibility between the organic working fluid and the lubricant, making it difficult to effectively separate and recycle them after mixing. (3) The addition of an organic working fluid and lubricant recovery system will increase the complexity of the organic Rankine cycle system, and corresponding monitoring tools need to be configured to ensure its normal operation.

[0027] Based on the above technical problems, the present invention provides a sealing system for an organic Rankine cycle system that can recover organic working fluid and lubricating oil. The system can recover the organic working fluid and lubricating oil of the organic Rankine cycle system, perform online monitoring, improve the use efficiency of the working fluid and lubricating oil, and play a sealing role.

[0028] like Figure 1 As shown, the sealing system for recovering organic working fluid and lubricating oil in an organic Rankine cycle system according to the present invention comprises:

[0029] An expander 1, wherein a first inlet of the expander 1 is connected to a working fluid pipeline, a second inlet of the expander 1 is connected to a lubricating oil delivery pipeline, a gas working fluid sealing channel and a lubricating oil channel are provided at the end of the expander 1, and a position of the lubricating oil channel inside the expander 1 is closer to the end of the expander 1 than the gas working fluid sealing channel; a heating separator 5, wherein a first inlet of the heating separator 5 is connected to a recovery pipeline of the expander 1, and an outlet of the heated separator 5 is connected to the working fluid pipeline through a working fluid pump 6; an air-cooled cooler 2, wherein an outlet of the heating separator 5 is connected to an inlet of the air-cooled cooler 2 through a lubricating oil recovery pipeline, and an outlet of the air-cooled cooler 2 is connected to a lubricating oil delivery pipeline.

[0030] After lubricating the expander 1, the lubricating oil is recovered into the heating separator 5 together with the organic working fluid leaked from the expander 1. According to the difference in boiling points between the organic working fluid and the lubricating oil, the temperature of the heating separator is controlled to separate the organic working fluid and the lubricating oil. The separated organic working fluid returns to the expander 1 to perform work, and the lubricating oil enters the air-cooled cooler 2 for cooling, and finally returns to the expander 1 for circulation. This system effectively solves the problems of leakage and recovery of organic working fluid and lubricating oil in the organic Rankine cycle system.

[0031] Since the expander 1 is provided with a gas working medium sealing channel and a lubricating oil channel. Both the gas working medium sealing channel and the lubricating oil channel are arranged at the end of the expander 1, and the position of the lubricating oil channel inside the expander 1 is closer to the end of the expander 1 than the gas working medium sealing channel. The gas source of the gas working medium sealing channel comes from the cylinder of the expander 1, and its high pressure is used to discharge to the end to isolate the external air and prevent the lubricating oil from entering the cylinder, thereby achieving a sealing effect. The lubricating oil channel is connected to the external lubricating oil delivery pipeline for lubricating oil replenishment.

[0032] Furthermore, a temperature measuring point is added to the shell of the expander 1, and a temperature sensor 4 is added before and after the air-cooled cooler 2. The sensor is connected to the central control system, so that the staff can monitor the operating temperature of the entire recovery system in real time to ensure the stability and safety of the system.

[0033] Furthermore, temperature sensors 4 are provided at the inlet and outlet of the air-cooled cooler 2, and temperature sensors 4 are also provided on the heating separator 5 and the expander 1. The temperatures of the heating separator 5 and the air-cooled cooler 2 are both controlled by the central control system, and the temperature sensor 4 has a monitoring and early warning function.

[0034] The heating separator 5 is equipped with a temperature sensor 4 and connected to the central control system to monitor the temperature data in real time. According to the boiling points of different organic working fluids and lubricating oils, the corresponding temperature is set, and the organic working fluid and lubricating oil are separated by heating. For different organic working fluids and lubricating oils, it is possible to consider adding equipment such as liquid storage tanks, condensers, and working fluid collection tanks according to their physical and chemical properties to improve the separation effect and speed of organic working fluids and lubricating oils. After being separated from the heating separator 5, the lubricating oil will enter the air-cooled cooler 2 for cooling. The air-cooled cooler 2 absorbs and discharges the heat in the lubricating oil through its internal heat dissipation device and external air circulation. After passing through the air-cooled cooler 2, the lubricating oil quickly drops to the normal operating temperature and returns to the lubricating oil pipeline for recycling.

[0035] Furthermore, the sealing equipment uses high-temperature seals for high-temperature working conditions to ensure that the seals can work normally in high-temperature environments. The O-ring material is perfluoroether rubber, which effectively alleviates the leakage of organic working fluids in the cylinder.

[0036] The technical solution of the present invention is described in detail below in conjunction with specific application examples.

[0037] A waste heat power generation project uses cyclopentane as the working fluid to recover the waste heat of the gas turbine flue gas. The gas turbine exhaust temperature is about 450℃, the flue gas flow rate is about 830t / h, and the expander lubricant is No. 46 turbine oil. In order to recover the cyclopentane working fluid and lubricating oil leaked during the operation of the ORC system, the system is equipped with a sealing system that can recover organic working fluids and lubricating oil.

[0038] After heat exchange with the heat transfer oil, the cyclopentane is heated to 256°C and becomes a gaseous working medium to do work in the expander 1. A portion of the cyclopentane is used as a sealing gas and is discharged from the gas working medium sealing channel to the gap between the rotor end and the cylinder of the expander 1 to the outside. At the same time, the lubricating oil delivery system of the expander 1 supplies No. 46 turbine oil to the expander 1, and the lubricating oil supply temperature is 45°C. Since the lubricating oil channel is closer to the outside of the end, the lubricating oil is carried by the cyclopentane gas working medium to the outside of the expander 1 and discharged, which prevents the lubricating oil and air from entering the expander 1 and achieves a sealing effect.

[0039] The discharged cyclopentane gaseous working fluid and lubricating oil enter the recovery pipeline at the end of the expander 1 together, and enter the heating separator 5. The cyclopentane working fluid discharged from the expander 1 is about 164°C, and the temperature of the discharged lubricating oil is about 65°C. Since cyclopentane has a low boiling point of about 49.3°C and the boiling point of No. 46 turbine oil is high, the temperature of the heating separator is set to 70°C. Under this environment, cyclopentane will maintain a gaseous state and be recovered by the working fluid pump 6 on the upper part of the heating separator 5 to the working fluid pipeline before entering the expander 1, and will be recycled together with the gaseous working fluid after heat exchange with the heat transfer oil.

[0040] The No. 46 lubricating oil always remains in liquid form in the heating separator 5, and the 70°C environment will not cause its temperature to be too high and cause failure. The lubricating oil enters the lubricating oil recovery pipeline from the valve at the bottom of the heating separator 5 and is transported to the air-cooled cooler 2 through the working fluid pump 6. After cooling to 45°C in the air-cooled cooler 2, it enters the expander 1 together with the lubricating oil of the lubricating oil system for recycling.

[0041] The temperatures of the heating separator 5 and the air-cooled cooler 2 are both controlled by the central control system. The system sets temperature limits for the heating separator 5, with an upper limit of 70°C and a lower limit of 68°C. When the temperature sensor in the heating separator 5 is lower than 68°C, the heater starts heating, and when the temperature sensor 4 is higher than 70°C, the heating separator 5 stops heating. Since the temperature of the cyclopentane gas working fluid is relatively high, the heater will not start most of the time, reducing energy consumption. Temperature sensors 4 are provided before and after the air-cooled cooler 2, and temperature limits are set for the air-cooled cooler 2. When the outlet temperature is higher than 46°C, the power of the air-cooled cooler 2 is increased to enhance the cooling effect. When the outlet temperature is lower than 42°C, the power of the air-cooled cooler 2 is reduced to reduce the cooling effect.

[0042] The central control system has a monitoring and early warning function through the temperature sensor 4. The system is equipped with temperature sensors 4 at key locations such as the heating separator 5, the air-cooled cooler 2, and the expander 1 housing. When the sensor temperature is too high or too low, the central control system will promptly alarm and notify the staff to ensure safe and stable operation of the system.

[0043] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A sealing system for recovering organic working fluid and lubricating oil in an organic Rankine cycle system, characterized in that: include: An expander (1), wherein a first inlet of the expander (1) is connected to a working medium pipeline, a second inlet of the expander (1) is connected to a lubricating oil delivery pipeline, a gas working medium sealing channel and a lubricating oil channel are provided at the end of the expander (1), and the lubricating oil channel is located inside the expander (1) closer to the end of the expander (1) than the gas working medium sealing channel; A heating separator (5), wherein a first inlet of the heating separator (5) is connected to a recovery pipeline of the expander (1), and an outlet of the heating separator (5) is connected to a working fluid pipeline via a working fluid pump (6).

2. The sealing system for recovering organic working fluid and lubricating oil in an organic Rankine cycle system according to claim 1, characterized in that: It also includes an air-cooled cooler (2), the outlet of the heating separator (5) is connected to the inlet of the air-cooled cooler (2) through a lubricating oil recovery pipeline, and the outlet of the air-cooled cooler (2) is connected to the lubricating oil delivery pipeline.

3. The sealing system for recovering organic working fluid and lubricating oil in an organic Rankine cycle system according to claim 2, characterized in that: Temperature sensors (4) are provided at the inlet and outlet of the air-cooled cooler (2).

4. The sealing system for recovering organic working fluid and lubricating oil in an organic Rankine cycle system according to claim 3, characterized in that: The temperature sensor (4) is also provided on the heating separator (5) and the expander (1).

5. The sealing system for recovering organic working fluid and lubricating oil in an organic Rankine cycle system according to claim 4, characterized in that: The temperatures of the heating separator (5) and the air-cooled cooler (2) are both controlled by a central control system.

6. The sealing system for recovering organic working fluid and lubricating oil in an organic Rankine cycle system according to claim 5, characterized in that: The temperature sensor (4) is provided with a monitoring and early warning function.

7. The sealing system for recovering organic working fluid and lubricating oil in an organic Rankine cycle system according to claim 5, characterized in that: The sealing material of the sealing system is perfluoroether rubber.

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