Steam condensation water energy recovery system and method

Abstract

The invention relates to the technical field of steam and heat energy utilization, and particularly discloses a steam condensation water energy recovery system and method.After condensation water passes through a first expansion machine and a first steam-liquid separator, hot water is output, and the first expansion machine is in transmission connection with a first compressor to output expansion work and output low-pressure steam. The invention further discloses a steam condensation water energy recovery system and method in the second form, after condensation water passes through two sets of expansion machines and a steam-liquid separator, hot water is output, the two expansion machines are in transmission connection with the power output unit to output expansion work, and the steam-liquid separator outputs low-pressure steam with two kinds of pressure. According to the invention, energy cascade recovery is carried out on the condensed water in a two-phase expansion mode, so that not only is the expansion work recovered, but also low-pressure steam and hot water can be obtained for production, meanwhile, possible loss caused by throttling and energy consumption of recompression of negative-pressure steam generated after complete flash evaporation are avoided, and efficient recovery and utilization of the energy of the condensed water are realized.

Description

Technical Field

[0001] The present invention belongs to the technical field of steam and heat energy utilization, and particularly relates to a steam condensate energy recovery system and method. Background Art

[0002] In industrial production, steam is widely used for heating and drying materials. During the process, a large amount of latent heat is released from the steam and it condenses into condensate with a certain temperature and pressure. At present, there are mainly two ways to recover the energy of the condensate. One is to utilize its sensible heat, that is, the condensate continues to release heat and cool down in the heat exchanger, and its sensible heat is used for heating. The other is to flash the condensate to reduce the pressure and turn it into two parts. Most of them become normal pressure water for production use, and a small part becomes negative pressure steam, which is then pressurized by a steam compressor or a steam ejector and used for heating. For example, the invention "A Condensate Water Delivery System" with the application number CN202411001959.7 and the invention "A Fully Closed Condensate Automatic Recovery Pump and Method" with the application number CN201110083232.4 both use steam as the power source to recover the steam released by the flashing of the condensate. Since flashing is an adiabatic throttling, which is a typical irreversible process, there must be a large available energy loss. Moreover, the hot water temperature generated after flashing is not high enough and often cannot meet the heating process temperature requirements. The steam pressure after flashing is relatively low, and additional work is required for pressurization before it can be used for the process. Therefore, the current operation method has low energy utilization efficiency and economy. How to economically and efficiently recover the energy of the condensate during the steam heating process is still a problem to be solved in many industrial productions. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a steam condensate energy recovery system and method for the energy recovery and utilization of steam condensate during the drying and heating processes in industries such as textile printing and dyeing.

[0004] To solve the above technical problem, the present invention provides a steam condensate energy recovery system, including a first expander. The condensate pipeline is connected to the hot water pipeline after passing through a first regulating valve, a first filter, a first expander, and a first vapor-liquid separator in sequence;

[0005] The first expander is drivingly connected to a first compressor through a first coupling; the gas outlet of the first vapor-liquid separator is connected to a first low-pressure steam pipeline through the first compressor.

[0006] The present invention also provides a second steam condensate energy recovery system, including a first expander and a second expander. The condensate pipeline is connected to the hot water pipeline after passing through a first regulating valve, a first filter, a first expander, a first vapor-liquid separator, a second regulating valve, a second filter, a second expander, and a second vapor-liquid separator in sequence;

[0007] The first expander and the second expander are respectively drivingly connected to the power output unit.

[0008] As an improvement to the second steam condensate energy recovery system of the present invention:

[0009] The power output unit includes a first generator and a second generator. The first expander is drivingly connected to the first generator through a first coupling, and the second expander is drivingly connected to the second generator through a second coupling;

[0010] The gas outlet of the first vapor-liquid separator is connected to the first low-pressure steam pipeline, and the gas outlet of the second vapor-liquid separator is connected to the second low-pressure steam pipeline through a third compressor.

[0011] As a further improvement to the second steam condensate energy recovery system of the present invention:

[0012] The power output unit includes a first compressor and a second compressor. The first expander is drivingly connected to the first compressor through a first coupling, and the second expander is drivingly connected to the second compressor through a second coupling;

[0013] The gas outlets of the first vapor-liquid separator and the second vapor-liquid separator adopt connection method one: the gas outlet of the first vapor-liquid separator is connected to the first low-pressure steam pipeline through a first compressor, and the gas outlet of the second vapor-liquid separator is connected to the second low-pressure steam pipeline through a second compressor;

[0014] Alternatively, the gas outlets of the first vapor-liquid separator and the second vapor-liquid separator adopt connection method two: the gas outlet of the first vapor-liquid separator is connected to the first low-pressure steam pipeline, and the gas outlet of the second vapor-liquid separator is connected to the second low-pressure steam pipeline through a first compressor and a second compressor.

[0015] As a further improvement to the second steam condensate energy recovery system of the present invention:

[0016] The gas outlet of the first vapor-liquid separator is connected to the first low-pressure steam pipeline, and the gas outlet of the second vapor-liquid separator is connected to the second low-pressure steam pipeline through a dual-drive compressor;

[0017] The power output unit includes a dual-drive compressor, or the power output unit includes a dual-drive compressor and a second generator: when the power output unit includes a dual-drive compressor, the first expander and the second expander are both drivingly connected to the dual-drive compressor through a first coupling and a second coupling respectively; when the power output unit includes a dual-drive compressor and a second generator, the first expander and the second expander are both drivingly connected to the dual-drive compressor through a first coupling and a second coupling respectively, and at the same time, the second expander is drivingly connected to the second generator through a third coupling.

[0018] The present invention provides a method for energy recovery using a steam condensate energy recovery system:

[0019] When the condensate passes through the first expander, it expands to do work to drive the first compressor. After expansion, the temperature and pressure of the condensate decrease to form a vapor-liquid mixture. Then, when passing through the first vapor-liquid separator, low-pressure steam and liquid water are separated. The low-pressure steam is compressed and pressurized by the first compressor and then supplied for production use, and the liquid water is supplied for production use through a hot water pipeline.

[0020] The present invention also simultaneously provides a method for energy recovery using a second steam condensate energy recovery system:

[0021] The condensate undergoes a first expansion to do work through the first expander. After expansion, the temperature and pressure of the condensate decrease to form a vapor-liquid mixture, and the first low-pressure steam and the first liquid water are separated through the first vapor-liquid separator;

[0022] The first liquid water undergoes a second expansion to do work through the second expander, and the temperature and pressure further decrease. The second low-pressure steam and the second liquid water are separated through the second vapor-liquid separator; the second liquid water is directly supplied for production use.

[0023] As an improvement to the method for energy recovery using the second steam condensate energy recovery system:

[0024] When the power output unit is the first generator and the second generator, the energy from the expansion work of the first expander is used to drive the first generator to generate electricity, and the energy from the expansion work of the second expander is used to drive the second generator to generate electricity. The obtained electric energy is all supplied for production use;

[0025] The second low-pressure steam is compressed and pressurized by the third compressor and then supplied for production use, and the first low-pressure steam is directly supplied for production use.

[0026] As a further improvement to the method for energy recovery using the second steam condensate energy recovery system:

[0027] When the power output unit is the first compressor and the second compressor, the energy from the expansion work of the first expander is used to drive the first compressor, and the energy from the expansion work of the second expander is used to drive the second compressor;

[0028] The first low-pressure steam is compressed and pressurized by the first compressor and then supplied for production use, and the second low-pressure steam is compressed and pressurized by the second compressor and then supplied for production use; or, the first low-pressure steam is directly supplied for production use, and the second low-pressure steam is compressed and pressurized twice by the first compressor and the second compressor and then supplied for production use.

[0029] As a further improvement to the method of energy recovery using the second steam condensate energy recovery system:

[0030] The first low-pressure steam is directly supplied for production use, and the second low-pressure steam is compressed and boosted by a dual-drive compressor before being supplied for production use;

[0031] When the power output unit is a dual-drive compressor, the energy generated by the expansion work of the first expander and the second expander is used to drive the dual-drive compressor;

[0032] Alternatively, when the power output unit is a dual-drive compressor and a second generator, the energy generated by the expansion work of the first expander is used to drive the dual-drive compressor, and the energy generated by the expansion work of the second expander is used to drive the dual-drive compressor and the second generator simultaneously; the electric energy obtained by the power generation of the second generator is supplied for production use.

[0033] The beneficial effects of the present invention are mainly reflected in:

[0034] The present invention conducts cascaded recovery and utilization of energy according to the temperature and pressure of the condensate, which can significantly improve the energy recovery efficiency and economy. First, a two-phase expansion method and device are adopted to expand the condensate at a certain temperature and pressure in a two-phase expander, and the output work is used to drive power equipment such as generators or compressors, avoiding the available energy loss caused by flashing and throttling, thereby improving the energy recovery and utilization efficiency of the condensate. After the condensate expands in the expander to an appropriate temperature and pressure and becomes a vapor-liquid two-phase mixture, it enters the vapor-liquid separator. After the steam separates the liquid water, it enters the low-pressure steam pipe network for production use, and the liquid water enters the expander to continue expanding and doing work to drive power equipment such as generators or compressors, further recovering and utilizing the energy of the condensate. The liquid water expands in the two-phase expander and becomes a two-phase mixture with a lower temperature and pressure before being discharged into the vapor-liquid separator. The steam is pressurized by mechanical or thermal recompression before being supplied for production use, and the liquid water is pumped out and sent to hot water users.

[0035] Through two expansions, not only the expansion work is recovered, but also low-pressure steam with different pressures can be obtained for production use. At the same time, the possible losses caused by throttling and the energy consumption of recompressing the negative-pressure steam generated after all flashing are avoided, realizing the efficient recovery and utilization of the energy of the condensate. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The following further details the specific embodiments of the present invention in conjunction with the drawings.

[0037] Figure 1 It is a schematic structural diagram of Scheme 1 of a steam condensate energy recovery system of the present invention;

[0038] Figure 2 It is a schematic structural diagram of Scheme 2 of a steam condensate energy recovery system of the present invention;

[0039] Figure 3 This is a schematic structural diagram of Scheme 3 of an energy recovery system for steam condensate in the present invention;

[0040] Figure 4 This is a schematic structural diagram of Scheme 4 of an energy recovery system for steam condensate in the present invention;

[0041] Figure 5 This is a schematic structural diagram of Scheme 5 of an energy recovery system for steam condensate in the present invention;

[0042] Figure 6 This is a schematic structural diagram of Scheme 6 of an energy recovery system for steam condensate in the present invention. Specific embodiments

[0043] The present invention will be further described below in conjunction with specific embodiments, but the protection scope of the present invention is not limited thereto:

[0044] Embodiment 1. An energy recovery and utilization system for condensate, Scheme 1, as Figure 1 shown, includes two expansion units, two power output units and two steam pipelines. The power output units in this embodiment include a first generator 9 and a second generator 10. Specifically:

[0045] The first expansion unit includes a first expander 5. After the condensate pipeline is connected to the first regulating valve 1, it sequentially passes through a first filter 3, a first expander 5 and a first vapor-liquid separator 12. The first generator 9 is drivingly connected to the first expander 5 through a first coupling 7. The first expander 5 is used to convert the potential energy of high-pressure condensate into mechanical energy, and then drive the first generator 9 to generate electricity. The condensate expands in the two-phase expander (the first expander 5), and the output work is used to drive power equipment such as generators, avoiding the available energy loss caused by flashing throttling. The first regulating valve 1 is used to regulate the flow rate of the input high-pressure condensate and at the same time control the pressure in the first vapor-liquid separator 12.

[0046] The second expansion unit includes a second expander 6. After the first vapor-liquid separator 12 is connected to the second regulating valve 2, it then sequentially passes through a second filter 4, a second expander 6 and a second vapor-liquid separator 11. The second generator 10 is drivingly connected to the second expander 6 through a second coupling 8. The second regulating valve 2 is used to regulate the flow rate of the saturated water flowing from the first expansion unit into the second expansion unit and at the same time control the pressure in the second vapor-liquid separator 11.

[0047] The first steam-liquid separator 12 and the second steam-liquid separator 11 are used to separate the wet steam generated after the condensate expands. The gas outlet is provided at the upper part of the first steam-liquid separator 12 or the second steam-liquid separator 11, and the liquid outlet is provided at the lower part of the first steam-liquid separator 12 or the second steam-liquid separator 11. In the two steam pipelines, the first low-pressure steam pipeline is connected to the gas outlet of the first steam-liquid separator 12. The expanded vapor-liquid two-phase mixture is separated into a vapor phase and a liquid phase in the first steam-liquid separator 12. The vapor phase is led out from the upper part, and the liquid phase is led out from the lower part to the second expansion unit. The gas outlet of the second steam-liquid separator 11 is connected to the second low-pressure steam pipeline through the third compressor 13. The expanded vapor-liquid two-phase mixture is separated into a vapor phase and a liquid phase in the second steam-liquid separator 11. The vapor phase is led out from the upper part, compressed and pressurized by the third compressor 13, and then output from the second low-pressure steam pipeline. The liquid phase is led out from the liquid outlet at the lower part of the second steam-liquid separator 11 and sent to the external hot water system through the hot water pipeline.

[0048] The energy recovery method of the condensate energy recovery and utilization system solution 1 is as follows:

[0049] 1. Energy recovery of condensate

[0050] 1.1 First energy recovery

[0051] The high-pressure condensate generated during the generation process flows into the first expansion unit through the condensate pipeline, and then enters the first expander 5 through the first regulating valve 1 and the first filter 3 for the first expansion work. After expansion, the temperature and pressure of the condensate decrease and become a vapor-liquid mixture with a pressure of 0.19 - 0.6 MPa. Then, the first low-pressure steam and the first liquid water are obtained through separation by the first steam-liquid separator 12. The first liquid water enters the second expansion unit through the pipeline.

[0052] 1.2 Second energy recovery

[0053] The first liquid water enters the second expander 6 through the second regulating valve 2 and the second filter 4 for the second expansion work, expanding into a vapor-liquid mixture with further reduced temperature and pressure and a pressure of 0.03 - 0.12 MPa, and is discharged into the second steam-liquid separator 11;

[0054] In the second steam-liquid separator 11, the vapor-liquid mixture is separated for the second time to obtain the second low-pressure steam and the second liquid water.

[0055] 2. Work done by the recovered energy

[0056] 2.1 The energy of the first expander 5 for expansion work is used to drive the first generator 9 to generate electricity, and the obtained electric energy is used for production;

[0057] 2.2 The energy of the second expander 6 for expansion work is used to drive the second generator 10 to generate electricity, and the obtained electric energy is used for production;

[0058] 2.3. The first low-pressure steam separated by the first vapor-liquid separator 12 (with a pressure equivalent to that in the first vapor-liquid separator 12, 0.19 - 0.6 MPa) flows out through the first low-pressure steam pipeline and is used for production;

[0059] 2.4. The second low-pressure steam separated by the second vapor-liquid separator 11 (with a pressure equivalent to that in the second vapor-liquid separator 11, 0.03 - 0.12 MPa) is compressed and boosted by the third compressor 13 and then flows out through the second low-pressure steam pipeline for production use. The second liquid water is sent into the hot water system for production use by a pump through the hot water pipeline.

[0060] In this embodiment, the high-pressure condensate in the production process undergoes the first expansion in the first expander 5, and the output work is used to drive the first generator 9 to generate electricity. It undergoes the second expansion in the second expander 6, and the output work is used to drive the second generator 10 to generate electricity. Through the two expansions, not only the secondary gradient recovery of the condensate energy is achieved, but also low-pressure steam with different pressures can be obtained, which are respectively supplied for production use through the first low-pressure steam pipeline and the second low-pressure steam pipeline, fully utilizing the energy of the condensate. At the same time, it avoids the possible energy loss caused by throttling and the energy consumption of recompressing the negative-pressure steam generated after all flashing, realizing the efficient recovery and utilization of the condensate energy. The output energy forms include pressurized steam and electricity, and the pressurized steam can be of two different pressures to meet the requirements of different energy forms in production.

[0061] Embodiment 2. A condensate energy recovery and utilization system, Scheme 2, as Figure 2 shown, includes two expansion units, two power output units, and two steam pipelines. The difference from Embodiment 1 is that the power output unit uses a compressor to replace the generator for doing work in recovering the energy of high-pressure condensate. Specifically:

[0062] The first expansion unit includes the first expander 5. The first regulating valve 1 is connected in sequence through the first filter 3, the first expander 5, and the first vapor-liquid separator 12. The first compressor 141 is drivingly connected to the first expander 5 through the first coupling 7. The gas outlet of the first vapor-liquid separator 12 is connected to the gas inlet of the first compressor 141 through a pipeline, and the gas outlet of the first compressor 141 is connected to the first low-pressure steam pipeline. The liquid outlet of the first vapor-liquid separator 12 is connected to the second expansion unit through a pipeline.

[0063] The second expansion unit includes a second expander 6. After the first vapor-liquid separator 12 is connected to the second regulating valve 2, it is then sequentially connected to a second filter 4, the second expander 6, and the second vapor-liquid separator 11. The second compressor 142 is drivingly connected to the second expander 6 through a second coupling 8. The gas outlet of the second vapor-liquid separator 11 is connected to the gas inlet of the second compressor 142 through a pipeline, and the gas outlet of the second compressor 142 is connected to the second low-pressure steam pipeline. The liquid outlet of the second vapor-liquid separator 11 is connected to a hot water pipeline.

[0064] The energy recovery method of the condensate energy recovery and utilization system solution 2 is as follows:

[0065] 1. Energy recovery of condensate

[0066] 1.1. The first energy recovery is the same as 1.1 of Embodiment 1.

[0067] 1.2. The second energy recovery is the same as 1.2 of Embodiment 1.

[0068] 2. Work done by the recovered energy

[0069] 2.1. The energy of the first expander 5 expanding and doing work is used to drive the first compressor 141;

[0070] 2.2. The energy of the second expander 6 expanding and doing work is used to drive the second compressor 142;

[0071] 2.3. The first low-pressure steam separated by the first vapor-liquid separator 12 is compressed and boosted by the first compressor 141, and then flows out through the first low-pressure steam pipeline for production use;

[0072] 2.4. The second low-pressure steam separated by the second vapor-liquid separator 11 is compressed and boosted by the second compressor 142, and then flows out through the second low-pressure steam pipeline for production use. The second liquid water is sent to the hot water system for production use by a pump through the hot water pipeline.

[0073] In this embodiment, the first expander 5 performs the first energy recovery on the energy in the flowing condensate, which is used to drive the first compressor 141 to compress and boost the gas flowing through the first compressor 141. The second expander 6 performs the second energy recovery on the energy in the flowing condensate, realizing the secondary gradient recovery of the condensate energy. At the same time, two low-pressure steams with different pressures are obtained for production processes, making full use of the energy of the condensate. For the pressurization operation of the steam, the energy of the condensate recovered for the first time is directly utilized, without additional mechanical pressurization equipment or separate pressurized steam, and the energy utilization efficiency is higher and more environmentally friendly.

[0074] Embodiment 3. A condensate energy recovery and utilization system solution 3, as Figure 3As shown in the figure, it includes two expansion units, two power output units and two steam pipelines, specifically:

[0075] The first expansion unit includes a first expander 5. The first regulating valve 1 is connected in sequence through a first filter 3, a first expander 5, and a first vapor-liquid separator 12. The transmission shaft of the first compressor 141 is drivingly connected to the first expander 5 through a first coupling 7. The gas outlet of the first vapor-liquid separator 12 is connected to the first low-pressure steam pipeline. The liquid outlet of the first vapor-liquid separator 12 is connected to the second expansion unit through a pipeline.

[0076] The second expansion unit includes a second expander 6. After the first vapor-liquid separator 12 is connected to the second regulating valve 2, it is then connected in sequence through a second filter 4, a second expander 6, and a second vapor-liquid separator 11. The second compressor 142 is drivingly connected to the second expander 6 through a second coupling 8. The gas outlet of the second vapor-liquid separator 11 is connected to the gas inlet of the second compressor 142 through a pipeline. The gas outlet of the second compressor 142 is connected to the gas inlet of the first compressor 141. The gas outlet of the first compressor 141 is connected to the second low-pressure steam pipeline. The liquid outlet of the second vapor-liquid separator 11 is connected to the hot water pipeline.

[0077] The energy recovery method of the condensate energy recovery and utilization system solution 3 is as follows:

[0078] 1. Energy recovery of condensate

[0079] 1.1. The first energy recovery is the same as 1.1 of Embodiment 1.

[0080] 1.2. The second energy recovery is the same as 1.2 of Embodiment 1.

[0081] 2. Work done by the recovered energy

[0082] 2.1. It is the same as 2.1 of Embodiment 2. The energy of the first expander 5 expanding and doing work is used to drive the first compressor 141;

[0083] 2.2. It is the same as 2.2 of Embodiment 2. The energy of the second expander 6 expanding and doing work is used to drive the second compressor 142;

[0084] 2.3. The first low-pressure steam obtained by separating the first vapor-liquid separator 12 directly flows out through the first low-pressure steam pipeline and is used for production;

[0085] 2.4. The second low-pressure steam obtained by separating the second vapor-liquid separator 11 is secondarily compressed and boosted by the second compressor 142 and the first compressor 141, and then flows out through the second low-pressure steam pipeline and is used for production. The second liquid water is sent to the hot water system for production use by a pump through the hot water pipeline.

[0086] The energy recovery of the condensate in this embodiment is the same as that in Embodiment 2. The first expander 5 recovers the energy in the flowing condensate for the first time to drive the first compressor 141 to compress and boost the gas flowing through the first compressor 141. The second expander 6 recovers the energy in the flowing condensate for the second time, realizing the secondary gradient recovery of the condensate energy. However, different from Embodiment 2 is the utilization of the low-pressure steam: the first low-pressure steam separated by the first vapor-liquid separator 12 is directly output for production use, while the second low-pressure steam separated from the second vapor-liquid separator 11 is continuously compressed and boosted by two compressors, that is, the expansion work generated by the first expander 5 and the second expander 6 is used to perform two-stage compression on the second low-pressure steam, so as to obtain steam with a higher pressure for production process use, making full use of the energy of the condensate to meet the needs of different pressure steam in production.

[0087] Embodiment 4. A condensate energy recovery and utilization system solution 4, as Figure 4 shown. Different from Embodiment 3, the power output unit adopts a dual-drive compressor 143, and the energy of the first expander 5 and the second expander 6 expanding to do work is used to drive the operation of the dual-drive compressor 143. Specifically:

[0088] The first expansion unit includes a first expander 5. The first regulating valve 1 is sequentially connected through a first filter 3, a first expander 5, and a first vapor-liquid separator 12. The gas outlet of the first vapor-liquid separator 12 is connected to the first low-pressure steam pipeline. The liquid outlet of the first vapor-liquid separator 12 is connected to the second expansion unit through a pipeline.

[0089] The second expansion unit includes a second expander 6. After the first vapor-liquid separator 12 is connected to the second regulating valve 2, it is then sequentially connected through a second filter 4, a second expander 6, and a second vapor-liquid separator 11. The gas outlet of the second vapor-liquid separator 11 is connected to the gas inlet of the dual-drive compressor 143 through a pipeline, and the gas outlet of the dual-drive compressor 143 is connected to the second low-pressure steam pipeline. The liquid outlet of the second vapor-liquid separator 11 is connected to the hot water pipeline.

[0090] The first expander 5 is connected to the dual-drive compressor 143 through a first coupling 7, and the second expander 6 is connected to the dual-drive compressor 143 through a second coupling 8.

[0091] The energy recovery method of the condensate energy recovery and utilization system solution 4 is as follows:

[0092] 1. Energy recovery of condensate

[0093] 1.1. First energy recovery, which is the same as 1.1 in Embodiment 1.

[0094] 1.2. Second energy recovery, which is the same as 1.2 in Embodiment 1.

[0095] 2. Work done by the recovered energy

[0096] 2.1. The energy for work done by the first expander 5 is used to drive the dual-drive compressor 143;

[0097] 2.2. The energy for work done by the second expander 6 is used to drive the dual-drive compressor 143;

[0098] 2.3. Consistent with 2.3 of Embodiment 3, the first low-pressure steam obtained by separation in the vapor-liquid separator 12 directly flows out through the first low-pressure steam pipeline and is supplied for production use;

[0099] 2.4. The second low-pressure steam obtained by separation in the second vapor-liquid separator 11 is compressed and boosted by the dual-drive compressor 143, then flows out through the second low-pressure steam pipeline and is supplied for production use, and the second liquid water is sent into the hot water system for production use by a pump through the hot water pipeline.

[0100] In this embodiment, the energy recovery of the condensate is consistent with that of Embodiment 3, and the secondary gradient recovery of the energy in the flowing condensate is carried out through the first expander 5 and the second expander 6; however, different from Embodiment 3, the power outputs of the first expander 5 and the second expander 6 are both used to drive the dual-drive compressor 143. Compared with the process of first expanding the condensate for power generation and then using the motor to drive the compressor to boost the steam pressure, it not only avoids the efficiency loss of energy conversion during the process, but also simplifies the system, reduces the cost and obtains steam with a higher pressure for production process use, making full use of the energy of the condensate to meet the needs of different pressure steam in production.

[0101] Embodiment 5. A condensate energy recovery and utilization system solution 5, as Figure 5 shown. Different from Embodiment 4, the power output unit further includes a second generator 10. The energy for work done by the second expander 6 is used to drive both the dual-drive compressor 143 and the second generator 10, that is, the second expander 6 is drivingly connected to the dual-drive compressor 143 through a second coupling 8 and is simultaneously drivingly connected to the second generator 10 through a third coupling 81, and the rest is the same as Embodiment 4.

[0102] The energy recovery method of the condensate energy recovery and utilization system solution 5 is as follows:

[0103] 1. Energy recovery of the condensate

[0104] 1.1. The first energy recovery is consistent with 1.1 of Embodiment 1.

[0105] 1.2. The second energy recovery is consistent with 1.2 of Embodiment 1.

[0106] 2. Work done by the recovered energy

[0107] 2.1. Consistent with 2.1 of Embodiment 4, the energy of the expansion work of the first expander 5 is used to drive the dual-drive compressor 143;

[0108] 2.2. The energy from the expansion work of the second expander 6 is used to drive the dual-drive compressor 143 and the second generator 10 at the same time. The electric energy generated by the second generator 10 is used for production;

[0109] 2.3. Consistent with 2.3 of Example 4, the first low-pressure steam separated by the first vapor-liquid separator 12 directly flows out through the first low-pressure steam pipeline for production use;

[0110] 2.4. Consistent with 2.4 of Example 4, the second low-pressure steam separated by the second vapor-liquid separator 11 is compressed and pressurized by the dual-drive compressor 143, flows out through the second low-pressure steam pipeline for production use, and the second liquid water is pumped into the hot water system through the hot water pipeline for production use.

[0111] The energy recovery of condensate in this embodiment is consistent with that in Embodiment 4. The energy in the condensate flowing through is recovered by the first expander 5 and the second expander 6 through a secondary gradient recovery. The energy output by the first expander 5 is also consistent with that in Embodiment 4 and is used to drive the dual-drive compressor 143. However, the difference from Embodiment 3 is that the energy from the expansion work of the second expander 6 is used to simultaneously drive the dual-drive compressor 143 and the second generator 10, thereby providing two different output forms of pressurized steam and electricity for use by production equipment. The pressurized steam also has two different pressures, which can fully utilize the energy of condensate and meet the needs of different energy forms in production.

[0112] Embodiment 6: A condensate water energy recovery and utilization system solution 6, such as Figure 6 As shown, it includes an expansion unit, a power output unit and a steam pipeline. The power output unit adopts a first compressor 141, specifically:

[0113] The first expansion machine 5 is connected to the first compressor 141 through the first coupling 7, and the condensate pipeline is connected to the first regulating valve 1, the first filter 3, the first expansion machine 5 and the first vapor-liquid separator 12 in sequence. The liquid outlet of the first vapor-liquid separator 12 is connected to the hot water pipeline, and the gas outlet is connected to the first low-pressure steam pipeline through the first compressor 141.

[0114] The energy recovery method of condensate water energy recovery and utilization system scheme 6 is:

[0115] 1. Energy recovery of condensed water

[0116] During the generation process, the high-pressure condensate flows into the condensate pipeline, and then enters the first expander 5 through the first regulating valve 1 and the first filter 3 to expand and do work. After expansion, the temperature and pressure of the condensate decrease and it becomes a vapor-liquid mixture with a pressure of 0.07 - 0.36 MPa. Then, it is separated by the first vapor-liquid separator 12 to obtain low-pressure steam and liquid water, and the liquid water is supplied for production use through the hot water pipeline.

[0117] 2. Work done for energy recovery

[0118] The expansion work in the first expander 5 drives the first compressor 141; the low-pressure steam separated by the first vapor-liquid separator 12 is compressed and pressurized by the first compressor 141 again, and after the pressure is increased, it is supplied for production process use.

[0119] Experiment:

[0120] For high-pressure condensate with different pressures and temperatures, when the pressure is reduced to different intermediate pressures by the conventional throttling method, only low-pressure wet steam can be obtained. The dryness of the wet steam (the mass content of steam in the wet steam) is shown in Table 1. Since the throttling process is irreversible, it causes the loss of available energy (expansion work), and the loss amount is proportional to the entropy production of the throttling process.

[0121] Table 1. Dryness of wet steam output by condensate through the conventional throttling method

[0122]

[0123] In contrast, when using the condensate energy recovery system of the present invention, high-pressure condensate with different pressures and temperatures undergoes isentropic expansion and pressure reduction through the first expansion unit of the present invention, and not only wet steam can be obtained, but also expansion work can be obtained. The expansion work output and the dryness of the wet steam (the mass content of steam in the wet steam) are shown in Table 2.

[0124] Table 2. Expansion work output and dryness of wet steam when condensate expands to different pressures

[0125]

[0126]

[0127] As can be seen from Table 2, when the condensed water with a pressure of 2.79-1.0 MPa and a temperature of 483.15-433.15 K (210-160° C.) is entropically expanded to 0.27-0.47 MPa, 33.7-1.07 kJ / kg of expansion work and 0.146-0.02 kg of steam can be obtained. In the actual expansion process, the expansion process of a two-phase expander such as a screw expander deviates from the isentropic expansion process, and the output expansion work will be reduced, but the amount of low-pressure steam obtained will be increased. From the comparison of Table 1 and Table 2, it can be seen that the amount of steam obtained by the condensed water energy recovery system of the present invention is equivalent to the amount of steam obtained by the conventional throttling method, but the present invention recovers the expansion work at the same time through two expansions to drive power equipment such as a generator or a compressor, thereby realizing the efficient recovery and utilization of condensed water energy.

[0128] Finally, it should be noted that the above examples are only some specific embodiments of the present invention. Obviously, the present invention is not limited to the above embodiments, and there are many variations. All variations that can be directly derived or associated with the content disclosed by a person skilled in the art should be considered as the protection scope of the present invention.

Claims

1. A steam condensate energy recovery system, characterized in that: It comprises a first expansion machine (5), wherein the condensate pipeline passes through a first regulating valve (1), a first filter (3), a first expansion machine (5) and a first vapor-liquid separator (12) in sequence and is then connected to a hot water pipeline; The first expander (5) is transmission-connected to the first compressor (141) via a first coupling (7); the gas outlet of the first vapor-liquid separator (12) is connected to the first low-pressure steam pipeline via the first compressor (141).

2. A steam condensate energy recovery system, characterized in that: The invention comprises a first expander (5) and a second expander (6), wherein the condensate pipeline passes through a first regulating valve (1), a first filter (3), a first expander (5), a first vapor-liquid separator (12), a second regulating valve (2), a second filter (4), a second expander (6), and a second vapor-liquid separator (11) in sequence, and is then connected to a hot water pipeline; The first expander (5) and the second expander (6) are respectively connected in transmission with the power output unit.

3. A steam condensate energy recovery system according to claim 2, characterized in that: The power output unit comprises a first generator (9) and a second generator (10); the first expander (5) is transmission-connected to the first generator (9) via a first coupling (7); and the second expander (6) is transmission-connected to the second generator (10) via a second coupling (8); The gas outlet of the first vapor-liquid separator (12) is connected to a first low-pressure steam pipeline, and the gas outlet of the second vapor-liquid separator (11) is connected to a second low-pressure steam pipeline via a third compressor (13).

4. A steam condensate energy recovery system according to claim 2, characterized in that: The power output unit comprises a first compressor (141) and a second compressor (142); the first expander (5) is transmission-connected to the first compressor (141) via a first coupling (7); and the second expander (6) is transmission-connected to the second compressor (142) via a second coupling (8); The gas outlets of the first vapor-liquid separator (12) and the second vapor-liquid separator (11) adopt connection mode 1: the gas outlet of the first vapor-liquid separator (12) is connected to the first low-pressure steam pipeline via the first compressor (141), and the gas outlet of the second vapor-liquid separator (11) is connected to the second low-pressure steam pipeline via the second compressor (142); Alternatively, the gas outlets of the first vapor-liquid separator (12) and the second vapor-liquid separator (11) adopt connection mode two: the gas outlet of the first vapor-liquid separator (12) is connected to the first low-pressure steam pipeline, and the gas outlet of the second vapor-liquid separator (11) is connected to the second low-pressure steam pipeline via the first compressor (141) and the second compressor (142).

5. The steam condensate energy recovery system according to claim 2, characterized in that: The gas outlet of the first vapor-liquid separator (12) is connected to the first low-pressure steam pipeline, and the gas outlet of the second vapor-liquid separator (11) is connected to the second low-pressure steam pipeline via the dual-drive compressor (143). The power output unit includes a dual-drive compressor (143), or the power output unit includes a dual-drive compressor (143) and a second generator (10): when the power output unit includes the dual-drive compressor (143), the first expander (5) is connected to the dual-drive compressor (143) through a first coupling (7), and the second expander (6) is connected to the dual-drive compressor (143) through a second coupling (8); when the power output unit includes the dual-drive compressor (143) and the second generator (10), the first expander (5) is connected to the dual-drive compressor (143) through a first coupling (7), and the second expander (6) is connected to the second generator (10) through a third coupling (81).

6. A method for energy recovery using a steam condensate energy recovery system as claimed in claim 1, characterized in that: When the condensate passes through the first expansion machine (5), it expands and performs work to drive the first compressor (141). After the expansion, the temperature and pressure of the condensate are reduced to become a vapor-liquid mixture. Then, when it passes through the first vapor-liquid separator (12), low-pressure steam and liquid water are separated. The low-pressure steam is compressed and pressurized by the first compressor (141) for use in production, and the liquid water is provided for use in production through a hot water pipeline.

7. A method for energy recovery using a steam condensate energy recovery system as claimed in any one of claims 2 to 5, characterized in that: The condensed water is expanded for the first time by the first expansion machine (5), and the temperature and pressure of the expanded condensed water are reduced to become a vapor-liquid mixture, which is separated by the first vapor-liquid separator (12) to obtain a first low-pressure steam and a first liquid water; The first liquid water undergoes a second expansion process in the second expansion machine (6), and its temperature and pressure are further reduced. The first liquid water is separated in the second vapor-liquid separator (11) to obtain second low-pressure steam and second liquid water. The second liquid water is directly used in production.

8. The method for energy recovery of a steam condensate energy recovery system according to claim 7, characterized in that: When the power output unit is a first generator (9) and a second generator (10), the energy generated by the expansion work of the first expander (5) is used to drive the first generator (9) to generate electricity, and the energy generated by the expansion work of the second expander (6) is used to drive the second generator (10) to generate electricity, and the obtained electric energy is used for production; The second low-pressure steam is compressed and pressure-raised by the third compressor (13) for use in production, and the first low-pressure steam is directly used in production.

9. The method for energy recovery of a steam condensate energy recovery system according to claim 7, characterized in that: When the power output unit is a first compressor (141) and a second compressor (142), the energy of the expansion work of the first expander (5) is used to drive the first compressor (141), and the energy of the expansion work of the second expander (6) is used to drive the second compressor (142); The first low-pressure steam is compressed and pressurized by the first compressor (141) for use in production, and the second low-pressure steam is compressed and pressurized by the second compressor (142) for use in production; or, the first low-pressure steam is directly used in production, and the second low-pressure steam is compressed and pressurized twice by the first compressor (141) and the second compressor (142) for use in production.

10. The method for energy recovery of a steam condensate energy recovery system according to claim 7, characterized in that: The first low-pressure steam is directly used for production, and the second low-pressure steam is compressed and pressure-raised by a dual-drive compressor (143) and then used for production; When the power output unit is a dual-drive compressor (143), the energy of the expansion work of the first expander (5) and the second expander (6) is used to drive the dual-drive compressor (143); Alternatively, when the power output unit is a dual-drive compressor (143) and a second generator (10), the energy generated by the expansion work of the first expander (5) is used to drive the dual-drive compressor (143), and the energy generated by the expansion work of the second expander (6) is used to simultaneously drive the dual-drive compressor (143) and the second generator (10); the electric energy generated by the second generator (10) is used for production.

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