Steam condensate energy recovery system

Abstract

The utility model relates to a steam condensate energy recovery system. The energy recovery system comprises a condensate collection unit and a steam condensate energy recovery unit, a steam pressurization unit; a medium pressure steam supply unit; a low-pressure steam pipe network unit; a steam flash unit; and optionally, a condensate heat exchange unit; the system is characterized in that flooding gas of the condensate collecting unit (100) is connected with the steam pressurizing unit (200) through a flooding gas discharging pipeline (101); medium-pressure steam provided by a medium-pressure steam providing unit (300) enters the steam pressurizing unit (200) through a medium-pressure steam inlet (202). And the pressurized steam is discharged through a pressurized steam outlet (203) and finally enters the low-pressure steam pipe network unit (400).

Description

Technical Field

[0001] The present application relates to an energy recovery system, and more particularly to a steam condensate energy recovery system for directly converting low-grade, non-recyclable flash gas from flash evaporation into steam that can be utilized by a low-pressure steam network through pressurization. Background Art

[0002] Steam is a critical resource and utility in many industrial processes, such as chemical production. In particular, in chemical production (e.g., petrochemicals), steam is often used as a heat source or driving force for various equipment. Steam heating typically produces a large amount of steam condensate. To recover the energy contained in the steam condensate, the condensate is typically directed into steam flash tanks for staged flash evaporation, typically at varying condensate temperatures and pressures. This produces saturated steam at reduced temperatures and pressures for subsequent reuse.

[0003] Those skilled in the art can, based on their experience, reasonably design a step-by-step flash evaporation of the steam condensate in a steam flash tank to gradually reduce the temperature and pressure of the steam condensate in order to better recover and utilize the energy of the steam condensate later.

[0004] High-pressure steam typically has very high temperatures and pressures, for example, temperatures of 300°C to 600°C and pressures of 6 MPa to 14 MPa. After multiple flash evaporations, the temperature and pressure are gradually reduced to the temperature and pressure ranges of medium-pressure steam and low-pressure steam.

[0005] However, after the final flash stage, the flash steam pressure drops to, for example, about 0.35 MPa (gauge pressure) and the temperature is around 147°C. The energy contained in the condensate after flash evaporation is often unusable. Typically, flash evaporation is performed in an atmospheric flash tank, reducing the condensate temperature to approximately 110°C before returning it to the boiler feed water treatment unit for recovery. However, the outgas produced by atmospheric flash evaporation is unusable due to its pressure being close to atmospheric pressure. Therefore, a certain amount of cooling water is required to cool the condensate and recover the steam.

[0006] The most common method for recovering overflow gas is to cool the condensate with cooling water. However, this method is not only uneconomical but also wastes a large amount of cooling water. Some facilities use this overflow gas by preheating the process material when treating it. However, since the pressure of the overflow gas is close to atmospheric pressure, it is difficult to transport the overflow gas, and the potentially usable process material is also limited.

[0007] The purpose of the utility model is to recover and utilize the energy of a large amount of overflow gas generated by an atmospheric pressure flash evaporation system. Utility Model Content

[0008] The present application discloses a steam condensate energy recovery system, which at least partially solves the above technical problems and realizes the effective recovery and utilization of a large amount of outgassing energy generated by the atmospheric pressure flash evaporation system.

[0009] According to one aspect of the present application, a steam condensate energy recovery system comprises:

[0010] a condensate collection unit 100 configured to receive and store condensate from the steam flash unit 500, the condensate collection unit 100 having a gas discharge line 101 for discharge above the condensate level and a condensate return line 103, the gas discharge line 101 being used to discharge gas generated during atmospheric pressure flash evaporation of the condensate from the condensate collection unit 100;

[0011] A steam boosting unit 200 having an air inlet 201, a medium-pressure steam inlet 202 and a boosted steam outlet 203;

[0012] A medium-pressure steam supply unit 300 , which provides medium-pressure steam and has at least one medium-pressure steam flow control valve 302 ;

[0013] a low-pressure steam network unit 400 receiving pressurized steam as at least part of the low-pressure steam;

[0014] as well as

[0015] a steam flash unit 500 connected to the condensate collecting unit 100 and providing condensate to the condensate collecting unit 100;

[0016] Among them, the air intake port 201 is connected to the air discharge pipeline 101 to receive air, the medium-pressure steam inlet 202 is connected to the medium-pressure steam supply unit 300 to receive medium-pressure steam, and the boost steam outlet 203 is connected to the low-pressure steam pipe network unit 400 to provide boost steam.

[0017] In some examples, the steam condensate energy recovery system further includes a heat exchange unit 600, which is configured to be connected to the vent exhaust line 101 and the condensate return line 103 of the condensate collection unit 100, for cooling at least a portion of the vent exhaust line 101 received through the vent exhaust line 101 to generate condensate, and returning the generated condensate to the condensate collection unit 100 via the condensate return line 103.

[0018] In some examples, the steam boosting unit 200 of the steam condensate energy recovery system is a steam jet pump, the pipe diameter at both ends of the steam jet pump is larger than the pipe diameter in the middle, wherein the aeration inlet 201 is provided in the middle of the steam jet pump.

[0019] In some examples, the steam flash unit 500 of the steam condensate energy recovery system is a low pressure flash unit.

[0020] In some examples, the steam provided by the steam flash unit 500 to the condensate collection unit 100 of the steam condensate energy recovery system has a gauge pressure of approximately 0.3 MPa to 0.5 MPa and a temperature of approximately 130 to 150° C. In some examples, the medium-pressure steam provided by the medium-pressure steam providing unit 300 of the steam condensate energy recovery system has a gauge pressure of approximately 1.0 MPa to 5.0 MPa and a temperature of 200 to 300° C.

[0021] In some examples, the pressurized steam of the steam condensate energy recovery system has a gauge pressure of 0.35-0.4 MPa or higher and a temperature of about 170° C. or higher.

[0022] In some examples, the condensate collection unit 100 of the steam condensate energy recovery system is further configured with a pressure controller 102, which is linked to the medium-pressure steam flow control valve (302).

[0023] In some examples, the condensate heat exchange unit 600 of the steam condensate energy recovery system has an inlet control valve 601 on a line receiving evaporation from the condensate collection unit 100 and an outlet control valve 602 on a line returning cooled evaporation condensate to the condensate collection unit 100 .

[0024] In some examples, the pressure controller 102 of the condensate collection unit 100 of the steam condensate energy recovery system is linked to the inlet control valve 601 and the outlet control valve 602 . BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is a schematic diagram of a steam condensate energy recovery system according to the present application, wherein:

[0026] 100 - condensate collection unit; 101 - aeration discharge line; 102 - pressure controller; 103 - condensate return line; 104 - condensate discharge pump;

[0027] 200 - steam booster unit; 201 - venting inlet; 202 - medium-pressure steam inlet; 203 - boosted steam outlet; 204 - control valve for venting to the steam booster unit; 205 - one-way control valve for venting to the steam booster unit, arranged in series with control valve 204;

[0028] 300-medium-pressure steam supply unit; 301-control valve for medium-pressure steam to steam booster unit; 302-medium-pressure steam flow regulating valve;

[0029] 400- low-pressure steam pipe network unit; 401- control valve from pressurized steam to low-pressure steam pipe network unit;

[0030] 500-steam flash unit;

[0031] 600- condensate heat exchange unit; 601- control valve for gas flow to the condensate heat exchange unit; 602- control valve for condensate to return to the condensate collection unit. DETAILED DESCRIPTION

[0032] An industrial steam system according to an embodiment of the present application is described below with reference to the accompanying drawings. Figure 1 The positions and connection sequences of various units, components, and pipelines are schematically illustrated and do not represent the actual or necessary positional relationships, relative sizes, or connection sequences of these units, components, and pipelines. Persons of ordinary skill in the art can, based on reading this application, make reasonable adjustments and changes to the positions, sizes, or connections of these units, components, and pipelines, and can also reasonably add or remove units, components, and pipelines without departing from the teachings of this application.

[0033] As mentioned in the present invention, "gas" refers to the steam obtained by flash evaporation of the liquid phase of the condensate collection unit 100 at normal pressure; the fundamental purpose of the present invention is to fully recover the energy present in the gas.

[0034] The condensate collection unit 100 described in the present invention refers to a device unit that receives and stores water vapor condensate with a certain temperature and pressure from the last-stage flash unit, and can generally be in the form of a storage tank, a storage kettle, a storage tank, etc.

[0035] The steam boosting unit 200 described in the present invention is a device for boosting the pressure of the vapor from the condensate collecting unit 100 to a level where its energy can be fully utilized.

[0036] In a specific embodiment of the present invention, the steam boosting unit 200 is a steam jet pump, which uses medium-pressure steam as power to generate low pressure at the suction port of the steam jet pump, thereby sucking the overflow gas into the jet pump and finally entering the low-pressure steam network of the factory together with the power steam, so that it can be used by all devices and equipment in the factory that require heat.

[0037] In one embodiment of the present invention, the steam jet pump has the following preferred structure: it has a basic fluid channel with a diameter that is set from large at the inlet to small and then to large at the outlet, that is, the diameter of the steam jet pump is large at both ends and small in the middle; the medium-pressure steam enters from the large-diameter inlet, and then as the diameter of the pipe decreases, its flow rate continues to increase, and forms the maximum flow rate at the smallest diameter, thereby generating the maximum suction negative pressure at the smallest diameter.

[0038] Without being limited by any theory, according to Bernoulli's principle, when the total energy of the fluid is approximately conserved, the flow rate of the fluid increases as the pipe diameter decreases, the kinetic energy of the fluid increases, and the static pressure energy decreases accordingly, thereby creating an area where the static pressure is lower than the aeration pressure at the minimum pipe diameter, thereby sucking the aeration into the steam jet pump.

[0039] In one embodiment of the present invention, the venting gas entering the steam jet pump through the control valve 204 is sucked into the steam boosting unit 200 through the venting gas inlet 201 provided at the minimum pipe diameter.

[0040] In one embodiment of the present invention, a one-way valve 205 is further arranged in series with the control valve 204 to prevent the medium-pressure steam from flowing back into the condensate collection unit 100 when the pressure at the aeration inlet 201 is higher than that of the condensate collection unit 100.

[0041] With the above-mentioned inlet arrangement, a specially configured delivery device such as a booster pump on the pipeline 101 for smoothly delivering the overflow gas to the booster device 200 can be omitted, thereby further simplifying the overall arrangement of the energy recovery device.

[0042] The medium-pressure steam supply unit 300 described in the present invention refers to a unit device for providing boosting power for the steam boosting unit 200 .

[0043] In one embodiment of the present invention, the medium-pressure steam provided by the medium-pressure steam providing unit 300 has a gauge pressure of about 1.0 MPa to 5.0 MPa and a temperature of 200 to 300° C., for example, a gauge pressure of 1.6 MPa and a temperature of about 250° C.

[0044] The low-pressure steam pipe network unit 400 described in the present invention refers to a low-pressure steam pipe network unit 400 for receiving pressurized steam for subsequent processing and utilization.

[0045] In one embodiment of the present invention, the steam in the low-pressure steam network unit 400 has a pressure of 0.35-0.4 MPa (gauge pressure) or even higher, and a temperature of about 170° C. or above.

[0046] The flash unit 500 described in the present invention is preferably a low-pressure flash unit in a step-by-step flash process; more preferably, the steam condensate from the low-pressure flash unit has a gauge pressure of about 0.3 MPa to 0.5 MPa and a temperature of about 130 to 150°C; for example, a gauge pressure of about 0.4 MPa and a temperature of about 140°C.

[0047] The condensate collection unit 100 of the present invention is the final flash unit of the step-by-step flash process, and is an atmospheric flash unit. The flash steam (i.e., vapor) from the condensate collection unit 100 has a gauge pressure of 0.1 MPa to 0.2 MPa and a temperature of approximately 110-120°C.

[0048] Those skilled in the art can reasonably select the condensate heat exchange unit 600 for use in the embodiment of the present invention based on experience, which can be used to condense the vapor discharged from the top of the condensate collection unit 100 through the pipeline 101 by entering the condensate heat exchange unit 600 for heat exchange when necessary, and return it to the condensate collection unit 100.

[0049] In general, this does not include Figure 1 The steam boosting unit 200, the medium-pressure steam supply unit 300 and the low-pressure steam network unit 400 shown in the figure; only the flash unit 500; the condensate collection unit 100 and the condensate heat exchange unit 600; and the corresponding connecting pipelines and various connecting control valves constitute a common gasification treatment process.

[0050] Specifically, condensate from the flash unit 500 is stored in the condensate collection unit 100. The condensate above the condensate collection unit 100 flows through a pipeline 101 and a control valve 601 into the condensate heat exchange unit 600. The condensate is directly condensed through heat exchange with cooling water entering the condensate heat exchange unit 600. The resulting condensate is returned to the condensate collection unit 100 through a valve body 602.

[0051] When necessary, the condensate in the condensate collecting unit 100 is directly discharged via the condensate discharge pump 104 .

[0052] Such a simple heat exchange condensation method has the disadvantages of large cooling water consumption, low cooling effect, and little heat recovery and utilization of the condensate.

[0053] In the technical solution according to the utility model, a steam condensate energy recovery system is provided, which includes: Figure 1 The condensate collection unit 100, steam boosting unit 200, medium-pressure steam providing unit 300 and low-pressure steam pipe network unit 400 shown in the figure; flash unit 500; and optional condensate heat exchange unit 600; and corresponding connecting pipelines and various connecting valves.

[0054] According to one embodiment of the present invention, the condensate from the flash unit 500 is stored in the condensate collection unit 100 .

[0055] According to one embodiment of the present invention, the flash unit 500 is a low-pressure flash unit.

[0056] The flash steam obtained by the low-pressure flash unit 500 generally has a gauge pressure of about 0.3 MPa to 0.5 MPa and a temperature of about 130 to 150° C.; for example, a gauge pressure of about 0.4 MPa and a temperature of about 140° C.

[0057] According to one embodiment of the present invention, the condensate collecting unit 100 is an atmospheric flash evaporation unit, and provides vapor having a gauge pressure of 0.1-0.2 MPa and a temperature of 110-120° C. by performing atmospheric flash evaporation operation.

[0058] The vapor generated by flash evaporation of the liquid in the condensate collection unit 100 under atmospheric pressure passes through the vapor discharge line 101 and enters the steam boosting unit 200 via the control valve 204 .

[0059] In one embodiment of the present invention, the steam boosting unit 200 uses medium-pressure steam from the medium-pressure steam supply unit 300 as power. The medium-pressure steam enters the medium-pressure steam inlet 202 of the steam boosting unit 200 through the switch control valve 301 and the flow control 302.

[0060] In one embodiment of the present invention, the medium-pressure steam has a gauge pressure of about 1.0 MPa to 5.0 MPa and a temperature of 200 to 300° C.; more specifically, the medium-pressure steam has a gauge pressure of 1.6 MPa and a temperature of about 250° C., for example.

[0061] In one embodiment of the present invention, the steam boosting unit 200 adopts a steam jet pump; and the steam jet pump has the following basic structure: the diameter of the steam jet pump at both ends is larger than the diameter at the middle, wherein the air intake port 201 is provided in the middle of the steam jet pump; that is, the steam jet pump has a basic fluid channel with a diameter from large to small and then to large; after the medium-pressure steam enters from the large-diameter part, as the diameter of the pipe continues to shrink, its flow rate continues to increase, and forms the maximum flow rate at the smallest diameter, thereby generating the maximum suction negative pressure at the smallest diameter.

[0062] In one embodiment of the present invention, the eddy current entering the steam boosting unit 200 through the control valve 204 is sucked into the steam boosting unit 200 through the eddy current inlet 201 provided at the minimum pipe diameter.

[0063] The medium-pressure steam entering from the medium-pressure steam inlet 202 generates suction due to the decreasing diameter of the steam jet pump pipe; the air entering from the air intake 201 set at the narrowest point of the steam jet pump pipe is mixed in the steam boosting unit 200 to obtain steam with increased pressure. The pressurized steam further passes through the steam boosting unit 200 with a pipe diameter gradually decreasing from small to large, and is discharged from the boosted steam outlet 203.

[0064] The venting gas mixed with the medium-pressure steam in the steam boosting unit 200 is pressurized as described above; usually, the pressurized steam is adjusted by the flow rate through the medium-pressure steam flow regulating valve 302 and the control valve 204 of the venting gas to the steam boosting unit, so that the pressurized steam enters the low-pressure steam pipe network unit 400 through the switch control valve 401, and finally meets the utilization of the factory equipment.

[0065] In one embodiment of the present invention, the overflow gas enters the steam boosting unit and is mixed with the medium-pressure steam to be boosted. The boosted steam has a gauge pressure of at least 0.35-0.4 MPa and above and a temperature of about 170°C or above.

[0066] According to an embodiment of the present invention, there is no need to provide a device for transmitting the overflow gas into the steam boosting unit 200, such as a pressure pump, between the condensate collection unit 100 and the steam boosting unit 200, thereby further reducing the equipment capital investment of the device; and the steam that originally could not be directly utilized after the final flash vaporization is specially pressurized to obtain low-pressure steam that can be uniformly utilized by factory equipment.

[0067] For example, when the temperature and pressure of the condensate collecting unit 100 increase, the flow regulating valve 302 after the medium-pressure steam outlet can be controlled and adjusted in conjunction with the pressure controller 102 provided on the condensate collector 100 to increase the flow of the medium-pressure steam, thereby correspondingly increasing the flow of the condensate sucked into the steam boosting unit 200 to reduce the pressure in the condensate collecting unit 100.

[0068] For example, when the vapor temperature and pressure in the condensate collection unit 100 increase to excessively high levels, so that the steam boosting unit 200 cannot fully and timely complete the boosting process of all vapors, the inlet control valve 601 and the outlet control valve 602 of the condensate heat exchange unit 600 disposed above the condensate collection unit 100 can be opened in conjunction with the pressure controller 102 disposed on the condensate collector 100; and the pressure in the condensate collection unit 100 can be reduced through heat exchange in the condensate heat exchange unit 600 until the vapor temperature and pressure in the condensate collection unit 100 are reduced to a level that can be easily controlled.

[0069] The industrial steam treatment system according to the present application has been described above with reference to the embodiments and illustrations. These embodiments and illustrations provide some exemplary implementations and do not indicate that the included features are preferred or essential features of the industrial steam treatment system according to the present application. Persons skilled in the art may modify and vary the described embodiments without departing from the teachings of the present application.

Claims

1. A steam condensate energy recovery system, characterized in that: The steam condensate energy recovery system includes: A condensate collection unit (100) is configured to receive and store condensate from a steam flash unit (500), the condensate collection unit (100) having a gas discharge line (101) for discharge above the condensate level and a condensate return line (103), the gas discharge line (101) being used to discharge gas generated by the condensate during atmospheric pressure flash evaporation from the condensate collection unit (100); A steam boosting unit (200), the steam boosting unit (200) having an air inlet (201), a medium-pressure steam inlet (202) and a boosted steam outlet (203); A medium-pressure steam supply unit (300) provides medium-pressure steam and has at least one medium-pressure steam flow control valve (302); a low-pressure steam network unit (400) receiving pressurized steam as at least part of the low-pressure steam; and a steam flash unit (500) connected to the condensate collecting unit (100) and providing steam condensate to the condensate collecting unit (100); The venting inlet (201) is connected to the venting outlet pipeline (101) to receive venting, the medium-pressure steam inlet (202) is connected to the medium-pressure steam supply unit (300) to receive medium-pressure steam, and the boost steam outlet (203) is connected to the low-pressure steam pipe network unit (400) to provide boost steam.

2. The steam condensate energy recovery system according to claim 1, characterized in that: The steam condensate energy recovery system further comprises a heat exchange unit (600) configured to be connected to the venting discharge line (101) and the condensate return line (103) of the condensate collection unit (100), for cooling at least a portion of the venting received via the venting discharge line (101) to generate condensate, and returning the generated condensate to the condensate collection unit (100) via the condensate return line (103).

3. The steam condensate energy recovery system according to claim 1, characterized in that: The steam boosting unit (200) is a steam jet pump, the pipe diameter at both ends of the steam jet pump is larger than the pipe diameter at the middle, wherein the air inlet (201) is provided at the middle of the steam jet pump.

4. The steam condensate energy recovery system according to any one of claims 1 to 3, characterized in that: The steam flash unit (500) is a low-pressure flash unit.

5. The steam condensate energy recovery system according to any one of claims 1 to 3, characterized in that: The steam condensate provided by the steam flash unit (500) to the condensate collecting unit (100) has a gauge pressure of about 0.3 MPa to 0.5 MPa and a temperature of about 130 to 150°C.

6. The steam condensate energy recovery system according to any one of claims 1 to 3, characterized in that: The medium-pressure steam provided by the medium-pressure steam providing unit (300) has a gauge pressure of about 1.0 MPa to 5.0 MPa and a temperature of 200 to 300°C.

7. The steam condensate energy recovery system according to any one of claims 1 to 3, characterized in that: The pressurized steam has a gauge pressure of 0.35-0.4 MPa or higher and a temperature of about 170° C. or higher.

8. The steam condensate energy recovery system according to claim 2, characterized in that: The condensate collection unit (100) is further provided with a pressure controller (102), and the pressure controller (102) is arranged in linkage with the medium-pressure steam flow control valve (302).

9. The steam condensate energy recovery system according to claim 8, characterized in that: The condensate heat exchange unit (600) has an inlet control valve (601) on a pipeline receiving aeration from the condensate collecting unit (100) and an outlet control valve (602) on a pipeline returning cooled aerated condensate to the condensate collecting unit (100).

10. The steam condensate energy recovery system according to claim 9, characterized in that: The pressure controller (102) of the condensate collection unit (100) is arranged in linkage with the inlet control valve (601) and the outlet control valve (602).

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