CN112923601A - Ethanol steam waste heat recovery method and device, ethanol steam dehydration method and system - Google Patents
Ethanol steam waste heat recovery method and device, ethanol steam dehydration method and system Download PDFInfo
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B27/00—Machines, plants or systems, using particular sources of energy
- F25B27/02—Machines, plants or systems, using particular sources of energy using waste heat, e.g. from internal-combustion engines
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/26—Drying gases or vapours
- B01D53/261—Drying gases or vapours by adsorption
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
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- B01D2253/00—Adsorbents used in seperation treatment of gases and vapours
- B01D2253/10—Inorganic adsorbents
- B01D2253/106—Silica or silicates
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- B—PERFORMING OPERATIONS; TRANSPORTING
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- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
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- Y02A30/27—Relating to heating, ventilation or air conditioning [HVAC] technologies
- Y02A30/274—Relating to heating, ventilation or air conditioning [HVAC] technologies using waste energy, e.g. from internal combustion engine
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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Abstract
The invention relates to the field of waste heat recovery, and discloses an ethanol steam waste heat recovery method which comprises the step of cooling ethanol steam by heat exchange with water, and is characterized in that at least part of the ethanol steam and water heat exchange mode comprises first heat exchange and second heat exchange which are sequentially carried out, the first heat exchange enables the temperature of the ethanol steam to be reduced to 90-100 ℃, preferably 95-100 ℃, the second heat exchange enables the temperature of the ethanol steam to be reduced to 70-85 ℃, preferably 75-80 ℃, and water after the first heat exchange is used for refrigerating by a refrigerating machine. The application of the ethanol steam waste heat refrigeration technology can replace the high energy consumption bottleneck of cooling the ethanol steam by adopting circulating cooling water after the molecular sieve is dehydrated in the domestic ethanol industry, reduce the production cost and improve the competitiveness of enterprises.
Description
Technical Field
The invention relates to the field of steam waste heat utilization and dehydration, in particular to an ethanol steam waste heat utilization and recovery method and device, and an ethanol steam dehydration method and system comprising the ethanol steam waste heat utilization and recovery method.
Background
Energy is indispensable resource for enterprise production, not only runs through each link of an enterprise, but also exists in each development stage of the enterprise, and the energy-saving, cost-reducing and benefit-improving effects are important fundamental work of the enterprise. In the industrial production of ethanol, energy management is enhanced, comprehensive utilization of waste heat resources is well done, the cost of production enterprises can be reduced, and the benefit is improved.
The ethanol production process usually comprises the working sections of liquefaction, fermentation, distillation, dehydration and the like, wherein in the fermentation working section, the temperature of fermented mash can influence the fermentation strength, the strain activity, the fermentation alcoholic strength and various technical indexes. In order to control the temperature of the fermented mash, a large amount of cold water is used for cooling the fermented mash. However, the production of cold water is usually performed by an electric refrigerator or a lithium bromide refrigerator of steam type in the industry, and the use of such a refrigeration system results in high energy consumption.
In the dehydration section of the ethanol production process, the ethanol vapor is usually dehydrated by a molecular sieve and then further cooled to obtain the finished ethanol product. The temperature of the ethanol steam discharged from the molecular sieve is higher, about 145 ℃, however, most ethanol production enterprises adopt indirect heat exchange with process materials or directly use circulating cooling water to cool the ethanol steam in a way of utilizing the waste heat of the ethanol steam at present. A large amount of heat contained in the ethanol steam with higher temperature is not fully and effectively recycled or is directly taken away by circulating cooling water through a heat exchanger, so that the waste of heat in the high-temperature ethanol steam is caused, the heat load of a circulating water system in project operation is increased, and a large amount of energy is consumed.
The waste heat resource can not be reasonably utilized, so that the production of the ethanol becomes a high-energy consumption project, the production cost of enterprises is increased in a phase-changing manner, and the environmental burden is also increased. At present, the contradiction between economic development and resource environment is increasingly prominent, and the significance is provided for how to optimize energy allocation in an ethanol project and reasonably utilize waste heat resources.
Disclosure of Invention
The invention aims to solve the problems of high energy consumption and waste heat waste in a fuel ethanol production device, and provides an ethanol steam waste heat recovery method and device, an ethanol dehydration method and system.
In order to achieve the above object, in a first aspect, the present invention provides a method for recovering ethanol steam waste heat, the method includes cooling ethanol steam by heat exchange with water, where at least part of the ethanol steam and water exchange includes a first heat exchange and a second heat exchange performed in sequence, the first heat exchange makes the temperature of the ethanol steam be 90-110 ℃, preferably 95-100 ℃, the second heat exchange makes the temperature of the ethanol steam be 70-85 ℃, preferably 75-80 ℃, and the water after the first heat exchange is used for refrigerating by a refrigerator.
In a second aspect, the invention provides a method for dehydrating ethanol steam, which comprises dehydrating ethanol steam containing water, and then recovering the residual heat of the ethanol steam from the dehydrated ethanol steam by adopting the method.
In a third aspect, the invention provides an ethanol steam waste heat recovery device, which comprises an ethanol steam source, a condensation unit and a refrigeration unit, wherein the condensation unit comprises a first condensation device and a second condensation device, the ethanol steam source is sequentially communicated with the first condensation device and the second condensation device to cool ethanol steam, and a refrigerant outlet of the first condensation device is connected with the refrigeration unit, so that the first condensation device provides energy for the refrigeration unit.
In a fourth aspect, the invention provides an ethanol dehydration system, which comprises an ethanol dehydration device and a heat recovery device, wherein the heat recovery device adopts the device, and the ethanol dehydration device provides ethanol steam for the heat recovery device.
By the technical scheme, the high-temperature ethanol steam waste heat refrigeration technology is successfully applied, which is a precedent of a waste heat resource innovation technology in the production process of the ethanol industry, and the application of the technology can replace a high energy consumption bottleneck that the high-temperature ethanol steam is cooled by circulating cooling water after molecular sieve dehydration in the domestic ethanol industry, so that the comprehensive utilization of waste heat resources in the production process is realized, and the circulating water consumption and the energy consumption of a refrigeration system are reduced; but also has great promotion significance for improving the innovation development of energy-saving emission-reducing technology in the ethanol industry, reducing the production cost and improving the enterprise competitiveness. In the embodiment of the invention, the waste heat is used as the driving heat source of the refrigerating machine, so that the power consumption of the whole plant is saved, the power price per degree is about 0.57 yuan according to the power price of the existing plant, and the energy cost of a fuel ethanol project of 30 ten thousand tons per year can be saved by 144 ten thousand yuan each year.
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FIG. 1 is a flow chart of the ethanol vapor waste heat recovery method and apparatus provided by the present invention;
FIG. 2 is a schematic diagram of an ethanol vapor waste heat recovery and dehydration system according to an embodiment of the present invention.
Detailed Description
The endpoints of the ranges and any values disclosed herein are not limited to the precise range or value, and such ranges or values should be understood to encompass values close to those ranges or values. For ranges of values, between the endpoints of each of the ranges and the individual points, and between the individual points may be combined with each other to give one or more new ranges of values, and these ranges of values should be considered as specifically disclosed herein.
In a first aspect, the invention provides an ethanol steam waste heat recovery method, which comprises the step of cooling ethanol steam by heat exchange with water, wherein at least part of the ethanol steam and water are subjected to heat exchange in a first heat exchange mode and a second heat exchange mode in sequence, the first heat exchange enables the temperature of the ethanol steam to be 90-110 ℃, preferably 95-100 ℃, the second heat exchange enables the temperature of the ethanol steam to be 70-85 ℃, preferably 75-80 ℃, and water after the first heat exchange is used for refrigerating by a refrigerating machine.
According to the invention, the ethanol steam is cooled in a sectional manner, the ethanol steam is firstly cooled to an intermediate temperature in the first stage, and then is further cooled to the temperature required by recovering the ethanol product, so that the heat of the intermediate temperature can be utilized in a two-stage cooling manner, and the adjustment of the condensation quantity of the ethanol steam is realized in a manner that the first heat exchange and the second heat exchange can be connected in series or in parallel, thereby remarkably reducing the consumption of circulating water in the second heat exchange.
The first heat exchange is such that the temperature of the ethanol vapour is between 90 and 110 c, preferably between 95 and 100 c.
The second heat exchange is such that the temperature of the ethanol vapour is in the range of 70-85 deg.c, preferably 75-80 deg.c.
Preferably, the temperature of the water before the first heat exchange is 60-75 ℃, preferably 65-70 ℃, and the temperature of the water after the first heat exchange is 85-97 ℃, preferably 90-95 ℃.
Preferably, the water before the first heat exchange is water used for refrigeration of a refrigerator.
Preferably, the method further comprises the step of sending the water after the first heat exchange into a hot water buffer tank for buffering before the water is used for refrigerating by the refrigerator, so that the flow and the temperature of the condensed water in the pipeline are stable, and the refrigerating effect of the refrigerator is ensured.
The number of the hot water buffer tanks is two or more, the hot water buffer tanks are not particularly limited in the invention and can be selected conventionally in the field, and the hot water buffer tanks are also provided with water replenishing pipelines for adding water at the start of the process or replenishing water loss caused by circulation.
Preferably, a circulating water pump is further provided between the hot water buffer tank and the refrigerator for providing driving force for the water in the pipeline. The circulating water pump of the present invention is not particularly limited, and may be conventionally selected in the art, and the number of pumps is not particularly limited.
Preferably, the first heat exchange and the second heat exchange are carried out in heat exchangers, and the first heat exchange is carried out in one or more heat exchangers arranged in parallel. The heat exchanger is not particularly limited in the present invention, and may be a conventional choice in the field, and preferably, the heat exchanger in the first heat exchange in the present invention is a spiral wound heat exchanger; the second heat exchanger may be a shell and tube heat exchanger or a tube heat exchanger.
Preferably, the ethanol vapor is sent to the heat exchanger through a conduit. Preferably, valves, such as flow valves, are provided on the conduits for controlling the amount of ethanol vapor entering each heat exchanger.
According to a preferred embodiment of the present invention, the ethanol vapor is divided into at least two streams, wherein one stream sequentially enters the first heat exchange heat exchanger and the second heat exchange heat exchanger through the pipeline for cooling, and the other stream directly enters the second heat exchange heat exchanger through the pipeline, so that the amount or temperature of the water exchanging heat with the first heat exchange heat exchanger can be flexibly adjusted. Therefore, according to a preferred embodiment of the present invention, the ethanol vapor directly enters the heat exchanger for the first heat exchange and the heat exchanger for the second heat exchange through pipes provided with valves, respectively, to control the amount of the at least part of the ethanol vapor. When the valve on the pipeline for directly entering the first heat exchange is closed, the ethanol steam directly carries out second heat exchange through the pipeline provided with the valve, and at the moment, the ethanol steam is cooled only by adopting a heat exchanger for second heat exchange; when the valve on the pipeline for directly feeding the ethanol steam into the second heat exchange is adjusted, the amount of the ethanol steam directly fed into the second heat exchange can be controlled.
Preferably, in order to recycle as much heat as possible from the ethanol vapor, the amount of ethanol vapor of the first heat exchange and the second heat exchange performed sequentially through the pipe is 60% or more, preferably 65 to 100% of the total amount of ethanol vapor to be heat exchanged.
Preferably, the temperature of the ethanol vapor before the heat exchange is 135-155 ℃, preferably 140-150 ℃. Preferably, the ethanol vapor originates from a molecular sieve dehydration unit.
The refrigerator is not particularly limited in the present invention, and may be a conventional one in the art, and a hot water type lithium bromide refrigerator is preferably used. The hot water type lithium bromide refrigerator uses water after the first heat exchange as a driving heat source.
According to a preferred embodiment of the present invention, the refrigerator is further provided with a bypass pipeline, and when the refrigerator is overhauled in a fault state or the temperature of the water deviates too much, for example, the temperature of the water is more than 97 ℃ or less than 85 ℃, a valve of the bypass pipeline can be opened, so as to directly convey the water in the pipeline to the heat exchanger for the first heat exchange, thereby protecting the refrigerator.
In a second aspect, the present invention provides a method for dehydrating ethanol vapor, which comprises dehydrating ethanol vapor containing water, and then recovering the ethanol vapor waste heat from the dehydrated ethanol vapor by the method described above.
Preferably, the dehydration mode comprises contacting the ethanol steam containing water with a molecular sieve for adsorption dehydration, and the dehydration conditions comprise the temperature of 145-160 ℃, preferably 150-155 ℃, the pressure of 200-250KPaG and the mass space velocity of 0.2-0.5h-1。
In the present invention, the mass space velocity refers to the weight of aqueous ethanol vapor passing through a unit weight of molecular sieve adsorbent per hour.
Preferably, the dehydration is carried out in a molecular sieve adsorption tower, the molecular sieve adsorption tower comprises at least two molecular sieve adsorption towers which are arranged in parallel, the method further comprises switching the water-containing ethanol steam into another molecular sieve adsorption tower for adsorption dehydration after the molecular sieve in one of the molecular sieve adsorption towers is saturated, and regenerating the molecular sieve adsorption tower saturated in molecular sieve adsorption. The molecular sieve adsorption column of the present invention is not particularly limited, and may be conventional equipment in the art. The mode of switching the ethanol vapor is not particularly limited, and may be selected conventionally in the field, for example, a mode of arranging a valve at the bottom of the molecular sieve adsorption tower, and switching the ethanol vapor by opening and closing the valve.
Preferably, the regeneration mode comprises contacting the dehydrated ethanol steam with the adsorption saturated molecular sieve under the condition of molecular sieve regeneration. The regeneration conditions are not particularly limited in the present invention, and may be selected conventionally in the field, for example, desorption regeneration of molecular sieve by using a vacuum system to form negative pressure.
In a third aspect, as shown in fig. 1, the invention provides an ethanol vapor waste heat recovery device, which includes an ethanol vapor source, a condensation unit and a refrigeration unit, wherein the condensation unit includes a first condensation device and a second condensation device, the ethanol vapor source is sequentially communicated with the first condensation device and the second condensation device to cool ethanol vapor, and a refrigerant outlet of the first condensation device is connected with the refrigeration unit, so that the first condensation device provides energy for the refrigeration unit.
Preferably, the first and second condensing means each comprise one or more heat exchangers arranged in parallel. According to a preferred embodiment of the invention, the first condensation device comprises a plurality of heat exchangers arranged in parallel and the second condensation device comprises one heat exchanger. Therefore, most of heat can be recycled by the first condensing device, and the amount of cooling water consumed by the second condensing device is greatly reduced.
Preferably, the ethanol steam source is directly communicated with the second condensing device through a pipeline provided with a valve.
Preferably, the apparatus further comprises a hot water buffer tank disposed between the first condensing means and the refrigerator.
Preferably, the driving heat source outlet of the refrigerator is communicated with the condensing agent inlet of the first condensing device.
Preferably, a flow self-control regulating valve is arranged between the outlet of the refrigerating machine and the condensing agent inlet of the first condensing device and used for regulating the flow of water in a pipeline. The flow self-control regulating valve is not particularly limited, and can be selected conventionally in the field.
Preferably, a flow meter is further arranged between the outlet of the refrigerating machine and the condensing agent inlet of the first condensing device, and is used for monitoring the flow of water in the pipeline. And a thermometer is also arranged between the outlet of the refrigerator and the condensing agent inlet of the first condensing device and used for monitoring the temperature of water in the outlet pipeline of the refrigerator.
Preferably, the flow self-control regulating valve can be interlocked with the flowmeter or the thermometer. The linkage system is not particularly limited in the present invention, and may be a linkage system conventionally selected in the art, for example, a linkage system using an SIS or DCS control system.
In a fourth aspect, the invention provides an ethanol steam dehydration system, which comprises an ethanol steam dehydration device and a heat recovery device, wherein the heat recovery device is the device, and the ethanol steam dehydration device provides ethanol steam for the heat recovery device.
Preferably, the ethanol steam dehydration device comprises at least two molecular sieve adsorption towers which are arranged in parallel, so that after the molecular sieve in one molecular sieve adsorption tower is adsorbed and saturated, the ethanol steam containing water is switched to the other molecular sieve adsorption tower for adsorption dehydration, and the molecular sieve adsorption tower with the saturated adsorption of the molecular sieve is regenerated. Thereby, the regeneration of the molecular sieve adsorption tower can be realized without interrupting the operation.
According to a preferred embodiment of the present invention, the ethanol steam dehydration system and the ethanol steam dehydration method provided by the present invention are as shown in fig. 2, the ethanol steam containing water is fed from the bottom of the molecular sieve adsorption tower a, at this time, the bottom valve and the top valve of the molecular sieve adsorption tower B are closed, and the ethanol steam enters the heat exchanger C of the first heat exchange through the first pipeline 1 provided with a valve to perform the first heat exchange, and then enters the heat exchanger D of the second heat exchange to perform the second heat exchange, and after two-stage condensation, the ethanol steam becomes the ethanol finished product and enters the finished product tank. And after the molecular sieve adsorption tower A is saturated in adsorption, closing a valve at the top of the molecular sieve adsorption tower A, simultaneously opening a valve at the bottom and a valve at the top of the molecular sieve adsorption tower B, communicating the molecular sieve adsorption tower A with a vacuumizing device, and performing desorption regeneration. The temperature level of the hot water obtained by the first heat exchange is higher, the hot water is buffered by one or more buffer tanks E arranged in series and then enters a refrigerator F to be used as a driving heat source, and the hot water is cooled and then circulates to be used as a coolant of a heat exchanger for the first heat exchange. Therefore, the part of hot water is recycled between the heat exchanger and the refrigerator to form a closed loop mode.
The present invention will be described in detail below by way of examples. In the following examples, the hot water type lithium bromide refrigerator model MZL-1220, which is available from Kawasaki air Conditioning Equipment, Inc., of the same party.
Example 1
As shown in fig. 2, the molecular sieve adsorption device comprises two molecular sieve adsorption towers a and B, the first condensing device C comprises three parallel spiral wound heat exchangers, and the second condensing device D comprises a fin heat exchanger.
And a flow regulating valve arranged on a pipeline between the first condensing device C and the refrigerating machine F is interlocked with the flowmeter to control the flow of water in the pipeline.
Sending the aqueous ethanol steam with ethanol concentration of 92-93 wt% at 140 ℃ and 150 ℃ into a molecular sieve adsorption tower A for adsorption dehydration, wherein the temperature of the molecular sieve adsorption tower A is about 145 ℃, the pressure is 250KPaG, and the filling amount of the molecular sieve in the molecular sieve adsorption tower A and the molecular sieve adsorption tower B is about 70t respectively; the dehydrated fuel ethanol steam is sequentially sent to heat exchangers of a first condensing device C and a second condensing device D, the first condensing device is provided with three spiral winding heat exchangers connected in parallel, the second condensing device is provided with one heat exchanger, the temperature of the ethanol steam cooled by the first condensing device C is about 95 ℃, and the temperature of the ethanol steam cooled by the second condensing device D is about 80 ℃.
And (3) exchanging heat between the condensed water from the refrigerator F and the ethanol steam through a first condensing device, wherein the temperature of the heated water is about 95 ℃, entering a hot water buffer tank E for buffering, and then pumping to a hot water type lithium bromide refrigerator through a circulating water pump. The condensed water is used as a driving heat source of the refrigerating machine F, the temperature of the condensed water after passing through the refrigerating machine is about 68 ℃, and then the condensed water enters the first condensing device C for absorbing heat. The cycle is thus performed.
And after the molecular sieve adsorption tower A is saturated in adsorption, closing a valve at the top of the molecular sieve adsorption tower A, simultaneously opening a valve at the bottom and a valve at the top of the molecular sieve adsorption tower B, communicating the molecular sieve adsorption tower A with a vacuumizing device, and performing desorption regeneration.
In the technical scheme, the flow rate of the ethanol steam is about 22t/h, the temperature is reduced from about 145 ℃ to 95 ℃, the heat released per hour is about 4300KW, and 370 multiplied by 10 is generated4Kcal refrigerating capacity can save electricity consumption by 250 ten thousand degrees every year, and the heat exchanger of the second condensing device uses cooling water of 1800m3H is used as the reference value. The results are shown in Table 1.
Comparative example 1
The ethanol vapor dehydration was carried out in the same manner as in example 1 except that the valve in the first conduit 1 was closed and the ethanol vapor from the top of the molecular sieve adsorption column A was introduced directly from the second conduit 2 into the heat exchanger of the second condensing unit D to carry out only the first heat exchange.
In the technical scheme, the flow rate of the ethanol steam is about 22t/h, the temperature is reduced from about 145 ℃ to 80 ℃, and the heat exchanger of the second condensing device D uses 2400m of cooling water3H is used as the reference value. The results are shown in Table 1.
TABLE 1
As can be seen from the results in table 1, example 1 using the ethanol vapor waste heat recovery device and the ethanol vapor dehydration system provided by the present invention has a significant energy saving effect, and compared with comparative example 1, on the one hand, the usage amount of cooling water is greatly reduced, and the water amount is saved by 25%, and on the other hand, because the temperature level of water after the first heat exchange is higher, the ethanol vapor waste heat recovery device and the ethanol vapor dehydration system can be used for refrigeration of a refrigerator, so that the power consumption of the refrigerator is greatly saved. The price of electricity per degree is about 0.57 yuan calculated according to the price of electricity used in the current factory, and the energy cost can be saved by 144 yuan each year for a fuel ethanol project of 30 ten thousand tons/year.
The invention recovers a large amount of waste heat in ethanol steam from the molecular sieve device by optimizing the waste heat utilization of the fuel ethanol, generates considerable refrigerating capacity by utilizing the hot water type lithium bromide refrigerator, provides a large amount of cold water for a fermentation working section, and can save the power consumption in the production process of the fuel ethanol. The application of the waste heat refrigeration technology can replace the high energy consumption bottleneck that the high-temperature ethanol steam is cooled by circulating cooling water after molecular sieve dehydration in the domestic ethanol industry. The comprehensive utilization of waste heat resources in the production process is realized, and the circulating water consumption and the energy consumption of a refrigeration system are reduced; but also has great promotion significance for improving the innovation development of energy-saving emission-reducing technology in the ethanol industry, reducing the production cost and improving the enterprise competitiveness.
The preferred embodiments of the present invention have been described above in detail, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, many simple modifications can be made to the technical solution of the invention, including combinations of various technical features in any other suitable way, and these simple modifications and combinations should also be regarded as the disclosure of the invention, and all fall within the scope of the invention.
Claims (19)
1. The method for recovering the ethanol steam waste heat comprises the step of cooling ethanol steam and water through heat exchange, and is characterized in that at least part of the ethanol steam and water are subjected to heat exchange in a first heat exchange mode and a second heat exchange mode sequentially, the first heat exchange mode enables the temperature of the ethanol steam to be reduced to 90-110 ℃, preferably 95-100 ℃, the second heat exchange mode enables the temperature of the ethanol steam to be reduced to 70-85 ℃, preferably 75-80 ℃, and water after the first heat exchange mode is used for refrigerating by a refrigerating machine.
2. A process according to claim 1, wherein the temperature of the water before the first heat exchange is 60-75 ℃, preferably 65-70 ℃, and the temperature of the water after the first heat exchange is 85-97 ℃, preferably 90-95 ℃.
3. The method according to claim 1 or 2, wherein the water before the first heat exchange is water after being refrigerated by a refrigerator.
4. The method according to any one of claims 1 to 3, wherein the method further comprises buffering the water after the first heat exchange in a hot water buffer tank before the water is used for refrigeration in the refrigerator.
5. The process of any one of claims 1-4, wherein the first and second heat exchanges are conducted in heat exchangers, and the first heat exchange is conducted in one or more heat exchangers arranged in parallel.
6. The process according to claim 5, wherein the ethanol vapor is sent to the heat exchanger through a pipeline, and the ethanol vapor is directly sent to the heat exchanger for the first heat exchange and the heat exchanger for the second heat exchange through pipelines provided with valves respectively so as to control the amount of the at least part of the ethanol vapor.
7. The process according to any one of claims 1 to 6, wherein the amount of ethanol vapor of the first heat exchange and the second heat exchange performed in sequence is 60% or more of the total amount of ethanol vapor to be heat exchanged.
8. The method as claimed in any one of claims 1 to 7, wherein the temperature of the ethanol vapor before the heat exchange is 135-155 ℃, preferably 140-150 ℃, and the ethanol vapor is from a molecular sieve dehydration device.
9. A method for the steam dehydration of ethanol, which comprises dehydrating hydrous ethanol steam and then recovering the residual heat of the ethanol steam by the method of any one of claims 1 to 8 after the dehydration.
10. The method as claimed in claim 9, wherein the dehydration manner comprises contacting the ethanol vapor containing water with a molecular sieve for adsorption dehydration, and the dehydration conditions comprise a temperature of 150--1。
11. The method of claim 9 or 10, wherein the dehydration is performed in a molecular sieve adsorption column comprising at least two molecular sieve adsorption columns arranged in parallel, and the method further comprises switching the aqueous ethanol vapor to another molecular sieve adsorption column for adsorptive dehydration after the molecular sieve in one of the molecular sieve adsorption columns is saturated, and regenerating the molecular sieve adsorption column saturated with the molecular sieve.
12. The method of claim 11, wherein the regenerating comprises contacting the dehydrated ethanol vapor with an adsorption saturated molecular sieve under molecular sieve regeneration conditions.
13. The utility model provides an ethanol steam waste heat recovery device, the device includes ethanol steam source, condensing unit and refrigerating unit, the condensing unit includes first condensing equipment and second condensing equipment, ethanol steam source communicates first condensing equipment and second condensing equipment in proper order, cools off ethanol steam, the refrigerant export of first condensing equipment with refrigerating unit connects, makes first condensing equipment for refrigerating unit provides the energy.
14. The apparatus of claim 13 wherein the first and second condensing means each comprise one or more heat exchangers arranged in parallel.
15. The apparatus of claim 13 or 14, wherein the source of ethanol vapor is in direct communication with the second condensing means through a valved conduit.
16. The apparatus according to any one of claims 13 to 15, further comprising a hot water buffer tank disposed between the first condensing means and the refrigerator, for allowing the refrigerant discharged from the first condensing means to enter the refrigerating unit after being buffered by the hot water buffer tank.
17. The apparatus of any one of claims 13 to 16, wherein a driving heat source outlet of the refrigerator is in communication with a refrigerant inlet of the first condensing means.
18. An ethanol steam dehydration system comprising an ethanol dehydration plant and a heat recovery plant, wherein the heat recovery plant is the plant of any one of claims 13 to 17, and the ethanol dehydration plant provides ethanol steam to the heat recovery plant.
19. The system of claim 18, wherein the ethanol dehydration device comprises at least two molecular sieve adsorption towers arranged in parallel, so that after the molecular sieve in one molecular sieve adsorption tower is saturated, the ethanol steam containing water is switched to the other molecular sieve adsorption tower for adsorption dehydration, and the molecular sieve adsorption tower saturated with the molecular sieve is regenerated.
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| CN109488400A (en) * | 2018-11-08 | 2019-03-19 | 国投生物科技投资有限公司 | A kind of alcohol fuel project waste heat comprehensive utilization system |
| CN209602411U (en) * | 2018-12-26 | 2019-11-08 | 日照岚山生化制品有限公司 | A kind of alcohol recovery system with UTILIZATION OF VESIDUAL HEAT IN |
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Application publication date: 20210608 |