Waste heat recovery system adopting heat pump technology in oil processing field

Abstract

The utility model discloses a waste heat recovery system adopting a heat pump technology in the field of oil processing, which comprises a plurality of water circulation purification trapping components, each water circulation purification trapping component is connected with a low-temperature hot water circulating pump, and the plurality of low-temperature hot water circulating pumps are connected in parallel with the cold side of a heat pump. A low-temperature hot water circulation assembly is formed by a water circulation purification trapping assembly, a low-temperature hot water circulation pump and a heat pump. The hot side of the heat pump is sequentially connected with the high-temperature hot water tank, the high-temperature hot water circulating pump and the equipment or the workshop section needing to be heated through pipelines, and the heat pump, the high-temperature hot water tank, the high-temperature hot water circulating pump and the equipment or the workshop section needing to be heated are connected to form a high-temperature water circulating loop assembly. According to the waste heat recovery system disclosed by the utility model, the waste heat recovery system is used for recovering and utilizing waste heat from a pretreatment device and a leaching device in the processing process of oil plants such as soybeans and rapeseeds, so that the consumption of steam can be reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of oil processing, in particular to a waste heat recovery system using a heat pump technology in the oil processing field. Background Art

[0002] Oil processing is the process of processing oil into edible oil and meal. Common methods include pressing and leaching. The leaching method has the advantages of low residual oil rate in the meal, high oil yield, low labor intensity, good working environment, and good meal quality. The leaching method is divided into two stages: oil pretreatment stage and leaching stage.

[0003] The oilseed pretreatment process is divided into: impurity removal, conditioning, crushing, peeling, flaking, puffing (soybean), steaming and frying pre-pressing (rapeseed) and other processes. Among them, the soybean puffing and cold drying unit or the rapeseed cake cooling unit will produce a large amount of hot air at about 60-75℃; the rapeseed steaming and frying unit will produce a large amount of hot air at about 85-100℃. However, soybeans (rapeseed) need to be heated, tempered, softened and dried in a conditioning tower before leaching, and this process requires heating or hot air drying.

[0004] The pretreated oil enters the leaching process and is extracted with n-hexane solvent to obtain mixed oil and wet meal. Using the boiling point difference between the solvent and the oil, the mixed oil passes through the first evaporator and the second evaporator to remove the n-hexane solvent to obtain crude oil. The wet meal is removed from the residual n-hexane solvent by the DT evaporator, and then dried and cooled by the DC drying and cooling machine to obtain finished meal for storage. Among them, the hot meal drying and cooling unit will generate a large amount of DC hot air at about 70 to 85°C. In the soybean (rapeseed) leaching process, in order to increase the leaching rate of oil and reduce the residual oil rate of the meal, it is necessary to heat the n-hexane solvent and the extractor; the mixed oil obtained by leaching is heated by pre-secondary steaming to better reduce the content of n-hexane in the mixed oil. The above process usually also requires the use of steam.

[0005] The low-temperature hot air from the cold drying box, steaming and frying pan, and DC drying and cooling machine not only contains a large amount of heat energy, but also contains a small amount of dust. Usually, this hot air is directly discharged into the atmosphere. This not only leads to a waste of heat energy, but also causes air pollution. The above problems not only lead to a large waste of energy resources in oil processing enterprises, causing certain economic losses; but also deviate from the national energy conservation and emission reduction plan goals. Utility Model Content

[0006] In view of the shortcomings of the prior art, the purpose of the utility model is to provide a waste heat recovery system using heat pump technology in the field of oil processing. The waste heat recovery system is used in the processing of oil such as soybeans and rapeseed to recover and utilize waste heat from pretreatment and leaching devices, thereby saving steam consumption. In order to achieve the above-mentioned purpose and other advantages according to the utility model, a waste heat recovery system using heat pump technology in the field of oil processing is provided, comprising:

[0007] Multiple water circulation purification and capture components, each of which is connected to a low-temperature hot water circulation pump, and multiple low-temperature hot water circulation pumps are connected in parallel to the cold side of the heat pump, and the water circulation purification and capture components, the low-temperature hot water circulation pump and the heat pump constitute a low-temperature hot water circulation component;

[0008] The hot side of the heat pump is connected to the high-temperature hot water tank, the high-temperature hot water circulation pump and the equipment or section to be heated in sequence through pipes, and the high-temperature water circulation loop component is formed by connecting the heat pump, the high-temperature hot water tank, the high-temperature hot water circulation pump and the equipment or section to be heated.

[0009] Preferably, the water circulation purification capture component includes a first waste heat collector and a first capture water circulation pump connected to the first waste heat collector through a pipeline, and the first waste heat collector is connected to a first low-temperature hot water circulation pump through a pipeline.

[0010] Preferably, the water circulation purification capture component includes a second waste heat collector and a second capture water circulation pump connected to the second waste heat collector through a pipeline, and the second waste heat collector is connected to a second low-temperature hot water circulation pump through a pipeline.

[0011] Preferably, the first low-temperature hot water circulation pump and the second low-temperature hot water circulation pump are connected in parallel to the cold side of the heat pump through pipelines, and the heat pump is further connected to the first waste heat collector and the second waste heat collector through pipelines respectively.

[0012] Preferably, when the waste heat recovery system is used in a rapeseed processing workshop, the first waste heat collector is connected to a hot air duct from a cold drying box in an oil pretreatment workshop and an exhaust steam duct from a steam-frying pan.

[0013] Preferably, the second waste heat collector is connected to the hot air duct from the DC dry cooler of the oil leaching workshop, and the low-temperature gas phase outlets at the top of the first waste heat collector and the second waste heat collector are directly connected to the atmosphere through pipes for exhaust or exhaust gas treatment.

[0014] Preferably, a demister, two groups of nozzles, a plurality of fillers and a water collection tank are installed inside the first waste heat collector and the second waste heat collector.

[0015] Preferably, one end of the heat pump is connected to a medium-pressure steam pipe, and the other drain end is connected to the high-temperature hot water tank through a pipe, and a nozzle is installed on the top of the high-temperature hot water tank; and when the waste heat recovery system is used in a rapeseed processing workshop, the low-temperature gas phase outlet at the top of the high-temperature hot water tank is directly connected to the DT degassing machine through a pipe.

[0016] Preferably, the equipment or section that needs to be heated refers to the equipment or section that needs to be heated during the oil processing process, including but not limited to tempering tower heating, solvent recovery heating, pre-secondary distillation heating and extractor heating.

[0017] Compared with the prior art, the utility model has the following beneficial effects: the waste heat recovery system of the present application is suitable for collecting low-temperature waste heat from pretreatment workshops and leaching workshops during the processing of oilseeds such as soybeans and rapeseed, and effectively reusing it.

[0018] The waste heat recovery system of the present application recovers the low-temperature waste heat generated in the soybean puffing and cold drying unit, rapeseed cake cooling unit and rapeseed steaming and frying unit in the oil pretreatment process, as well as the hot meal drying and cooling unit in the oil extraction process. The low-temperature waste heat is converted into high-quality thermal energy through a heat pump and used in equipment or work sections that require steam heating, mainly including but not limited to heating of the quenching and tempering tower, heating of recovered solvents, heating of pre-secondary steaming and heating of the extractor, thereby saving a lot of steam consumption.

[0019] The waste heat recovery system of the present application captures a small amount of dust in the system during the process of recovering low-temperature waste heat, purifies the hot air discharged into the atmosphere, and reduces pollution to the atmosphere.

[0020] The waste heat recovery system of the present application does not require major changes to the original device and pipelines, and involves less new equipment, so the investment cost and maintenance cost are low.

[0021] The waste heat recovery system of this application uses medium-pressure steam and low power consumption to convert low-temperature waste heat into a large amount of high-quality thermal energy. The later operating costs are little affected by the fluctuation of electricity prices. The total operating cost of the system is very low, but it creates considerable and sustainable economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a structural schematic diagram of a waste heat recovery system using heat pump technology in the oil processing field according to the utility model. DETAILED DESCRIPTION

[0023] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0024] Reference Figure 1 , a waste heat recovery system using heat pump technology in the field of oil processing, comprising: a plurality of water circulation purification and capture components, each of which is connected to a low-temperature hot water circulation pump, a plurality of low-temperature hot water circulation pumps are connected in parallel to the cold side of a heat pump 7, and a low-temperature hot water circulation component is formed by the water circulation purification and capture components, the low-temperature hot water circulation pump and the heat pump 7;

[0025] The hot side of the heat pump 7 is connected to the high-temperature hot water tank 8, the high-temperature hot water circulation pump 9 and the equipment or section to be heated in turn through pipelines, and the high-temperature water circulation loop assembly is formed by connecting the heat pump 7, the high-temperature hot water tank 8, the high-temperature hot water circulation pump 9 and the equipment or section to be heated. One end of the heat pump 7 is connected to a medium-pressure steam pipeline, and the other drain end is connected to the high-temperature hot water tank 8 through a pipeline, and a nozzle is installed at the top of the high-temperature hot water tank 8. The hot side outlet of the heat pump 7 is connected to the nozzle at the top of the high-temperature hot water tank 8 through a pipeline. The bottom end of the high-temperature hot water tank 8 is connected to the inlet of the high-temperature hot water circulation pump 9 through a pipeline, and the outlet of the high-temperature hot water circulation pump 9 is connected to the equipment or section to be heated through a pipeline. And when the waste heat recovery system is used in a rapeseed processing workshop, the gas phase outlet at the top of the high-temperature hot water tank 8 is directly connected to the DT degassing machine through a pipeline.

[0026] Further, the water circulation purification capture assembly includes a first waste heat capturer 1 and a first capture water circulation pump 2 connected to the first waste heat capturer 1 through a pipeline, and the first waste heat capturer 1 is connected to a first low-temperature hot water circulation pump 3 through a pipeline. The outlet of the first capture water circulation pump 2 is connected to a nozzle below the water collection tank of the first waste heat capturer 1 through a pipeline. The first waste heat capturer 1 is connected to the inlet of the first low-temperature hot water circulation pump 3 through a pipeline. The water circulation purification capture assembly includes a second waste heat capturer 4 and a second capture water circulation pump 5 connected to the second waste heat capturer 4 through a pipeline, and the second waste heat capturer 4 is connected to a second low-temperature hot water circulation pump 6 through a pipeline. The outlet of the second capture water circulation pump 5 is connected to the nozzle below the water collection tank of the second waste heat capturer 4 through a pipeline. The second waste heat capturer 4 is connected to the inlet of the second low-temperature hot water circulation pump 6 through a pipeline.

[0027] The first waste heat collector 1 and the second waste heat collector 4 are both equipped with a demister, two groups of nozzles, a plurality of fillers and a water collecting tank.

[0028] Furthermore, the first low-temperature hot water circulation pump 3 and the second low-temperature hot water circulation pump 6 are connected in parallel to the cold side of the heat pump 7 through pipes, and the heat pump 7 is further connected to the first waste heat collector 1 and the second waste heat collector 4 through pipes respectively.

[0029] Furthermore, when the waste heat recovery system is used in a rapeseed processing workshop, the first waste heat collector 1 is connected to a hot air duct from a cold drying box in an oil pretreatment workshop and an exhaust steam duct from a steam-frying pan.

[0030] Furthermore, the second waste heat collector 4 is connected to a hot air duct from a DC drying and cooling machine in the oil extraction workshop, and the low-temperature gas phase outlets at the tops of the first waste heat collector 1 and the second waste heat collector 4 are directly connected to atmospheric exhaust or exhaust gas treatment through pipes.

[0031] Furthermore, the equipment or section that needs to be heated refers to the equipment or section that needs to be heated during the oil processing process, including but not limited to tempering tower heating, solvent recovery heating, pre-secondary distillation heating and extractor heating.

[0032] Working principle: After the oil is removed from the impurities, it enters the conditioning tower for heating, conditioning, softening and drying. If the oil is soybean, it needs to be crushed and peeled. After the peeled soybean is rolled, it enters the extruder and is injected with heating steam. The temperature of the soybean extruded material rises and the moisture content increases. Therefore, it needs to enter the cold drying box and use countercurrent cold air to dry and cool it to achieve a better leaching effect. In this process, a large amount of hot air with dust and a temperature of about 60-75°C will be generated. If the oil is rapeseed, the rapeseed embryo flakes need to be steamed and pre-pressed. In the steaming and frying process, a large amount of waste gas with dust and a temperature of about 85-100°C will also be generated. The pretreated soybean extruded material or rapeseed cake is transported to the leaching workshop through a scraper. The temperature of the extractor is controlled at 50-58°C, and the preheated n-hexane solvent is used to spray the soybean extruded material or rapeseed cake in a countercurrent manner to obtain mixed oil and wet meal. Wet meal contains a lot of residual solvent and water, which needs to be removed by DT degassing machine to remove the n-hexane solvent, and DC drying and cooling machine to reduce the moisture from about 18.5% to about 13%. During the drying and cooling process, a lot of hot air with water vapor and a temperature of about 70-85℃ will also be generated.

[0033] A large amount of low-temperature waste heat is generated during the oil pretreatment and leaching process. We have designed a waste heat recovery system using heat pump technology in the oil processing field. It uses a certain amount of medium-pressure steam and less electricity through a heat pump to convert low-temperature waste heat into high-quality heat energy.

[0034] In the oil pretreatment workshop, the hot air from the cold drying box and the exhaust gas from the steaming and frying pan enter the first waste heat collector 1 through the pipeline. The nozzle below the water collection tank of the first waste heat collector 1 sprays water to capture a small amount of dust in the hot air, thereby obtaining clean hot air. The captured water is continuously circulated and transported to the nozzle below the water collection tank of the waste heat collector 1 through the first captured water circulation pump 2. In the oil leaching workshop, the hot air from the DC drying and cooling machine enters the second waste heat collector 4 through the pipeline. The nozzle below the water collection tank of the second waste heat collector 4 sprays water to capture a small amount of dust in the hot air, thereby obtaining clean hot air. The captured water is continuously circulated and transported to the nozzle below the water collection tank of the second waste heat collector 4 through the second captured water circulation pump 5.

[0035] Subsequently, the clean hot air in the first waste heat collector 1 and the second waste heat collector 4 rises and exchanges heat with the low-temperature circulating water sprayed on the top of the first waste heat collector 1 and the second waste heat collector 4; the temperature of the hot air decreases, and after the droplets are removed by the demister, it is discharged into the atmosphere or transported to the exhaust gas treatment device; the temperature of the low-temperature circulating water increases, and is transported to the cold side inlet of the heat pump 7 through the first low-temperature hot water circulation pump 3 and the second low-temperature hot water circulation pump 6 respectively. At this time, the low-temperature circulating water carries a large amount of low-temperature waste heat.

[0036] At the same time, the high-temperature circulating water at the hot side inlet of the heat pump 7 absorbs the heat energy of the low-temperature circulating water through the heat pump 7 and the medium-pressure steam of 6 to 10 bar, and the temperature rises from 55 to 88°C to 85 to 118°C, and then enters the nozzle of the high-temperature hot water tank 8. When the waste heat recovery system is used in a rapeseed processing workshop, more low-temperature waste heat will be discharged during rapeseed steaming and frying, and the high-temperature hot water in the high-temperature hot water tank 8 will flash and generate low-pressure steam of about 1400 mbarA to 1600 mbarA, which is transported to the DT steamer through the pipeline at the top of the high-temperature hot water tank 8 for meal steaming and degassing.

[0037] Finally, the high-temperature hot water circulation pump 9 delivers the high-temperature hot water to the equipment or section that needs to be heated. After the heat energy of the high-temperature hot water is fully utilized, it returns to the hot side inlet of the heat pump 7 and is heated again. In this way, low-temperature waste heat is repeatedly absorbed to release high-quality heat energy.

[0038] Through the above operation, a novel low-grade waste heat recovery system for an oil pretreatment / leaching device provided by the utility model can be realized. The advantages of a novel low-grade waste heat recovery system for an oil pretreatment / leaching device provided by the utility model are as follows:

[0039] (1) The low-temperature waste heat generated in the soybean puffing and cold drying unit, rapeseed cake cooling unit and rapeseed steaming and frying unit in the oilseed pretreatment workshop, as well as the hot meal drying and cooling unit in the oilseed extraction workshop, is captured and recovered by water. The low-temperature waste heat is converted into high-quality thermal energy through a heat pump and used in equipment or work sections that require steam heating, mainly including but not limited to heating of the quenching and tempering tower, heating of recovered solvents, heating of pre-secondary steaming and heating of the extractor, thereby saving a lot of steam consumption.

[0040] (2) A water collecting tank is respectively provided inside the first waste heat collector 1 and the second waste heat collector 4. After absorbing the heat energy of the clean hot air, the collected water forms clean low-temperature hot water for recycling, which effectively avoids the direct use of low-temperature hot water mixed with dust, which affects the overall process operation.

[0041] (3) Two groups of nozzles are respectively arranged inside the first waste heat collector 1 and the second waste heat collector 4. The nozzles below the water collection tank can capture a small amount of dust in the hot air to obtain clean hot air, which is then discharged into the atmosphere or transported to the exhaust gas treatment device, thereby reducing pollution to the atmosphere; the nozzles at the top are used to capture the heat energy of the above clean hot air and reuse it, thereby saving a lot of steam consumption. In the long run, better economic benefits are created.

[0042] (4) A gas phase outlet is provided on the top of the high-temperature hot water tank 8, which is connected to the DT degassing machine through a pipeline. When the waste heat recovery system is used in a rapeseed processing workshop, more low-temperature waste heat will be discharged during rapeseed steaming and frying. The high-temperature hot water in the high-temperature hot water tank 8 flashes to produce low-pressure steam of about 1400mbarA to 1600mbarA, which can be used as direct gas for the DT degassing machine for meal degassing.

[0043] (5) The present invention does not require major modifications to the original device and pipelines. It only requires the addition of less equipment and simpler pipelines to the original device, so the investment cost and maintenance cost are low.

[0044] (6) The utility model uses medium-pressure steam and low power consumption to convert low-temperature waste heat into a large amount of high-quality heat energy through the heat pump 7. The later operating costs are little affected by the fluctuation of electricity prices. The total operating cost of the system is very low, but it creates considerable and sustainable economic benefits.

[0045] The number of devices and processing scale described here are used to simplify the description of the utility model. The application, modification and variation of the utility model are obvious to those skilled in the art.

[0046] Although the implementation scheme of the utility model has been disclosed as above, it is not limited to the applications listed in the specification and implementation scheme. It can be fully applied to various fields suitable for the utility model. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the utility model is not limited to the specific details and the illustrations shown and described here.

Claims

1. A waste heat recovery system using heat pump technology in the field of oil processing, characterized in that: include: A plurality of water circulation purification and capture components, each of which is connected to a low-temperature hot water circulation pump, and the plurality of low-temperature hot water circulation pumps are connected in parallel to the cold side of a heat pump (7), and the water circulation purification and capture components, the low-temperature hot water circulation pumps and the heat pump (7) form a low-temperature hot water circulation component; The hot side of the heat pump (7) is connected to the high-temperature hot water tank (8), the high-temperature hot water circulation pump (9) and the equipment or work section to be heated in sequence through pipelines, and the high-temperature water circulation loop component is formed by connecting the heat pump (7), the high-temperature hot water tank (8), the high-temperature hot water circulation pump (9) and the equipment or work section to be heated.

2. A waste heat recovery system using heat pump technology in the oil processing field as claimed in claim 1, characterized in that: The water circulation purification and capture component comprises a first waste heat collector (1) and a first capture water circulation pump (2) connected to the first waste heat collector (1) via a pipeline, and the first waste heat collector (1) is connected to a first low-temperature hot water circulation pump (3) via a pipeline.

3. A waste heat recovery system using heat pump technology in the oil processing field as claimed in claim 2, characterized in that: The water circulation purification capture component comprises a second waste heat collector (4) and a second capture water circulation pump (5) connected to the second waste heat collector (4) via a pipeline, and the second waste heat collector (4) is connected to a second low-temperature hot water circulation pump (6) via a pipeline.

4. A waste heat recovery system using heat pump technology in the oil processing field as claimed in claim 3, characterized in that: The first low-temperature hot water circulation pump (3) and the second low-temperature hot water circulation pump (6) are connected in parallel to the cold side of the heat pump (7) through pipelines, and the heat pump (7) is further connected to the first waste heat collector (1) and the second waste heat collector (4) through pipelines.

5. A waste heat recovery system using heat pump technology in the oil processing field as claimed in claim 2, characterized in that: When the waste heat recovery system is used in a rapeseed processing workshop, the first waste heat collector (1) is connected to a hot air duct from a cold drying box in an oil pretreatment workshop and an exhaust steam duct from a steam frying pan.

6. A waste heat recovery system using heat pump technology in the oil processing field as claimed in claim 3, characterized in that: The second waste heat collector (4) is connected to a hot air duct from a DC drying and cooling machine in an oil extraction workshop, and the low-temperature gas phase outlets at the tops of the first waste heat collector (1) and the second waste heat collector (4) are directly connected to atmospheric exhaust or exhaust gas treatment through pipelines.

7. A waste heat recovery system using heat pump technology in the oil processing field as claimed in claim 6, characterized in that: The first waste heat collector (1) and the second waste heat collector (4) are both equipped with a defoamer, two groups of nozzles, a plurality of fillers and a water collection tank.

8. A waste heat recovery system using heat pump technology in the oil processing field as claimed in claim 4, characterized in that: One end of the heat pump (7) is connected to a medium-pressure steam pipeline, and the other drain end is connected to the high-temperature hot water tank (8) through a pipeline. A nozzle is installed at the top of the high-temperature hot water tank (8); and when the waste heat recovery system is used in a rapeseed processing workshop, the flash steam gas phase outlet at the top of the high-temperature hot water tank (8) is directly connected to the DT degassing machine through a pipeline.

9. A waste heat recovery system using heat pump technology in the oil processing field as claimed in claim 1, characterized in that: The equipment or work section that needs to be heated refers to the equipment or work section that needs to be heated during the oil processing process, including but not limited to tempering tower heating, solvent recovery heating, pre-secondary distillation heating and extractor heating.

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