CN112944955A - Heat exchanger and methanol rectification system using same - Google Patents
Heat exchanger and methanol rectification system using same Download PDFInfo
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- CN112944955A CN112944955A CN202110279437.3A CN202110279437A CN112944955A CN 112944955 A CN112944955 A CN 112944955A CN 202110279437 A CN202110279437 A CN 202110279437A CN 112944955 A CN112944955 A CN 112944955A
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- heat exchange
- tower
- exchange group
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- reboiler
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F28—HEAT EXCHANGE IN GENERAL
- F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
- F28D7/00—Heat-exchange apparatus having stationary tubular conduit assemblies for both heat-exchange media, the media being in contact with different sides of a conduit wall
- F28D7/0066—Multi-circuit heat-exchangers, e.g. integrating different heat exchange sections in the same unit or heat-exchangers for more than two fluids
- F28D7/0075—Multi-circuit heat-exchangers, e.g. integrating different heat exchange sections in the same unit or heat-exchangers for more than two fluids with particular circuits for the same heat exchange medium, e.g. with the same heat exchange medium flowing through sections having different heat exchange capacities or for heating or cooling the same heat exchange medium at different temperatures
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D3/00—Distillation or related exchange processes in which liquids are contacted with gaseous media, e.g. stripping
- B01D3/007—Energy recuperation; Heat pumps
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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
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
- Y02P70/10—Greenhouse gas [GHG] capture, material saving, heat recovery or other energy efficient measures, e.g. motor control, characterised by manufacturing processes, e.g. for rolling metal or metal working
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- Thermal Sciences (AREA)
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- General Engineering & Computer Science (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
The invention provides a methanol rectification system, which applies a heat exchanger and comprises a crude alcohol preheater, a crude distillation tower, a pressurizing tower and a rectification tower which are sequentially connected through pipelines, wherein a steam buffer tank is connected with the crude distillation tower and the pressurizing tower through pipelines, the pipelines of the steam buffer tank, the crude distillation tower and the pressurizing tower are respectively connected with a first reboiler and a second reboiler, the pipeline of the pressurizing tower, which is connected with the rectification tower, is connected with a third reboiler, the pipeline of the crude distillation tower, which is connected with the pressurizing tower, is connected with an infusion pump, the first reboiler and the second reboiler are both connected with a condensate tank through pipelines, the condensate tank is connected with the crude alcohol preheater through a pipeline, and the bottom of the rectification tower is connected with the heat exchanger through a pipeline. The invention solves the problems of low heat utilization rate of a methanol rectification system and less total heat recovery of the whole device in the prior art, and has the effect of improving the utilization rate of the total waste heat.
Description
Technical Field
The invention relates to the technical field of methanol rectification, in particular to a heat exchanger and a methanol rectification system using the same.
Background
At present, methanol production devices in China, particularly small methanol production devices, generally have the phenomenon of high methanol rectification steam consumption, and generally, 2.5t of steam (0.35MPa) is consumed for producing 1t of refined methanol, even more than 3.0 t. The steam cost consumed by the rectification of the methanol accounts for more than 80 percent of the rectification cost (water, electricity and steam) of the methanol, so that the research on reducing the steam consumption of the rectification of the methanol has certain practical significance.
The temperature of the bottom of a main rectifying tower in a methanol rectifying system is 104-110 ℃, residual liquid generated by rectification is sent out by a residual liquid pump for treatment, and because the residual liquid has high temperature and the pH value of 4.5-5.5 is acidic, if the residual liquid is directly sent out, not only is heat loss caused, but also the pipeline of the residual liquid is easy to erode, corrode and thin, so that a heat exchanger with strong heat exchange capacity is urgently needed to be designed to utilize the heat energy of the residual liquid; for example, in a methanol recovery tower or a methanol rectification tower waste heat utilization system disclosed in patent document CN212395918, an absorption heat pump is used to absorb heat energy of steam at the top of the methanol rectification tower, and then the absorbed heat energy is used to heat the tower bottom liquid, and then the residual heat is fully utilized, but the heat pump has high energy consumption and high input cost, a common heat exchanger cannot fully utilize the heat energy of the residual liquid, and in the methanol rectification system, only the waste heat at the top of the methanol rectification tower is utilized, and the total heat recovered is limited.
Disclosure of Invention
Aiming at the defects in the prior art, the invention provides a heat exchanger and a methanol rectification system using the same, and solves the problems that the methanol rectification system in the prior art is low in heat utilization rate and small in total heat recovery amount of the whole device.
According to the embodiment of the invention, the heat exchanger comprises a shell, a feeding pipe fixedly connected to the top of the shell and a discharging pipe fixedly connected to the bottom of the shell, wherein a first heat exchange group, a second heat exchange group and a third heat exchange group are fixedly connected to the inside of the shell from top to bottom in sequence, the first heat exchange group and the third heat exchange group are horizontally and fixedly arranged at the inner top and the inner bottom of the shell respectively through two parallel first tube plates and two parallel third tube plates, the second heat exchange group is fixedly arranged at the inner middle part of the shell in an inclined manner through a second tube plate, the side wall of the shell is fixedly connected with connecting pipes for sequentially communicating the interiors of the first heat exchange group, the second heat exchange group and the third heat exchange group, heat exchange pipes vertical to the corresponding tube plates are fixedly connected to the interiors of the first heat exchange group, the second heat exchange group and the third heat exchange group, a heat source pipe and a liquid outlet pipe are fixedly connected, the drain pipe is communicated with the inside of the first heat exchange group.
Preferably, a plurality of groups of second heat exchange groups are fixedly arranged in the shell.
Preferably, the heat exchange tubes in the first heat exchange group penetrate through the first tube plate at the top, and the length of the heat exchange tubes penetrating through the first tube plate is gradually reduced from the middle part to the periphery of the first tube plate.
Preferably, the methanol rectification system comprises a crude alcohol preheater, a crude distillation tower, a pressurizing tower and a rectification tower which are sequentially connected through pipelines and are used for rectifying methanol, and further comprises a steam buffer tank, wherein the steam buffer tank is connected with a first reboiler and a second reboiler through pipelines, the first reboiler and the second reboiler are respectively connected with the crude distillation tower and the pressurizing tower through circulating pipelines, the pipeline connecting the pressurizing tower and the rectification tower is connected with a third reboiler, each pipeline is connected with an infusion pump used for transporting condensed water and methanol, the first reboiler and the second reboiler are both connected with a condensate tank through pipelines, the condensate tank is connected with the crude alcohol preheater through pipelines, the pipeline between the crude distillation tower and the pressurizing tower is connected with a heat exchanger, the bottom of the rectification tower is connected with the heat exchanger through a pipeline, and a heat source pipe of the heat exchanger is connected with the bottom of the rectification tower, the feed pipe of the heat exchanger is connected with the bottom of the crude distillation tower.
The outer wall of the condensate tank is coated with a layer of heat preservation cotton.
Compared with the prior art, the invention has the following beneficial effects:
1. the heat exchanger heats methanol flowing through the heat exchange tubes by arranging a plurality of heat exchange groups, residual liquid enters the heat exchanger through a heat source tube, the flow direction of the residual liquid is opposite to that of the methanol in the heat exchanger, and the methanol liquid with the temperature lower than that of the residual liquid is heated by utilizing the heat energy of the residual liquid in multiple stages; the heat exchange tube in the second heat exchanger inclines relative to the axis of the shell, so that the methanol slides down along the side wall of the shell of the heat exchange tube, the tube pass of the heat exchange tube is increased relatively, the heat energy of residual liquid flowing through the heat exchange set is fully utilized, and the utilization rate of heat is improved.
2. The energy-saving and emission-reducing methanol rectification system transports high-temperature condensed water in the first reboiler and the second reboiler to the crude alcohol preheater through the condensate tank, so that the crude alcohol is heated before entering the crude distillation tower, and the consumption of steam in the crude distillation tower is reduced; the residual liquid of the rectifying tower is used for heating the methanol after the crude distillation through the heat exchanger, so that the consumption of steam in the rectifying tower is reduced, the temperature of the residual liquid is reduced, the corrosion of a residual liquid pipeline can be slowed down, the waste heat is fully utilized on the whole, the consumption of the steam is reduced, and the energy conservation and emission reduction are realized.
Drawings
FIG. 1 is a production process diagram of an embodiment of the present invention.
Fig. 2 is a schematic view of the internal structure of the heat exchanger according to the embodiment of the present invention.
In the above drawings: 1. a steam buffer tank; 2. a first reboiler; 3. a crude distillation tower; 4. a crude alcohol preheater; 5. a second reboiler; 6. a pressurized column; 7. a third reboiler; 8. a rectifying tower; 9. an infusion pump; 10. a condensate tank; 200. a heat exchanger; 201. a housing; 202. a feed pipe; 203. a discharge pipe; 204. a heat source tube; 205. a connecting pipe; 206. a heat exchange pipe; 207. a liquid outlet pipe; 210. a first heat exchange set; 211. a first tube sheet; 220. a second heat exchange group; 221. a second tube sheet; 230. a third heat exchange group; 231. a third tube sheet.
Detailed Description
The technical solution of the present invention is further explained with reference to the drawings and the embodiments.
As shown in fig. 2, in order to fully utilize the raffinate in the rectification column, an embodiment of the invention provides a heat exchanger, which includes a shell 201, a feeding pipe 202 fixedly connected to the top of the shell 201, and a discharging pipe 203 fixedly connected to the bottom of the shell 201, a first heat exchange set 210, a second heat exchange set 220, and a third heat exchange set 230 are fixedly connected to the inside of the shell 201 from top to bottom in sequence, the first heat exchange set 210 and the third heat exchange set 230 are horizontally and fixedly installed at the inner top and the inner bottom of the shell 201 through two parallel first tube plates 211 and third tube plates 231, respectively, the second heat exchange set 220 is fixedly installed at the inner middle of the shell 201 in an inclined manner through a second tube plate 221, the side wall of the shell 201 is fixedly connected to a connecting pipe 205 for sequentially communicating the first heat exchange set 210, the second heat exchange set 220, and the third heat exchange set 230, heat exchange pipes 206 perpendicular to the corresponding tube plates are fixedly connected to the inside of the first heat exchange set 210, the side wall of the shell 201 is fixedly connected with a heat source pipe 204 and a liquid outlet pipe 207, the heat source pipe 204 is communicated with the inside of the third heat exchange set 230, and the liquid outlet pipe 207 is communicated with the inside of the first heat exchange set 210.
The residual liquid enters the shell 201 through the heat source pipe 204, the methanol enters the shell 201 through the feeding pipe 202, the residual liquid heats the methanol through the heat exchange pipe 206 in the third heat exchange group 230, the second heat exchange group 220 and the first heat exchange group 210, the flowing direction of the residual liquid is opposite to that of the methanol, and the heat energy in the residual liquid is fully utilized in a convection mode; the second tube plate 221 is obliquely arranged in the shell 201, so that the heat exchange tube 206 fixedly arranged on the second tube plate 221 is oblique, and further, methanol flows down from the side wall of the heat exchange tube 206, and the methanol flowing through the heat exchange tube 206 fully absorbs heat, meanwhile, the heat exchange time of the methanol is increased, the heat energy of residual liquid is fully utilized, and meanwhile, the heat exchange tube 206 obliquely arranged increases the tube pass of the methanol flowing through the heat exchange tube 206.
As shown in fig. 2, in order to increase the number of the heat exchange tubes 206 in the second heat exchange group 220, in another embodiment of the present invention, a plurality of groups of second heat exchange groups 220 are fixedly installed in the casing 201; when the heat exchange tubes 206 in the second heat exchange group 220 are long, the heat exchange tubes 206 are obliquely arranged, so that the number of the heat exchange tubes 206 arranged on the second tube plate 221 is reduced, the contact area between the heat exchange tubes 206 in the second heat exchange group 220 and residual liquid is reduced, the number of the heat exchange tubes 206 in the second heat exchange group 220 is increased by arranging the plurality of groups of second heat exchange groups 220 in the shell 201, the total area of the heat exchange tubes 206 in the second heat exchange group 220 can be increased, and the heat exchange efficiency of the second heat exchange group 220 is improved.
As shown in fig. 2, in order to prevent methanol from passing through the heat exchange tubes 206 in the middle of the first heat exchange group 210, and reduce the utilization rate of heat, the heat exchange tubes 206 in the first heat exchange group 210 pass through the first tube sheet 211 at the top, and the lengths of the heat exchange tubes 206 passing through the first tube sheet 211 are gradually decreased from the middle to the periphery of the first tube sheet 211; part of the methanol passes through the heat exchange tubes 206 in the middle of the first tube sheet 211, the rest of the methanol falls on the first tube sheet 211, and as the amount of the methanol on the first tube sheet 211 increases, the methanol flows in from the heat exchange tubes 206 at the edge of the first tube sheet 211 and gradually extends towards the middle of the first tube sheet 211.
As shown in fig. 1, in order to improve the utilization rate of the waste heat in the rectification apparatus, the embodiment of the present invention provides a methanol rectification system, which applies the heat exchanger 200, and comprises a crude alcohol preheater 4, a crude distillation column 3, a pressurizing column 6 and a rectification column 8 which are connected in sequence through a pipeline and are used for rectifying methanol, and further comprises a steam buffer tank 1, wherein the steam buffer tank 1 is connected with a first reboiler 2 and a second reboiler 5 through a pipeline, the first reboiler 2 and the second reboiler 5 are respectively connected with the crude distillation column 3 and the pressurizing column 6 through a circulating pipeline, the pipeline connecting the pressurizing column 6 and the rectification column 8 is connected with a third reboiler 7, each pipeline is connected with an infusion pump 9 for transporting condensed water and methanol, the first reboiler 2 and the second reboiler 5 are both connected with a condensate tank 10 through pipelines, the condensate tank 10 is connected with the crude alcohol 4 through a pipeline, the pipeline between the crude distillation column 3 and the pressurizing column 6 is connected with the heat exchanger 200, the bottom of the rectifying tower 8 is connected with a heat exchanger 200 through a pipeline, a heat source pipe 204 of the heat exchanger 200 is connected with the bottom of the rectifying tower 8, and a feeding pipe 202 of the heat exchanger 200 is connected with the bottom of the rough distillation tower 3; methanol firstly passes through a crude alcohol preheater 4 and then enters a crude distillation tower 3, condensate obtained after steam used for heating the methanol in a first reboiler 2 and a second reboiler 5 is liquefied is transported to a condensate tank 10 through a pipeline, then the condensate in the condensate tank 10 is transported to the crude alcohol preheater 4 through an infusion pump 9, the crude alcohol preheater 4 heats the methanol by utilizing heat in the condensate water, the methanol after temperature rise enters the crude distillation tower 3, the amount of the steam used for heating the methanol in the crude distillation tower 3 is reduced, and further energy conservation is realized; meanwhile, the bottom residual liquid generated by rectifying the methanol in the rectifying tower 8 is conveyed into the heat exchanger 200 through the infusion pump 9, the methanol subjected to rough distillation is conveyed into the heat exchanger 200 through a pipeline, the residual liquid and the methanol are subjected to heat exchange in the heat exchanger 200, the heat in the residual liquid is fully utilized, and the methanol enters the rectifying tower 8 after the heat exchange of the methanol is completed through the pressurizing tower 6 and the third reboiler 7, so that the rectification of the methanol is realized.
In a preferred embodiment, in order to reduce the heat energy loss of the condensed water in the condensate tank 10, the outer wall of the condensate tank 10 is coated with a layer of heat preservation cotton; the heat energy loss of the condensate in the condensate tank 10 is reduced by the heat insulation cotton.
Finally, the above embodiments are only for illustrating the technical solutions of the present invention and not for limiting, although the present invention has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions may be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all of them should be covered in the claims of the present invention.
Claims (5)
1. The utility model provides a heat exchanger, includes casing (201), fixed connection at inlet pipe (202) and fixed connection discharging pipe (203) of casing (201) bottom at casing (201) top, its characterized in that: a first heat exchange group (210), a second heat exchange group (220) and a third heat exchange group (230) are fixedly connected to the inside of the shell (201) from top to bottom in sequence, the first heat exchange group (210) and the third heat exchange group (230) are horizontally and fixedly installed at the inner top and the inner bottom of the shell (201) through a first tube plate (211) and a third tube plate (231) which are parallel to each other respectively, the second heat exchange group (220) is fixedly installed at the inner middle part of the shell (201) in an inclined manner through a second tube plate (221), the side wall of the shell (201) is fixedly connected with a connecting pipe (205) which is used for sequentially communicating the first heat exchange group (210), the second heat exchange group (220) and the third heat exchange group (230) with the inside, heat exchange pipes (206) which are vertical to the corresponding tube plates are fixedly connected to the inside of the first heat exchange group (210), the second heat exchange group (220) and the third heat exchange group (230), and the side wall of the shell (201, the heat source pipe (204) is communicated with the inside of the third heat exchange group (230), and the liquid outlet pipe (207) is communicated with the inside of the first heat exchange group (210).
2. A heat exchanger as claimed in claim 1, wherein: and a plurality of groups of second heat exchange groups (220) are fixedly arranged in the shell (201).
3. A heat exchanger as claimed in claim 1, wherein: the heat exchange tubes (206) in the first heat exchange group (210) penetrate through the first tube plate (211) at the top, and the length of the heat exchange tubes (206) penetrating through the first tube plate (211) is gradually reduced from the middle part to the periphery of the first tube plate (211).
4. A methanol rectification system, which applies a heat exchanger as claimed in any one of claims 1 to 3, and comprises a crude alcohol preheater (4), a crude distillation tower (3), a pressurizing tower (6) and a rectification tower (8) which are connected in sequence through pipelines and are used for rectifying methanol, and further comprises a steam buffer tank (1), wherein the steam buffer tank (1) is connected with a first reboiler (2) and a second reboiler (5) through pipelines, the first reboiler (2) and the second reboiler (5) are respectively connected with the crude distillation tower (3) and the pressurizing tower (6) through circulating pipelines, the pipeline of the pressurizing tower (6) connected with the rectification tower (8) is connected with a third reboiler (7), and each pipeline is connected with an infusion pump (9) used for transporting condensed water and methanol, and is characterized in that: the first reboiler (2) and the second reboiler (5) are both connected with a condensate tank (10) through pipelines, the condensate tank (10) is connected with a crude alcohol preheater (4) through a pipeline, a heat exchanger (200) is connected on a pipeline between the crude distillation tower (3) and the pressurizing tower (6), the bottom of the rectifying tower (8) is connected with the heat exchanger (200) through a pipeline, a heat source pipe (204) of the heat exchanger (200) is connected with the bottom of the rectifying tower (8), and a feeding pipe (202) of the heat exchanger (200) is connected with the bottom of the crude distillation tower (3).
5. A methanol rectification system as claimed in claim 4, wherein: the outer wall of the condensate tank (10) is coated with a layer of heat preservation cotton.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110279437.3A CN112944955A (en) | 2021-03-16 | 2021-03-16 | Heat exchanger and methanol rectification system using same |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110279437.3A CN112944955A (en) | 2021-03-16 | 2021-03-16 | Heat exchanger and methanol rectification system using same |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN112944955A true CN112944955A (en) | 2021-06-11 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202110279437.3A Pending CN112944955A (en) | 2021-03-16 | 2021-03-16 | Heat exchanger and methanol rectification system using same |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN112944955A (en) |
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2021
- 2021-03-16 CN CN202110279437.3A patent/CN112944955A/en active Pending
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