CN-224207418-U - Multi-effect energy-saving methanol rectifying device

CN224207418UCN 224207418 UCN224207418 UCN 224207418UCN-224207418-U

Abstract

The utility model provides a multi-effect energy-saving methanol rectifying device which can greatly reduce the operation energy consumption. The whole device at least comprises five towers of a light component removing tower (T300), a first rectifying tower (T310), a second rectifying tower (T320), a third rectifying tower (T330), a fourth rectifying tower (T340) and the like and matched equipment thereof. Can be used for various methanol solvent recovery and rectification procedures of a methanol synthesis device to produce national standard high-grade methanol, american standard AA-grade methanol products or methanol products with other specifications. Overcomes the defects of the prior art, the steam unit consumption of the refined methanol product can be reduced to below 0.48, and the method has remarkable practicality and economic benefit and wide application prospect.

Inventors

LAN RENSHUI
HUANG GUIMING
CAO HAILONG
DONG SHUNLI
TANG WEI

Assignees

天津市新天进科技开发有限公司

Dates

Publication Date: 20260508
Application Date: 20250305

Claims (9)

1. A multi-effect energy-saving methanol rectification device is characterized by mainly comprising five towers of a light component removal tower (T300), a first rectification tower (T310), a second rectification tower (T320), a third rectification tower (T330) and a fourth rectification tower (T340) and connecting pipelines; The raw material crude methanol feed pipeline is respectively connected with the cold side inlets of a feed methanol preheater (E3403) and a feed wastewater preheater (E3404); The system comprises a feed methanol preheater (E3403) and a feed wastewater preheater (E3404), wherein a cold side outlet of the feed methanol preheater (E3404) is connected to the middle part of a light component removal tower (T300), the top of the light component removal tower (T300) is connected with a hot side inlet of a first rectifying tower feed preheater (E3101), a hot side condensate outlet of the first rectifying tower feed preheater (E3101) is connected with the top of the light component removal tower (T300), a hot side non-condensable gas outlet of the first rectifying tower feed preheater (E3101) is connected with a non-condensable gas discharge pipeline, the bottoms of the light component removal tower (T300) are respectively connected with a tube side inlet of a reboiler (E3001) of the light component removal tower, a cold side inlet of the first rectifying tower feed preheater (E3101) is connected to a tower kettle of the light component removal tower (T300), and a cold side outlet of the first rectifying tower feed preheater (E3101) is connected to a middle part feed inlet of the first rectifying tower (T310); The top of the first rectifying tower (T310) is connected with a first rectifying tower condenser (E3103), a condensate outlet of the first rectifying tower condenser (E3103) is respectively connected with the top of the first rectifying tower (T310) and a hot side inlet of a feed methanol preheater (E3403), a middle feed inlet of the first rectifying tower (T310) is connected with a cold side outlet of the feed preheater (E3101) of the first rectifying tower, the bottom of the first rectifying tower (T310) is connected with a tube side inlet of a first rectifying tower reboiler (E3102) and a second rectifying tower (T320), and a tube side outlet of the first rectifying tower reboiler (E3102) is connected to a tower kettle of the first rectifying tower (T310); the top of the second rectifying tower (T320) is connected with the shell side of a reboiler (E3102) of the first rectifying tower, the outlet of condensate in the shell side of the reboiler (E3102) of the first rectifying tower is respectively connected with the top of the second rectifying tower (T320) and the hot side inlet of a feed methanol preheater (E3403), the bottom of the second rectifying tower (T320) is respectively connected with the tube side inlet of a reboiler (E3201) of the second rectifying tower and the tube side inlet of a third rectifying tower (T330), and the outlet of the tube side of the reboiler (E3201) of the second rectifying tower is connected to the bottom of the second rectifying tower (T320); the top of the third rectifying tower (T330) is respectively connected with the shell pass of a light component removal tower reboiler (E3001) and the shell pass of a second rectifying tower reboiler (E3201), the shell pass condensate outlet of the light component removal tower reboiler (E3001) and the shell pass condensate outlet of the second rectifying tower reboiler (E3201) are respectively connected with the top of the third rectifying tower (T330) and the hot side inlet of a feed methanol preheater (E3403), and the bottom of the third rectifying tower (T330) is respectively connected with the tube pass inlet of the third rectifying tower reboiler (E3301) and the hot side inlet of a fourth rectifying tower (T340); the top of the fourth rectifying tower (T340) is connected with the shell side of a third rectifying tower reboiler (E3301), the shell side condensate outlet of the third rectifying tower reboiler (E3301) is respectively connected with the top of the fourth rectifying tower (T340) and the hot side inlet of a feed methanol preheater (E3403), the bottom of the methanol rectifying side (L340) of the fourth rectifying tower is respectively connected with the tube side inlet of the methanol rectifying side reboiler (E3401) and the hot side inlet of a feed wastewater preheater (E3404), the tube side outlet of the methanol rectifying side reboiler (E3401) of the fourth rectifying tower is connected to the tube side kettle of the methanol rectifying side (L340) of the fourth rectifying tower, the side line near the feed of the methanol rectifying side (T340) of the fourth rectifying tower is connected with the hot side inlet of a fusel oil cooler (E3407), and the bottom of the ethanol rectifying side (R340) of the fourth rectifying tower is respectively connected with the ethanol side reboiler (E3402) of the ethanol rectifying side reboiler (E3401) and the hot side inlet of the fourth rectifying tower (E3402) to the hot side inlet of the ethanol rectifying side (E3402); The hot side outlet of the feed methanol preheater (E3403) is connected with the hot side inlet of the methanol product cooler (E3405), and the hot side outlet of the methanol product cooler (E3405) is connected with a methanol product extraction pipeline; The hot side outlet of the feed wastewater preheater (E3404) is connected with the hot side inlet of the wastewater cooler (E3406), the hot side outlet of the wastewater cooler (E3406) is respectively connected with the top of the light component removal tower (T300) and the wastewater discharge pipeline, the hot side outlet of the fusel oil cooler (E3407) is connected with the fusel oil product extraction pipeline, and the hot side outlet of the ethanol cooler (E3408) is connected with the ethanol product extraction pipeline.
2. The device according to claim 1, wherein the lower part of the fourth rectifying tower (T340) adopts a baffle tower structure, the baffle (S340) divides the lower part of the fourth rectifying tower (T340) into a methanol stripping side (L340) and an ethanol rectifying side (R340) so as to realize that waste water (35) is discharged from the tower kettle of the methanol stripping side (L340) of the fourth rectifying tower (T340), fusel oil (33) with low methanol and ethanol content is extracted from the lower side line of a feed inlet of the methanol stripping side (L340) of the fourth rectifying tower (T340), and ethanol product (40) is extracted from the tower kettle of the ethanol rectifying side (R340) of the fourth rectifying tower (T340).
3. The apparatus according to claim 1, wherein the fourth rectifying column (T340) is not provided with a partition structure, but is provided with a conventional partition-free structure, so that recovery of ethanol (40) is achieved by extracting fusel oil (33) from a position above a feed inlet of the fourth rectifying column (T340), and extracting the material at a bottom of the fourth rectifying column (T340) as wastewater (35).
4. The apparatus of claim 1, wherein a stripping column (T340S) is added, the fourth rectifying column (T340) is not in a baffle structure, but in a conventional baffle-free structure, so that the purpose of recovering ethanol (40) is realized by feeding a side line liquid phase material (42) of the fourth rectifying column (T340) into the top of the stripping column (T340S), returning a gas phase material (43) at the top of the stripping column (T340S) into the fourth rectifying column (T340), and extracting and recovering ethanol (40) from the bottom of the stripping column (T340S).
5. The apparatus according to claim 1, wherein a recovery column (T350) is added, and the fourth rectifying column (T340) is not provided with a partition structure but is provided with a conventional partition-free structure, so that the recovery column (T350) can use the gas phase at the top of the second rectifying column (T320) or the third rectifying column (T330) or the fourth rectifying column (T340) as a heat source or an external heat source.
6. The device according to claim 2, wherein a light component removing tower (T300) is additionally arranged at the periphery of the light component removing tower (T300), a tower kettle and a reboiler (E3001) of the light component removing tower are shared with the light component removing tower (T300), the tower top gas phases of the light component removing tower (T300) and the light component removing tower (T300D) are used as heating sources of a tower kettle of a third rectifying tower (T330) to provide required heat for the third rectifying tower (T330), and the refined methanol product is extracted from the tower top of the light component removing tower (T300D).
7. The apparatus of claim 2, wherein the light component removal column (T300) is connected in parallel with a fifth rectifying column (T360) to achieve the purpose that the gas phase at the top of the fourth rectifying column (T340) is divided into two parts, one part is used as a heating source of a tower bottom of the light component removal column (T300) to provide required heat for the light component removal column (T300), the other part is used as a heating source of a tower bottom of the fifth rectifying column (T360) to provide required heat for the fifth rectifying column (T360), the gas phase at the top of the light component removal column (T300) and the gas phase at the top of the fifth rectifying column (T360) are used as a heating source of a tower bottom of the third rectifying column (T330) to provide required heat for the third rectifying column (T330), and the top of the fifth rectifying column (T360) is used for producing refined methanol products.
8. The apparatus according to claim 2, wherein the upper part of the light component removing tower (T300) adopts a baffle tower structure, a second baffle (S300) divides the upper part of the light component removing tower (T300) into a pre-rectifying side (R300) and a methanol rectifying side (L300), so that the gas phases at the top of the pre-rectifying side (R300) and the methanol rectifying side (L300) are used as heating sources of tower bottoms of the third rectifying tower (T330) to provide required heat for the third rectifying tower (T330), the refined methanol product is extracted from the tower top of the methanol rectifying side (L300), and the lower part of the light component removing tower (T300) is of a conventional baffle-free structure.
9. The apparatus of claim 1 wherein each column is typically operated under conditions of: the operating pressure range of the top of the light component removing tower (T300) is 60-300 kPa; the operating pressure range of the top of the first rectifying tower (T310) is 25-150 kPa; The operating pressure range of the top of the second rectifying tower (T320) is 60-300 kPa; The operating pressure range of the top of the third rectifying tower (T330) is 100-600 kPa; The operating pressure range of the top of the fourth rectifying tower (T340) is 250-1300 kPa.

Description

Multi-effect energy-saving methanol rectifying device Technical Field The multi-effect energy-saving methanol rectifying device provided by the utility model can be used for rectifying procedures of various methanol solvent recovery and methanol synthesis devices to produce superior methanol products. Background Methanol is an important organic chemical raw material and a novel energy fuel, and has wide application in the fields of chemical industry, light industry and clean energy. In the industrial production process of synthetic methanol, the energy consumption of the refining process of crude methanol is one of the key factors influencing the production cost of methanol. Fig. 1 is a four-tower (three towers plus one tower) methanol rectification process widely adopted at present, namely, a recovery tower T104 is added to three towers such as a pre-tower T101, a pressurizing tower T102, a first rectification tower T103 and the like, and a national standard superior product or a American standard AA-level methanol product is produced. Removing light components from the top of the pre-tower, rectifying the crude methanol 10 after the distillation by a pressurizing tower and a first rectifying tower, respectively obtaining methanol products at the top discharge 24 of the pressurizing tower and the top discharge 14 of the first rectifying tower, and extracting fusel 42 from the side line of the first rectifying tower. The pressurized column overhead vapor phase 21 heats the first rectifying column bottoms. The first rectifying tower side line fusel 42 and the first rectifying tower kettle liquid 15 enter a recovery tower, a recovered methanol product 29 is obtained from the top of the recovery tower, fusel oil 30 is extracted from the side line of the recovery tower, and the waste water 33 is discharged from the bottom of the recovery tower. Although the technology of the method is mature, the energy consumption of production is high, and the equipment is huge in scale as the scale of the device is increased. Is unfavorable for the construction, economy and stable operation of increasingly large methanol production devices. The Chinese patent CN 201420664698.2 discloses a technological method of a flexible methanol rectifying device capable of producing MTO grade and AA grade methanol, and the core content of the technological method is based on the four-tower double-effect rectifying process widely adopted at present, and the energy saving purpose is achieved by utilizing the heat of condensate of heating steam or the heat exchange of cold and hot liquid in the system. It is apparent that the sensible heat transfer between such materials has very limited effect in reducing the operating energy consumption of the whole rectification system. CN 201910655239.5 discloses an improved three-tower three-effect crude methanol refining process method, which is characterized in that the operating pressure of a first rectifying tower and a second rectifying tower is increased, so that the first rectifying tower, the second rectifying tower and a pre-rectifying tower are subjected to three-effect heat integration operation. Separating the gas phase at the top of the second rectifying tower to provide heat for the pre-rectifying tower. Compared with CN 201420664698.2, the process method has higher energy-saving effect. However, as no methanol product is produced at the top of the pre-rectifying tower in the system, the energy provided by the second rectifying tower for the pre-rectifying tower belongs to the single-effect methanol rectifying process. The first rectifying tower and the second rectifying tower in the system both produce methanol products at the top of the tower, and only the energy provided by the first rectifying tower for the second rectifying tower belongs to the double-effect methanol rectifying process, so that the process method has certain improved energy-saving effect, but the energy-saving effect is not ideal. CN201711022448.3 discloses a "three-effect rectification system and process for methanol", CN 201811025624.3 discloses a "vacuum thermal coupling methanol rectification method and device", which all adopt three-effect thermal integration operation for the rectification column for producing methanol products in the system, wherein the first effect with the lowest operation pressure is a reduced pressure rectification column. The vacuum rectifying tower is beneficial to improving the relative volatility of the separation system and obtaining higher purity of methanol products. The pre-rectifying towers of the two patent processes are heated by fresh steam, and the thermal integration operation is not carried out with the methanol rectifying tower, so that the energy-saving effect is limited to a certain extent. CN200910068170.2 adopts a five-tower heat integration device to carry out the technological method of methanol rectification, crude methanol in the tower kettle of a pre-rectifying tow