Three-tower rectification system for preparing high-purity methanol from industrial methanol

Abstract

The utility model discloses a three-tower rectification system for preparing high-purity methanol by using industrial methanol, which is characterized in that a pre-rectifying tower is connected with a condenser device, the condenser device is connected with a pre-rectifying tower reflux tank, the pre-rectifying tower reflux tank is connected with the pre-rectifying tower, and the pre-rectifying tower is connected with a first pre-rectifying tower reboiler; the auxiliary pre-rectifying tower reboiler is connected with the pressurized rectifying tower, the auxiliary pre-rectifying tower reboiler is connected with the pre-rectifying tower, the pre-rectifying tower is connected with the preheater device, the pressurized rectifying tower is connected with the normal-pressure rectifying tower reboiler, the pressurized rectifying tower reflux tank is connected with the pressurized rectifying tower, and the pressurized rectifying tower reflux tank is connected with the preheater device. The preheater device is connected with the second condenser device; the pressurized rectifying tower is connected with the normal-pressure rectifying tower, the normal-pressure rectifying tower is connected with the third condenser device, and the normal-pressure rectifying tower reflux tank is connected with the normal-pressure rectifying tower. According to the methanol purification device, organic matters, acid radical ions, water and other organic impurities in methanol are removed, the cost is reduced, and the purity of methanol is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of methanol preparation, in particular to a three-tower distillation system for preparing high-purity methanol using industrial methanol. Background Art

[0002] Methanol, as one of the important basic organic chemical raw materials, plays a very important role in the world economy. With the increasing shortage of world energy, methanol has gradually become an important energy substitute. In recent years, the domestic market demand for high-purity methanol has grown rapidly and the gap is large, especially high-purity and high-specification products, which are extremely valuable for market development.

[0003] At present, there are two methods for preparing high-purity methanol. One is to directly synthesize high-purity methanol with high-purity raw gas, but the synthesis process requires a clean reaction environment, equipment and strict reaction conditions. my country has not yet mastered this technology. The other method is to purify crude methanol to produce industrial methanol. Crude methanol will produce some impurities during the synthesis reaction. In addition, methanol will also introduce some impurities during storage and transportation. Industrial methanol includes impurities such as organic matter (alcohols, aldehydes, ketones, ethers, esters, alkanes, etc.), ions (metal ions and acid radical ions) and water. The purification methods for organic impurities mainly include conventional distillation, chemical purification, reactive distillation and extractive distillation, etc. The purification methods for metal ions and acid radical ions mainly include sub-boiling distillation and ion exchange resin methods. The purification methods for water mainly include chemical purification and pervaporation membrane methods.

[0004] However, the traditional purification methods for removing organic matter, metal ions and water still result in the purity of industrial methanol failing to meet international high-purity methanol product standards. Utility Model Content

[0005] The utility model aims to provide a three-tower distillation system for preparing high-purity methanol from industrial methanol, so as to remove organic impurities such as organic matter, acid radical ions and water in methanol, reduce costs and improve the purity of methanol.

[0006] The utility model is implemented by the following technical scheme: a three-tower distillation system for producing high-purity methanol using industrial methanol, comprising: a pre-distillation tower, a pressure distillation tower and an atmospheric distillation tower;

[0007] The feed inlet of the pre-distillation tower is connected to the cold source outlet of the first preheater, the feed inlet of the pre-distillation tower is connected to the outlet of the alkali preparation tank, the heat source inlet of the first preheater is connected to the heat source outlet of the preheating device, the cold source inlet of the first preheater is connected to the discharge port of the crude methanol intermediate tank area, the cold source inlet of the first preheater is connected to the discharge port of the crude methanol flash tank, the discharge port at the bottom of the pre-distillation tower is connected to the preheating inlet of the preheater device, the preheating outlet of the preheater device is connected to the feed inlet of the pressurized distillation tower, and the bottom liquid outlet of the pressurized distillation tower is connected to the feed inlet of the atmospheric distillation tower;

[0008] The top gas outlet of the pre-distillation tower is connected to the cold source inlet of the condenser device, the cold source outlet of the condenser device is connected to the feed inlet of the pre-distillation tower reflux tank, the discharge port of the pre-distillation tower reflux tank is connected to the reflux port of the pre-distillation tower, the top gas outlet of the pressure distillation tower is connected to the heat source inlet of the atmospheric distillation tower reboiler, the heat source outlet of the atmospheric distillation tower reboiler is connected to the gas inlet of the atmospheric distillation tower, the condensation outlet of the atmospheric distillation tower is connected to the heat source inlet of the atmospheric distillation tower reboiler, the outlet of the atmospheric distillation tower reboiler is connected to the second inlet of the pressure distillation tower reflux tank, the outlet of the pressure distillation tower reflux tank is connected to the reflux port of the pressure distillation tower, the top gas outlet of the atmospheric distillation tower is connected to the condensation inlet of the third condenser device, the condensation outlet of the third condenser device is connected to the inlet of the atmospheric distillation tower reflux tank, and the outlet of the atmospheric distillation tower reflux tank is connected to the reflux port of the atmospheric distillation tower;

[0009] The tail gas outlet of the reflux tank of the pre-distillation tower is connected to the water washing inlet of the tail gas water washing tower, the water washing outlet of the tail gas water washing tower is connected to the tail gas reflux port of the reflux tank of the pre-distillation tower, the heat source inlet of the reboiler of the secondary pre-distillation tower is connected to the second gas outlet at the top of the pressurized distillation tower, the heat source outlet of the reboiler of the secondary pre-distillation tower is connected to the inlet of the pre-distillation tower, the inlet of the secondary pre-distillation tower reboiler is connected to the condensation outlet of the pre-distillation tower, and the outlet of the secondary pre-distillation tower reboiler is connected to the inlet of the reflux tank of the pressurized distillation tower; the outlet of the reflux tank of the pressurized distillation tower is connected to the second preheating inlet of the preheater device, the second preheating outlet of the preheater device is connected to the condensation inlet of the second condenser device, the condensation outlet of the second condenser device is connected to the inlet of the refined methanol collecting tank; the condensation outlet of the second condenser device is connected to the inlet of the second refined methanol collecting tank; the outlet of the reflux tank of the atmospheric distillation tower is connected to the inlet of the refined methanol collecting tank, and the outlet of the reflux tank of the atmospheric distillation tower is connected to the inlet of the second refined methanol collecting tank.

[0010] Further, the condenser device includes a first air cooler, a second air cooler, a first water cooler, and a second water cooler;

[0011] The cold source inlet of the first air cooler and the cold source inlet of the second air cooler are both connected to the top air outlet of the pre-distillation tower, the cold source outlet of the first air cooler is connected to the cold source inlet of the first water cooler, and / or the cold source outlet of the first air cooler is connected to the cold source inlet of the second water cooler, the cold source outlet of the second air cooler is connected to the cold source inlet of the first water cooler, and / or the cold source outlet of the second air cooler is connected to the cold source inlet of the second water cooler, and the cold source outlet of the first water cooler and the cold source outlet of the second water cooler are both connected to the feed port of the reflux tank of the pre-distillation tower.

[0012] Further, the preheater device includes a second preheater and a third preheater;

[0013] The preheating inlet of the second preheater is connected to the discharge port at the bottom of the pre-distillation tower, the preheating outlet of the second preheater is connected to the preheating inlet of the third preheater, and the preheating outlet of the third preheater is connected to the feed port of the pressurized distillation tower.

[0014] Furthermore, the preheating inlet of the second preheater is connected to the outlet of the reflux tank of the pressurized distillation tower; the preheating outlet of the second preheater is connected to the condensing inlet of the second condenser device.

[0015] Further, the second condenser device includes a third air cooler and a third water cooler;

[0016] The second preheating outlet of the second preheater is connected to the condensation inlet of the third air cooler, the condensation outlet of the third air cooler is connected to the condensation inlet of the third water cooler, the condensation outlet of the third water cooler is connected to the inlet of the refined methanol collection tank, and the outlet of the third water cooler is connected to the inlet of the second refined methanol collection tank.

[0017] Further, the third condenser device includes a fourth air cooler, a fourth water cooler and a fifth water cooler;

[0018] The condensation inlet of the fourth air cooler is connected to the top gas outlet of the atmospheric distillation tower, the condensation outlet of the fourth air cooler is connected to the condensation inlet of the fourth water cooler, the condensation outlet of the fourth water cooler is connected to the condensation inlet of the fifth water cooler, and the condensation outlet of the fifth water cooler is connected to the inlet of the reflux tank of the atmospheric distillation tower

[0019] Furthermore, the gas outlet of the tail gas water washing tower is connected to the gas inlet of the liquid sealing tank of the pre-distillation tower.

[0020] Furthermore, the impurity outlet of the atmospheric distillation tower is connected to the inlet of the fusel oil recovery device, and the liquid outlet of the atmospheric distillation tower is connected to the wastewater inlet of the wastewater treatment device.

[0021] Further, the fusel oil recovery device includes a fusel oil tank and a fusel oil storage tank;

[0022] The impurity outlet of the atmospheric distillation tower is connected to the inlet of the fusel alcohol oil tank, and the outlet of the fusel alcohol oil tank is connected to the inlet of the fusel alcohol storage tank; a water cooling coil is arranged in the fusel alcohol oil tank, and a fusel alcohol pump is arranged between the outlet of the fusel alcohol oil tank and the inlet of the fusel alcohol storage tank.

[0023] Further, the wastewater treatment device includes a wastewater cooler, a waste liquid tank and a wastewater processor;

[0024] The inlet of the wastewater cooler is connected to the liquid outlet of the atmospheric distillation tower, the outlet of the wastewater cooler is connected to the inlet of the waste liquid tank, the outlet of the waste liquid tank is connected to the inlet of the wastewater processor, and a wastewater pump is arranged between the outlet of the waste liquid tank and the inlet of the wastewater processor.

[0025] Advantages of the utility model:

[0026] In the utility model, the condenser device is used to condense the steam flowing out of the top of the pre-distillation tower, and the reflux tank of the pre-distillation tower is used to reflux the condensed steam into the pre-distillation tower, so that the steam of the pre-distillation tower is vaporized and condensed for many times, and the non-condensable gas in the steam and the low-boiling point components dissolved in the steam are removed, thereby improving the purity of methanol. The discharge port at the bottom of the pre-distillation tower is connected with the preheating inlet of the preheater device, and the preheater device is used to heat the liquid at the bottom of the pre-distillation tower, so that the liquid at the bottom of the pre-distillation tower is easy to vaporize when it enters the pressurized distillation tower, thereby reducing the pressure in the pressurized distillation tower. The consumption of steam, the second condensing device is used to condense the top steam of the pressurized distillation tower that provides heat for the pre-distillation tower, the pressurized distillation tower reflux tank is used to return the liquid to the pressurized distillation tower so that the top steam of the pressurized distillation tower is condensed and vaporized to achieve efficient distillation of the top steam of the pressurized distillation tower, the third condenser device is used to condense the top steam of the atmospheric distillation tower, the atmospheric distillation tower reflux tank is used to return the condensed steam to the atmospheric distillation tower so that the steam of the pressurized distillation tower is vaporized and condensed, and the fusel oil and water in the methanol are removed, thereby improving the purity of the methanol. The utility model adopts a three-tower distillation process, which can remove organic impurities such as organic matter, acid radical ions and water in refined methanol, reduce costs, and improve the purity of methanol. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0028] Figure 1 It is a schematic diagram of a three-tower distillation system for producing high-purity methanol using industrial methanol, provided in an embodiment of the utility model.

[0029] Figure 1 10-pre-distillation tower, 11-pressure distillation tower, 12-atmospheric distillation tower, 13-alkali preparation tank, 14-first preheater, 15-condenser device, 151-first air cooler, 152-second air cooler, 153-first water cooler, 154-second water cooler, 16-pre-distillation tower reflux tank, 17-tail gas washing tower, 18-pre-distillation tower liquid seal tank, 19-second pre-distillation tower reboiler, 20-pressure distillation tower reflux tank, 21-preheater device, 210-second preheater, 211 -third preheater, 22-second condenser device, 220-third air cooler, 221-third water cooler, 23-atmospheric distillation tower reboiler, 24-third condenser device, 240-fourth air cooler, 241-fourth water cooler, 242-fifth water cooler, 25-atmospheric distillation tower reflux tank, 26-wastewater treatment device, 260-wastewater cooler, 261-waste liquid tank, 262-wastewater treatment device, 27-fusel oil recovery device, 270-fusel oil tank, 271-fusel alcohol storage tank. DETAILED DESCRIPTION

[0030] 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 of 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.

[0031] Figure 1 This is a schematic diagram of a three-tower distillation system for producing high-purity methanol using industrial methanol provided by the embodiment of the utility model. Figure 1The three-tower distillation system for preparing high-purity methanol using industrial methanol comprises: a pre-distillation tower 10, a pressure distillation tower 11 and a normal pressure distillation tower 12; the feed inlet of the pre-distillation tower 10 is connected to the cold source outlet of the first preheater 14, the feed inlet of the pre-distillation tower 10 is connected to the outlet of the alkali preparation tank 13, the heat source inlet of the first preheater 14 is connected to the heat source outlet of the preheater device 21, the cold source inlet of the first preheater 14 is connected to the discharge port of the crude methanol intermediate tank area, the cold source inlet of the first preheater 14 is connected to the discharge port of the crude methanol flash tank, the discharge port at the bottom of the pre-distillation tower 10 is connected to the preheating inlet of the preheater device 21, the preheating outlet of the preheater device 21 is connected to the feed inlet of the pressure distillation tower 11, and the pressure distillation The bottom liquid outlet of the tower 11 is connected to the feed inlet of the atmospheric distillation tower 12; the top gas outlet of the pre-distillation tower 10 is connected to the cold source inlet of the condenser device 15, the cold source outlet of the condenser device 15 is connected to the feed inlet of the pre-distillation tower reflux tank 16, the discharge port of the pre-distillation tower reflux tank 16 is connected to the reflux port of the pre-distillation tower 10, the gas outlet of the top of the pressure distillation tower 11 is connected to the heat source inlet of the atmospheric distillation tower reboiler 23, the heat source outlet of the atmospheric distillation tower reboiler 23 is connected to the gas inlet of the atmospheric distillation tower 12, the condensation outlet of the atmospheric distillation tower 12 is connected to the heat source inlet of the atmospheric distillation tower reboiler 23, the outlet of the atmospheric distillation tower reboiler 23 is connected to the second inlet of the pressure distillation tower reflux tank 20, the pressure distillation tower 12 is connected to the heat source inlet of the atmospheric distillation tower reboiler 23, the pressure ... The outlet of the distillation tower reflux tank 20 is connected to the reflux port of the pressure distillation tower 11, the top gas outlet of the atmospheric distillation tower 12 is connected to the condensation inlet of the third condenser device 24, the condensation outlet of the third condenser device 24 is connected to the inlet of the atmospheric distillation tower reflux tank 25, and the outlet of the atmospheric distillation tower reflux tank 25 is connected to the reflux port of the atmospheric distillation tower 12; the tail gas outlet of the pre-distillation tower reflux tank 16 is connected to the water washing inlet of the tail gas washing tower 17, the water washing outlet of the tail gas washing tower 17 is connected to the tail gas reflux port of the pre-distillation tower reflux tank 16, the heat source inlet of the auxiliary pre-distillation tower reboiler 19 is connected to the second gas outlet at the top of the pressure distillation tower 11, and the heat source outlet of the auxiliary pre-distillation tower reboiler 19 is connected to the inlet of the pre-distillation tower 10 The inlet of the secondary pre-distillation tower reboiler 19 is connected to the condensation outlet of the pre-distillation tower 10, and the outlet of the secondary pre-distillation tower reboiler 19 is connected to the inlet of the pressure distillation tower reflux tank 20; the outlet of the pressure distillation tower reflux tank 20 is connected to the second preheating inlet of the preheater device 21, the second preheating outlet of the preheater device 21 is connected to the condensation inlet of the second condenser device 22, and the condensation outlet of the second condenser device 22 is connected to the inlet of the refined methanol collecting tank; the condensation outlet of the second condenser device 22 is connected to the inlet of the second refined methanol collecting tank; the outlet of the atmospheric distillation tower reflux tank 25 is connected to the inlet of the refined methanol collecting tank, and the outlet of the atmospheric distillation tower reflux tank 25 is connected to the inlet of the second refined methanol collecting tank;

[0032] The pre-distillation tower 10 is used to receive the mixed liquid of crude methanol and alkali to distill and purify the pre-crude methanol and remove the low-boiling point components and non-condensable gases with a boiling point lower than that of methanol; the pressure distillation tower 11 is used to distill and purify the methanol liquid in the tower bottom of the pre-distillation tower 10 to obtain refined methanol and to provide heat for the reboiler of the atmospheric distillation tower 12; the atmospheric distillation tower 12 is used to distill and purify the tower bottom of the pressure distillation tower 11 to obtain refined methanol and remove the miscellaneous alcohols and waste water dissolved in the methanol;

[0033] The condenser device 15 is used to condense and liquefy the methanol vapor in the pre-distillation tower 10, the second condenser device 22 is used to condense part of the methanol, and the third condenser device 24 is used to play a condensing role; the pre-distillation tower reflux tank 16 is used to separate the methanol, low-boiling light components and non-condensable tower gas condensed in the pre-distillation tower 10, the pressure distillation reflux tank 20 is used to provide a stable reflux liquid to the pressure distillation tower 11 during the reflux process, and the atmospheric distillation tower reflux tank 25 is used to provide a stable reflux liquid to the atmospheric distillation tower 12 during the reflux process;

[0034] The tail gas washing tower 17 is used to wash and recover part of the methanol in the reflux tank 16 of the pre-distillation tower, and the atmospheric distillation tower reboiler 23 is used to provide a heat source for the atmospheric distillation tower 12; the first preheater 14 is used to preliminarily heat the crude methanol to increase the temperature of the crude methanol, and the preheater device 21 is used to heat the methanol solution in the bottom of the pre-distillation tower 10;

[0035] Specifically, the crude methanol from the crude methanol intermediate tank area and the crude methanol flash tank is heat-exchanged with the steam from the preheater device 21 in the first preheater 14 to a temperature of 65° C. After the heat exchange, the crude methanol is mixed with the sodium hydroxide solution from the alkali preparation tank 13 and then enters the pre-distillation tower 10. The gas and low-boiling impurities dissolved in the crude methanol are removed at the top of the pre-distillation tower 10. The methanol vapor at the top of the pre-distillation tower 10 is condensed to 45° C. through the condenser device 15. The condensed methanol liquid is refluxed to the pre-distillation tower 10 through the pre-distillation tower reflux tank 16. The uncondensed methanol vapor in the pre-distillation tower reflux tank 16 is washed with water by the tail gas washing tower 17 and then refluxed to the pre-distillation tower 10 through the pre-distillation tower reflux tank 16. The crude methanol is vaporized in the pre-condensing distillation tower and then condensed by the condenser device 15. The low-boiling point components and insoluble gases dissolved in the crude methanol are separated by repeatedly vaporizing and condensing the crude methanol.

[0036] The methanol solution in the bottom of the pre-distillation tower 10 is heated by the preheater device 21 and then heat exchanged in the pressurized distillation tower 11. The temperature of the methanol vapor after heat exchange reaches 100°C. The methanol vapor is then heated by the reboiler of the pressurized distillation tower to make the temperature of the methanol vapor reach 120°C. Most of the methanol vapor in the pressurized distillation tower 11 flows to the atmospheric distillation tower 12 through the reboiler 23 of the atmospheric distillation tower. The heat released after condensation in the atmospheric distillation tower 12 is used to heat the atmospheric distillation tower 12. The condensed methanol flows to the reflux tank 20 of the pressurized distillation tower. A part of the methanol liquid in the reflux tank 20 of the pressurized distillation tower enters the pressurized distillation tower 11 through the pressurized tower reflux pump, and the other part flows into the second condenser device 22 through the preheater device 21. If the purity of methanol after condensation by the second condenser device 22 is qualified, the condensed methanol enters the refined methanol collection tank; if the purity of methanol after condensation by the second condenser device 22 is unqualified, the condensed methanol enters the second refined methanol collection tank; the methanol liquid in the bottom of the pressure distillation tower 11 directly enters the atmospheric distillation tower 12; the methanol vapor flowing out of the atmospheric distillation tower 12 reaches 40°C after condensation by the third condenser device 24 and enters the atmospheric distillation tower reflux tank 25; part of the methanol liquid flowing out of the atmospheric distillation tower reflux tank 25 enters the atmospheric distillation tower 12; if the purity of the remaining methanol is qualified, the remaining methanol flows to the refined methanol collection tank; if the purity of the remaining methanol is unqualified, the remaining methanol flows to the second refined methanol collection tank;

[0037] In the utility model, the condenser device 15 is used to condense the steam flowing out of the top of the pre-distillation tower 10, and the pre-distillation tower reflux tank 16 is used to reflux the condensed steam into the pre-distillation tower 10, so that the steam of the pre-distillation tower 10 is vaporized and condensed for many times, and the non-condensable gas in the steam and the low-boiling point components dissolved in the steam are removed, thereby improving the purity of methanol. The discharge port at the bottom of the pre-distillation tower 10 is connected to the preheating inlet of the preheater device 21, and the preheater device 21 is used to heat the liquid at the bottom of the pre-distillation tower 10, so that the liquid at the bottom of the pre-distillation tower 10 enters the pressurized distillation tower 11 and is easily vaporized, thereby reducing the steam in the pressurized distillation tower 11. The consumption of steam, the second condenser device 22 is used to condense the top steam of the pressurized distillation tower 11 that provides heat for the pre-distillation tower 10, the pressurized distillation tower reflux tank 20 is used to reflux the liquid to the pressurized distillation tower 11 so that the top steam of the pressurized distillation tower 11 is condensed and vaporized to achieve efficient distillation of the top steam of the pressurized distillation tower 11, the third condenser device 24 is used to condense the top steam of the atmospheric distillation tower 12, the atmospheric distillation tower reflux tank 25 is used to reflux the condensed steam to the atmospheric distillation tower 12 so that the steam of the pressurized distillation tower 11 is vaporized and condensed, and the fusel oil and water in the methanol are removed, thereby improving the purity of the methanol. The utility model adopts a three-tower distillation process, which can remove organic impurities such as organic matter, acid radical ions and water in refined methanol, reduces costs, and improves the purity of methanol.

[0038] See also Figure 1, further, on the basis of the above embodiment, the condenser device 15 includes a first air cooler 151, a second air cooler 152, a first water cooler 153 and a second water cooler 154; the cold source inlet of the first air cooler 151 and the cold source inlet of the second air cooler 152 are both connected to the top gas outlet of the pre-distillation tower 10, the cold source outlet of the first air cooler 151 is connected to the cold source inlet of the first water cooler 153, and / or the cold source outlet of the first air cooler 151 is connected to the cold source inlet of the second water cooler 154, the cold source outlet of the second air cooler 152 is connected to the cold source inlet of the first water cooler 153, and / or the cold source outlet of the second air cooler 152 is connected to the cold source inlet of the second water cooler 154, and the cold source outlet of the first water cooler 153 and the cold source outlet of the second water cooler 154 are both connected to the feed port of the pre-distillation tower reflux tank 16;

[0039] The first air cooler 151 and the second air cooler 152 are used to condense the steam of the pre-distillation tower 10, and the first water cooler 153 and the second water cooler 154 are used to re-condense the liquid of the first air cooler 151 and the second air cooler 152;

[0040] Specifically, the steam of the pre-distillation tower 10 is condensed through the first air cooler 151 and the second air cooler 152, and then condensed through the first water cooler 153 and the second water cooler 154 and flows into the pre-distillation tower reflux tank 16, so that the temperature of the methanol reaches 45°C;

[0041] In the utility model, the first air cooler 151, the second air cooler 152, the first water cooler 153 and the second water cooler 154 are provided to condense methanol, remove low-boiling point components dissolved in methanol, reduce the content of organic impurities in methanol, and improve the purity of methanol.

[0042] Continue to see Figure 1 Further, on the basis of the above embodiment, the preheater device 21 includes a second preheater 210 and a third preheater 211; the preheating inlet of the second preheater 210 is connected to the discharge port at the bottom of the pre-distillation tower 10, the preheating outlet of the second preheater 210 is connected to the preheating inlet of the third preheater 211, and the preheating outlet of the third preheater 211 is connected to the feed port of the pressurized distillation tower 11;

[0043] Among them, the second preheater 210 and the third preheater 211 are used to heat the methanol liquid in the bottom of the pre-distillation tower 10. The liquid at the bottom of the pre-distillation tower 10 enters the second preheater 210 for heating and then enters the third preheater 211 for heating. This arrangement reduces the consumption of steam in the pressurized distillation tower 11 and reduces costs.

[0044] Continue to see Figure 1Further, based on the above embodiment, the preheating inlet of the second preheater 210 is connected to the outlet of the pressurized distillation tower reflux tank 20; the second outlet of the second preheater 210 is connected to the inlet of the second condenser device 22;

[0045] Part of the methanol liquid in the reflux tank 20 of the pressurized distillation tower is heated by the second preheater 210, so that the low boiling point components in the methanol are separated from the methanol, thereby improving the purity of the methanol.

[0046] Continue to see Figure 1 Further, on the basis of the above embodiment, the second condenser device 22 includes a third air cooler 220 and a third water cooler 221; the second outlet of the second preheater 210 is connected to the inlet of the third air cooler 220, the outlet of the third air cooler 220 is connected to the inlet of the third water cooler 221, the outlet of the third water cooler 221 is connected to the inlet of the refined methanol collecting tank, and the outlet of the third water cooler 221 is connected to the inlet of the second refined methanol collecting tank;

[0047] Specifically, part of the methanol in the reflux tank 20 of the pressurized distillation tower is heated by the second preheater 210, and then condensed by the third air cooler 220 and the third water cooler 221 in sequence, and then flows to the refined methanol collection tank to collect the methanol. If the purity of the condensed methanol is unqualified, the methanol flows to the second refined methanol collection tank;

[0048] In the present invention, the third air cooler 220 and the third water cooler 221 are used to fractionate part of the methanol in the reflux tank 20 of the pressurized distillation tower, thereby improving the purity of the methanol.

[0049] Continue to see Figure 1 Further, on the basis of the above embodiment, the third condenser device 24 includes a fourth air cooler 240, a fourth water cooler 241 and a fifth water cooler 242; the condensation inlet of the fourth air cooler 240 is connected to the top gas outlet of the atmospheric distillation tower 12, the condensation outlet of the fourth air cooler 240 is connected to the condensation inlet of the fourth water cooler 241, the condensation outlet of the fourth water cooler 241 is connected to the condensation inlet of the fifth water cooler 242, and the condensation outlet of the fifth water cooler 242 is connected to the first inlet of the atmospheric distillation tower reflux tank 25;

[0050] Specifically, the 65°C methanol vapor discharged from the atmospheric distillation tower 12 is condensed by the fourth air cooler 240, and then cooled to 40°C by the fourth water cooler 241 and the fifth water cooler 242 before entering the atmospheric distillation tower reflux tank 25, thereby purifying the methanol and improving the purity of the methanol.

[0051] Continue to see Figure 1 , further, on the basis of the above embodiment, the gas outlet of the tail gas water washing tower 17 is connected to the gas inlet of the pre-distillation tower liquid seal tank 18;

[0052] The non-condensable gas insoluble in methanol in the reflux tank 16 of the pre-distillation tower flows into the tail gas water washing tower 17 for water washing, and then enters the pre-distillation tower liquid seal tank 18 for washing and then goes to the flare combustion, thereby realizing the treatment of the non-condensable gas.

[0053] Continue to see Figure 1 , further, on the basis of the above embodiment, the impurity outlet of the atmospheric distillation tower 12 is connected to the inlet of the fusel oil recovery device 27, and the liquid outlet of the atmospheric distillation tower 12 is connected to the wastewater inlet of the wastewater treatment device 26;

[0054] Specifically, the fusel oil separated by the atmospheric distillation tower 12 flows to the fusel oil recovery device 27 and the separated waste water flows to the waste water treatment device 26, thereby achieving the treatment of the fusel oil and the waste water.

[0055] Continue to see Figure 1 Further, on the basis of the above embodiment, the fusel oil recovery device 27 includes a fusel oil tank 270 and a fusel alcohol storage tank 271; the impurity outlet of the atmospheric distillation tower 12 is connected to the inlet of the fusel oil tank 270, and the outlet of the fusel oil tank 270 is connected to the inlet of the fusel alcohol storage tank 271; a water cooling coil is provided in the fusel oil tank 270, and a fusel alcohol pump is provided between the outlet of the fusel oil tank 270 and the inlet of the fusel alcohol storage tank 271;

[0056] Specifically, the fusel oil separated from the atmospheric distillation tower 12 flows to the fusel oil tank 270, where the fusel oil is cooled to room temperature by a water cooling coil and then pumped to the fusel oil storage tank 271, thereby realizing the recovery of the fusel oil.

[0057] Continue to see Figure 1 Further, on the basis of the above embodiment, the wastewater treatment device 26 includes a wastewater cooler 260, a waste liquid tank 261 and a wastewater processor 262; the wastewater inlet of the wastewater cooler 260 is connected to the liquid outlet of the atmospheric distillation tower 12, the outlet of the wastewater cooler 260 is connected to the inlet of the waste liquid tank 261, the outlet of the waste liquid tank 261 is connected to the inlet of the wastewater processor 262, and a wastewater pump is provided between the outlet of the waste liquid tank 261 and the inlet of the wastewater processor 262;

[0058] Specifically, the wastewater discharged from the bottom of the atmospheric distillation tower 12 is cooled by the wastewater cooler 260 and then sent to the waste liquid tank 261, and then pressurized by the wastewater pump to the external wastewater processor 262 for treatment, thereby realizing the recycling of the wastewater.

[0059] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A three-tower distillation system for producing high-purity methanol using industrial methanol, characterized in that: include: Pre-distillation tower, pressure distillation tower and atmospheric distillation tower; The feed inlet of the pre-distillation tower is connected to the cold source outlet of the first preheater, the feed inlet of the pre-distillation tower is connected to the outlet of the alkali preparation tank, the heat source inlet of the first preheater is connected to the heat source outlet of the preheating device, the cold source inlet of the first preheater is connected to the discharge port of the crude methanol intermediate tank area, the cold source inlet of the first preheater is connected to the discharge port of the crude methanol flash tank, the discharge port at the bottom of the pre-distillation tower is connected to the preheating inlet of the preheater device, the preheating outlet of the preheater device is connected to the feed inlet of the pressurized distillation tower, and the bottom liquid outlet of the pressurized distillation tower is connected to the feed inlet of the atmospheric distillation tower; The top gas outlet of the pre-distillation tower is connected to the cold source inlet of the condenser device, the cold source outlet of the condenser device is connected to the feed inlet of the pre-distillation tower reflux tank, the discharge port of the pre-distillation tower reflux tank is connected to the reflux port of the pre-distillation tower, the gas outlet of the pressurized distillation tower top is connected to the heat source inlet of the atmospheric distillation tower reboiler, the heat source outlet of the atmospheric distillation tower reboiler is connected to the gas inlet of the atmospheric distillation tower, the condensation outlet of the atmospheric distillation tower is connected to the atmospheric distillation tower reboiler, and the condensation outlet of the atmospheric distillation tower is connected to the atmospheric distillation tower reboiler. The heat source inlet of the tower reboiler is connected, the outlet of the atmospheric distillation tower reboiler is connected to the second inlet of the reflux tank of the pressurized distillation tower, the outlet of the reflux tank of the pressurized distillation tower is connected to the reflux port of the pressurized distillation tower, the top gas outlet of the atmospheric distillation tower is connected to the condensation inlet of the third condenser device, the condensation outlet of the third condenser device is connected to the inlet of the reflux tank of the atmospheric distillation tower, and the outlet of the reflux tank of the atmospheric distillation tower is connected to the reflux port of the atmospheric distillation tower; The tail gas outlet of the reflux tank of the pre-distillation tower is connected to the water washing inlet of the tail gas water washing tower, the water washing outlet of the tail gas water washing tower is connected to the tail gas reflux port of the reflux tank of the pre-distillation tower, the heat source inlet of the reboiler of the auxiliary pre-distillation tower is connected to the second gas outlet at the top of the pressurized distillation tower, the heat source outlet of the reboiler of the auxiliary pre-distillation tower is connected to the inlet of the pre-distillation tower, the inlet of the reboiler of the auxiliary pre-distillation tower is connected to the condensation outlet of the pre-distillation tower, and the outlet of the reboiler of the auxiliary pre-distillation tower is connected to the inlet of the reflux tank of the pressurized distillation tower; The outlet of the reflux tank of the pressurized distillation tower is connected to the second preheating inlet of the preheater device, the second preheating outlet of the preheater device is connected to the condensation inlet of the second condenser device, the condensation outlet of the second condenser device is connected to the inlet of the refined methanol collection tank; the condensation outlet of the second condenser device is connected to the inlet of the second refined methanol collection tank; the outlet of the reflux tank of the atmospheric distillation tower is connected to the inlet of the refined methanol collection tank, and the outlet of the reflux tank of the atmospheric distillation tower is connected to the inlet of the second refined methanol collection tank.

2. A three-tower distillation system for producing high-purity methanol using industrial methanol according to claim 1, characterized in that: The condenser device comprises a first air cooler, a second air cooler, a first water cooler and a second water cooler; The cold source inlet of the first air cooler and the cold source inlet of the second air cooler are both connected to the top gas outlet of the pre-distillation tower, the cold source outlet of the first air cooler is connected to the cold source inlet of the first water cooler, and / or the cold source outlet of the first air cooler is connected to the cold source inlet of the second water cooler, the cold source outlet of the second air cooler is connected to the cold source inlet of the first water cooler, and / or the cold source outlet of the second air cooler is connected to the cold source inlet of the second water cooler, and the cold source outlet of the first water cooler and the cold source outlet of the second water cooler are both connected to the feed port of the reflux tank of the pre-distillation tower.

3. A three-tower distillation system for producing high-purity methanol using industrial methanol according to claim 1, characterized in that: The preheater device includes a second preheater and a third preheater; The preheating inlet of the second preheater is connected to the discharge port at the bottom of the pre-distillation tower, the preheating outlet of the second preheater is connected to the preheating inlet of the third preheater, and the preheating outlet of the third preheater is connected to the feed port of the pressurized distillation tower.

4. A three-tower distillation system for producing high-purity methanol using industrial methanol according to claim 3, characterized in that: The preheating inlet of the second preheater is connected to the outlet of the reflux tank of the pressurized distillation tower; the preheating outlet of the second preheater is connected to the condensation inlet of the second condenser device.

5. A three-tower distillation system for producing high-purity methanol using industrial methanol according to claim 4, characterized in that: The second condenser device includes a third air cooler and a third water cooler; The second preheating outlet of the second preheater is connected to the condensation inlet of the third air cooler, the condensation outlet of the third air cooler is connected to the condensation inlet of the third water cooler, the condensation outlet of the third water cooler is connected to the inlet of the refined methanol collection tank, and the outlet of the third water cooler is connected to the inlet of the second refined methanol collection tank.

6. A three-tower distillation system for producing high-purity methanol using industrial methanol according to claim 1, characterized in that: The third condenser device includes a fourth air cooler, a fourth water cooler and a fifth water cooler; The condensation inlet of the fourth air cooler is connected to the top air outlet of the atmospheric distillation tower, the condensation outlet of the fourth air cooler is connected to the condensation inlet of the fourth water cooler, the condensation outlet of the fourth water cooler is connected to the condensation inlet of the fifth water cooler, and the condensation outlet of the fifth water cooler is connected to the inlet of the reflux tank of the atmospheric distillation tower.

7. The three-tower distillation system for producing high-purity methanol from industrial methanol according to claim 1, characterized in that: The gas outlet of the tail gas water washing tower is connected to the gas inlet of the liquid sealing tank of the pre-distillation tower.

8. The three-tower distillation system for producing high-purity methanol from industrial methanol according to claim 1, characterized in that: The impurity outlet of the atmospheric distillation tower is connected to the inlet of the fusel oil recovery device, and the liquid outlet of the atmospheric distillation tower is connected to the wastewater inlet of the wastewater treatment device.

9. A three-tower distillation system for producing high-purity methanol using industrial methanol according to claim 8, characterized in that: The fusel oil recovery device comprises a fusel oil tank and a fusel oil storage tank; The impurity outlet of the atmospheric distillation tower is connected to the inlet of the fusel alcohol oil tank, and the outlet of the fusel alcohol oil tank is connected to the inlet of the fusel alcohol storage tank; a water cooling coil is arranged in the fusel alcohol oil tank, and a fusel alcohol pump is arranged between the outlet of the fusel alcohol oil tank and the inlet of the fusel alcohol storage tank.

10. A three-tower distillation system for producing high-purity methanol using industrial methanol according to claim 8, characterized in that: The wastewater treatment device includes a wastewater cooler, a waste liquid tank and a wastewater treatment device; The wastewater inlet of the wastewater cooler is connected to the liquid outlet of the atmospheric distillation tower, the outlet of the wastewater cooler is connected to the inlet of the waste liquid tank, the outlet of the waste liquid tank is connected to the inlet of the wastewater processor, and a wastewater pump is arranged between the outlet of the waste liquid tank and the inlet of the wastewater processor.

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