Process and plant for distillation of methanol with heat recuperation

一种甲醇、粗甲醇的技术,应用在蒸馏甲醇领域,能够解决消耗、大能量等问题,达到节省能量、减小生产成本的效果

Active Publication Date: 2014-10-15
CASALE SA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] As far as the plant is concerned, the described configuration with two columns is simple, but it mainly has the following disadvantages: due to the heat supply to the bottom reboiler and due to the consumption of cooling water and / or electrical energy for the top condenser, so consume a lot of energy
Another issue presents itself as equipment (column) size proportional to the cost of the complete equipment

Method used

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  • Process and plant for distillation of methanol with heat recuperation
  • Process and plant for distillation of methanol with heat recuperation
  • Process and plant for distillation of methanol with heat recuperation

Examples

Experimental program
Comparison scheme
Effect test

no. 1 approach

[0051] figure 1 The scheme shown includes a topped column 100 , a finishing column 400 and a distillation column 200 , a distillation column 300 . The distillation column 200, the distillation column 300, and the distillation column 400 are operated in series under reduced pressure (p2>p3>p4). The topping column 100 operates at a pressure p1 of typically about 1.5 bar; in this example, the pressure p4 of the column 400 is substantially equal to the topping pressure p1 , ie, p4 ≈ p1 .

[0052] In this description, no account is taken of the pressure drops for concentration and distribution due to piping, valves, auxiliary parts, etc. Each column has a nominal pressure; the pressure of the gas at the top of the column and the liquid withdrawn from the bottom of the column are slightly different, as is known to those skilled in the art.

[0053] The topped column 100 includes a bottom reboiler 101 and a top condenser 102 . Column 200 , column 300 , and column 400 include botto...

no. 2 approach

[0069] figure 2 Another preferred embodiment is shown. The same reference numerals are used for the figure 1 equivalent parts.

[0070] said figure 2 refers to an embodiment in which the pressure p4 in the column 400 is substantially greater than the topping pressure p1. For example, the pressure p1 is about 1 bar to 1.5 bar and the pressure p4 is at least 2 bar, preferably 3 bar to 5 bar. In this case, the gaseous stream 404 of distilled methanol taken from the top of the tailing column 400 has a higher temperature and higher pressure (typically 3 to 5 bar and in excess of 100° C.), and the distilled methanol The gaseous stream 404 can serve as a useful heat source for the reboiler 101 of the topped column.

[0071] exist figure 2 In the embodiment of , a portion 440 of said stream 404 is sent to reboiler 101 and is cooled, preferably condensed, in said reboiler 101 , while the remaining portion 414 is sent to overhead condenser 402 . Condensate 415 formed in reboiler...

Embodiment 1

[0074] The stream of crude methanol has the following composition: 83% methanol CH 3 OH, 15% H 2 O, 1.9% dissolved gas, 0.1% impurity. Assume that the output of AA grade methanol is 5000t / d.

[0075] According to the prior art, a conventional plant comprises: a topped column at a pressure of 1.5 bar, a finishing column at a pressure of 1.5 bar, a distillation column at a pressure of 8 bar and a temperature of about 130°C. Under these conditions, it can be calculated as follows: The total energy consumption for the bottom reboiler: 0.63Gcal / ton (referring to the distillation of methanol per ton); The heat exchanged by the top condenser: 0.60Gcal / ton.

[0076] now refer to figure 1 A schematic diagram of , with the following pressures and temperatures.

[0077] Pressure p1 in the topped column: 1.5 bar.

[0078] Temperature at the bottom of the column (stream 105): 90 °C.

[0079] Stream 204: 19 bar, 63°C.

[0080] Stream 205: 171 °C.

[0081] Stream 304: 9 bar, 132°C. ...

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Abstract

Process and plant for refining crude methanol, comprising at least three distillation stages operating in cascade at decreasing pressures, wherein a first stage (200) operates at a maximum distillation pressure (p2), a second stage (300) operates at a medium distillation pressure (p3), and a final distillation stage (400) operates at a minimum distillation pressure (p4), wherein the first stage and the distillation stage each produce a respective gaseous stream (204, 304) of distilled methanol, and a respective solution containing methanol that is fed to the next distillation stage, and wherein at least one first gaseous stream of distilled methanol (204), produced in the first distillation stage, and a second gaseous stream of distilled methanol (304), produced in the second distillation stage, are used as heat sources to heat the second distillation stage and the final distillation stage, respectively.

Description

technical field [0001] The present invention relates to methods and plants for distilling methanol. Background technique [0002] It is well known that the product of a plant for synthesizing methanol (usually defined as crude methanol) contains by-products of the synthesis reaction (including ethanol, ketones, polyols) and some dissolved gases (mainly including H 2 , CO, CO 2 , N 2 and CH 4 ) in methanol solution. [0003] Crude methanol is distilled to meet the purity specifications required by the market. For example, Grade AA specifications require a minimum methanol concentration of 99.85% by weight and require no more than 10 ppm ethanol by weight. [0004] Known distillation processes are basically based on one or more rectification columns. Typically, a rectification column is capable of separating light products (eg, gases) at the top and heavier products (eg, aqueous solutions) at the bottom or end. [0005] The first widely used process and associated plant...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01D3/00B01D3/14
CPCB01D3/143C07C29/80B01D3/007B01D3/002Y02P70/10B01D3/14C07C31/04
Inventor 埃尔曼诺·菲利皮拉法埃莱·奥斯图尼
Owner CASALE SA
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