Method and device for dehydrating and refining biofuel

A biofuel and biological technology, applied in the fields of biofuels, chemical instruments and methods, preparation of hydroxyl compounds, etc., can solve the problems of waste of energy consumption, reduce the relative volatility of alcohol and water, and reduce the efficiency of rectification and separation, and achieve huge market applications. Prospects, high relative volatility, and the effect of improving separation efficiency

Active Publication Date: 2015-01-07
NANJING UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Since ethanol and water will form an ethanol-water azeotrope, it is difficult to achieve complete dehydration with a single rectification method, and most of them need to be further dehydrated through steps such as azeotropic rectification, extractive rectification and molecular sieve adsorption, thus making the entire process bloated complex, high energy consumption
Among them, the introduction of entrainer or extraction agent not only increases the economic cost but also brings great harm to the environment, while the molecular sieve adsorption method has the problems of low primary recovery and high energy consumption.
Chinese patent CN102260140A proposes to condense all the gas near the azeotropic composition at the top of the rectification tower into liquid, then heat it to 80-90°C and send it into the pervaporation membrane module. This process causes a huge waste of energy consumption. Severe concentration polarization and temperature polarization occur during the vaporization process
Chinese patent CN103071307A adopts pressurized rectification, and the gas at the outlet of the partial condenser directly enters the steam permeation separation device for dehydration; the disadvantage is that pressurized rectification will reduce the relative volatility of alcohol and water, reduce the efficiency of rectification separation, and increase energy consumption. The steam permeation separation device is a low-pressure separation device of <0.2Mpa (gauge pressure). The operating pressure is low, resulting in low flux and a large membrane area required. The pressure is easy to fluctuate, and the corresponding equipment investment cost is relatively high

Method used

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  • Method and device for dehydrating and refining biofuel

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0016] Example 1 Dehydration and refining of ethanol fermentation broth

[0017] use figure 1 The shown device dehydrates and refines the ethanol fermentation liquid. The dehydration process is as follows:

[0018] Put the ethanol fermentation liquid with a water content of 92wt.% into the raw material tank 1, and under the promotion of the feed pump 2, preheat the fermented liquid in the raw material tank 1 through the preheater 3 to 78 ~ After 85°C, it is sent to the rectification tower 4. The total number of trays in the rectification tower is 12, and the feeding position is the 10th theoretical plate. The reboiler 8 maintains a tower bottom temperature of 95-105° C. under the heat supply conditions of the saturated water vapor from the steam boiler 18 and the anhydrous alcohol vapor on the retentate side of the steam permeation membrane separation unit 10; meanwhile, the rectification tower 4 The top of the tower is controlled to be 70-80°C by condensing the reflux...

Embodiment 2

[0019] Example 2 Dehydration and purification of ethanol fermentation broth with a water content of 95wt.%.

[0020] Present embodiment is that water content is its refining process with embodiment 1, and difference with embodiment 1 is:

[0021] The raw material is fermented liquid ethanol with a water content of 95wt.%.

[0022] The total number of plates in the rectification tower is 12, and the feeding position is the fifth theoretical plate;

[0023] Fermentation broth preheating temperature 80 ~ 90 ℃;

[0024] The flow rate of feed pump 2 is 20000kg / h;

[0025] The top reflux ratio is 2.8~3.5;

[0026] The temperature at the top of the tower is controlled at 85-95°C;

[0027] The temperature of the tower kettle is controlled at 100-110°C;

[0028] The water content in the uncondensed gas through the partial condenser 5 is 20 wt.%;

[0029] Compressor pressure increased by 0.5Mpa (gauge pressure);

[0030] The vacuum pressure on the permeate side is 1500Pa;

[003...

Embodiment 3

[0033] Example 3 Dehydration and purification of butanol fermentation broth

[0034] The present embodiment refining process is the same as embodiment 1, and difference with embodiment 1 is:

[0035] The raw material is a butanol fermentation broth with a water content of 98wt.%.

[0036] The total number of trays in the rectification tower is 20, and the feed position is the 10th theoretical tray;

[0037] The preheating temperature of the fermentation broth is 80-90°C;

[0038] The flow rate of feed pump 2 is 25000kg / h;

[0039] The top reflux ratio is 1~3.5;

[0040] The temperature at the top of the tower is controlled at 85-95°C;

[0041] The temperature of the tower kettle is controlled at 100-110°C;

[0042] The water content in the uncondensed gas through the partial condenser 5 is 30 wt.%;

[0043] Compressor pressure increased by 0.5Mpa (gauge pressure);

[0044] The vacuum pressure on the permeate side is 1300Pa;

[0045] The steam permeation membrane separa...

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Abstract

The invention relates to a method for dehydrating and refining biofuel. The method comprises the following steps: carrying out normal-pressure rectification on fermentation liquor for preparing biofuel alcohol, wherein the tower bottom temperature is 95-105 DEG C, and the tower top temperature is 70-95 DEG C; separating waste water from the bottom of a rectifying tower, partially condensing the gas output from the rectifying tower top through a fractional condenser, and returning the condensate to the rectifying tower, wherein the reflux ratio is 1-3.5; pressurizing the uncondensed gas to be greater than 0.3Mpa and then introducing into a vapor permeation membrane separator, sucking with a vacuum pump at the permeation side, extracting water vapor from the permeation side of the vapor permeation membrane separator and cooling and collecting; and outputting anhydrous alcohol gas from the retentate side, and condensing to obtain an anhydrous alcohol liquid product containing water lower than 0.1wt%. The invention also provides a special device for the method. According to the method and device, normal-pressure rectification, a compressor and the novel efficient vapor permeation membrane separator are combined to be used for dehydrating biofuel alcohol, and the method and device have the advantages that energy-saving and efficient effects are achieved, the device is small in occupation area, environment-friendly and simple to operate, and the like.

Description

technical field [0001] The present invention relates to a method and device for dehydration and purification of biofuels, in particular to a method and device for dehydration and purification of biofuels that integrate a rectification tower, a compressor, a new type of high-efficiency steam permeation membrane separation device, and thermal energy secondary utilization technology , belonging to the separation domain. Background technique [0002] With the rapid development of industry, the consumption of energy is increasing day by day, and fuel resources such as oil and coal, which are natural energy sources, are bound to be exhausted day by day. In order to cope with the energy crisis, new energy sources must be opened up. The research on the preparation of fuel alcohol by biomass fermentation began in the late last century. The fuel is obtained from the fermentation liquid of corn and other food crops through dehydration. It is not limited by natural resources and is a su...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C29/76C07C29/80C07C31/08C07C31/12
CPCC07C29/76C07C29/80Y02E50/10C07C31/08C07C31/12Y02P20/10
Inventor 顾学红徐树峰张玉亭郭海超徐南平
Owner NANJING UNIV OF TECH
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