Hyperfiltration-distillation integration process for reclaiming glycerin from low-concentration sweet water

A low-concentration, reverse osmosis technology, applied in the field of reverse osmosis-distillation integrated process, can solve the problems of wasting glycerin resources, environmental pollution, difficult to realize self-protection, etc., and achieve the effect of large processing capacity, low energy consumption and low cost

Inactive Publication Date: 2008-03-12
ZHEJIANG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The actual industrial operation shows that for sweet water with a glycerin content of not less than 5%, it can be profitable by adopting pretreatment, double-effect evaporation, distillation and other process routes to recover; but for sweet water with a glycerin content of less than 4%, it is difficult to adopt the above-mentioned process. Realize self-protection, so low-concentration sweet water with a glycerin content of less than 3% is mostly discharged directly in China, which not only wastes precious glycerin resources, but also causes serious pollution to the environment

Method used

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  • Hyperfiltration-distillation integration process for reclaiming glycerin from low-concentration sweet water

Examples

Experimental program
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Effect test

Embodiment 1

[0031]Take 100kg of acidic sweet water with a glycerol content of 1.1% (mass percentage, the same below), add quicklime to neutralize to neutrality, then add polyferric sulfate, filter after flocculation and precipitation; the filtrate passes through a plate-type cellulose acetate asymmetric membrane under a pressure of 1MPa Component reverse osmosis concentrates to obtain a concentrated solution with a glycerol concentration of 1.4%, and the concentrated solution is subjected to double-effect evaporation to remove water and some salts to obtain crude glycerin; the crude glycerin is purified by vacuum distillation and mixed bed ion exchange resin column at an operating pressure of 2mmHg (201 × 7 type strongly basic styrenic anion exchange resin and 001 × 7 type strongly acidic styrenic cation exchange resin are mixed in a volume ratio of 1: 2) and after active carbon decolorization, 0.88 kg of glycerin product is obtained, and in the product, glycerin The content of 98.6%, the ...

Embodiment 2

[0033] Take 100kg of acidic sweet water with a glycerin content of 2.0%, add sodium hydroxide solution to neutralize to neutrality, then add polyaluminum trichloride, filter after flocculation and precipitation; the filtrate is concentrated by reverse osmosis through a plate polyamide composite membrane module under a pressure of 2MPa Obtain the concentrated solution that glycerol concentration is 3.6%, and the concentrated solution obtains crude glycerin after three-effect evaporation removes water and part salt; Crude glycerin is refined under vacuum distillation, mixed-bed ion-exchange resin column (201 × 7 mmHg) under operating pressure Type strong basic styrenic anion exchange resin and 001 * 7 type strongly acidic styrenic cation exchange resin are mixed by volume ratio 1: 1) and activated carbon decolorize to obtain glycerol product 1.74kg, and the content of glycerol in the product is 98.7% , The recovery rate of glycerol was 85.9%.

Embodiment 3

[0035] Take 100kg of alkaline sweet water with a glycerin content of 1.8%, add sulfuric acid solution to neutralize it to neutrality, then add alum, flocculate and precipitate, and filter; the filtrate is concentrated under a pressure of 3 MPa by reverse osmosis through a plate-type polybenzimidazolone membrane module to obtain glycerin Concentration is the concentrated solution of 4.4%, and the concentrated solution obtains crude glycerin after double-effect evaporation removes water and part of salt; Crude glycerin is through vacuum distillation under the operating pressure of 6mmHg, and the column refining of mixed bed ion exchange resin (201 × 7 strong Basic styrene-based anion-exchange resin and 001 × 7 type strongly acidic styrene-based cation-exchange resin are mixed by volume ratio 2: 1) and activated carbon decolorize to obtain glycerin product 1.54kg, and the content of glycerol in the product is 98.5%. The recovery rate was 84.3%.

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Abstract

The present invention discloses an integration technics with anti-penetration and distillation to recycle a glycerin in low-concentration sweet water. The steps for the present invention are as follows: (1) the pH value for the low-concentration sweet water is adjusted to litmusless by using of a neutralization agent, and then a flocculating agent is added into the sweet water; after being deposited, the mixture is to be filtered; (2) the filter liquid is condensed into a condensing liquid through an anti-penetration film component in the pressure of 1-8MPa; the condensing liquid is vaporized with multi-aspects to get rid of water and part of salt; and then a coarse glycerin; (3) the coarse glycerin is decompressed, distilled, ion-exchanged with resin refining in a mixing bed, and decolored with an active carbon to create the glycerin product with the purity more than 98.5 percent. The present invention can be used in medicine industry and foodstuff industry and so on. The technics has the advantages of low resource consumption, large treatment quantity and low cost and so on. The present invention can not only bring much better economical benefit by changing uselessness into usefulness, but also has greater environmental and social benefit.

Description

technical field [0001] The invention relates to a reverse osmosis-distillation integrated process for recovering glycerin in low-concentration sweet water. Background technique [0002] Glycerin (glycerin, glycerine, glycerol), also known as glycerin, CAS No.: 56-81-5, molecular formula: C 3 h 8 o 3 , molecular weight 92.09. Glycerin is an important chemical raw material, widely used in organic chemical industry, polymer synthesis, daily chemicals, textiles, coatings, leather, tobacco, food and medicine. There are three main methods for the production of glycerol. The first is the method of extracting glycerin from natural oils, including saponification and oil hydrolysis; the second is to use carbohydrates as raw materials to produce glycerin by microbial fermentation, that is, fermentation, which includes fermentation of raw materials such as molasses and starch; The third is to use petrochemical products as raw materials to synthesize glycerin by chemical methods, th...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C31/22C07C29/74
CPCY02P20/10
Inventor 吕秀阳朱思佳陈欢林
Owner ZHEJIANG UNIV
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