CN101648114A

CN101648114A - Method for reclaiming methenamine and glycin in glycin mother liquid by using nano-filtering technique

Info

Publication number: CN101648114A
Application number: CN200910176940A
Authority: CN
Inventors: 刘长飞
Original assignee: Individual
Current assignee: Individual
Priority date: 2009-09-25
Filing date: 2009-09-25
Publication date: 2010-02-17

Abstract

The invention belongs to the field of recycling resources in a glycin (amino acetic acid) production trade, and provides a method for separating and reclaiming methenamine and glycin in a glycin mother liquid by using a nano-filtering film. The molecular weight intercepted by the used nano-filtering film is 50-300 daltons; the operating pressure is 1.8-4.0MPa; the operating temperature is 20-50DEGC; and most of ammonium chloride in the glycin mother liquid enters a nano-filtering permeation liquid by penetrating through the nano-filtering film through the separation of the nano-filtering film, and the methenamine and most of the glycin are intercepted into an intercepting liquid. The methenamine and the glycin in the intercepting liquid are recycled.

Description

Utilize nanofiltration to reclaim the method for methenamine and glycine in the glycin mother liquid

Technical field

The invention belongs to the recycling field of resource in glycine (amion acetic acid) production industry.

Technical background

Domestic traditional glycine production technology adopts monoxone and liquefied ammonia to carry out ammonolysis reaction in the presence of methenamine, then uses the separating out alcohol method separation of glycine.Methenamine as catalyst in this production method is drained (producing the methenamine that one ton of glycine consumes the 160-200 kilogram) with waste water after reaction finishes, and has not only wasted valuable resource, has also polluted environment.When alcohol is analysed separation of glycine, the mixed liquor outflow of the glycine of 10%---15% with the first alcohol and water arranged, wasted valuable resource equally.

Nanofiltration (NF) is a kind of new membrane isolation technics that grows up over nearly 20 years, and NF membrane is the composite charged film that has nanometer micropore, is fit to molecular weight is separated between the daltonian organic molecule of 150-1000 based on its screening principle;

Based on its charge effect, be fit to separating with monovalention and multivalent ion and neutral substance.

Summary of the invention

The invention provides a kind of method of utilizing NF membrane separate to reclaim methenamine and glycine in the glycin mother liquid.

The glycin mother liquid of indication of the present invention comprises following two kinds of mother liquors:

A: glycine methanol mother liquor (alcohol analyse glycine after remaining mother liquor)

Glycine methanol mother liquor composition is as follows:

Produce the mother liquor that contains methyl alcohol that one ton of glycine will give off 12 cubic metres of left and right sides volumes.Alcohol analyses behind the glycine that the volume of methyl alcohol accounts for about 80% in the remaining mother liquor, and the volume of water accounts for 20%, is called methanol mother liquor here.Methanol mother liquor contains the ammonium chloride of wanting about 5%, about 1.2% methenamine, about 1% glycine;

B: glycine dealcoholization mother liquid

The glycine dealcoholization mother liquid is meant that the glycine methanol mother liquor reclaims the aqueous solution that is left behind the methyl alcohol through rectifying column.

The present invention realizes by the following method:

Utilize nanofiltration equipment, the molecular weight that the NF membrane of using is held back is 50--300 dalton; Operating pressure 1.8-4.0Mpa; 20 ℃ of operating temperatures--50 ℃; By the separation of NF membrane, the most of ammonium chloride in the glycin mother liquid sees through NF membrane and enters into nanofiltration through the liquid the inside, and most of methenamine and most glycine are trapped the liquid the inside of damming.The methenamine and the glycine of liquid the inside of damming obtains recycling.

One, handle the glycine methanol mother liquor:

Step 1, glycine methanol mother liquor concentrate by nanofiltration equipment and separate.20 ℃ of operating temperatures--50 ℃; Dam liquid when being concentrated into the 5-10% of initial charge volume when nanofiltration, stop to concentrate;

Another kind of processing method:

The glycine methanol mother liquor concentrates by nanofiltration equipment and separates, when nanofiltration is dammed liquid when being concentrated into 30% left and right sides of initial charge volume, add a part of liquid flux (water, methyl alcohol or alcohol-water mixture) in liquid is dammed in nanofiltration, the volume of the liquid flux that replenishes is the nanofiltration long-pending 50%--150% of liquid that dams; Continue to use nanofiltration equipment to concentrate and separate, stop to concentrate when being the 5%-10% of methanol mother liquor volume of former adding when the volume of the liquid that dams;

Step 2, nanofiltration are dammed liquid through decompression distillation recovery methyl alcohol, and the remaining aqueous solution contains the methenamine of recovery, glycine, ammonium chloride.Cold true recovery ammonium chloride crystals, the link that remaining filtered fluid turns back to glycine production recycles, and methenamine in the filtered fluid and glycine obtain reclaiming;

Step 3, nanofiltration see through liquid and send into rectifying column recovery methyl alcohol.Dealcoholysis solution concentrates through double-effect evaporation and reclaims byproduct ammonium chloride;

Two, handle the glycine dealcoholization mother liquid:

Step 1, glycine dealcoholization mother liquid concentrate by nanofiltration equipment and separate.20 ℃ of operating temperatures--50 ℃; Dam liquid when being concentrated into 50% left and right sides of initial charge volume when nanofiltration, add a part of water in liquid is dammed in nanofiltration, the volume of supplementing water is the nanofiltration long-pending 50%--300% of liquid that dams; Continue to use nanofiltration equipment to concentrate and separate, stop to concentrate when being the 20%--30% of dealcoholization mother liquid volume of former adding when the volume of the liquid that dams;

Step 2, the nanofiltration liquid that dams at first decolours. and the method for decolouring is to use active carbon to add the catalysed oxidation processes of hydrogen peroxide. and the link that the filtered fluid after the decolouring turns back to glycine production recycles, and methenamine in the filtered fluid and glycine obtain reclaiming;

Step 3, nanofiltration see through liquid and concentrate recovery byproduct ammonium chloride through double-effect evaporation;

Embodiment:

Get 50L glycine methanol mother liquor, use the nanofiltration testing equipment to carry out concentrating and separating.Select SR2 (2540) model of U.S. Ke Shi company, molecular cut off is 150 daltonian NF membrane, operating pressure 2.0-2.2Mpa; Operating temperature 20--50 ℃; Dam liquid when being concentrated into 15L when nanofiltration, stop to concentrate;

In liquid is dammed in nanofiltration, add the 15L aqueous solvent, continue to use nanofiltration equipment to concentrate and separate,, stop when operating pressure rises to 3.0Mpa concentrating when the volume of the liquid that dams is 5L.

Methyl alcohol is reclaimed in the concentrate decompression distillation, and the remaining aqueous solution contains methenamine, glycine, ammonium chloride.

Claims

1, the invention provides a kind of method of utilizing nanofiltration separate to reclaim methenamine and glycine in the glycin mother liquid.Its molecular weight of holding back of employed NF membrane is 50---300 dalton; Operating pressure 1.8-4.0Mpa; 20 ℃-50 ℃ of operating temperatures.The glycin mother liquid of indication of the present invention comprises glycine methanol mother liquor and glycine dealcoholization mother liquid.

2, the glycine methanol mother liquor concentrates by nanofiltration equipment and separates, and dams liquid when being concentrated into the 5-10% of initial charge volume when nanofiltration, stops to concentrate; Also can glycine methyl alcohol mother concentrate by nanofiltration equipment and separate, when nanofiltration is dammed liquid when being concentrated into 30% left and right sides of initial charge volume, add a part of liquid flux (water, methyl alcohol or alcohol-water mixture) in liquid is dammed in nanofiltration, the volume of the liquid flux that replenishes is the nanofiltration long-pending 50%-150% of liquid that dams; Continue to use nanofiltration equipment to concentrate and separate, stop to concentrate when being the 5%-10% of methanol mother liquor volume of former adding when the volume of the liquid that dams.

3, the nanofiltration of glycine methanol mother liquor is dammed liquid through decompression distillation recovery methyl alcohol.The remaining cold true recovery ammonium chloride crystals of liquid, the link that remaining filtered fluid turns back to glycine production recycles, and methenamine in the filtered fluid and glycine obtain reclaiming.

4, the glycine dealcoholization mother liquid concentrates by nanofiltration equipment and separates.Dam liquid when being concentrated into 50% left and right sides of initial charge volume when nanofiltration, add a part of water in liquid is dammed in nanofiltration, the volume of supplementing water is the nanofiltration long-pending 50%--300% of liquid that dams; Continue to use nanofiltration equipment to concentrate and separate, stop to concentrate when being the 20%--30% of dealcoholization mother liquid volume of former adding when the volume of the liquid that dams.

5, the nanofiltration liquid that dams at first decolours. and the method for decolouring is to use active carbon to add the catalysed oxidation processes of hydrogen peroxide. and the link that the filtered fluid after the decolouring turns back to glycine production recycles, and methenamine in the filtered fluid and glycine obtain reclaiming.