CN107441669A

CN107441669A - A kind of method of heterogeneous catalysis hydrolysis melamine, cyanuric acid and melamine OAT waste residues

Info

Publication number: CN107441669A
Application number: CN201610373976.2A
Authority: CN
Inventors: 张涛; 唐盛伟; 梁斌; 龚海
Original assignee: Sichuan University
Current assignee: Sichuan University
Priority date: 2016-05-31
Filing date: 2016-05-31
Publication date: 2017-12-08
Anticipated expiration: 2036-05-31
Also published as: CN107441669B

Abstract

The present invention relates to the method for a kind of heterogeneous catalysis hydrolysis melamine, cyanuric acid and melamine OAT waste residues, catalyst is made using activated alumina or boehmite, in closed pressure vessel, carry and hydrolyzed under pressure, temperature is 190 DEG C ~ 240 DEG C, melamine, cyanuric acid and melamine OAT waste residues can be decomposed into ammonia and carbon dioxide, the wherein main component of melamine OAT waste residues is melamine, ammeline, ammelide, cyanuric acid.At the same time, ammonia caused by hydrolysis and carbon dioxide are the unstripped gas for producing urea, can be with urea plant coproduction, therefore process provides a kind of method of effective resource recycling, suitable for the industrial enterprise of current production melamine.

Description

A kind of heterogeneous catalysis hydrolysis melamine, cyanuric acid and melamine OAT waste residues Method

Technical field

The present invention relates to a kind of heterogeneous catalysis hydrolysis melamine, cyanuric acid and melamine OAT waste residue methods, category In fixed-end forces and recycling economy technical field.

Background technology

Melamine is widely used in synthetic plastic, water soluble paint, viscous glutinous as a kind of important chemical intermediate Agent, fiber and fire retardant.The global demand to melamine in 2015 is all constantly increasing every year at 2,000,000 tons or so It is long.In the technique of Production of Melamine by High Pressure Process, melamine OAT waste residues can be produced, yield is quite huge, and these waste residues are such as Fruit can not obtain relatively reasonable disposal, and environment will certainly be affected, while can also reduce chemical resource Utilization rate.The main component of melamine OAT waste residues is melamine, ammeline, ammelide, trimerization Cyanic acid, they are all the nitrogen-containing compounds containing triazine ring, generally highly stable, it is difficult to by general physically or chemically Method is degraded.It is at present industrially to use high-temperature high-pressure hydrolysis, without using catalyst, directly by three under 285 DEG C, 8.5MPa Poly cyanamid OAT waste residues are decomposed into ammonia and carbon dioxide, and ammonia and carbon dioxide are also the unstripped gas of production urea simultaneously.This method The green circulatory production of melamine is realized, but the higher hydrolysis temperature of this method and pressure make it that operation energy consumption is higher, it is right Equipment requirement is harsh, have impact on the application and popularization of technique.Therefore using the method for catalyzing hydrolysis, reaction temperature is reduced, so as to Reducing the utilization of the running cost and equipment investment of hydrolysis for melamine OAT has important practical value.

It is otherwise using also having carried out to melamine OAT waste residues in addition to foregoing high-temperature high-pressure hydrolysis Research, but all fail to industrialize.A kind of method is that the various components separated in OAT are used, and is such as separated by adjusting pH value Melamine [WO in OAT:0136397 A1], but a large amount of soda acid amounts are consumed in technique, and only reclaimed melamine therein Amine；It can also be separated according to each component sublimation point difference, but higher [the Saito S. Sublimatographic of energy consumption analysis; Sublimatographic separation of melamine, ammerine, ammeride and cyanuric acid[J]. Japan analyst, 1978, 27: 321-325.].Another method is to utilize melamine OAT waste residues prepare other products, such as prepare sulfonated amino resin, or prepare cyanuric acid, but due to OAT complicated components, prepare Obtained product active ingredient is low, complex process [Lahalih SM, Absihalabi M. Recovery of solids from melamine waste effluents and their conversion to useful products[J]. Ind Eng Chem Res. 1989,28(4):500-504；EP:0124710,1984；US:4963674.1990；Ren Baozeng, Luo Ting Bright, the such as Li Chen prepares cyanuric acid environment [J] environmental projects with the solid waste discharged in Melamine Production, and 2003,21 (4):4-44]。

Using activated alumina or boehmite as catalyst in the present invention, can under relatively low temperature conditionss, Melamine, cyanuric acid or melamine OAT waste residues are hydrolyzed to ammonia and carbon dioxide, effectively improve conventional high-temperature high pressure The shortcomings that Hydrolyze method.

The content of the invention

The present invention relates to the method for a kind of heterogeneous catalysis hydrolysis melamine, cyanuric acid and melamine OAT waste residues, Compared with existing industrial treatment OAT waste residue technologies, the beneficial effects of the invention are as follows the reaction for reducing traditional industry hydrolysis process Temperature, so as to reduce energy consumption and the excessive demand to equipment, realize efficient, green solid waste recovery and Utilize.Specific technical scheme is as follows：

It will be placed in autoclave, protect containing melamine, the solution of cyanuric acid or melamine OAT waste residues or suspension Certain liquid-solid ratio is held, at 190 ~ 240 DEG C, makees catalyst using activated alumina or boehmite, system carries pressure Under continuously stir 1 ~ 10h of reaction, you can melamine, cyanuric acid or melamine OAT waste residues are hydrolyzed to ammonia and titanium dioxide Carbon.

Process conditions are that the concentration of melamine, cyanuric acid or melamine OAT waste residues is 0.05g/L ~ 20g/L, The activated alumina of addition or the mass ratio of boehmite catalyst are 0.1% ~ 10%, and reaction temperature is 190 ~ 240 DEG C, Reaction time is 1 ~ 10 h.

The method of heterogeneous catalysis hydrolysis melamine OAT waste residues of the present invention, reaction principle used are：Trimerization Cyanamide, ammeline, ammelide are under the catalytic action of activated alumina or boehmite, its triazine Amino on ring is gradually substituted by hydroxyl, ultimately produces cyanuric acid, and cyanuric acid is further hydrolyzed to ammonia and titanium dioxide Carbon.Its course of reaction such as accompanying drawing 1.

Brief description of the drawings

Fig. 1 is melamine, ammeline, ammelide, cyanuric acid in activated alumina or intends thin water The hydrolysis path profile of ammonia and carbon dioxide is progressively hydrolyzed under the catalytic action of aluminium stone.

Embodiment

For preferably the present invention will be described, it is as follows to enumerate embodiment：

Embodiment 1

Melamine initial concentration is 0.67g/L, and the mass ratio for adding activated alumina is 3.8%, and reaction temperature is 220 DEG C, instead It is 5 hours between seasonable, solution after reaction is detected, the degradation rate of melamine is 99.8%, the yield of ammonia and carbon dioxide For 96.1%.

Embodiment 2

Melamine initial concentration is 2.4g/L, and the mass ratio for adding boehmite is 4.6%, and reaction temperature is 200 DEG C, instead It is 7 hours between seasonable, solution after reaction is detected, the degradation rate of melamine is 93.2%, the yield of ammonia and carbon dioxide For 91.7%.

Embodiment 3

Cyanuric acid initial concentration is 0.67g/L, and the mass ratio for adding activated alumina is 3.8%, and reaction temperature is 220 DEG C, instead It is 2 hours between seasonable, solution after reaction is detected, the degradation rate of cyanuric acid is 98.4%, the yield of ammonia and carbon dioxide For 97.5%.

Embodiment 4

Cyanuric acid initial concentration is 5.0g/L, and the mass ratio for adding boehmite is 1.2%, and reaction temperature is 190 DEG C, instead It is 6 hours between seasonable, solution after reaction is detected, the degradation rate of cyanuric acid is 99.1%, the yield of ammonia and carbon dioxide For 98.4%.

Embodiment 5

Melamine OAT waste residues initial concentration is 16.67g/L, and the mass ratio for adding activated alumina is 3.6%, and reaction temperature is 220 DEG C, the reaction time is 7 hours, and solution after reaction is detected, and the degradation rate of melamine OAT waste residues is 93.4%, ammonia Yield with carbon dioxide is 92.0%.

Embodiment 6

Melamine OAT waste residues initial concentration is 10.0g/L, and the mass ratio for adding boehmite is 2.8%, and reaction temperature is 200 DEG C, the reaction time is 8 hours, and solution after reaction is detected, and the degradation rate of melamine OAT waste residues is 91.7%, ammonia Yield with carbon dioxide is 90.4%.

Embodiment 7

Melamine OAT waste residues initial concentration is 20.0g/L, and the mass ratio for adding activated alumina is 7.9%, and reaction temperature is 240 DEG C, the reaction time is 6 hours, and solution after reaction is detected, and the degradation rate of melamine OAT waste residues is 94.7%, ammonia Yield with carbon dioxide is 92.5%.

Claims

1. a kind of method of heterogeneous catalysis hydrolysis melamine, cyanuric acid and melamine OAT waste residues, it is characterised in that A certain amount of melamine, cyanuric acid and melamine OAT waste residues use active oxidation in the closed pressure resistant container containing water Aluminium or boehmite make catalyst, are heated to temperature as 190 DEG C ~ 240 DEG C, keep system pressure itself, continuous heating stirring 1 ~ 10h, until melamine, cyanuric acid and melamine OAT waste residues are hydrolyzed to ammonia and carbon dioxide.

A kind of 2. method of heterogeneous catalysis hydrolysis melamine OAT waste residues according to claim 1, it is characterised in that Described is heterogeneous for the solid catalyst system and catalyzing of liquid.

A kind of 3. method of heterogeneous catalysis hydrolysis melamine OAT waste residues according to claim 1, it is characterised in that Described catalyst is activated alumina or boehmite.

A kind of 4. method of heterogeneous catalysis hydrolysis melamine OAT waste residues according to claim 1, it is characterised in that The concentration of melamine, cyanuric acid or melamine OAT waste residues is 0.05g/L ~ 20g/L, the activated alumina of addition or The mass ratio of boehmite catalyst is 0.1% ~ 10%, and reaction temperature is 190 ~ 240 DEG C, and the reaction time is 1 ~ 10 h。