CN1164355C - Catalyst Membrane Separation Method for Heterogeneous Suspension State Catalytic Reaction - Google Patents

Abstract

The invention relates to a catalyst membrane separation method for heterogeneous suspension state nano catalytic reaction, wherein a catalyst separation process and a catalytic reaction process are coupled in the same system, materials in a reaction kettle are continuously pumped by a pump and are sent into an inorganic membrane tube with the average pore diameter of 2-200 nanometers and continuously circulate between the reaction kettle and the inorganic membrane tube, a liquid phase product is continuously separated through the membrane tube by utilizing the screening principle of the inorganic membrane, and a suspension state catalyst is intercepted in the membrane tube and returns to the reaction kettle again along with a circulating material to be recovered. Effectively solves the difficult problem of separating and recycling the nano catalyst in the heterogeneous suspension state nano catalytic reaction.

Description

The catalyst membrane separation method of heterogeneous suspension nano catalysis reaction

(one) technical field

The present invention relates to the catalyst membrane separation method of a kind of separation method of nanocatalyst, particularly heterogeneous suspension nano catalysis reaction.

(2) background technology field

Nanocatalyst is because its particle is small, and specific area is big, and key attitude and the surface atom coordination not congruent characteristic different with granule interior on surface caused the increase of surface-active position, thereby is a kind of novel effective catalyst, be called as the 4th generation catalyst.Because this catalyst particle size≤10 ^-7Rice, have very thin uniform outer surface layer and special crystal structure, the surface state of its atom level can cause the variation of surface electronic state, and this good surface characteristic and unique electronic structure help absorbing the carrying out of absorption and surface chemical reaction, thereby nanocatalyst has light specific gravity, specific area is big, the reactivity height, selectivity is strong, long service life, outstanding advantage such as good operation performance, these character provide good prospect for its application at catalytic field.This catalyst is applicable to various types of chemical reactions, especially catalytic oxidation, reduction and cracking reaction all had advantages of high catalytic activity and good catalytic selectivity, caused domestic and international chemistry, chemical industry expert's great attention, its application will have an immense impact on to chemical industry, field of petrochemical industry, becomes the important high-tech sector that each developed country, each big petrochemical corporation (complex) competitively develop.Many developed countries all drop into great amount of manpower, financial resources are carried out the research of nano particle as high performance catalyst.For example the Nano ST of the Nano center of the U.S., Japan all classifies the research of nanocatalyst as the focus development project, and some achievements in research or transform to the practical stage.The basis and the application study of nanocatalyst are carried out in the also organizational strength energetically of many scientific research institutions of China, institution of higher learning, and have obtained certain achievement.But, at present both at home and abroad the research of nanocatalyst is also mainly concentrated on the evaluation etc. of preparation, finishing, sign and the reactivity worth of nanocatalyst, the research that separates the aspect with product with the closely-related suspension nano catalyst of commercial Application then seldom.

In the liquid phase heterogeneous catalytic reaction, the use of catalyst often is divided into two kinds of forms: support type, floating type.Though the separation of loaded catalyst is reclaimed the problem ratio and is easier to solve, when tiny catalyst granules loaded on the carrier, its active sites can obviously reduce, and this will reduce activity of such catalysts inevitably.It is undisputable fact that the catalytic activity of suspended state catalyst is higher than loaded catalyst.But the use of suspended state catalyst will relate to the separation problem of catalyst and product inevitably.Particularly after the catalyst granules nanometer, use methods such as traditional flotation, gravitational settling, centrifugal sedimentation, cake filtration, in-depth filtration all can not effectively the suspension nano catalyst to be separated fully with liquid-phase product, add in addition to react under the harsh conditions such as high temperature, high pressure of being everlasting and carry out, what relate to often is organic or the corrosivity system, and this just makes nanocatalyst very difficult with separating of product.Nanocatalyst can not separate fully and will cause two problems with product: a large amount of losses of expensive nanocatalyst and nanocatalyst be to the influence of target product quality, and this also is the main cause that nanocatalyst so far can not large-scale industrial application.

Therefore, how effectively separating and reclaim nanocatalyst, is the key and problem anxious to be solved of efficiently using nanocatalyst and nanocatalyst large-scale industrial application veritably.

(three) summary of the invention

The catalyst membrane separation method that the purpose of this invention is to provide a kind of heterogeneous suspension nano catalysis reaction; it can thoroughly separate liquid phase material with the solid phase nanocatalyst of suspension from the material of heterogeneous suspension nano catalysis reaction; avoid catalyst particles to sneak in the product; guarantee product purity, solved the suspension nano catalyst and easily run off, be difficult to separate a difficult problem that reclaims and influence product purity.

The inventive method is made up of catalytic reaction and catalyst separation two parts, catalytic reaction adopts the fine catalyst of average grain diameter 1nm～100nm, has a kind of liquid phase material that is in the reactant at least, other reactant can be liquid phase or gas phase, reactant and nanocatalyst add reactor and are mixed into the heterogeneous suspension system, and process conditions are routinely reacted; The invention is characterized in that separation process and catalytic reaction process with catalyst are coupled in the same system, promptly it is sent into and pass through inorganic film tube continuously by the material in the direct continuous drawing reactor of pump, the average pore size of inoranic membrane is 2～200 nanometers, material is under the conveying of pump, continuously between reactor and inorganic film tube assembly, circulate, utilize the screening principle of inorganic separating film, the solid phase nanocatalyst is trapped in the film pipe and constantly circulates with recycle stock, in this process, liquid-phase product continuously sees through the inoranic membrane outflow system, and the catalyst suspension that does not see through continuously returns reactor, thereby realizes Separation of Solid and Liquid.

In the inventive method, catalytic reaction can be to adopt to react the intermittent mode that afterwards separates earlier with the film separation process, also can adopt the mode of carrying out continuously simultaneously.Batch (-type) is to carry out after material circulation separation process question response still internal reaction finishes.Suspension is continuous enrichment along with the separation of liquid phase, and the solid phase weight content reaches at 0.1～15% o'clock in recycle stream, and material is thick paste, and flowability obviously reduces, and causes pump to extract resistance when excessive, the separation process termination of pumping that finishes.Catalyst has been recovered in the reactor, participates in next catalytic reaction again; Continous way is that the separation process of catalyst and the charging of reactor are carried out simultaneously continuously, promptly carry out catalytic reaction to the reactor continuous feed on one side, extracting on one side the material film that circulates from still separates, continuous separated and collected liquid-phase product, simultaneously constantly isolated catalyst is returned reactor, continue to participate in catalytic reaction.This method is by regulating the mean residence time that film sees through the rate of outflow control material in reactor of liquid.Continuity method is applicable to generally and need growing quantity-produced occasion in one period that separation process stops with the end of catalytic process.

The said inoranic membrane of the inventive method can be selected pottery, metallic material film or their composite material film, for example can select for use by α-Al ₂O ₃For supporting the zirconia ceramics film of body.

In sum, the present invention will react with separating to be coupled in the same device and finish, adopt inorganic separating film high temperature resistant, high pressure resistant, corrosion-resistant, anti-organic system to reclaim nanocatalyst, by with the integrated nano catalysis reaction process of inoranic membrane, nanocatalyst is separated fully with product, with the recovery fully of assurance nanocatalyst and the purity of target product.The present invention has solved the difficult problem that nanocatalyst separates recovery in the heterogeneous suspension nano catalysis reaction effectively, and this efficient use and industrialization promotion to nanocatalyst has realistic meaning.

(four) description of drawings

Accompanying drawing is the catalyst film piece-rate system flow chart of heterogeneous suspension nano catalysis reaction of the present invention.

(five) specific embodiment

Batch (-type) catalyst inoranic membrane separation process embodiment below in conjunction with accompanying drawing technological process explanation heterogeneous suspension nano catalysis reaction.

As shown in drawings: 1 is source of the gas, can control the pressure of nano catalysis reaction by the pressure-reducing valve on the steel cylinder 1.Stirred tank 4 has automatic speed regulation temperature controller 5, and conduit 3 leads to the reactor bottom, so that the gas, liquid, solid three-phase fully contacts.2-2 is an exhaust-valve.Discharge nozzle 6 is at the bottommost of reactor 4.Product pump 7 is used for convey materials.8 is the inorganic separating film assembly, in this example, adopts by α-Al ₂O ₃For supporting the zirconia ceramics membrane module of body.The average pore size of used film is relevant with the required catalyst grain size that separates, and separating average grain diameter as need is that then can to adopt average pore size be the inoranic membrane of 50nm for the nanocatalyst of 20nm.Stop valve 2-7 is used to regulate the pressure of recoil steam.9 is the product jar, is used to collect liquid-phase product.

A certain proportion of raw material and nanocatalyst are added in the autoclave 4.Feed earlier 3 atmospheric unstripped gas, shut off valve 2-1, and open exhaust-valve 2-2, drain unstripped gas and air, the step 4 above repeating time.After treating that air displacement finishes, by regulating on the steel cylinder 1 pressure-reducing valve, the pressure in the autoclave 4 is kept within the specific limits, open automatic speed regulation temperature controller 5, regulate suitable temperature and rotating speed, heterogeneous suspension nano catalysis reaction is normally carried out in reactor 4.When the flowmeter P on the reactor 4 shows that gas flow is zero, illustrate that reaction finishes.After reaction finished, shut off valve 2-1 opened exhaust-valve 2-2, unnecessary gas in the reactor 4 of draining, and close this valve.Open valve 2-3, valve 2-4, valve 2-5, valve 2-6, the liquid phase material in the still and the mixture of solid phase nanocatalyst enter inorganic separating film assembly 8 by pipeline 6 and pump 7.By control valve 2-4, valve 2-5 and valve 2-6, inoranic membrane 8 is operated, under suitable operating pressure and cross-flow velocity so that cross-flow filtration can successfully carry out.After aforesaid operations was finished, system carried out the separation removal process of nanocatalyst automatically, and Partial Liquid Phase sees through permeable membrane and discharges and be collected into the product jar 9 from the film pipe outside, and the nanocatalyst tunicle of solid phase is held back and returned in the reactor with concentrate.Along with liquid-solid continuous separation, solid phase enrichment gradually in the recycle stream, when the solid content of nanocatalyst in the recycle stream reached 12% (weight), separation process was finished, at this moment, termination of pumping 7, shut off valve 2-3, valve 2-4, valve 2-5, valve 2-6 again.Solid phase nanocatalyst after concentrating has been got back in the autoclave 4, so that continue to use during secondary response down.In above-mentioned Separation of Solid and Liquid process, according to circumstances the instantaneous unlatching Pressure Steam Valve 2-7 in timing or not timing ground carries out the instantaneous high pressure recoil to membrane module, pollutes with phase shift films.

Claims (4)

1, the catalyst membrane separation method of heterogeneous suspension nano catalysis reaction, form by catalytic reaction and catalyst separation two parts, catalytic reaction adopts the fine catalyst of average grain diameter 1nm～100nm, has a kind of liquid phase material that is in the reactant at least, reactant and nanocatalyst add reactor and are mixed into the heterogeneous suspension system, and process conditions are routinely reacted; It is characterized in that the separation process and the catalytic reaction process of catalyst are coupled in the same system, it is sent into and pass through inorganic film tube continuously by the material in the direct continuous drawing reactor of pump, the average pore size of inoranic membrane is 2～10 nanometers, material is under the conveying of pump, continuously between reactor and inorganic film tube assembly, circulate, utilize the sieving actoion of inorganic separating film, the solid phase nanocatalyst is trapped in the film pipe and constantly circulates with recycle stock, in this process, liquid-phase product continuously sees through the inoranic membrane outflow system, and the catalyst suspension that does not see through continuously returns reactor, realizes Separation of Solid and Liquid.

2, the catalyst membrane separation method of heterogeneous suspension nano catalysis reaction according to claim 1, it is characterized in that catalytic reaction and film separation process are step, be to carry out after material circulation separation process question response still internal reaction finishes, recycle stock is continuous enrichment along with the separation of liquid phase, the solid phase weight content reaches termination of pumping in 0.1～15% o'clock in recycle stock, separation finishes, and the catalyst that returns reactor participates in next catalytic reaction again.

3, the catalyst membrane separation method of heterogeneous suspension nano catalysis reaction according to claim 1, the separation process and the nano catalysis reaction in the reactor that it is characterized in that catalyst carry out simultaneously continuously, promptly carry out catalytic reaction to the reactor continuous feed on one side, extracting on one side the material film that circulates from still separates, continuous separated and collected liquid-phase product, simultaneously constantly isolated catalyst is returned reactor, continue to participate in catalytic reaction.

4,, it is characterized in that said inoranic membrane is pottery, metal or its composite material film according to the catalyst membrane separation method of claim 1 or 2 or 3 described heterogeneous suspension nano catalysis reactions.