Thin film evaporation: film wiped film evaporator evaporator is generally scraper, can be in high viscosity material form a thin film evaporator in evaporation, accelerate the evaporation rate; Form a thin film by mechanical force, and in the process of evaporation scraper constantly rotating, the thickness of the membrane must be uniform. Scraper and evaporator wall between 0.5 ~ 1 mm clearance requirements, therefore, the evaporator cylinder machining precision demand is higher, scraper is consumable, in use process will continue to wear, wall gap more than 1 mm, treatment effect is not ideal, if the film evaporator for regeneration of waste lubricating oil, due to long-term exposure to the material, agglomerate, scraper town can form solid yi also recovered oil color was yellow red, scraper also needs regular cleaning and maintenance, replacement cost is too high. So thin film evaporator cbd crystallization equipment is not suitable for high viscosity of lubricating oil, thin film evaporation is suitable for low viscosity fluid, such as plant essential oil, etc. Vacuum distillation, the boiling point of liquid, it is to point to its saturation vapor pressure is equal to the temperature at which the outside pressure, so the liquid boiling point is changing along with the change of outside pressure, if by means of vacuum pump to reduce the internal pressure of the system and can reduce the boiling point of liquid, which is the theory basis of vacuum distillation operation. According to this principle, under the high vacuum, used oil can be fully distillation, vacuum distillation technology in the world, have been used for many years, molecular distillation and more stable, more suitable for processing waste engine oil, the investment of smaller and more mature, simple and convenient operation, simple maintenance. Is the regeneration process, including distillation, production to meet the requirements of natural oil base oil regeneration of base oil, modulation of low, medium and high-grade products, quality and production of oil from the natural oil. Reactive distillation (ReactiveDistillation) process, completely changed for a long time people the traditional understanding of reaction and separation process, it makes the physical process of chemical reaction and distillation separation together, is a new kind of special distillation process is accompanied by a chemical reaction.
Hand in hand with the reaction with distillation method to isolate the product process. Is to improve the efficiency of separation and a kind of combined reaction with distillation separation operation; Also can be in order to improve the reaction conversion rate and with the help of the distillation separation means a reaction process. For reversible reaction, when the volatility of a product is greater than the reactants, the steam from the liquid phase, if the product can destroy the balance of the original, the reaction to the direction of the products, thus can improve the one-way conversion rate, to a certain extent, the reversible reaction is irreversible reaction. Application is very wide, such as esterification, ester exchange, saponification, amination, hydrolysis, isomerization, alkylation, halide, dehydration, acetylation and nitration reaction, such as specific reactions, for example, see the table below: reaction distillation is only applicable to reaction process and reaction distillation separation of components of chemical reactions that can be performed under the condition of the same temperature. If the reaction components between persistence boiling phenomenon, or a very close to the boiling point of reactant and product, reaction rectification technology is not applicable. Business has reached a scale or conducted laboratory research on the industry of important reaction rectification process mainly includes the following types:
1, alkylation
Ethylene and benzene alkylation RD tower is made up of two parts, the upper filled within a specially designed strapping package Y type molecular sieve, the lower column plate installation, ethylene feed from bottom of catalyst layer, benzene from reflux drum tower, the characteristics of the process is the reaction temperature is conditioned by the saturation point temperature, avoid the generation of hot reaction zone, improve decarboxylation after extraction the service life of catalyst, by-products two ethylene-propylene three isopropyl benzene and benzene return RD tower, olefin transfer reaction with benzene to generate more isopropyl benzene, eliminate the cycle of a large amount of benzene, the heat used efficiently. 50% of energy compared with the traditional process, the process of RD, investment by 25%. But the activity and selectivity of catalyst is large, so must develop a suitable catalyst.
2, composite process
The reaction rectification technology can make the olefin molecule selectively composite, because the precision of temperature control and wide distribution will reduce the ideal product of dimer, trimer, or the formation of polymer, butene composite reaction rectification process has industrial permission.
3, olefin selective hydrogenation
It has been proved that the reaction distillation can make do not need to choose the hydrogenation of olefins impurities, lose its chemical activity, or is not conducive to the rectification separation to remove. At present, the applicable reaction distillation technology are: butadiene, pentadiene and diallyl selective hydrogenation.
4, ester transfer
Some chemical reaction used by acid is corrosive. In order to avoid acid corrosion, can be in the form of ester into acid. Methyl formate decomposition, for example, may generate formic acid and methanol, and formic acid once formed was balanced reaction consume, so to avoid the corrosion of formic acid.
5, oxidative dehydrogenation
If there is a suitable catalyst, can produce isobutene oxidation of isobutane dehydrogenation.
6, etherification reaction
Methyl tert-butyl ether (MTBE) is a product of technology RD industrial success, this process compared with the traditional process has no external circulation and cooling reactor; Through an effective removal catalyst poison, prolong the service life of catalyst; Make full use of the reaction gives off heat, high conversion rate of reactants and high product purity, etc.
7, esterification and hydrolysis
Synthesis and hydrolysis of methyl acetate (MeOAc) catalytic distillation technology is a hot topic of research and development at home and abroad in recent years, due to the esterification of acetic acid and methanol limited by chemical equilibrium, and have multiple azeotrope in the system, so the traditional process is very complex, multiple reactor and distillation.
8, other reaction
Other possible reaction distillation method of areas including: oxidation, electrochemical, syngas reactions, from alcohol and ammonia selectively producing amine, carboxyl reaction. In addition, with the introduction of the third component entrainer (reaction), reaction distillation technique can be used to separate a mixture of boiling point is very close to. Such as: separation of C1 aromatics, chloroaniline. A mixture of methyl pyridine equivalent points isomer.
