Technical Features and Application of Chemical Separation Equipment
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Keywords: Technical Features and Application of Chemical Separation Equipment
Chemical separation equipment technology has the following characteristics:
(1) The diversity of chemical separation technologies
Due to the wide range of applications of chemical separation technology, the diversity of separation technologies is determined. According to the mechanism, they can be roughly divided into 5 categories: 1 new phase is generated for separation (eg, distillation, crystallization); 2 is added to the new phase for separation (eg, extraction, absorption); 3 is separated with a separator (eg, membrane separation); 4 Separation with solid reagents (such as adsorption, ion exchange); 5 separation using external force fields and gradients (such as centrifugal extraction and electrophoresis, etc.), their characteristics and design methods are different.
Keller summarized some common separation techniques and application maturity diagrams in 1987. Distillation, extraction, absorption, crystallization, etc. are still the most widely used separation technologies. Although the concept of liquid membrane separation is clever, it is technically limited, and it has only been applied in drug release.
(2) The complexity of chemical separation technology
The importance and diversity of chemical separation technology determine its complexity. Even for mature technologies such as distillation and extraction, the design of large multi-component systems is still a difficult task. The problem is the lack of basic characteristics data and reliable design methods for large towers. For high-temperature, high-pressure, multi-component, and strong non-ideal systems, it is difficult to accurately calculate equilibrium data and molecular diffusion coefficients, and even physical properties such as interfacial tension viscosity are difficult to obtain.
Coupled separation techniques such as catalysts and reactive extractions have even less basic data. The main difficulty in the enlargement of large-scale tower design is that the two-phase flow and mass transfer characteristics in the tower are very complex and the digital model is not yet perfect. Although the balance-level model that has been used for more than a hundred years is simple and intuitive, the disadvantages of the multi-component separation process are obvious. Non-equilibrium models are known to have the advantage of potentially creating a new era of plate separation equipment design and simulation, but lack of mass transfer coefficient experimental data and model parameters are too many, making it difficult for engineering applications. The software that has been developed is powerful and has been used in engineering design, but engineering experience and pilot test are still indispensable.
(3) Prospectiveness of separation technology
With the development of basic industries and high technologies such as energy, resources, environment, and new materials, classification technologies are facing new opportunities and challenges. The separation process in the petrochemical sector requires further energy conservation and consumption reduction, making full use of energy and resources. The pace of large-scale production plants is accelerating, and energy consumption and costs are continuously decreasing. In biopharmaceutical engineering, with the development of genetic engineering and cell engineering, biopharmaceuticals have developed rapidly. Supercritical extraction using CO2 as a solvent has the advantages of non-polluting products and high selectivity. Chromatographic separation, electrophoretic separation and other methods have been successfully applied to production and laboratory research because of their high efficiency, normal temperature and pressure characteristics. With the strengthening of environmental awareness, waste disposal has attracted attention. From the perspective of industrial ecology, wastes discharged from many processes are no longer useless, but are not fully utilized. Three-waste treatment is a new challenge to separation technology.
(4) Particularity of separation technology
Competition promotes the strengthening of the separation process. The strengthening of the separation process includes two aspects of the new device and new process method. Any new chemical separation technology that can make the equipment smaller, energy efficient, and conducive to sustainable development belongs to the strengthening of the separation process. This is one of the important trends in the development of chemical separation technology.
Coupled separation techniques are of interest. Catalyst coupling, membrane distillation, adsorption distillation, reaction extraction, complex adsorption, reverse micelles, membrane extraction, fermentation extraction, chemical adsorption, and electrophoretic extraction have achieved significant development and industrialization. Coupled separation techniques may solve many tasks that traditional separations have difficulty performing. Electrokinetic coupling chromatography can efficiently separate vitamins.
Information technology has promoted the development of separation technologies. Separation science and technology have the characteristics of multi-discipline, and the combination of information technology and traditional chemical methods has accelerated the progress of separation technology.