Recovery and purification systems

The carbon black (soot) produced in the partial combustion and electrical discharge processes is of rather small particle si2e and contains substantial amounts of higher (mostly aromatic) hydrocarbons which may render it hydrophobic, sticky, and difficult to remove by filtration. Electrostatic units, combined with water scmbbers, moving coke beds, and bag filters, are used for the removal of soot. The recovery is illustrated by the BASF separation and purification system (23). The bulk of the carbon in the reactor effluent is removed by a water scmbber (quencher). Residual carbon clean-up is by electrostatic filtering in the case of methane feedstock, and by coke particles if the feed is naphtha. Carbon in the quench water is concentrated by flotation, then burned. 

Recovery and Purification. AH processes for the recovery and refining of maleic anhydride must deal with the efficient separation of maleic anhydride from the large amount of water produced in the reaction process. Recovery systems can be separated into two general categories aqueous- and nonaqueous-based absorption systems. Solvent-based systems have a higher recovery of maleic anhydride and are more energy efficient than water-based systems. 

Electrolyte. The ideal electrolyte, ie, the fluid part of the cell, for organic synthesis would give high solubiHty to the organic, possess good conductivity, have low cost, contain easy recovery and purification, and be noncorrosive. Quaternary ammonium salts provide many of the above criteria ia aqueous systems. A coacise compilation of solveats and salts used ia electroorganic chemistry is available (40). 

Gouthro, R.P. and Vaz, L., Recovery and purification of nickel salts and chromic acid using the RECOFLO system, Eco-Tec, Technical Paper 145, presented at the Metal Finisher s Association of India, Mumbai, India, September 1999. Available at http //www.eco-tec.com/main/electroplate.htm. 

In this review, we focus on the use of plant tissue culture to produce foreign proteins that have direct commercial or medical applications. The development of large-scale plant tissue culture systems for the production of biopharmaceutical proteins requires efficient, high-level expression of stable, biologically active products. To minimize the cost of protein recovery and purification, it is preferable that the expression system releases the product in a form that can be harvested from the culture medium. In addition, the relevant bioprocessing issues associated with bioreactor culture of plant cells and tissues must be addressed. 

The inherent complexity and chemical diversity of biomass predicts the recovery and purification of proteins from such a source will be an extremely challenging task. We have been studying this problem with a long-term research goal of identifying and establishing experimental conditions which may be applicable for protein purification from all biomass systems. 

Most of the variables of these processes were monitored, material and energy balances were determined, pathway analysis was performed, regulation of growth and product formation was investigated, recovery and purification of the products were established and the systems were modelled. 

Special applications The environmental control and life support system on a spacecraft maintains a safe and comfortable environment, in which the crew can live and work, by supplying oxygen and water and by removing carbon dioxide, water vapor, and trace contaminants from cabin air. It is apparent that the processes aimed at the recycling of air and water are vital for supporting life in the cabin. These recycling processes include separation and reduction of carbon dioxide, removal of trace gas-phase contaminants, recovery and purification of humidity condensate, purification and polishing of wastewater streams, and are performed totally or in part by adsorption equipment (Dabrowski, 2001). ... 

Fermentation is typically conducted in dilute suspension culture. The low concentration in such systems limits reaction efficiency, and the presence of particulate and colloidal solids poses problems for product recovery and purification. By circulating the fermentation broth through an ultrafiltration system, it is possible to recover product continuously as they are generated while minimizing loss of enzyme or cells and keeping product concentration in the bioreactor below the self-inhibition level for the biocatalyst. This process is referred to as perfusion. As the ultrafiltration unit is part of the production process, the entire system is often considered a membrane reactor. 

The recovery and purification of a bioproduct is carried out to isolate it from its production system (cell culture, plant or animal tissues), and to obtain the required purity and formulation. Before establishing a strategy for recovery and purification, it is essential to collect all available information related to the protein and to the medium where it is found. Usually, not only the theoretical information, but also preliminary experiments are needed. It is also noted that the feasibility of a process on a laboratory scale does not guarantee its feasibility on an industrial scale. 

Richard Blackmore (Baxter Hemoglobin Therapeutics) presented work on a fully automated small-scale model of a pilot-scale purification process for recombinant hemoglobin. This paper employed the scaled-down system to examine how the system will respond to feedstock changes. Interestingly, the operating temperature of the post cell lysis heat step was found to influence both the Q column yield and final product quality in an unexpected manner. The use of a fully automated, unattended, multistep purification system offers distinct advantages with respect to speed and efficiency in purification, as well as an analytical tool to understand interactions within the recovery and purification process. 

The recovery and purification of furfural from aqueous effluents by high-pressure extraction is of technical interest. Alternative extraction tests with supercritical carbon dioxide were carried out [1,2]. Further research [3-5] led to the conclusion that carbon dioxide is a good alternative to organic solvents with comparable and even better extraction results. For all these experiments the system furfural - water without acetic acid was used. 

Mattiasson, B. Kaul, R. Use of aqueous two phase systems for recovery and purification in biotechnology. In Separation, Recovery and Purification in Biotechnology, Recent Advances and Mathematical Modelling Asenjo, J.A., Hong, J., Eds. American Chemical Society Washington, DC, 1986 78-92. 

Szlag DC, Giuhano A, and Snyder SM, A low-cost aqueous two phase system for affinity extraction. In Hamel JFP, Hunter JB, and Sikdar SK, eds. Doivnstream Processing and Bioseparation, Recovery and Purification of Biological Products. ACS Symp. Ser. 419, ACS Press, Washington, 1990 pp. 71-86. 

Distillation is the baseline process for the chemical process industry, with 40,000 columns in operation in the US, handling 90-95% of all separations for product recovery and purification. The capital invested in distillation systems in the US alone is at least 8 billion [1]. 

Use of Aqueous Two-Phase Systems for Recovery and Purification in Biotechnology... 

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