Purification Costs Range

One will notice the specific conditions of the example given in Fig. 7-3  

Ideal Case. If, in the previous example, the two products alone were present in the crude and had to be separated, cycle time would be reduced from 9 to 6 min, injected quantities would be increased up to lOOg per injection and yield would be as high as 95%. Production rate would then reach 6.8 tonnes per year on a 200 mm ID column. All other expenses being unchanged (investment, labor, energy, etc.), the purification cost would then be about US 92 per kg. 

Worst Case. One of the worst possible cases (from an economics point of view) has been studied too. To make comparison easier with the above case, figures have been projected for a 200 mm ID column. 

A racemic mixture of enantiomers has to be separated in two fractions of 99% purity. Due to the low capacity of the packing material used, very small quantities can 

Packing price is difficult to evaluate since it is not commercially available we evaluate it to twice the price of the above example. Other expenses are identical. 

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Proteins such as antibodies, enzymes, hormones and vaccine antigens can be used to prevent, diagnose and treat a range of diseases. Such molecules are therefore of paramount importance in health and medicine. Historically, many of these proteins have been isolated from human or animal sources. However, the low quantities present in such source material coupled with safety risks and high purification costs have limited the availability of protein therapeutics and vaccines for many types of disease. 

Capital cost range from about US 0.98/annual kg of product to US 1.41/annual kg of product for the processes with purification, but only US 0.39/annual kg for simple glycolysis. 

The treatment costs for the GHEA Associates process depend on the soil matrix, properties, chemical composition of the contaminants, and other site-specific factors. The commercial-scale, integrated process, consists of the extraction and wash liquor purification steps. The estimated costs for the process range from 50 to 80 per ton of soil treated. Other separation processes have estimated treatment costs ranging from 90 to 200 per ton (D13377H, pp. 793, 799). 

Organic solvents that are soluble in water can have large values when stripped out, but because of subsequent purification costs and the large range of possible concentrations in the waste water, no helpful indication of the possible economics can be made. It will be clear when considering the costs of stripping that it is possible for the value of the recovered solvent to pay for the removal of pollution from the effluent. 

Selectivity. Solvent selectivity is intimately linked to the purity of the recovered extract, and obtaining a purer extract can reduce the number and cost of subsequent separation and purification operations. In aqueous extractions pH gives only limited control over selectivity greater control can be exercised using organic solvents. Use of mixed solvents, for example short-chain alcohols admixed with water to give a wide range of compositions, can be beneficial in this respect (6). 

The reductive carbonylation has an advantage of low feedstock cost. A wide range of homogenous metal complexes have been tested for both reactions (1-16). The major drawback of the use of metal complex catalysts is the difficulty of catalyst recovery and purification of the reaction products (12). In addition, the gaseous reactants have to be dissolved in the alcohol/amine mixture in order to have an access to the catalyst. The reaction is limited by the solubility of the gaseous CO and 02 reactants in the liquid alcohol reactant (17). 

Costs of treatment techniques vary strongly. The costs not only depend on the type of treatment process but also on the concentrations of the pollutants to be removed, and the required removal efficiency of the pollutants. Most treatment steps have been developed for the treatment of wastewater at a temperature above zero degree Celsius as lower limit and somewhat above ambient temperature as upper limit. An exception is anaerobic treatment, which is often also applied at temperatures of about 60°C. In general little or no experience is available with the purification of wastewater at temperatures above 50° C. Experimental research is necessary to assess the feasibility of a treatment step in that temperature range. 

Some typical commercial biotechnology products are citric acid, semi-synthetic penicillins and cephalosporins, and vitamin B12. World production volumes and bulk prices show a considerable range of values. Prices tend to be inversely proportional to the amount of product sold, that is, the scale of production, and to the concentration at which it can be produced in the bioreactor. The importance of the concentration at which each product is produced in determining the cost of purification and isolation, and thus the... 

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