Plants solvents

Recovering and recycling organic compounds make possible some cost savings in the pollution control equipment. Savings may be in raw material costs, which are normally the most significant item of a chemical plant. Solvent recovery is best suited for applications dealing with expensive or easily... 

In a resin plant, solvents were directed from storage tanks to a blender by means of solvent charging manifold. Because of the poor panel layout and labeling of the charging manifold, a worker made connections that pumped solvent to blender 21A instead of 12A as directed by the instructions. An earlier error had left the valve open from the charging manifold to blender 21A and hence the misdirected solvent degraded a batch already in the blender (this example will be analyzed in more detail in Chapter 7). 

Feather, A. Bouwer, W. Swarts, A. Nagel, V. Pilot-plant solvent extraction of cobalt and nickel for Avmin s Nkomati project. International Solvent Extraction Conference, Cape Town, South Africa, Mar. 17-21, 2002, 946-951. 

The cost of this system is very site specific. It is dependent on many factors, including hydrogeology, geology, and water chemistry. There is currently only one example of the actual costs for the use of this technology. In the treatment performed at a former AT T plant, solvent was removed at a cost of 132/lb. The total cost of operations at the site was 3.44 million (D14286J, p. 7). 

Organophosphorus types Plants Solvent extraction from freeze-dried sample GC with ECD - [70]... 

Pyridate and its metabolite Plants Solvent extraction HPLC and MS-MS - [75,76]... 

For large-scale purification, the Purex Plant solvent extraction bank was used first to separate Am-Cm from the Pu in the target element and then to separate Am-Cm from the A1 in the target element. In each of the four campaigns that have been processed, the Pu in the target element has been purified by the normal Purex flowsheet. In each case, the Am-Cm fraction was initially rejected to the waste (1AW) stream. 

Capital cost. In the early stages of a new process the throughput of solvent may be very much less than the design capacity of the plant. Solvent recovery is typical of the activities that can be contracted out until the equipment required can be justified on a rate of return basis. 

The ideal would be to operate as close to the miscibility curve as possible. However, this curve shifts depending on the Basestock. Wax molecules in heavier grades come out of solution earlier and this has the effect of shifting the miscibility curve to the left. Plants equipped with solvent splitters to separate the MEK from the MIBK or Toluene after it has been recovered in the DWO and Wax recovery sections may blend to the optimum solvent composition for each Basestock. Manufacturers without the capability to change solvent composition will set the plant solvent composition based on... 

The conventional separation scheme is to leach the primary ore or concentrates and use the resulting solution containing the rare earth mixtures as the feedstock to the solvent extraction plant. Solvent extraction of the rare earth mixture in the leached solution separates them into bulk concentrates of light (La, Ce, Pr, Nd, etc.), middle (Sm, Eu, Gd, etc.) and heavy (Tb, Dy, Ho, Er, Tm, Yb, Lu, Y) rare earths. A typical solvent extraction of rare earths in a HCl medium is with di-2-ethylhexyl phosphoric acid, HDEHP, in a kerosene diluent. The individual rare earth is separated from the bulk light, middle, and heavy rare earth solution mixtures by additional individual rare earth solvent extraction streams. The number of stages for solvent extraction cascades or batteries increases with the increase in purity of each individual rare earth produced. Further purification... 

Stewart, E. J., and Lanning, R. A., 1991, A Systematic Technical Approach To Reducing Amine Plant Solvent Losses, Laurance Reid Gas Conditioning Conference Proceedings, University of Oklahoma, Norman, OK. 

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