Process design chemical solvent processes

SIKICH Emergency Management Planning Handbook SMALLWOOD Solvent Recovery Handbook SMITH Chemical Process Design... 

Recovery of the solvent, sometimes by chemical means but more often by distillation, is almost always required, and the recoveiy system ordinarily is considered an integral part of the absorption-system process design. A more efficient solvent-stripping operation normally will result in a less costly absorber because of a smaller concentration of residual dissolved solute in the regenerated solvent however, this may increase the overall cost of solvent recoveiy. A more detailed discussion of these and other economic considerations is presented later in this section. 

These solvent-free conditions are included in the twelve principles of Green Chemistry [25], and facilitate the design of sustainable processes for the chemical industry. 

Hostrup, M., Harper, P. M., Gani, R., 1999, Design of environmentally benign processes Integration of solvent design and separation process synthesis, Computers and Chemical Engineering, 23(1999) 1395-1414. 

Solvents play an important role in organic synthesis. Choice of solvent is important in improving and deciding the chemical process. Selection of solvents should be such that it has minimal effect on the environment. Today chemists are interested in designing solvents which does not pose any risk to human health and the environment. The reason why solvents are of great environmental concern is that... 

Different balance between intermolecular forces can be accessible via partition coefficients measured in solvents systems other than the traditional 1-octanol/water. Therefore there was a growing interest in the partition processes in several solvent/ water systems [64, 65] and in particular the critical quartet of solvents which was designed to merge the main information about a solute concerning its partition and transport. Only a few studies have been performed to characterize the lipophilicity profile of new chemical entities in different solvent/water systems and consequently the number of methods attempting to model such partitioning systems is limited. 

The benefits from tuning the solvent system can be tremendous. Again, remarkable opportunities exist for the fruitful exploitation of the special properties of supercritical and near-critical fluids as solvents for chemical reactions. Solution properties may be tuned, with thermodynamic conditions or cosolvents, to modify rates, yields, and selectivities, and supercritical fluids offer greatly enhanced mass transfer for heterogeneous reactions. Also, both supercritical fluids and near-critical water can often replace environmentally undesirable solvents or catalysts, or avoid undesirable byproducts. Furthermore, rational design of solvent systems can also modify reactions to facilitate process separations (Eckert and Chandler, 1998). 

Pollution Prevention, Green Chemistry, and die Design of Safer Chemicals Solvent Replacement For Green Processing Solvents—Molecular Trees For Green Chemistry... 

The lack of satisfactory solvent recovery methods prior to 1930 prevented the use of selective solvents more suitable for lubricating oils. The major part of any solvent extraction plant is its complex solvent recovery system. Chemical engineering s contributions to distillation theory and process design resulted in the development of efficient solvent recovery techniques. In 1933, as illustrated by Figure 3, large commercial plants were... 

Good engineering prachce is to design chemical processes with an emphasis on recovering and reusing spent solvents [8]. However, not aU solvents will be recovered, and these will eventually need to be disposed. When disposing of solvent waste, there are several factors which must be considered to determine the appropriate waste heatment or disposal method. Some of these factors include the cost of disposal methods, overall toxicity of the waste, and environmental impact in the case of accidental and intenhonal releases. 

Another important area of chemical engineering applications is in the selection of solvents, co-solvents, or entrainers—generally summarized as solvents—in the early phase of a process design, development, or optimization project. For such tasks, beyond the fixed essential starting materials and products of the process, a large number of compounds has to be considered as potential... 

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