Evaporation/distillation

Drying refers to the removal of water from a substance through a whole range of processes, including distillation, evaporation, and even physical separations such as with centrifuges. Here, consideration is restricted to the removal of moisture from solids and liquids into a gas stream (usually air) by heat, namely, thermal drying. Some of the types of equipment for removal of water also can be used for removal of organic liquids from solids. 

Like distillation, evaporation can be represented as a box. This again assumes that any heating or cooling required by the feed and concentrate will be included with the other process streams in the grand composite curve. 

Vaporization and diffusion of flammable or toxic liquids or gases is a primary consideration with distillation, evaporation, extraction, and absorption operations. The basic principle of safety for tliese unit operations is contaimnent of the materials witliin the system. These operations should be conducted outdoors whenever possible. In tliis way, any accidental release of flammable or... 

Although absorptiometric detection via preceding colour reactions is still mainly used, CFA has shown increasing versatility not only in detection choice but also in sample pre-treatment, such as (partial) dialysis, distillation, evaporation to dryness, digestion, long-term incubation and coated-tube separation a review was published by Snyder83. 

Methods have been described for the determination of total fatty acids in raw sewage sludge. These methods [30-32] require a concentration steps such as simple distillation, steam distillation, evaporation, or extraction [33-35] which resulted in great losses of the volatile matter [36, 37],... 

In the distillation, evaporated gas flows to the condensation tube with circular motion to remove centrifiigally large particles formed when bubbles on the water surface were broken. 

An essential step in industrial solvent extraction is the regeneration of the extractant. This can be done in many ways, e.g., by distillation, evaporation, or stripping (back-extraction). While distillation and evaporation do not discriminate between solutes (the diluent is simply removed by heating), stripping, by careful choice of strip solution and conditions, can be made highly selective. Alternatively, aU the solutes can be stripped and then subjected to a selective extraction by changing the extractant examples of both types of process will be found in Chapter 13. The possibilities are many, and it may be worthwhile to explore new paths. 

Essence oil and aqueous essence (sometimes called aqueous aroma) are both formed from the condensate from steam distillation/evaporation of citrus juices. These products consist of volatile juice compounds and do not contain non-volatile pigments. 

Batch Distillation Evaporation and Condensation Continuous Distillation Fractionation Rectification Reflux Distillation Vacuum Distillation Steam Distillation Azeotropic Extractive Distillation Destructive Distillation Molecular Distillation Distillation by Compression and Sublimation)... 

The solvents were then passed over anhydrous sodium sulfate to remove residual water and concentrated to 10 mL by Vigneux distillation evaporation and to 3 mL by evaporation under nitrogen. 

The component C in the separated extrael from the stage eonlaet shown in Figure I may he separated from the solvent B by distillation, evaporation, or other means, allowing solvent B to be reused for further extraction. Alternatively, die extract can be subjected lo back-extraction (stripping) with solvent A under different conditions, eg. a different temperature again, the stripped solvent B can be reused for further extraction. Solvent recovery is an important factor in the economics of industrial extraction processes... 

Safety and product stability issues associated with the distillation/evaporation process are discussed in Chapter 4. 

In distillation, evaporation occurs first. This means that when the boiling liquid reached 212° F., the boiling point of water, the molecules of water jumped off the surface in the form of invisible water vapor. When these molecules reached the ice-cold jar, their temperature quickly went down, and they changed back to liquid water. All the molecules of sodium chloride, sucrose, and copper sulfate remained in the flask. Each of these substances evaporates at a different temperature, and all of their evaporating temperatures are much higher than that of water. This makes distillation an easy way to separate solid contaminants from water. Unfortunately, the process would be too slow and too expensive to use in large cities, where enormous quantities of purified water are needed. 

The reactor effluent usually contains a mixture of reactants and products. It is fed into a separation section where the products are separated by some means from the reactants. Because of their economic value, reactants are recycled back to upstream units toward the reactor. The products are transported directly to customers, are fed into storage tanks, or are sent to other units for further processing. The separation section uses one or more of the fundamental unit operations distillation, evaporation, filtration, crystallization, liquid-liquid extraction, adsorption, absorption, pressure-swing adsorption, etc. In this book we typically use distillation as the separation method because of its widespread use and our considerable experience with it. Everyone is a victim of his or her experience. Our backgrounds are in petroleum processing... 

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