Unit chemical operation

Another step in laboratory automation to be achieved is the conversion of standard chemical procedures such as titrations or thermal gravimetric analysis, into unit laboratory operations. A procedure could then be selected from these laboratory operations by an expert system and translated by the system to produce a set of iastmctions for a robot. The robot should be able to obey specific iastmctions, such as taking a specified sample aliquot and titrating it using a specified reagent. 

The Texaco gasifier and a similar unit developed by The Dow Chemical Company are pressurized entrained gasifiers. At the top pulverized coal is mixed with reaction gas and is blown down into the gasifier. The reaction products leave from the side, and ash is blown down to a water pool where it is quenched. These units have operated at an Eastman Kodak facUity in Kingsport, Tennessee and at the Coolwater power station in California for an integrated combined cycle power plant. 

The unit is operated in the following way The reactants (see Table 5 for mixed acid compn) are introduced thru inlets (4) and (5), mixed with the help of turbine (8) and circulated thru pipe system (1), (3) and (6), chemical reaction and physical exchange being simultaneously effected. They are continuously transported to the separator in the form of an emulsion. ... 

In the multi-purpose batch chemical plant context, continuous utilization of multiple unit operations on-plant is extremely difficult and rarely achieved. In addition, for many batch chemical operations, it is not uncommon for there to be long reaction times, extended periods of time at reflux, extended filtration times, drying times, and so on. Each... 

Operating costs can be estimated based on statistical analysis of operating costs in existing plants. Costs of waste disposal can be evaluated in the same way as costs for any chemical process since procedures for disposal include, in fact, unit chemical processes and operations. Costs of utilities and maintenance are best assessed based on the company data banks. Typical utility figures per m capacity of reactors in MPPs are 800-1100 kg steam/h, 60-80 kW power, and 7,000-8,000 kJ/h refrigeration capacity. 

Liston, Donald M. "Safety Aspects of Site Selection, Plant Layout, and Unit Plot Planning." In H. H. Fawcett and W. S. Wood (eds.), Safety and Accident Prevention in Chemical Operations, pp. 35-59. New York Wiley, 1982. 

CDHydro [Catalytic distillation hydrogenation] A process for hydrogenating diolefins in butylene feedstocks. It combines hydrogenation with fractional distillation. Developed by CDTECH, a partnership between Chemical Research Licensing Company and ABB Lummus Crest. The first plant was built at Shell s Norco, LA, site in 1994. Ten units were operating in 1997. 

COPE [Claus Oxygen-based Process Expansion] A modification of the Claus process, which improves the recovery of the sulfur. The combustion stage uses oxygen instead of air. Introduced in 1985 and now licensed by Air Products Chemicals and Goar, Allison Associates. In 1990, six units were operating in the United States. 

Drizo A variation of the glycol process for removing water vapor from natural gas, in which the water is removed from the glycol by stripping with a hydrocarbon solvent, typically a mixture of pentanes and heavier aliphatic hydrocarbons. The process also removes aromatic hydrocarbons. Last traces of water are removed from the triethylene glycol by stripping with toluene in a separate, closed loop. Invented in 1966 by J. C. Arnold, R. L. Pearce, and H. G. Scholten at the Dow Chemical Company. Twenty units were operating in 1990. U.S. Patent 3,349,544. 

Econamine A process for removing acid gases from natural gas by selective absorption in diglycolamine (also called [2-(2-aminoethoxy) ethanol], and DGA). Developed by the Fluor Corporation, the El Paso Natural Gas Company, and the Jefferson Chemical Company and widely used. Later versions, developed by Fluor Daniel International, include the Fluor Daniel Econamine and the Econamine FG processes. More than 30 units were operating in 1996. See also Aromex. 

Pyrotol A process for making benzene from pyrolysis gasoline by hydrocracking. Developed by Houdry Process and Chemical Company. In 1987, 13 units were operating worldwide. 

Chemical Corporation in the 1960s and now offered for license by Union Carbide Chemicals Plastics Company. Over 50 units were operating in 1996. See also SOLINOX. 

Developed and jointly licensed by Shell Oil Company and Dow Chemical Company. Introduced in 1987 by 1996, more than 20 units were operating and 10 were in design or under construction. The first application in coke making, in a plant near Pittsburgh, PA, was announced in 1996. 

The generation of the (2S,3R) diol 4 from 1 is the consequence of a multlenzymic process involving two distinct chemical operations (2) (i) Addition of a unit equivalent to acetaldehyde onto thesiface of the carbonyl carbon atom of the unsaturated aldehyde to form a (3R) -hydroxyketone, in an acyloin of type condensation, and (ii) reduction of the latter intermediate on the face of the carbonyl group to give rise to the diol actually isolated (Eq. 2). 

The liquid waste must be pumpable. Contaminants must be in particulate form, or it must be possible to precipitate dissolved contaminants such as metal ions chemically. Separation must provide an advantage. The EPOC microfiltration technology does not remove volatile organic compounds (VOCs) from liquids. The unit s operation is affected by cold weather. 

Geigy started production of simazine in 1956 in Schweizerhalle, near Basel, Switzerland 2 years later, atrazine also was produced. Use of triazines for weed control to improve crop yields grew quickly, and a production facility was installed at McIntosh, Alabama in 1959. Smaller production units were operated in Mexico, Brazil, and Australia, and important development work by Geigy led to improved production processes. In 1970 a continuous process production unit was built by Geigy Agricultural Chemicals in the United States. 

The dynamic simulation file prepared in Aspen Plus is exported in Aspen Dynamics [10]. We select the flow-driven simulation mode. Aspen Dynamics files have already implemented the basic control loops for levels and pressures. Units with fast dynamics, such as the evaporator or some heat exchangers, may be handled as steady state. The implementation of control loops for the key operational units, chemical reactor and distillation columns, take into account some specific issues from the plantwide perspective, which are developed in detail in Luyben et al. [8]. 

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