Chemical processes commercialization

The metal is isolated commercially by a complex chemical process, the final stage of which is the hydrogen reduction of ammonium ruthenium chloride, which yields a powder. The powder is consolidated by powder metallurgy techniques or by argon-arc welding. 

The scientific basis of extractive metallurgy is inorganic physical chemistry, mainly chemical thermodynamics and kinetics (see Thermodynamic properties). Metallurgical engineering reties on basic chemical engineering science, material and energy balances, and heat and mass transport. Metallurgical systems, however, are often complex. Scale-up from the bench to the commercial plant is more difficult than for other chemical processes. 

In many chemical processes the catalyst particle size is important. The smaller the aluminum chloride particles, the faster it dissolves in reaction solvents. Particle-size distribution is controlled in the manufacturer s screening process. Typical properties of a commercial powder are shown in Table 2. 

Sulfamic acid has a unique combination of properties that makes it particularly well suited for scale removal and chemical cleaning operations, the main commercial appHcations. Sulfamic acid is also used in sulfation reactions, pH adjustment, preparation of synthetic sweeteners (qv), and a variety of chemical processing appHcations. Salts of sulfamic acid are used in electroplating (qv) and electroforrning operations as well as for manufacturing flame retardants (qv) and weed and hnish killers (see Herbicides). 

Although benzene prices have escalated in recent years, a concurrent need for butenes for use in alkylates for motor fuel has also increased and butane prices have also escalated. As a result, a search for alternative feedstocks began and Amoco Chemical Co. commercialized a process in 1977 to produce maleic anhydride from butane. A plant in JoHet came on-stream in 1977 with a capacity of 27,000 t/yr (135,136). No new plants have been built in the United States based on butenes since the commercialization of butane to maleic anhydride technology. In Europe and particularly in Japan, however, where butane is in short supply and needs for butenes as alkylation feed are also much less, butenes may become the dominant feedstock (see Maleic anhydride). 

By-Product Calcium Sulfate. There are many iadustrial chemical processes that produce by-product calcium sulfate in one of its forms. Whereas the most common is the neutralization of spent sulfuric acid, many of those processes do not produce a commercially useful by-product because of contaminants, particle size, or volume produced. There are, however, six chemical processes that do produce sufficient volume to have potential commercial value. Each is named after its chemical process. 

Classification Process simulation refers to the activity in which mathematical models of chemical processes and refineries are modeled with equations, usually on the computer. The usual distinction must be made between steady-state models and transient models, following the ideas presented in the introduction to this sec tion. In a chemical process, of course, the process is nearly always in a transient mode, at some level of precision, but when the time-dependent fluctuations are below some value, a steady-state model can be formulated. This subsection presents briefly the ideas behind steady-state process simulation (also called flowsheeting), which are embodied in commercial codes. The transient simulations are important for designing startup of plants and are especially useful for the operating of chemical plants. 

Once the objective and the constraints have been set, a mathematical model of the process can be subjected to a search strategy to find the optimum. Simple calculus is adequate for some problems, or Lagrange multipliers can be used for constrained extrema. When a Rill plant simulation can be made, various alternatives can be put through the computer. Such an operation is called jlowsheeting. A chapter is devoted to this topic by Edgar and Himmelblau Optimization of Chemical Processes, McGraw-HiU, 1988) where they list a number of commercially available software packages for this purpose, one of the first of which was Flowtran. 

Small batch retorts, heated electrically or hy combustion, are widely used as carburizing furnaces and are applicable also to chemic processes involving the heat treating of particulate sohds. These are mounted on a structural-steel base, complete with cyhnder, furnace, drive motor, burner, etc. Units are commercially av able in diameters from 0.24 to 1.25 m and lengths of 1 to 2 m. Continuous retorts with helical internal spirals are employed for metal-heat-treating purposes. Precise retention control is maintained in these operations. Standard diameters are 0.33, 0.5, and 0.67 m with effec tive lengths up... 

Commercial centrifuges of this type have bowl diameters ranging from 0.3 to 2.4 m (12 to 96 in). The large sizes are used on heavy-duty apphcations such as coal dewatering and are limited by stress considerations to operate at 300g. The intermediate sizes for chemical process service develop up to lOOOg (see Table 18-10). 

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