Process technologies differences

Microemulsions of droplet sizes <0.1 pm will not be covered here, since product and emulsifier composition, stability and process technology differ from those in mini- and macroemulsion technology. 

Ammonia and nitric acid have been selected as process examples in this book and are treated in detail in Sections 6.1 and 6.4, respectively. Urea is produced industrially by reaction of ammonia and CO2 via the intermediate product ammonium carbamate ([H2N-COO][NH4]). While the formation of the carbamate intermediate is exothermic and quantitative under the applied reaction conditions (200 °C, 250bar), urea forms from the intermediate by liberation of vater in a slightly endothermic equilibrium reaction. Existing process technologies differ in their ways of carbamate decomposition as well as ammonia and CO2 recycling. State-of-the-art urea plants produce up to 1.700 tons of urea per day and are often linked to ammonia plants as CO2 is a by-product of NH3 production from natural gas. 

There can be an element of maintenance costs that is fixed and an element which is variable. Fixed maintenance costs cover routine maintenance such as regular maintenance on safety valves which must be carried out irrespective of the rate of production. There also can be an element of maintenance costs which is variable. This arises from the fact that certain items of equipment can need more maintenance as the production rate increases. Also, royalties which cover the cost of purchasing another company s process technology may have different bases. Royalties may be a variable cost, since they can sometimes be paid in proportion to the rate of production. Alternatively, the royalty might be a single-sum payment at the beginning of the project. In this case, the single-sum payment will become part of the project s capital investment. As such, it will be included in the annual capital repayment, and this becomes part of the fixed cost. 

After development of a new process scheme at laboratory scale, constmction and operation of pilot-plant faciUties to confirm scale-up information often require two or three years. An additional two to three years is commonly required for final design, fabrication of special equipment, and constmction of the plant. Thus, projections of raw material costs and availabiUty five to ten years into the future become important in adopting any new process significantly different from the current technology. 

The basic process technology in vaccine production consists of fermentation for the production of antigen, purification of antigen, and formulation of the final vaccine. In bacterial fermentation, technology is weU estabHshed. For viral vaccines, ceU culture is the standard procedure. Different variations of ceU line and process system are in use. For most of the Hve viral vaccine and other subunit vaccines, production is by direct infection of a ceU substrate with the vims. 

Process Technology Considerations. Innumerable complex and interacting factors ultimately determine the success or failure of a given ethylene oxide process. Those aspects of process technology that are common to both the air- and oxygen-based systems are reviewed below, along with some of the primary differences. 

Measurement Error Uncertainty in the interpretation of unit performance results from statistical errors in the measurements, low levels of process understanding, and differences in unit and modeled performance (Frey, H.C., and E. Rubin, Evaluate Uncertainties in Advanced Process Technologies, Chemical Engineering Progress, May 1992, 63-70). It is difficult to determine which measurements will provide the most insight into unit performance. A necessary first step is the understanding of the measurement errors hkely to be encountered. 

In the tables of relevant Standards in this book while the latest editions of the standards are provided, it is possible that revised editions have become available. With the advances of technology and/or its application, the updating of standards is a continuous process by different standards organizations. It is therefore advisable that for more authentic references, readers should consult the relevant organizations for the latest version of a standard. 

The use of CA has proved to be beneficial for companies introducing a new product, when an opportunity exists to use new processes/technologies or when design rules are not widely known. Design conformance problems can be systematically addressed, with potential benefits, including reduced failure costs, shorter product development times and improved supplier dialogue. A number of detailed case studies are used to demonstrate its application at many different levels. 

The processing technologies for elastomeric blends, thermoplastic elastomer-based on mechanical mixing, and elastomer-plastic vulcanizates are distinctly different. Depending on the type and nature of blend, size, and their final application, a wide range of processing equipment is now in use both industrially as well as in laboratory scale preparation. 

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