Product/process engineering stage

Similarly, the scientist must think through how the material will be added and taken away from the processor on a commercial scale. Without this forethought, I have seen many times processes that come to production which are very labor intensive. If the development scientists work with production and engineering departments from an early stage, these difficulties can be avoided. 

In the engineering development stage, a practical and workable design is developed. Prototype samples are produced on equipment located at the Technical Center that duplicates the production process to be used. A portion of the materials evaluation work is also performed at this time. Candidate materials are given performance tests and moldability is analyzed in detail. Cost and reliability factors are also considered at this time. 

The cell potential for such a process is shown in Fig. 15.28 (Dandapani, 1987). In fact, at about 80 °C and pH 14, polysulfides are first produced, but pure sulfur precipitates on cooling. The process has been developed to an engineering stage (Petrov and Srinivasan, 1996). It is necessary to protect the cathode against catalytic inactivation by polysulfide (i.e., a membrane must be used). For continuous use, the pH must be controlled. The cooling and production of S may be best carried out outside the cell. 

The goal of conceptual process engineering is to develop a skeletal scheme for a material-making facility, as may be represented by a flowsheet, to implement the chemical conversion of available raw materials into desired product materials, fit for use, at the desired scale, safely, responsibly, economically, and on time. This flowsheet will be refined and optimized in subsequent basic and detailed engineering stages of the innovation process on the basis of additional experimental information, detailed calculations, standards, expert opinion, available equipment and construction capabilities, and other input. It is most desirable that this initial conceptual process scheme prove to be a better starting point for the remainder of the innovation process than other possible flowsheets. A flowsheet does not exist until it has been first synthesized. 

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