Process issues

If properly established, the management of change mutual-review agreement and designated points of contact should preclude most 

Example 5-1. Sample toller management of change form, page 1 

Completed by CAF Initiator - Thia ronrt should be used witlt proceduie PSM-ADM-11, Management of Change Applicable Cost Codes for Affected Equipment/Area  

Teehnieal Basis (Check all that apply O Production Rates O Envir, Control O Experimentation 

Reason for the Change O Improved Safety O Envir. Control O Essential to Operation 

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Adequate configuration control of product design and processes issues... 

A separate set of processibility issues involves health, safety, and environmental concerns. Ozone-depleting compounds (ODCs), such as trichloroethane and... 

Troubleshooting deals with identifying and solving problems. Problems can be immediate or long term and can be associated with off-spec products, poor efficiency, process improvements, capacity increases, or potential shutdown items. Problems can be related to management, operation, hardware and equipment, or process issues. Solutions can include improved operating procedures and training, preventative maintenance, or installation of new equipment or controls. 

Note that these equations allow the residence time and conversion to be computed, but other process issues are neglected. For example, although assumption 1 is considered, any solvent exhibits some vapor pressure and thus can be extracted by the outlet hydrogen feed. 

Gas mixture, hydrogen content of, 13 790 Gas mobility control processes, issues in, 16 626... 

The rates of these reactions depend upon the contaminant concentration and the inherent rate constants of the reactions. While the exact nature of these reactions differ for each type of chemically amplified system and are not fully understood, this generalized discussion is sufficient to understand many of the process issues. 

In some mixture design problems (such as formulations), it may not be necessary to consider processing issues and hence we would not have the process model constraints. In this case the problem becomes a simple mixing problem, which would already have been addressed by the miscibility criteria in sub-problem 4M. Hence, for these problems, we will not need sub-problem 5M. Also in some cases we might have to identify a mixture whose constituents perform different functions such as solvents and anti solvents for crystallization. In such cases we would have to formulate and solve more than one single compound design problems to identify the constituents and then solve the final two sub-problems to identify the optimal mixture. In certain cases we may not have process model constraints, however, we may still have to solve an optimization problem with other constraints, in sub-problem 4 and sub-problem 5m respectively. 

A literature based case study has been compiled to better illustrate some of the process issues that can occur as a result of technology transfer. 

Raw Materials Raw materials have a significant impact on the manufacturing process. Issues such as availability and reliability of supply, reactivity, toxicity, handling, and storage have to be considered. Cost is another factor to take into account. Often, trade-offs between costs, manufacturing processes, and yields are considered. 

Numerous biocatalytic routes to this challenging intermediate have been reported. " For example. Fox et al. have recently developed an efficient regioselective cyanation starting from low-cost epichlorohydrin (Scheme 1.26). Initial experiments found that halohydrin dehydrogenase from Agrobacterium radiobacter expressed in E. coli produced the desired product, but inefficiently. To meet the projected cost requirements for economic viability, the product needed to be produced at 100 g L with complete conversion and a 4000-fold increase in volumetric productivity. The biocatalyst needed to function under neutral conditions to avoid by-product formation, which causes downstream processing issues. 

Process/Engineering Development (15,25,34) There are numerous engineering and process issues that are being addressed by fuel processor developers. Several major issues are ... 

Usnally IWE does not pose grave problems, if snitable countermeasures have been contemplated a priori. In process sampling obtaining a constant increment mass has many advantages, and is thus often given a high priority. For practical purposes, this can be considered effectuated if the relative variation between increment masses remains below, say, 20% [2,3,9,14]. In order not to confuse the process issues needlessly, below we shall assume that all IWE issues have been dealt with properly (i.e. eliminated). 

Earlier reference was made to published articles that described the use of optimization techniques for coating processes. In particular, the one presented by Porter et al. (7) provides a useful example of how aesthetic, functional, and processing issues can be dealt with. The key elements of the study that formed the basis for this article are listed in Table 3, while typical results obtained in this study are summarized in Table 4. From these data, it is possible to optimize the coating process with respect to ... 

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