Design considerations cycle

To the process designer, life-cycle analysis is useful because focusing exclusively on waste minimization at some point in the life cycle sometimes creates problems elsewhere in the cycle. The designer can often obtain useful insights by changing the boundaries of the system under consideration so that they are wider than those of the process being designed. 

J. N. Chapman and N. R. Johanson, "Design Considerations for a Class of 600 MWe MHD Steam Combined Cycle Plants," 28th Intersociety Energy Conversion Engineering Conference, Adanta, Ga., Aug. 1993. 

Performance In general, a service performs more poorly than an in-process method call due to network latency and bandwidth constraints. To make things worse, a service may call other services to fulfill its responsibilities—a chain of services. Performance has to be a design consideration throughout the development cycle. 

Continuons emulsion polymerization is one of the few chemical processes in which major design considerations require the use of dynamic or unsteady-state models of the process. This need arises because of important problems associated with sustained oscillations or limit cycles in conversion, particle number and size, and molecular weight. These oscillations can occur in almost all commercial continuous emulsion polymerization processes such as styrene (Brooks et cl., 1978), styrene-butadiene and vinyl acetate (Greene et cl., 1976 Kiparissides et cl., 1980a), methyl methacrylate, and chloropene. In addition to the undesirable variations in the polymer and particle properties that will occur, these oscillations can lead to emulsifier concentrations too low to cover adequately the polymer particles, with the result that excessive agglomeration and fouling can occur. Furthermore, excursions to high conversions in polymer like vinyl acetate... 

Traditional methods for clean manufacturing focus on waste or energy audits, which are summarized in Section 4.1. New methods focus on life cycle design, life cycle assessment, production planning models with environmental considerations, and environmental management systems, which are described in Sections 4.2, 4.3, 4.4, and 4.5, respectively. 

Design considerations include the proximity to other metallic structures and existing CP systems, the type of grounding, the estimated remaining service life of the tank, the type and temperature of the stored product, the amount of product stored, the cycling rates, the method of tank bottom plate construction, the type of tank foundation, the type of secondary containment, if any, and the backfill soil characteristics. 

Equipment design follows the selection of a cleaning cycle and work handling method. Important design considerations to achieve effective, economical, and safe operation are summarized below. 

The first design considerations for the HHV plant began with a system, where a fossil-fired heater replaced the nuclear heat source. However, because of the desired peak temperatures of 850 C (1000 °C for shorter periods) and the design pressure of 50 bar there were feasibility concerns about the lifetime capability of such a fossil-fired heater. Thus a test circuit was chosen comparable to a closed-cycle gas turbine plant as shown in Fig. 5. 

Requirements for each element or component derived from system level goals and requirements Alternatives in design The initial design Life cycle consideration in design... 

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