Design process operational stage

The overall costs will be mainly driven by the procurement/cultivation of the selected biomass and immobilisation process. There are a number of cost-saving opportunities during the design and operational stage of the process ... 

The timing of such a sequence of HAZOPs is important in making the project both worthwhile and cost effective [Ford 90]. Successful studies have been performed on systems in both the design and operating stages, however, modifications are much easier and less expensive to implement in the early stages of the project On the other hand, a sufficient level of detail must be defined for both the control system and process prior to the study ... 

There are many other sources of waste associated with process operations which can only be taken care of in the later stages of design or after the plant has been built and has become operational. For example, poor operating practice can mean that the process operates under conditions for which it was not designed, leading to waste. Such problems might be solved by an increased level of automation or better management of the process. These considerations are outside the scope of this text. 

Clearly, some of these measures to reduce waste in process operations—such as design for low process inventory—can be taken into consideration at the early stages of design, but many cannot. We should be aware of the problem and do whatever we can in the early stages to prevent problems later. 

FIG. 14-23 Stable operating region, plates. (Smith, Design of Equilibrium Stage Processes, McGraw-Hill, New Yoik, 1963.)... 

As the process moves from the process development stage to the design and construction stage the chemistry, unit operations, and type of equipment have been set. The design and construction stage needs to focus primarily on equipment specifications, piping and instrumentation design, installation details, and layout for an inherently safer installation. 

The design methodology is a description of a technical design process that covers the whole lifetime of the production process. Most decisions concerning industrial ventilation are made at the design stage, and are reflected in construction, operation, maintenance, service, etc. 

After tlie system has been defined, a hazard evaluation technique can be used to identify different types of hazards within tlie system components and to propose possible solutions to eliminate the hazards. This topic is treated in more detail in the next t o chapters. These procedures are e.xtremely useful in identifying system modes and failures that can contribute to the occurrence of accidents diey should be an integral part of different phases of process development from conceptual design to installation, operation, and maintenance. The hazard evaluation tecliniques tliat are useful in tlie preliminary and detailed stages of tlie design process include ... 

The most recent UK Royal Ordnance Factory (ROF) continuous process for the manuf of TNT is described by Thomas (Ref 90b). It uses a novel method of achieving continuous counter-current contacting between heavy and light phases in the trinitration section and some of the washing stages . The plant is also designed to operate based on the use of 96—100% sulfuric acid in the trinitration stage instead of the oleum used at Radford TNT Purification. 

What-if analysis involves the examination of possible deviations from the design, construction, modification, or operating intent of a process. It can be used to examine virtually any aspect of facility design or operation. Because it is so flexible, it can be performed at any stage in the life of a process using whatever process information and knowledge is available. 

This procedure is based on the use of checklists which are applied to every stage of process design and operation to ensure compliance with standards, codes, good engineering practices, and well defined operating procedures. In this way, prior experiences can be implemented and used to prevent recurrence of incidents that may have happened in die past. Examples of checklists can be found in [2,3,251]. 

Several safety analysis methods have been developed already. Some of them are internationally known and proved, some have been used and developed more or less inside companies. Information requirements of the methods are different, also the results produced vary. Thus different safety methods are suitable for different stages of process development, design and operation (Fig. 3). Some safety analysis methods are discussed below in more detail. 

This chapter contains examples of optimization techniques applied to the design and operation of two of the most common staged and continuous processes, namely, distillation and extraction. We also illustrate the use of parameter estimation for fitting a function to thermodynamic data. 

Realistically, the information available to perform risk studies varies over the lifetime of a process. During the early stages of process development, analysis teams may only have access to basic chemical reactivity hazard data, such as may be obtained from suppliers and literature resources. By the time a facility reaches the detailed design phase, most of the basic design and operating information should be available and used in any study of the facility hazards and risks. 

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