The Production System

There are several criteria that a biocide for injection water must meet. 

Stability. The biocide must be stable in the injection water long enough that it is active once it is injected downhole. Since most surface waters are neutral to slightly alkaline in pH, care should be taken to use a biocide that is stable at pH s of 7 and above. Also, it is possible that the distance from the water treatment plant to the injection wells could be quite far. Hence, stability and activity of the biocide in the injection water for a period of several days may be required to ensure effectiveness. In Alaska for example, the distance from the Kuparak Seawater Treatment Plant to the Alpine field is approximately 25 miles. A short-lived biocide would not be effective in oilfields where there is a large distance from the treatment plant to the injection wells. 

Compatibility with other system additives. This is another important requirement for the injection water biocide. The most common concern about chemical incompatibilities is an interaction between the biocide and the oxygen scavenger. Most commercially available biocides for oilfield use will react with the bisulfite based oxygen scavengers and become deactivated. This interaction will be discussed in greater detail in the discussion of the commonly used oilfield biocides. 

Efficacy. With some biocides, notably the quaternary ammonium biocides, there are concerns about the hardness of the water affecting the efficacy of the biocide. This concern generally stems from the observation 

Other considerations. Other considerations for an injection water biocide include whether the system can tolerate a biocide that foams. Quaternary ammonium compounds are effective biocides but some quats have a tendency to foam. Lastly, safety and handling considerations are very important in the choice of a biocide. All biocides should be handled with extreme care so it is critical that the choice of a biocide includes a complete and thorough evaluation and understanding of the safety requirements detailed in the Material Safety Data Sheets for each product. 

Whatever method of manufacturing is used, the importance of process control and quality through every step cannot be overemphasized. The specihc steps include (a) monitoring and controlling the production process from stock culture stage through inoculum preparahon, (b) seed, pilot plant, and production 

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The above example is a simple one, and it can be seen that the individual items form part of the chain in the production system, in which the items are dependent on each other. For example, the operating pressure and temperature of the separators will determine the inlet conditions for the export pump. System modelling may be performed to determine the impact of a change of conditions in one part of the process to the overall system performance. This involves linking together the mathematical simulation of the components, e.g. the reservoir simulation, tubing performance, process simulation, and pipeline behaviour programmes. In this way the dependencies can be modelled, and sensitivities can be performed as calculations prior to implementation. 

Breakdown and subsequent repair is clearly non-scheduled, but gives rise to nonavailability of the item. Some non-critical items may actually be maintained on a breakdown basis, as discussed in Section 11.3. Flowever, an item which is critical to keeping the production system operating will be designed and maintained to make the probability of breakdown very small, or may be backed up by a stand-by unit. 

Enhancements to the process may be required due to sub-optimal initial design of the equipment, or to implement new technology, or because an idea for improving the production system has emerged. De-bottlenecking would be an example of an... 

Therapeutics. Therapeutic materials represent a class of polypeptides that are a low volume, high value product. The production system need not be very efficient but the quaHty of the recombinant protein has to be extremely pure (33,34). Thus high cost mammalian production systems can be tolerated. However, some of the therapeutic proteins such as insulin, human growth hormone, interleukins, interferon, and streptokinase are produced microbially. 

The standard method to synthesize MWCNTs is based on the electric-arc experiment proposed by Ebbesen and Ajayan [8]. Basically, the production system is similar to the one used by Kratschmer et al. [11] to produce macroscopic quantities of C o and the main difference between the two experiments is the inert gas pressure, that must be rather low (20-100 mbar) for an efficient fullerene production [11], but must be increased to 350-700 mbar to generate nanotubes efficiently [8],... 

The ASME code requires every pressure vessel that can be blocked in to have a relief valve to alleviate pressure build up due to thermal expan sion of trapped gases or liquids. In addition, the American Petroleum Institute Recommended Practice (API RP) 14C, Analysis, Design, Installation and Testing of Basic Surface Safety Systems on Offshore Production Platforms, recommends that relief valves be installed at vari ous locations in the production system and API RP 520, Design and Installation of Pressure Relieving Systems in Refineries, recommends various conditions for sizing relief valves. 

Very few data [47] relating to the disposal of used ionic liquids are available. In Difasol technology, the used ionic liquid is taken out of the production system and the reactor is refilled with fresh catalyst solution. 

Dilution rate 0.2 h 1 produces efficient substrate conversion and has an OTR that the system can just about provide. Dilution rate 0.1 h 1 gives better substrate conversion but lower productivity. The chosen dilution rate would be just below 0.2 h 1. In practice dilution rates of between 0.1 h 1 and 0.2 h 1 are used to operate the production system. 

Often, the IT life cycle planning today is cost-, project-, reaction-, or necessity-based rather than being based on a well-maintained masterplan. This is not necessarily bad. Projects are sponsored by the local department. Hence project teams are closer to where the needs and record keeping rules are defined. However, the project teams need to understand the technology directions of the larger organization to ensure that the proper infrastructure is in place to support the production system. 

Whether the husbandry of the production system is being efficiently carried out, and how much scope there is to increase reproductive efficiency in the sheep flock, for instance, by reducing the number of barren ewes and by reducing the number of lambs lost before sale. 

Before beginning to farm organically, it is important to do as much as possible to ascertain the best market for your likely organic products and to marry this with the type of farming that you want to do and the production systems which suit the farm you want to either buy or convert. The best market can be defined as the one that will provide the highest and most regular income. 

In the first stage of the LCA analysis, it is necessary to define the objective and the scope of the paper before the actual start [35]. The study goal and scope definition determine the next procedure character and the circumstances in which the study outputs are valid [32]. [36] requires to establish a study goal and scope while the study scope means to determine the product system, the functional unit and system boundaries, to determine allocation rules, the assessment methodology, hypothesis and limits and data quality. 

During the life cycle assessment, the study authors are very often confronted with the fact that the product system has at its end more than one output. In these cases, we use the allocation. Allocation means the assignment of the share of total environmental burden to particular outputs [32]. The Standard recommends to avoid the allocation whenever possible, e.g. by extending systems or sub-division processes [36]. 

The inventory tasks is to collect environmentally important information about relevant processes involved in the product system. Inventory collects information about unit processes at first and subsequently, an inventory of inputs and outputs of the system and its surroundings is carried out. The goal is the identification and quantification of all elementary flows associated with product system. Inventory analysis is the nature of the technical implementation of LCA studies. It is an essential part of a study, has high demands for data availability, practical experience in modelling product systems and, in the case of using database tools, it is necessary to master them perfectly and to understand their function [46]. The inventory phase principle is data collection that is used to quantify values of the elementary flows. This phase represents a major practical part of the LCA study, time consuming and with demands for data availability and author s experience with modelling product system studies [47],... 

Evaluated systems were modelled with the cradle to gate principle, thus the product system of particular foods was terminated at the point of entry into the school canteen. The following presentation of food and related activities, as well as waste management of the product and its packaging materials were not included in the LCA. One kg of the final food was selected as a functional unit. In the case the allocation was necessary, the weight-economic allocation was used. 

Extraction of PHA from plants is likely to be a major factor affecting the production cost of PHA from crops and, therefore, the economic viability of this approach. In contrast to production of PHA from bacterial fermentation, where the production system is designed to produce only PHA, an agricultural production of PHA is likely to be most viable only through the recovery of not only PHA but also all other useful components of the harvested crop, i.e., oil, proteins, and carbohydrates. This fact, combined with the lower level of PHA accumulation in plants in comparison to micro-organism, is likely to make PHA recovery from plants a challenging task. 

Describe (where possible) the production system components (e.g. crop or livestock health management practices, soil fertilisation methods, crop rotation designs, livestock feeding and husbandry regimes, crop varieties/livestock breeds used) responsible for differences in food quality and safety between production systems ... 

Within each species, individual promoters resulted in distinct, tissue-dependent accumulation patterns. The cauliflower mosaic virus (CaMV) 35S promoter, for example, led to high-level accumulation in callus and leaves whereas the maize ubiqui-tin-1 promoter was the best choice for producing recombinant proteins in cereal seeds even though it is not in itself seed-specific [23]. The lack of such comparative studies for proteins other than rAbs makes it difficult to generalize an optimal expression strategy for all proteins. Tables 7.1 and 7.2 list recombinant proteins expressed in plants and provide details of the production system, promoters and other regulatory elements used in each case. 

Several key issues have to be addressed in the downstream processing of biopharmaceuticals regardless of the expression system. The removal of host cell proteins and nucleic acids, as well as other product- or process-related or adventitious contaminants, is laid down in the regulations and will not differ between the individual expression hosts. The identity, activity and stability of the end product has to be demonstrated regardless of the production system. The need for pharmaceutical quality assurance, validation of processes, analytical methods and cleaning procedures are essentially the same. 

The yeast Hansenula polymorpha serves as the production system for a recombinant hepatitis B vaccine (Berna Biotech AG [8] and yeast is also used to produce granulocyte-macrophage colony stimulating factor (GM-CSF), marketed as Leukine by Schering AG. 

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