Continuous process factory

The first environment in which the authors implemented a behavioural safety programme was in a moderate sized continuous process factory. This successful intervention encouraged the company to document and publish their perceptions and experiences for the benefit of other organizations. These insights also provided us with valuable feedback for use in the further development of what has become known as the UMIST model. In this chapter we present their views and impressions and then describe how our original model has developed with the lessons of experience. 

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. 

Development of automated batch process control systems has lagged behind that of continuous process control. Flexible factory scale commercial systems have only begun to appear in the last five years (1-4). Increases in the performance/price ratio of small computers are now making automation of laboratory scale batch processes more practical. 

Most hterature references to pharmaceutical primary process monitoring are for batch processes, where a model of the process is built from calibration experiments [110, 111]. Many of these examples have led to greater understanding of the process monitored and can therefore be a precursor to design of a continuous process. For example, the acid-catalysed esterification of butan-l-ol by acetic acid was monitored through a factorial designed series of experiments in order to establish reaction kinetics, rate constants, end points, yields, equilibrium constants and the influence of initial water. Statistical analysis demonstrated that high temperatures and an excess of acetic acid were the optimal conditions [112]. 

Starch recovery, as presently practiced, depends on a continuous supply of fresh root. Hence, factories are located close to the root producing areas. In Brazil, the processing season can be as short as six months. In Thailand, continuous processing is possible, although some starch producers are known not to operate during part of the rainy season when the starch content of cassava root is low and operating economics are less favorable. 

During World War II a continuous process for nitrating toluene to TNT developed by J. Meissner [19] and patented in 1941 was introduced at the Schlebusch factory in Germany. The nitration unit consisted of 5 nitrators and 4 separators, as shown in the schematic diagram in Fig. 86. Both the nitrators and the separators... 

Scale In our modem society most processing is not done locally by the producer but in large-scale factory conditions. The processes described in most recipes relate to a small scale, and are not directly transferable to large-scale, continuous processing. 

Seong-Sil-Kang et al. (36) studied wastes from squid processing factories because they contain high levels of EPA and DHA. Extractions were performed with and without 3% ethanol as entrainer in a semi continuous flow extractor with pressures in the range of 83-138 bar and temperatures of 25-50°C to improve the extraction efficiency. The extracts they obtained contained high levels of DHA, EPA and other PUPA. Highest extraction yield was achieved at 124 bar and 40°C with or without ethanol. Major fatty acids detected in the extracts (in addition to DHA and EPA) were myristic acid, palmitic acid, palmitoleic acid, oleic acid and arachidic acid. 

The NG manufacturing process also was being made continuous but the work was taking place outside the United Kingdom. The Schmid continuous process appeared in 1927 (15) and eventually was first installed in a British government factory at Holton Heath in 1937. 

On March 22, 1841, the first factory legislation appeared in France. This legislation concerned the employment of children in factories and government workshops using mechanical power or carrying on continuous processes. It also provided for a system of safety inspections. 

Production The production culture may be a batch of several hundred roller bottles, 30 to 50 cell factories, or a single bioreactor for suspension (100 to 10,000 L) or microcarrier (50 to 500 L) ceUs. Although batch-type production is still the most common process, continuous processes where the product is harvested daily over a long period (20 to 100 d) are being increasingly used. Culture systems based on hollow fibers, porous microcarriers, or other immobilization techniques are used for continuous perfusion processes. During the production phase, the virus seed or a promoter (e.g., for interferon) may be added. 

Fermentation. The term fermentation arose from the misconception that black tea production is a microbial process (73). The conversion of green leaf to black tea was recognized as an oxidative process initiated by tea—enzyme catalysis circa 1901 (74). The process, which starts at the onset of maceration, is allowed to continue under ambient conditions. Leaf temperature is maintained at less than 25—30°C as lower (15—25°C) temperatures improve flavor (75). Temperature control and air diffusion are faciUtated by distributing macerated leaf in layers 5—8 cm deep on the factory floor, but more often on racked trays in a fermentation room maintained at a high rh and at the lowest feasible temperature. Depending on the nature of the leaf, the maceration techniques, the ambient temperature, and the style of tea desired, the fermentation time can vary from 45 min to 3 h. More highly controlled systems depend on the timed conveyance of macerated leaf on mesh belts for forced-air circulation. If the system is enclosed, humidity and temperature control are improved (76). 

The table of results is laid out in a column, and a second column is constructed in which in the hrst four rows the results would be added sequentially in pahs, e. g. Xi + X2, xj, + X4, x + jcg etc., and the lower four rows are calculated by subuacting the second value from dre preceding value thus, JC2 — JCi, JC4 — JC3 etc., a thh d column is prepared from these results by canying out the same sequence of operations. The process is continued until there are as many columns as the number of variables. Thus in the present tluee-variable, two level-study the process is repeated tluee times (Table 15.1), and in the general -variable, two-level case it is repeated n times. (The general description of uials of this kind where tlrere are n variables and two levels, is 2 factorial uials ). 

Strict control of the fusion process is imperative. In addition to thickness, hardness, continuity and adhesion checks, correct cure may be assessed by differential scanning calorimetry techniques, which are designed to measure any difference in the glass transition temperature of a laboratory-cured powder and the cured coating taken from the factory-coated pipe. 

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