Process plant operation

The intention of this section is to provide a selection of case studies of varying complexity and from different stages of chemical process plant operation. The purpose of these case studies is to indicate that human error occurs at all stages of plant operation, and to emphasize the need to get at root causes. The case studies are grouped under a number of headings to illustrate some of the commonly recurring causal factors. Many of these factors will be discussed in later chapters. 

Weather data for a number of years should be assembled for each community being studied. Particular attention should be given to such natural disasters as hurricanes, earthquakes, and floods, which often can be predicted from meteorological data. In certain locations these catastrophic events must be assumed to be probable and this increases construction costs. E.xtremely cold weather often hampers process plant operation and requires special construction features to protect equipment from freezing. Predominantly warm weather permits cheaper construction but may also reduce the efllcicncy of the labor force. 

Many of the quantities required to be measured in process plant operation are not, in themselves, electrical, and if electrical or electronic instrumentation is to be used then these need to be converted to electrical signals using a transducer. The transducer is a physical object and its presence will have an effect on the quantity being sensed. Whether or not this effect is significant will depend on the particular application. In all cases, it is advisable to consider carefully the balance between the requirement that the transducer should, on the one hand, cause the minimum interference with the quantity being measured and, on the other, that it should be intimately associated with the effect being measured. 

One risk-reduction option is to construct a new blast-resistant building in the same location as the existing building. This involves demolishing the existing building, which may cause significant disruption to process plant operations. 

A common deaerator malfunction. Big Jim was once a high-school teacher in New Orleans. I do not quite understand the connection, but many high-school teachers become really good process plant operators. Perhaps they find the work less hazardous. Big Jim became an operator at the utility complex for a major New Orleans area sugar refinery. Here is a rather neat problem that Jim and I solved together. 

Probably only 20 percent of process plant operators or engineers ever work on the sort of boilers shown in Figs. 15.2 and 15.3. However, 90 percent of process plant personnel will, at one time or another, in all likelihood operate a waste-heat boiler. In many petroleum refineries and chemical plants, most of the plant s steam is generated in such waste-heat boilers. One of the most common such boilers is the kettle boiler, shown in Fig. 15.4. 

The operator forms an essential link in any total plant instrumentation and control strategy, and the conveying of information to the process plant operator and the speed at which the operator is able to respond are important considerations. Methods of presentation of information (concerning plant status) to the plant operator, manager or engineer are undergoing a considerable evolution and the effectiveness of the presentation of process data is dependent upon the hardware employed to visualise the data and the protocol used to display it. 

Commercial plants Spheripol technology is used for about 50% of the total global PP capacity. There are 94 Spheripol process plants operating worldwide with total capacity of about 17 million tpy. Single-line design capacity is available in a range from 40,000 to 550,000 tpy. 

Poultry fat is rendered mainly from poultry offal collected in packing plants but may include renderings from mortalities, hatchery rejects, and condemned or unmarketable parts of birds. Much of the rendered poultry fat and meal is produced and recycled in integrated growing-processing plant operations, and only limited amounts are available in the open market. 

Yet from these studies it follows that heat and mass transfer phenomena by no means can be ignored. Kung [b6] showed that among wood particles of 2, 0.2, 0.02 cm only the smallest ones showed a uniform temperature distribution. Hence in actual pyrolysis reactors the rate of conversion will usually be controlled by heat transfer. When the latter is very slow, as in the Destrugas process, plant operating capacity may be strongly affected by the moisture content of the refuse. 

Because most process plants operate close to ambient pressure conditions, gas pressure is not a major effect, except that one has to ensure the casing is gas tight and will withstand the operating conditions, i.e., to prevent either the egress of process gas or the in leakage of ambient air. 

Knowledge-Based Real Time Sensor Interpretation for Process Plants Operation Instruction System Qualitative Modeling of Dynamic Systems... 

Petrochemical plant engineers seem to be accepting ball valve applications at a much greater rate than oil refiners or gas processing plant operators. The fire hazard in process areas seems to be the deciding factor. 

Many sugarbeet processing plants operate lime kilns on-site to produce both the quicklime and the carbon dioxide required for the purification process. Shaft kilns are generally used, burning lump limestone. A few plants calcine the dried carbonation sludge, using rotary and circular multiple hearth kilns [30.6]. 

Process plant operations are generally much more smooth and reliable than they were some years ago. One downside to this situation is that operators have less experience than they had in the past of running the process under upset conditions. They can gain some of this experience through the use of simulated upsets. 

The test certificates for such analysis should mention the reference of order (name of client, order number, a copy of original specifications), production batch number, date of manufacture, and manufacturer s code—for ease of identification of the reaction units, process plants, operation sequence, or conditions maintained during production on the date of manufacture in future. These will be useful if any communication (complaint or compliment) is received about the product. 

Ensuring smooth process plant operations by quality/analysis checks at every stage of manufacture, e.g. analysis of raw materials at the time of procurement, progress of reaction, activity of catalysts, refinement of crude products into acceptable grade by controls on flow, temperature, and concentration. Reducing equipment breakdowns by better process control and timely alarms for abnormal situations. 

In conclusion to this section, the project engineer is reminded that the handling of solid materials can present major hazards to process plant operators. Reference should be made to BS5667, the equivalent... 

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