Process plants

Rase, H. F., Chemical Reactor Design for Process Plants, vol. 1, Wiley, New York, 1977. 

Here we shall restrict consideration to safety and health considerations that can be built in while the design is developing rather than the detailed hazard and operability studies that take place in the later stages of design. The three major hazards in process plants are fire, explosion, and toxic release. ... 

The first major hazard in process plants is fire, which is usually regarded as having a disaster potential lower than both explosion or toxic release. However, fire is still a major hazard and can, under the worst conditions, approach explosion in its disaster potential. It may, for example, give rise to toxic fumes. Let us start by examining the important factors in assessing fire as a hazard. 

The energy released in an explosion in a process plant is either chemical or physical ... 

The gas processing options described in the previous section were designed primarily to meet on-site usage or evacuation specifications. Before delivery to the customer further processing would normally be carried out at dedicated gas processing plants, which may receive gas from many different gas and oil fields. Gas piped to such plants is normally treated to prevent liquid drop out under pipeline conditions (dew point control) but may still contain considerable volumes of natural gas liquids (NGL) and also contaminants. 

The diagram below shows a typleal arrangement of land based facilities in a situation where there are some eonstraints on the location of wellsites and processing plant. 

Frozen fish fingers and similar products are made from a mixture of different fish that arrive at the processing plant as frozen blocks of the average size 62.7 x 254 x 482 mm (thick x width x length). The frozen blocks are minced and the still frozen minced fish blocks are mixed and pressed into the desired shape, covered with batter and bread crumbs, baked on the outside (still with a frozen core), packed and stored in a deep freezer. 

Hard pellets are the type preferred if the species under culture will accept them. Semimoist feeds are most commonly used in conjunction with feeding young fishes and species that find hard pellets unpalatable. Moist feeds, which contain high percentages of fresh fish, are usually available only in the vicinity of fish-processing plants. 

Aquaculturists may harvest, and even process their own crops, although custom harvesting and hauling companies are often available in areas where the aquaculture industry is sufficiently developed to support them. Some processing plants also provide harvesting and hve-hauling services. 

Centralized processing plants specifically designed to handle regional aquaculture crops are estabUshed in areas where production is sufficiently high. In coastal regions, aquacultured animals are often processed in plants that also service capture fisheries. 

Marketing can be done by aquaculturists who operate their own processing faciUties. Most aquaculture operations depend on a regional processing plant to market the final product. In all cases aquaculturists should remember that their job is not complete until the product reaches the consumer in prime condition. 

Sorted plastic packaging materials are shipped, usually in bales, to processing plants to be converted to polymer resins. The bales are broken and the bottles sorted to ensure that only one type of polymer is further processed. Processing consists of chopping and grinding the bottles into flakes. These flakes are washed. Processing steps such as flotation are used to remove polymeric contaminants from the flakes (15,16). The flakes are melted and converted into pellets. 

Shell Higher Olefin Process) plant (16,17). C -C alcohols are also produced by this process. Ethylene is first oligomerized to linear, even carbon—number alpha olefins using a nickel complex catalyst. After separation of portions of the a-olefins for sale, others, particularly C g and higher, are catalyticaHy isomerized to internal olefins, which are then disproportionated over a catalyst to a broad mixture of linear internal olefins. The desired fraction is... 

Approximately 50—55% of the product from a coal-tar refinery is pitch and another 30% is creosote. The remaining 15—20% is the chemical oil, about half of which is naphthalene. Creosote is used as a feedstock for production of carbon black and as a wood preservative. Because of modifications to modem coking processes, tar acids such as phenol and cresyUc acids are contained in coal tar in lower quantity than in the past. To achieve economies of scale, these tar acids are removed from cmde coal tar with a caustic wash and sent to a central processing plant where materials from a number of refiners are combined for recovery. 

Food processing firms producing heat-preserved, frozen, dehydrated, or chemically preserved foods may be classified by their finished products. Companies may be further grouped based on whether they process raw materials into ingredients, such as in poultry and meat processing plants, or whether they take these ingredients and convert them to ready-to-eat consumer products. 

Recovery from Bayer Liquor. The significant amount of primary gallium is recovered from the alumina industry. The main source is the sodium aluminate Hquor from Bayer-process plants that produce large quantities of alumina. Several methods have been developed to recover gallium from Bayer Hquor. 

The seaweed is harvested by raking and hand-gathering. Mechanized harvesting or use of divers has met with limited success. The collected seaweed is dried mechanically in many areas and shipped to the processing plants. 

Fig. 1. Subsystems and flows associated with a process plant.

Ideally, a process plant should be examined for its total energy consumption (see Energy management). Other plant energy systems are under consideration (18) and should eventually be included in this type of analysis. This would include not only process thermal energy and shaft energy, but pumping requirements and electrical power as well. 

In 1991, U.S. plant capacity for producing acetylene was estimated at 176, 000 t/yr. Of this capacity, 66% was based on natural gas, 19% on calcium carbide, and 15% on ethylene coproduct processing. Plants currendy producing acetylene in the United States are Hsted in Table 13. 

MIDREX Process. The primary components of a MID REX process plant include the shaft furnace, reformer, and heat recuperator. These components are supported by ancillary systems for handling iron ore, gas, water, and direct reduced iron. A flow sheet is shown in Figure 1. 

Since 1960, portable stone-processing plants have grown steadily. Although such units are relatively small, companies utilize them to supplement the permanent facilities at times of peak demand or to provide stand-by capacity. 

Other natural gas Hquids include natural gasoline [8006-61 -9] which is composed of the pentanes and heavier components of the natural gas stream, and ethane [74-84-0]. Most recendy ethane has become the principal product of natural gas processing plants. 

Design and Construction ofiEP-Gas Installations at Marine Terminals, Natural Gas Processing Plants, Refineries, Petrochemical Plants, and Tank Farms, API Standard 2510, 4th ed., American Petroleum Institute, Washington, D.C., Dec. 1978. 

The basic seed processing plant design is based on 70% removal of the sulfur contained in the coal used (Montana Rosebud), which satisfies NSPS requirements. Virtually complete sulfur removal appears to be feasible and can be considered as a design alternative to minimize potential corrosion problems related to sulfur in the gas. The estimated reduction in plant performance for complete removal is on the order of 1/4 percentage point. The size of the seed processing plant would have to be increased by roughly 40% but the corresponding additional cost appears tolerable. The constmction time for the 500 MW plant is estimated to be ca five years. 

Future Methanol Processes. The process route for methanol synthesis has remained basically unchanged since its inception by BASF in 1923. The principal developments have been in catalyst formulation to increase productivity and selectivity, and in process plant integration to improve output and energy efficiency while decreasing capital cost. 

Hard rock mining of these ore bodies requkes drilling and blasting with ammonium nitrate and dynamite. After blasting, the ore is reduced in size with a drop ball and then loaded on tmcks for transportation to the processing plant. Mica, quartz, and feldspar concentrates are separated, recovered, and sold from the hard rock ore. 

Shipping. Bulk milk is hauled to the processing plant in insulated tanks using tmck tanks or trader tankers. The milk is transferred from the bulk tank to the tanker with a positive or centrifugal-type pump. For routes of some distance, pick-up every other day reduces handling costs. 

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