Process unit road

EXHIBIT 5-23 Typical Process Unit Road and Paving Arrangement... 

The siting of the main process units will determine the layout of the plant roads, pipe alleys and drains. Access roads will be needed to each building for construction, and for operation and maintenance. 

On the aesthetic side, it is likely that intensified process plants will be less intrusive on the environment, making them far less of an eyesore than the unsightly and massive constructions that are characteristic of present processing units. In some cases the plant may be mobile, thereby offering the opportunity for distributed manufacturing of chemicals close to the point of utilisation. This may reduce the quantities of hazardous products currently being transported by road and rail, thereby improving safety. The... 

GeneralLayout The general layout specifies the location of process units, utilities units, roads, building and fencing. 

The residue remaining after vacuum rectification is called Goudron . This may be used for blending to produce road asphalt or residual fuel oil, or it may be used as a feedstock for thermal cracking or coking units. Vacuum rectification units are an essential part of the many processing units required for the production of lubricants. 

If possible, direct unloading into process units shall be explored to save cost and contamination due to repeated handling in the premises (sulphur procured in road trucks can be unloaded directly in the melter, rock phosphate unloaded directly on to the grids of crushers, bauxite lumps into loading hoppers of belt conveyors, and alkali in day tanks) or... 

Process units, buildings, and groups of off-site areas (e.g., tank farms) are serviced by auxiliary roads for maintenance and fire fighting. Equipment location must facilitate in-place maintenance by mobile equipment. Process equipment must be enclosed in shelters only when required by extreme climatic conditions or client preferences. 

Process plants are to be serviced by roads adjacent to process units, utility plants, materials-handling and... 

For maintenance and safety, the principal access to and from most process units is by auxiliary roads, Ideally, the unit battery limits should be positioned 50 ft (15,000 mm) from the centerline of the main plant roads. This allows adequate space for ditch drainage and firefighting facilities and avoids obstructing roads when such items as heat exchanger tube bundles are removed. Access ways or spur roads should be provided within the unit for access to items that require servicing or for components that require removal for off-site repair. Clearance according to project specification should be provided over roads and ac-... 

Apart from building that house equipment (e.g., compressor houses), it is often necessary to position control houses, substations, analyzer houses, and operator shelters within the process unit battery limits. Administration buildings and warehouses are generally located away from process unit areas. Control houses and substations are usually located at the edge of the unit adjacent to a plant road, 50 ft (15,000 mm) from the operating equipment. As seen in Exhibit 3-24, analyzer houses and operator shelters should be located next to the equipment that they service. 

Within the conventional inline process unit, drums and their related items are generally located on either side of a central pipe rack serviced by auxiliary roads for maintenance access. In certain cases (e.g., for flash drums and deaerators), drums can be located above the pipe rack. In chemical plants, drums are generally located at all levels of enclosed or open-sided structures. For eixample, Exhibit 5-4 shows the drum location in a tower reflux system. Exhibit 5-5 shows the typical location of feed surge and compressor suaion drums, and Exhibit 5-6 shows the drum locations in an enclosed chemical plant stnicture. 

Size and weight determine the maximum size of for the vessels in large process units. High-pressure reactors can only be built in a few special factories in Italy and Japan. They can weigh more than 2200 tons and their diameters may exceed 15 feet (5 meters), but it must be possible to move them over existing road and to lift them with available cranes. 

Crude oil is seldom distilled at temperatures above about 650 "F. At higher temperatures, coke will form and plug the lower section of the crude oil distillation tower. Therefore, the portion with a boiling point above bSC F is not vaporized—or at least not with the processing units introduced so far. This residual liquid is disposed of as industrial fuel oils, road oils, and so forth. The residual is sometimes called reduced crude because the lighter fractions have been removed. 

The term bitumen is used in France to designate petroleum products, as in Great Britain and Germany. In the United States on the other hand, the equivalent material is designated by the expression asphalt-cement . In France, asphalt is a mastic, a mixture of bitumen and powdered minerals, poured in place. This mixture can be either natural or reconstituted by an industriai process. Asphait (French meaning) is utilized on roads, particularly in urban centers as well as for sidewalk surfacing. 

Evaporites are important sources of economic minerals that have been exploited for at least the past 6000y. For example, the evaporite mineral trona (NaHCOj -Na2C03 2H2O) was used by the ancient Egyptians to preserve mummies. Evaporite salts continue to be used for food preservation, construction, road deicing, and in industrial processes. The marine evaporites of Saskatchewan (Canada) are the world s largest source of potash (KCl), which is used as an agricultural fertilizer. In the United States,... 

A large proportion of the circa 3.7 x 106 t/yr of natural mbber used in tires is consumed in tmck tires, off-the-road tires, and aircraft tires, all of which demand a low heat buildup performance. The retreading of tmck tires was also the province of natural mbber until the precured process was developed. Prior to the advent of this technique, the tack of natural mbber was essential for the unvulcanized mbber to adhere onto the buffed carcass, and the thickness of the shoulder region was such that the low heat buildup of natural mbber was essential to ensure that no failure occurred in service. With the precured tread process neither of these attributes were necessary and, synthetic mbber, which was and continues to be used, was found to give particularly good wear performance under low severity conditions, especially in the United States. However, work (56) has shown that natural mbber-based formulations can be developed which give a similar order of wear performance to the all-synthetic mbber tread, but with the additional benefit of lower rolling resistance, and hence better fuel economy. 

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