Overhead facilities

Figure 4. View of overhead facilities showing exhaust and electrical service channel...

Overheads (e.g., safety services, laboratories, personnel facilities, administrative services, etc.)... 

Indirect Manufacturing Costs Estimates for the cost of payroh overhead, control laboratoiy, general plant overhead, packaging, and storage facilities are best based on company records for similar processes. 

The potentials from larger grounding installations on the soil surface are essentially flatter but more extended than those from overhead power line pylons (e.g., power stations, transformers and switchboard plants). The maximum expected grounding voltage in case of failure and its variation at the soil surface can be obtained from the facility s management. 

In the depropanizer tower the propane and lighter gases are taken overhead to become feed to the ethylene and propylene recovery facilities. Separation is accomplished at a relatively low overhead temperature of -25°F to minimize reboiler fouling by olefin polymerization. 

Butane and heavier bottoms from the depropanizer flow to the debutanizer where the C4 stream (almost entirely olefins and diolefins) is taken overhead and sent to butadiene and isobutylene recovery facilities. 

The Cj plus bottoms from the demethanizer then go to the deethanizer. A propylene-propane bottoms product containing 90-92% propylene is obtained which may either be sold, used directly as propylene- 90, or further purified. The ethylene-ethane overhead from the deethanizer is separated in the splitter tower yielding a 99.8% overhead ethylene product at -25°F. The ethane bottoms at -l-18°F may either be sent to fuel gas or used as feed to an ethane cracking furnace. Overall ethylene recovery in these facilities is about 98%. The product is of very high purity with less than 50 parts per million of non-hydrocarbon contaminants and a methane plus ethane level below 250 ppm. 

Utility companies have a power system network including large generating plants, overhead transmission lines, power substations which reduce transmission line voltages to distribution line voltages, and over-head/underground distribution lines which carry power to the end users (such as a production facility). 

Thermoeconomics of the LHS system involves fixed capital investment, operational and maintenance cost, and exergy costs (Domanski and Fellah, 1998). Total fixed capital investment consists of (i) direct expenses that are equipment cost, materials, and labor, (ii) indirect project expenses that are freight, insurance, taxes, construction, overhead, (iii) contingency and contractor fee, and (iv) auxiliary facilities, such as site development, auxiliary buildings. 

The mbber cement is then sent to storage tanks where antioxidants and extenders are mixed in. The mbber cement is pumped from the storage tank to the coagulator where the mbber is precipitated with hot water under violent agitation. The solvent and unreacted monomer are first steam stripped overhead and then condensed, decanted, and recycled to the feed stage. The bottom water layer is discharged to the wastewater treatment facility. 

Allocated Capital This is capital that is shared due to its proportionate share use in a new facility. Such items include intermediate chemicals, utihties, services and sales, administration, research, and engineering overhead. 

The system uses no fuel or fuel transport, packaging, storage, and disposal systems and needs no intermediate refining facilities and operations. The resulting overhead and financial savings are vast and significant. 

Since HtS dissolved in water is very corrosive to carbon 4 steel, a comprehensive corrosion-control program is being conducted. In the field, each well is treated once per month by displacing inhibitor down to the perfora-. tions with stock tank oil. Corrosion coupons in the flow-lines are inspected every 6 months Little corrosion has been detected in the field. In the plants, corrosion in-hibitor is added daily to the gas-sweetening solvent, the salt water system, and the stabilizer overhead. Inhibitor is -Jj also added to bulk chemicals as received. Numerous corrosion coupons and probes are installed in each facility and are pulled for inspection every 1 to 3 months Corrosion rates have been low (less than I mil/year) asY result of the inhibitor injection program. 

Plant overhead costs do not vary widely with changes in the production, either. Generally, these costs take into account medical services, general plant maintenance, quality-control laboratories, storage facilities, etc. In this discussion we do not consider them, because we think the plant as part of an existing industry. 

The estimated capital requirements represent an approximate 5% annual inflation of the total price actually paid for the Miami facility. Changes in the amortization period or interest rate can significantly affect annual capital charges. Also note that no direct costs for supervision and overhead are included. 

Cracking, desulfurization, and demetallization reactions take place via thermal and catalytic reactions. In the upper section of the reactor, vapor is disengaged from the slurry, and hydrogen and other gases are removed in a high-pressure separator. The liquid condensed from the overhead vapor is distilled and then flows out to the secondary treatment facilities. 

Gas outlets. Sufficient liquid disentrainment from the overhead gas is usually required. This may be achieved by providing sufficient vertical height above the top tray, installation of mist eliminators, or providing external knockout facilities downstream of the column. 

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