Utilities process water cost

This term includes, power, steam, compressed air, cooling and process water, and effluent treatment unless costed separately. The quantities required can be obtained from the energy balances and the flow-sheets. The prices should be taken from Company records, if available. They will depend on the primary energy sources and the plant location. The figures given in Table 6.5 can be used to make preliminary estimates. The current cost of utilities supplied by the utility companies electricity, gas and water, can be obtained from their local area offices. 

Utilities include the costs of electricity, generating steam, cooling water etc., and emphasises the importance of good equipment and efficient processing and energy-audits for energy conservation and consequent financial savings. 

The 2-butanol feedstock is conventionally obtained by the sulfuric acid-catalyzed addition of water to -butenes. This is a two-step reaction involving sulfation and hydrolysis in which the conversion of -butenes is 90% and selectivity to 2-butanol is 95% (15). During operation the sulfuric acid becomes diluted and must be reconcentrated before reuse. In 1983 Deutsche Texaco commercialized a single-step route in which 2-butanol is formed by the hydration of -butenes in the presence of a strongly acidic ion-exchange resin containing sulfonic acid groups (16—18). The direct reaction is carried out at 150—160°C and 7 MPa. Virtually anhydrous 2-butanol is recovered in this process (19). Direct hydration requires lower utilities and investment costs, operates at 99% selectivity to 2-butanol, but is hindered by low (5—15%) -butene conversion per pass. 

Utilities include steam, electricity, fuel, cooling water, process water, coirqjressed air, refrigeration, and waste treatment. Utility equipment is usually located outside of the process area and may supply several processes. We may consider each utility as a product, and estimate its cost according to the procedure outlined in Table 2.1. The cost of steam, electricity, and refrigeration depends mainly on fuel costs. Local utilities may give electric power costs, and the Federal Power Commission publishes rates for all public utihties in the United States. Table 2.3 lists approximate utility rates. 

The water consumed in process washes and scrubbers is harder to estimate, but since no process water consumption was listed under utilities, we can assume as a first approximation that all the process water needs are met by internal recycles. This gives a total waste-water flow of 191,408 + 82,032 = 273,440 MT/y. The waste-water stream is assigned a cost of 1.5/MT (see Section 6.4.6)... 

Utilities. The utility requirements for a process are obtained from both a material and energy balance. The unit costs for each utility may be obtained from plant expense sheets, the accounting department, or a utility superintendent. These costs often increase continually, so they should be reviewed frequently. Utilities are usually steam (high-, medium-, and low-pressure) and their associated unit costs, electricity, natural gas, cooling tower water, and treated or city water. Sometimes instrument air, demineralized water, and refrigeration are considered utilities if they come from a central source and are not tied to a given process. 

Despite their high cost and the long process involved in their development, immunochemical techniques may soon have broad applicability in the environmental field. Antibody production is the key step of any immunochemical technique. Immunosensors yield the best results for pesticides determination104 in terms of both accuracy and reliability. The most reliable immunosensors are piezoelectric. They assure a good sensitivity and limit of detection.105 The main problem for piezoelectric immunosensors utilization for water analysis is their low sensitivity, which results in a decrease in the S/N ratio because of the impurities present in water (from matrix or other sources). 

After the process information has been integrated into one or more flow sheets, the economic aspects of the design are next considered. This involves (1) an estimate of the types and sizes of equipment and materials, buildings, ground area, and utility facilities (2) a determination of what the process will cost based on physical facilities and construction charges (3) a cost estimate of utilities consumption (steam, electricity, water, fuel), labor and supervision personnel requirements, maintenance and repairs, raw materials, and finance charges (interest, taxes, insurance, medical benefits, etc.). 

Freshwater sources generally consist of ground and surface water sources. In rare cases, water may be obtained from sea or ocean water by desalination processes that are relatively costly. Most municipal systems utilize surface water whereas most of the industrial consumers of water prefer to pump water from ground sources than to obtain it from municipal systems. Tap water provided by the municipal system to the community is treated to an extent which generally finds a balance between the economy and the practicality of the treatment and the safety of the water delivered. Nevertheless, the basic principle is that the quality of the water should be suitable for consumers to drink and use for domestic purposes without subsequent risk of adverse effects on their health throughout their lifetime. Also, special attention is necessary to protect vulnerable groups, such as pregnant women and children. 

Allocated costs, Cgnoo nre included to provide or upgrade off-site utility plants (steam, electricity, cooling water, process water, boiler feed water, leMgeration, inert gas, fuels, etc.) and related facilities for liquid waste disposal, solids waste disposal, off-gas treatment, and wastewater treatment. Some typical capital investment costs for utility plants, estimated by Busche (1995), are shown in Table 16.12. Cogeneration plants can provide both steam and electricity by burning a fuel. When utilities, such as electricity, are purchased firom vendors at so many cents per kilowatt-hour, that cost includes the vendor investment cost. Thus, a capital cost for the plant is then not included in the capital cost estimate. 

Utility Facilities are the facilities required to support the battery-limits plant, This may include water treatment, steam generation, electricity, and cooling for process water and waste water treatment. Utility facilities support production. Utility facilities can range from 35% of the battery-limits plant cost for grass-roots installations to 10% for an addition to an existing production site. 

Utilities include electricity, steam, process fuel, process water, boiler feedwater, cooDng water, deionized water, compressed air, instrument air, refrigeration, inert gas, and effluent treatment. The unit use is dependent on die process technology, and the cost is site dependent. For each utility, unit use and unit cost should be recorded. The estimated use of utilities for different fertiDzer processes is shown in Table 21.6. Some offsite utilities such as electricity are often priced with a fixed cost component and a variable cost component. The fixed and variable portions need to be calculated separately to provide an average variable cost per unit of production for a given annual production. 

Another important consideration is the waste stream generated during the downstream processing. Waste costs can significantly contribute to the overall product cost. Due to this, various material and water recycle steps are usually utilized in a manufacturing plant. Waste treatment considerations also heavily restrict the choice of process additives. 

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