Cost sheet operating factor

The sodium softener selected to treat this water is a duplex, 150-gpm system with 54-inch diameter by 72-inch side sheet vessels. Each vessel contains 50ft3 of resin. Since the duplex system operates with one vessel on line and one vessel in stand-by, the total system regenerates 2.4 times per day. At a salt dosage of 15 pounds per cubic foot, the system uses about 1,800 pounds (820 kg) of salt per day or 27.4 tons per month, assuming a 100% operating factor. At a salt cost of 80 per ton, the total month cost for salt is about 2,200.3... 

Many continuing costs are associated with the operation of a chemical plant. These are included in the cost sheet shown in Table 17.1, which is patterned after one prepared by Busche (1995) and includes representative unit costs (typical factors) that can be used for early estimates when more exact costs are not available. 

Cooling Water System. A list of cooling duties will be available at this point so the cost estimate for this system can be factored or estimated based on a similar operating system. For a more definitive estimate based on initial or detailed layout, it is probably best to use a contractor or consultant skilled in these designs. If a cooling tower is involved, the groundwork will already have been set. This basis can be passed along on specification sheets provided in the Appendix to a vendor for quotes. 

As in any process development work, the data have to be examined critically to make certain that there is sufficient reason to carry the project on to the next phase. Thus, if a particular system has poor stripping characteristics, it is very doubtful whether any improvement can be made by going to a larger scale, in which case the investigation may have to be terminated. However, if the bench data have produced sufficient information to draw a conceptual flow sheet, then a decision can be made on whether to run a small-scale continuous operation or a pilot plant. Many other factors have to be considered in making this decision, such as the economics of the process, cost of... 

The cost of manufacturing thermoformed, polystyrene foam sheet parts is less dependent on raw material cost than other extrusion processes. This is largely due to the combined effects of additional energy costs required to operate two extruders, heat removal requirements in the secondary extruder, cost of pelletizing (densifying) regrind and the relatively low output of the process for the equipment scale and cost. Typical cost factors for the manufacture of thermoformed polystyrene foam sheet products include raw materials 35%, labor 27%, sales and administration 16%, depreciation 8%, utilities 7% and other 7%. 

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