Estimation of production cost and revenue

Variable Cost of Production

Estimating Variable Production Costs

Raw Materials Cost

These are the costs of chemical feed stocks required by the process. Feed stocks flow rates are obtained from PFD [6].

Utilities Cost

These are the costs of the various utilities streams required by the process. The flowrates for the utilities streams are located on the PFD [6]. This includes:

• Fuel gas, oil, or coal
• Electric power
• Steam
• Cooling water
• Process water
• Boiler feed water
• Air
• Inert gas
• Refrigeration

Waste Disposal Costs

These are defined as the cost of waste treatment to protect the environment [6].

Fixed Cost of Production

Estimating Fixed Production Costs

Labor Costs

These are the costs attributed to the personnel required to operate the process plant [6].

Maintenance Costs

Part of these costs are associated with labor and materials necessary to maintain plant production [6].

Research and Development

These are the costs of research done in developing the process and/or products. This includes salaries for researchers as well as funds for research related equipment and supplies [6].

Revenues

The revenues of a process are the income earned form sales of the main products and the by-products. Revenue can be impacted by market fluctuations and production rates.

By-Product Revenues

Besides selling the main product from a process, by-products from separations and reactions can also be valuable in the market. Often it is more difficult to decide which by-products to recover and purify than it is to make decisions on the main product.

By-products made in stoichiometric ratios from reactions must be either sold off or managed through waste disposal. Other by-products are sometimes produced through feed impurities or by nonselective reactions. There are several potential valuable by-products from a process:

1. Materials produced in stoichiometric quantities by the reactions that create the main product. If they are not recovered then the waste disposal expenses will be large.
2. Components that are produced in high yield by side reactions.
3. Components formed in high yield from feed impurities. Many sulfurs are produced as a by-product of fuels manufacture.
4. Components that are produced in low yield but have high value. An example includes acetophenone which is recovered as a by-product of phenol manufacture.
5. Degraded consumables (e.g. solvents, etc.) that have reuse value.

A rule of thumb that can be used for preliminary screening of by-products for large plants is that for by-product recovery to be economically feasible the net benefit must be greater than $200,000 a year. A net benefit can be calculated by adding the possible resale value of the by-product and the avoided waste disposal cost [1].

Margin

The gross margin of a process is defined as the sum of product and by-product revenues minus the raw material cost.

Gross margin = Revenues - Raw materials costs

Because raw materials are most often the most expensive variable cost of a process, the gross margin is a good gauge as to what the total profitability of a process will be. Raw materials and product pricing are often subject to high degrees of variability which can be difficult to forecast. The size of margins are highly versatile depending on the industry. For many petrochemical industries the margin may be only 10%; however, for industries such as food additives and pharmaceuticals the margins are generally much higher [1].

Profits

There are several standards for calculating company profits. The cash cost of production (CCOP) is the sum of the fixed and variable production costs.

CCOP = VCOP + FCOP

where VCOP is the variable cost of production and FCOP is the fixed cost of production.

Gross profit, which should not be confused with gross margin, is then calculated by the following equation, Gross profit = Main product revenues - CCOP

Finally profit can be calculated by subtracting the income taxes that the plant would be subject to depending on the tax code of the county the plant is located in.

Net profit = gross profit - taxes

References

1. Wankat, P.C. (2012). Separation Process Engineering. Upper Saddle River: Prentice-Hall.
2. Towler, G.P. and Sinnot, R. (2012). Chemical Engineering Design: Principles, Practice and Economics of Plant and Process Design.Elsevier.
3. Biegler, L.T., Grossmann, L.E., and Westerberg, A.W. (1997). Systematic Methods of Chemical Process Design. Upper Saddle River: Prentice-Hall.
4. Peters, M.S. and Timmerhaus, K.D. (2003). Plant Design and Economics for Chemical Engineers, 5th Edition. New York: McGraw-Hill.
5. Seider, W.D., Seader, J.D., and Lewin, D.R. (2004). Process Design Principles: Synthesis, Analysis, and Evaluation. New York: Wiley.
6. Turton, R.T., Bailie, R.C., Whiting, W.B., and Shaewitz, J.A. (2003). Analysis, Synthesis, and Design of Chemical Processes Upper Saddle River: Prentice-Hall.