Page 57 - Chemical process engineering design and economics

Production and Capital Cost Estimation 43

CAPITAL COSTS

To calculate several of the cost items listed in Table 2.1, requires the depreciable
and fixed capital costs. The depreciable capital cost is the capital required for
equipment and its installation or modification in the process, and all the facilities
required to operate the process. There is some variation in the definition of fixed
capital cost. References [1-5], define the fixed capital as consisting of the depre-
ciable capital cost, land cost, and site or land development cost. Woods [10], how-
ever, omits land cost and land development cost so that that the fixed capital cost
equals the depreciable capital cost. We will adopt the first definition here. For
now, assume that we know the depreciable capital cost. We will develop a proce-
dure for its evaluation later. In Example 2.1 estimate the production cost using
Table 2.1.
Example 2.1 Estimating the Production Cost of Ethylenediamine_______

Ethylenediamine is used to produce chelating agents and carbamate fungicides.
Monoethanolamine (MEA), reacts with ammonia and hydrogen to produce ethyl-
enediamine. The reaction occurs in the gas phase over a catalyst at temperatures <
300 °C (572 °F) and pressures > 250 bar (246.7 atm) [12]. Other details of the
process are proprietary. The products are:

ethylenediamine (EDA) - 74%
diethyltriamine (BETA) - 8%
piperazine (PIP) - 4%
aminoethylpiperazine (AEP) -10%
hydroxyethylpiperazine (HEP) - 4%

Data (March 1978)
Fixed Capital Cost $10.3xlO s
Interest Rate 10 % /yr
Utility Costs (kg total products)
6
7
Electricity 3.56xl0 J/kg total products @ 4.17xlO~ c/J
Steam (1.03 kPa) 18.1 kg st./kg total products @ 0.0113 c/kg
3
Water 0.1528 m /kg total products @ 3.17 c/m 3
Operating Labor Rate 8.61 $/h
Land Cost 0.015 x depreciable capital cost
Land Development Cost 0.021 x depreciable capital Cost
Total Raw Material Cost 79.8 c/kg
If the production rate is 10,0001/yr (metric tons per year) (11030 tons/yr) of
total product, find the production cost of one kilogram of total product?

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