Page 24 - Design of Simple and Robust Process Plants

1.2 The Process Plant of the 21st Century: Simple and Robust 7
Capital-related cost:
Maintenance cost 2% of DFC
Operational cost 2% of DFC
Depreciation 10 % of DFC
Capital cost 10 % of DFC

Total capital-related cost 24 % of DFC

Total capital cost
related to investment 24 % ” 1.1 ” DFC = 26.4 % of DFC = 2.64 MM

The annual profit per investment becomes:
revenues variablecost :264 DFC†=year
Annual profit/investment = 100 %
1:1 DFC
20 MM 16 MM :264 DFC†=year
Annual profit/investment = 100 %
1:1 DFC
which is equal to 12.36 % for a DFC of 10 MM

The sensitivity of the economic performance of the process plant as a function of
the DFC is shown in Table 1.2. An additional column has been added for a capital-
related cost alternative of 0.2” DFC. This might be realized by a longer depreciation
period, or a lower capital cost.
The results in Table 1.2show that, compared with a DFC of 10 MM at capital-related
cost of 0.264 ” DFC, the economic performance is strongly related to the DFC.
A decrease of the DFC by 25 % to 7.5 MM doubles the economic performance
to 24 %.
An increase of the DFC by 20 % to 12 MM halves the economic performance
to 6 %
A similar strong relationship between profit and DFC can be concluded from the
column with the lower capital-related cost.

Table 1.2. Sensitivity of economic performance versus investment.

DFC of facility Annual profit/ Annual profit/
(MM) investment * investment +
7.5 24.48 30.3
10 12.36 18.18
126.30 12.12
15 0.24 6.06
20 ±5.82 0.0
* % at capital cost 0.264 of DFC.
+ % at capital cost 0.2of DFC.