Environmental Engineering Reference
In-Depth Information
Evaluate performance functions
ε
C
and EP over the conversion interval
0.3 <
X
< 0.975 and make a Pareto plot (EP vs.
ε
C
). What is the design point
{
X
∗
,
ε
C
,EP
∗
} that you would advise to the management as being the optimum
and why?
7.2 Analysis of Economic Potentials for Fischer-Tropsch Conversion
Each level of design has its own economic potential function. The definition of
economic potential for the input
output level (1) is given by Equation (7.3),
along with a feasible range for the profitability margin (0.50
-
-
0.75). Taking that
range as criterion, has the Fischer
Tropsch base case design presented in
Section 7.9 a satisfactory profitability margin? The economic results in
Table 7.4 can be used for making an assessment.
-
The prices of hydrocarbons can be volatile over time. How much (by which
fraction) can the product prices approximately drop before the lower limit on the
profitability margin is reached while assuming the feed and waste costs remain
constant?
7.3 Sensitivities in the Design of the Fischer-Tropsch Conversion
Consider the process block for the Fischer
Tropsch conversion with syngas
recycle in Figure 7.12. The physical and economic models in Section 7.9 can
be used with the base case feed composition Equation (7.12) and design condi-
tions Equation (7.17). Determine and report for the next four design sensitivity
cases with a one-at-a-time change in a design variable:
-
η
1. Increase in CO conversion (
: 0.50
)
0.54)
λ
2. Increase in separation efficiency (
: 1.00
)
1.04)
3. Increase in production rate (
F
5
,
C
4+
: 9.20
)
10.0)
4. Increase in recycle fraction (
r
: 0.90
)
0.94)
the following quantities on an hourly basis:
The extents of the reactions
The species flows in the reactor outlet stream (3) and the process outlet
stream (5)
The total molar flow rate of feed stream (1)
The economic potential (EP
1
)
The capital cost
The economic potential (EP
3
)
The carbon atom efficiency
The molar fraction of water in the effluent of the conversion unit (stream 3)
Explain the differences in economic and carbon atom efficiency performances
and the reactor effluent water fraction, relative to their base case values.
Search WWH ::
Custom Search