Cost analysis without including carbon cost (Case Study 2)
% Oil firing
Calc. eff. in %
Total fired duty
Cost of carbon
Cost of fuel oil +
Cost of FG
Total cost
in Gcal/h
in Rs/h
associated atomising
in Rs/h
in Rs/h
steam in Rs/h
0
92
21.74 21.83 21.93 22.03 22.12 22.22
0 0 0 0 0 0
0
66,163 53,162 40,046 26,815 13,467
66,163 65,112 64,053 62,985 61,906 60,819
20 40 60 80
91.6 91.2 90.8 90.4
11,951 24,007 36,169 48,439 60,819
100
90
0
Table 3
67 , 000
87 , 500 88 , 000 88 , 500 89 , 000 90 , 000 89 , 500 90 , 500 91 , 000
66 , 000
65 , 000
64 , 000
63 , 000
62 , 000
61 , 000
60 , 000
87 , 000
0
20
40
60
80
100
120
0
20
40
60
80
100
120
% of oil ring
% of oil ring
However, fuel oil firing emits higher carbon than fuel gas firing. Thus, if carbon cost is included in estimating the operational cost of fuel, the economics change completely. Table 3 shows the operational cost variation of firing fuel oil from 0% (100% fuel gas firing) to 100% (0% fuel gas firing). Case Study 2 is performed for a 20 Gcal/h absorbed duty fired heater. Though such a detailed assessment is not carried out while evaluating fuel switchover, a gradual increase in fuel gas is considered for this study to clarify the graph represented in Figure 2 . Going forward, as soon as a carbon cost is allocated to the tonne of CO₂ emitted, which in this case is €50/tonne, in line with the EU ETS, the operating costs seem to change significantly, as shown in Table 4 . Figure 2 Operational cost economics without carbon cost (Case Study 2)
When represented pictorially, the operational curve for the revised evaluation with carbon cost appears as shown in Figure 3 . Thus, the stark reversal of the operat - ing curve is evident. Without carbon cost in the reckoning, fuel oil gains over fuel gas firing by a large margin, and in this process, the efficiency of the equipment is sacrificed to an extent. However, with carbon cost included in the total cost of operation, fuel gas firing is a clear winner. The mandate to shift to cleaner fuels came into practice due to greenhouse emission reduction requirements binding for each industry. Naturally, economics were not in favour until CO₂ pricing emerged. An important corollary of this case study is that carbon cost is a vital cog in promoting energy efficiency. Figure 3 Operational cost economics including carbon cost (Case Study 2 modified)
Cost analysis including carbon cost (Case Study 2 modified)
% Oil firing
Calc. eff. in %
Total fired duty
Cost of carbon
Cost of fuel oil +
Cost of FG
Total cost
in Gcal/h
in Rs/h
associated atomising
in Rs/h
in Rs/h
steam in Rs/h
0
92
21.74 21.83 21.93 22.03 22.12 22.22
21,172 22,895 24,634 26,387 28,156 29,941
0
66,163 53,161 40,046 26,815 13,467
87,335 88,008 88,687 89,372 90,063 90,761
20 40 60 80
91.6 91.2 90.8 90.4
11,952 24,007 36,170 48,440 60,819
100
90
0
Table 4
73
PTQ Q3 2024
www.digitalrefining.com
Powered by FlippingBook