Encyclopedia of Environmental Science and Engineering, Volume I and II

416 FOSSIL FUEL CLEANING PROCESSES

In case 2, although metals content is also low (
40 PPM),

hydrogen consumption is exceptionally high. This is due to

the fact that conversion was not minimized and 7% naphtha

and 13% middle-distillate was produced by hydrocracking.

Case 3 is characteristic of high metals content (
320 PPM)

oils from that area. As noted previously, catalyst deactivation

increases with metals content. Therefore, catalyst addition rates

are higher, resulting in increased operating costs. To compensate

for the reduced catalyst activity, higher operating temperatures

and/or residence times are used.

Cases 4–6 summarize vacuum residua operations.

Desulfurization rates for vacuum residua are lower than for

atmospheric. The asphaltenes and metallic compounds reside

in the vacuum residuum, consequently increasing catalyst

deactivation rates and therefore catalyst costs per barrel. In

all the cases depicted (4–6) hydrogen consumption, relative

FRESH CATALYST

REACTOR

II

REACTOR

I

FEED OIL

MAKE-UP

HYDROGEN

RECYCLE HYDROGEN

THE H-OIL PROCESS

LIQUID

PRODUCT

FIGURE 3

TABLE 2

H-OIL desulfurisation of atmospheric and vacuum residuals

Type-Feed (A-atmos) (V-vacuum) Case 1A Case 2A Case 3A Case 4V Case 5V Case 6V

Source Kuwait W. Texas Venezuela Kuwait W. Texas Venezuela

Feedstock data —— — —— —

Sulfur (Wt%) 3.8 2.5 2.2 5.0 2.2 2.9

Vanadium and nickel (PPM) 60 40 320 90 55 690

975ºF —— — —— —

Vol% 45 45 52 80 70 75

Sulfur, Wt% 5.3 3.2 2.8 5.3 2.7 3.2

Yield, quality (400ºF) —— — —— —

Vol% 99.3 96.0 94.2 94.7 92.9 92.9

% S 0.9 0.4 0.9 1.8 0.6 1.2

Chemical H 2 —— — —— —

Consumption (SCI-/BBL)

For S removal (est.) 290 210 140 340 170 200

Total 490 670 470 660 640 920

Economics (Relatives) —— — —— —

Capital inv. est. 6.7 7.8 6.9 7.9 8.3 8.9

OP cost, (20,000 BPSD UNIT) 33 40 39 44 46 65

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