Sulfuric acid, byproduct, price

An improved magnesium oxide (MgO) flue gas desulfurization process and its comparative economics are described. Innovations made include the use of a spray dryer, a cyclic hotwater reheater, and a coal-fired fluidized-bed reactor for regeneration of the MgO absorbent. Several technical concerns with the proposed design are addressed, including fly ash and chloride buildup. The economic evaluation shows the process to have a capital investment of about seven percent less than that of a conventional MgO scrubbing process and a 40 percent smaller annual revenue requirement. Finally, a sensitivity analysis is shown relating annual revenue requirements to the byproduct sulfuric acid price credit. 

Since the annual revenue requirements for the spray dryer and conventional MgO processes appear to be sensitive to the byproduct credit for sulfuric acid, and since sulfuric acid prices have risen dramatically in the last few years, the sensitivity of the first-year annual revenue requirements to the price of byproduct sulfuric acid was projected. The results are shown in Figure 3. 

As is apparent from this figure the first-year annual revenue requirements can vary somewhat, depending on the price received from the byproduct sulfuric acid. The base-case credit of 65/ton of 10055 H2SO4 results in a first-year annual revenue requirement of 10.47 mills/kWh for the spray dryer MgO process and 14.69 mills/kWh for the conventional MgO process. At a byproduct credit of 35/ton which is approximately equivalent to the price of sulfuric acid in the past (or which could be the 1984 price netted after transportation costs are subtracted for a utility situated far from the ultimate consumer), the first-year annual revenue requirements for the spray dryer MgO process rise nearly 10 percent to 11.53 mills/kWh. This cost, although slightly lower than that for the limestone scrubbing process, is essentially equivalent given the accuracy associated with this study. For... 

Sensitivity of annual revenue requirements to byproduct sulfuric acid price. 

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