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Abstract:
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The continuous or intermittent use of natural gas in place of
oil or coal in existing utility boilers would reduce emissions of sulfur and
thereby the concentration of sulfate ions in precipitation. This report
examines the technological feasibility and capital cost of retrofitting oil
and coal fired utility boilers to burn intermittently natural gas and the
parent fuel. Using extensive studies of the retrofitting of such boilers to
burn synthetic gas of low to moderate heating value (LBG), it is found that
natural gas closely simulates the combustion properties of LBG of medium
heating value. Based upon this comparison, it is concluded that little or no
modifications to the boiler are required to achieve the same boiler rating as
when burning the original fuel, and that only a small efficiency penalty must
be paid. Examination of the history of four eastern utility boiler
conversions from oil to natural gas confirms these performance estimates, and
shows that conversion costs for in-plant equipment are very small, less than
19 $(1985)/KW in all instances, while conversion times are less than one year
(with little down time beyond that required for annual maintenance).
Pipelining costs will vary with the local conditions. |
