This report discusses the terms 'modification' and 'reconstruction' as related to New Source Performance Standards (NSPS) for SO2 emissions from coal-fired boilers greater than 250 million Btu per hour input. An analysis of current boiler technology indicates there are few physical or operational changes that would qualify as modifications or reconstruction in the sense of altering SO2 emissions from a boiler system. This is true because SO2 emissions are a function of the sulfur content of the fuel and are not affected by furnace and boiler design and operating parameters. Two situations which could be construed as modifications affecting SO2 emissions would be conversion of a wood burning facility to coal or the use coal/oil slurries in a boiler originally designed for oil. Neither of these are expected to be widespread occurrences. First, there are few wood-fired boilers in the size range covered by NSPS and, secondly, it is doubtful there would be any incentive for such units to switch from a cheap waste fuel to a more expensive primary fuel. Boilers using coal/oil slurries have only recently been proposed and are still at an experimental stage. Also discussed in this report are some of the constraints that could inhibit an existing facility from installing flue gas desulfurization equipment.

Project Officers: K.R. Durkee and K.R. Woodward. Prepared by GCA Corporation under Contract Number 68-02-2607. Includes bibliographical references (page 20).

This report discusses the terms "modification" and "reconstruction" as related to New Source Performance Standards (NSPS) for SOb2s emissions from coal-fired boilers greater than 250 million Btu per hour input. An analysis of current boiler technology indicates there are few physical or operational changes that would qualify as modifications or reconstruction in the sense of altering SOb2s emissions from a boiler system. This is true because SOb2s emissions are a functionsof the sulfur content of the fuel and are not affected by furnace and boiler design and operating parameters. Two situations which could be construed as modifications affecting SOb2s emissions would be conversion of a wood burning facility to coal or the use coal/oil slurries in a boiler originally designed for oil. Neither of these are expectd to be widespread occurrences. First, there are few wood-fired boilers in the size range covered by NSPS and, secondly, it is doubtful there would be any incentive for such units to switch from a cheap waste fuel to a more expensive primary fuel. Boilers using coal/oil slurries have only recently been proposed and are still at an experimental stage. Also discussed in this report are some of the constraints that could inhibit an existing facility from installing flue gas desulfurization equipment.