1.1 The Global Emissions Challenge

The global challenge of sulfur oxide emissions from fossil fuels is a defining issue for the energy and chemical industries. In the United States alone, over thirty million tons of sulfur dioxide are discharged into the atmosphere annually, with 75% of this total resulting directly from fuel combustion. While post-combustion flue gas treatment is a common mitigation strategy, treating fuels prior to combustion presents a potentially more energy-efficient and proactive approach to emissions control.

1.2 Regulatory and Economic Drivers

The imperative to clean fossil fuels is driven by a combination of stringent environmental regulations and complex economic factors. Legislative actions have set firm limits on the allowable sulfur content of fuels. Notable examples include regulations in California limiting fuel oil to 0.5% sulfur or less, an even stricter 0.3% sulfur limit on oil in effect in New York City since 1968, and a 1% sulfur limit on coal established in Massachusetts. Such regulations are increasingly being considered across the Atlantic seaboard. While desulphurisation adds to the initial cost of fuel, these expenses can be offset by savings in transportation and the reduced need for capital-intensive flue gas desulphurisation systems.

1.3 The Dual Challenge for Industry

The chemical and power industries are tasked with striking a delicate balance between two often-competing public requirements: providing increased quantities of energy to fuel economic growth and preparing cleaner fossil fuels to protect environmental quality. With global energy demand projected to rise, the use of more remote and often higher-sulfur crude oils is increasing, threatening to double worldwide sulfur dioxide emissions. This dynamic forces industries to desulfurize more fuel more completely and/or remove a greater amount of sulfur dioxide from stack gases.

1.4 Transition to Technology Analysis

This report will now proceed with a detailed examination of the specific desulphurisation technologies and strategic considerations for each of the primary fossil fuels: fuel oil, natural gas, and coal.