The emission of sulfur dioxide when high-sulfur coal is burned is restricted by law. New coal-burning plants usually comply with the law by installing expensive equipment to filter sulfur dioxide from their emissions. These new plants could save money by installing .

The correct answer is: Using a cost-effective dispensing or cleaning instrument that can remove sulphur chemically from coal before combustion.

Explanation:

Coal is a rich source of chemical energy. It is burnt in the presence of air (oxygen) or made to undergo combustion to obtain huge amount of energy in the form of heat that can be transformed into other forms of energy like electricity.Often natural coal remains associated with impurities like sulphur.Combustion of sulphur generates sulphur dioxide which is a major air pollutant.This is the reason why the sulphur needs to be removed from coal.Removal of sulphur in the form of sulphur dioxide is a costly process as the filter required for sulphur dioxide filtration is expensive.This is the reason why new coal burning plants need to look for alternate strategy to remove the sulphur.This can be done by chemically removing sulphur from coal before the process of combustion by converting sulphur to hydrogen sulphide, sulphuric acid or sulphate salts.The chemical removal of sulphates is less costly.

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