Introduction
The Environmental Protection Agency (EPA) has taken a keen interest in the application and promotion of desulfurization technologies for the purification of flue gas from thermal power plants. The purpose of this paper is to provide a detailed analysis of the underlying technology, discuss the potential environmental benefits of its implementation, and evaluate the factors that may impact its wider application.
Technology Description
The desulfurization technology involves the use of a variety of processes such as wet scrubbing, electrostatic precipitation and dry sorbent injection to reduce the sulfur content of flue gases. Wet scrubbing is by far the most common form of desulfurization technology utilized due to its high removal efficiency rate, relatively low operating costs and its ability to be used with a variety of stream configurations.
In wet scrubbing systems, an absorbent (usually lime or limestone) is injected into flue gases and reacts with the sulfur dioxide present. The reaction creates a liquid slurry (gypsum) which is then removed from the system.
Benefits of Desulfurization
The most obvious benefit of desulfurization technology lies in its ability to reduce levels of sulfur dioxide in flue gases, thus improving the air quality of the surrounding environment. In addition, it may also help to mitigate other air pollutants such as particulate and nitrous oxide, as well as reduce energy consumption due to reduced cooling and heating requirements.
Costs of Desulfurization
The costs associated with implementing desulfurization technology can be further categorized into capital, operating and maintenance costs. The capital cost typically depends on the type of equipment and system chosen, however, overall capital costs are known to increase with rising sulfur dioxide concentrations. Operating and maintenance costs are generally sensitive to total sulfur dioxide removal efficiency and the type of absorbent used in the wet scrubbing system.
Factors Impeding the Wider Application
The wider application of desulfurization technologies is limited by several factors. These include the time and cost associated with the installation and maintenance of the equipment, the local availability of suitable absorbents, and the current shortage of skilled personnel with the relevent expertise to run such highly automated operations.
Conclusion
Desulfurization technology offers considerable potential for reducing the sulfur content of flue gases from thermal power plants, however, the implementation and wider application of such technology is currently limited by a number of factors. A detailed analysis of the technological and cost implications of desulfurization, as well as effective policies to address skilled personnel shortages, will be necessary to ensure the success of such a project.
