Seawater Scrubbing for the Removal of Sulfur Dioxide in a Steam Turbine Power Plant

Abstract

The most popular method of controlling sulfur dioxide (SO2) emissions in a steam turbine power plant is a flue gas desulfurization (FGD) process that uses lime/limestone scrubbing. Another relatively newer FGD technology is to use seawater as a scrubbing medium to absorb SO2 by utilizing the alkalinity present in seawater. This seawater scrubbing FGD process is viable and attractive when a sufficient quantity of seawater is available as a spent cooling water within reasonable proximity to the FGD scrubber. In this process the SO2 gas in the flue gas is absorbed by seawater in an absorber and subsequently oxidized to sulfate by additional seawater. The benefits of the seawater FGD process over the lime/limestone process and other processes are; 1) The process does not require reagents for scrubbing as only seawater and air are needed, thereby reducing the plant operating cost significantly, and 2) No solid waste and sludge are generated, eliminating waste disposal, resulting in substantial cost savings and increasing plant operating reliability. This paper reviews the thermodynamic aspects of the SO2 and seawater system, basic process principles and chemistry, major unit operations consisting of absorption, oxidation and neutralization, plant operation and performance, cost estimates for a typical seawater FGD plant, and pertinent environmental issues and impacts. In addition, the paper presents the major design features of a seawater FGD scrubber for the 130 MW oil fired steam turbine power plant that is under construction in Madinat Yanbu Al-Sinaiyah, Saudi Arabia. The scrubber with the power plant designed for burning heavy fuel oil containing 4% sulfur by weight, is designed to reduce the SO2 level in flue gas to 425 ng/J from 1,957 ng/J.

Minimization of SO2 Emissions at ADGAS (Das Island, UAE): I- Current vs. Modified Schemes

“…• Utilization of free seawater and air along with their availability results in a significant reduction in the SW-FGD plant operating costs [20,21].…”

“…• Waste disposal is not a concern in the SW-FGD process as it does not generate any waste. This eliminates any cost to be spent on waste disposal, and leads to higher reliability [20,22].…”

Kinetics of the Iron(II)- and Manganese(II)-Catalyzed Oxidation of S(IV) in Seawater with Acetic Buffer: A Study of Seawater Desulfurization Process

“…Finally, the liquid waste is cooled down and discharged back to the sea. Compared to the wet limestone process, SFGD has two main advantages: (1) because seawater itself is alkaline (pH 7.5–8.3), alkaline absorbent is not necessary in the scrubber, and (2) the effluent seawater treatment process is much simpler, as only a simple aeration basin is needed to oxidize S(IV) to S(VI), a natural component of seawater. ,, To date, many countries, including Norway, , Malaysia, Indonesia, Saudi Arabia, and China, ,− have installed SFGD technology.…”

Study on the Relationship between Absorbed S(IV) and pH in the Seawater Flue Gas Desulfurization Process

“…To date, many countries, including Norway, , Malaysia, Indonesia, Saudi Arabia, and China, − have installed SFGD technology. The thermal power plants along the coastal area of eastern China, which is highly industrialized and has a high population density, account for one-third of the total thermal power plant output capacity of the entire country.…”

“…1,4,5 Indeed, Tilly et al found seawater scrubbing to be the "best practicable environmental option" among four different desulfurization processes (spray drying, wet limestone, Wellman−Lord, and seawater scrubbing). 6 To date, many countries, including Norway, 7,8 Malaysia, Indonesia, Saudi Arabia, 9 and China, 10−12 have installed SFGD technology. The thermal power plants along the coastal area of eastern China, which is highly industrialized and has a high population density, account for one-third of the total thermal power plant output capacity of the entire country.…”