E.C. Gaston Steam Plant

The E.C. Gaston Steam Plant has been in operation for over 50 years near Wilsonville, Alabama in Shelby County. The first two units began producing in 1960, and three more units followed as demand increased. Today the combined output of the five units is 1,880 megawatts. Two of the five units run on maxDNA Distributed Control Systems, while two more run on MAX1000, D level Distributed Control Systems. Eventually the goal is to have units 1 thru 4 operating on maxDNA so that the technology level for the first four units is the same. MaxDNA is the most current automation system, so upgrading the two units on MAX1000 will bring them up to current technology standards. The benefit of like technology among the units is that there are savings in the maintenance of the units, as well as having to only stock spare parts for one type of technology rather than two. Employees also need to be trained on only one type of technology, which could result in a savings of man hours. The first two units are Babcock & Wilcox (B&W) coal-fired, with 18 opposed burners. These two units each produce 1,700,000 pounds of steam per hour, which in turn is turned into electricity. Coal is pulverized before being supplied to the furnace. The pulverizing process is done by B&W Type EL Pulverizer mills. Feedwater, which is converted into steam, is provided by three motor-driven boiler feed pumps. Each pump has a hydraulic coupling, which controls the rate of the water flow. The maxDNA DCS’s monitor performs several functions, including data acquisition, data links to other balance-of-plant systems, boiler safety and burner management, boiler-turbine control, and soot blower sequential control. The upgrade for the two outdated units is being delivered as a turnkey control system, so that downtime will be minimal. The control system includes backup power (UPS), equipment housing, and a control room. To make the transition to the new system as smooth as possible, the operators were involved in the system design and implementation of the data acquisition screens. Over 200 display screens were configured as part of this new system. Despite these improvements to the equipment used in this power plant, materials likely used to construct the facility itself remain a potential threat. In fact, the Environmental Protection Agency’s Toxic Release Inventory ranked this plant at number 14 in terms of coal waste. Other materials this plant might have released in large quantities is asbestos, which was used to provide insulation in these structures. Although an effective protective additive to reinforce insulation against heat, fire and chemicals, asbestos also poses significant health risks when humans come into contact with it, leading to the development of diseases like asbestosis and mesothelioma. References: