NEWS RELEASE NOVEMBER 2011
Power Plants should be Producers of Chemicals and Pure Water
Fossil-fired power plants convert less than half the energy in the fuel into power. However, by operating the plant as a producer of power and of other synergistic products the net greenhouse gases are reduced. There are many combinations which result in a lower combined cost for the power and the product. These are the conclusions reached in Fossil & Nuclear Power Generation published by the McIlvaine Company.
Some of these combinations are well established: power plus desalination, power plus district heating, power plus disposal of sewage sludge, power plus disposal of municipal solid waste. But there are many other combinations which need to be pursued.
There is a big potential to manufacture hydrochloric acid. Coal-fired power plants generate hydrogen chloride during coal combustion. New regulations require that it be removed from the exhaust gas. The cost to make salable acid is no more than the cost of scrubbing and disposing conventionally. By eliminating the chloralkali plants, which would otherwise produce the acid, there is a big environmental benefit.
Regulators in Pennsylvania and other states and countries who are starting to take advantage of gas shale extraction are searching for ways to cost effectively handle the fracturing flow back water. This water contains 10 times the amount of salt found in seawater. Thousands of trucks are utilized in transporting this slurry to a final destination. The first choice was municipal wastewater treatment plants. However, the highly acidic water killed the microbes which make biological treatment successful, so this option was eliminated.
The preferred option now is evaporation and generation of distilled water and solids. Rather than achieve this in a dedicated plant it will be better to utilize the waste heat from coal-fired power plants in the area. Power plants run at peak load during the daytime but run at lower capacity during the night. So with batch holding tanks for the wastewater, the evaporation process can be conducted in the off peak hours.
Cellulosic ethanol plants provide a unique synergy with coal-fired generators. Acids produced by the power plant can be used for the first stage sugar separation. Steam produced by the power plant can be used for processing. Biosolid waste produced by the ethanol plant can be burned as supplemental fuel in the power plant.
The Spiritwood Station under construction in Jamestown, North Dakota incorporates a number of integrated processes. The plant owned by Great River Energy will be in operation next year. Here are some of the innovative processes incorporated:
- Provide steam to Cargill Malt.
- Utilize innovative technologies to dry the lignite used as the fuel.
- Utilize wastewater from the Cargill Malt plant and the City of Jamestown.
- Supply steam to the Dakota Spirit AgEnergy plant which will convert wheat straw into cellulosic ethanol.
- Burn purified lignin pellets produced by the ethanol plant to replace some of the lignite.
Electricity generators, regulators, and in particular, environmentalists have to start thinking more innovatively about the very big opportunity to coordinate power production with other products to improve the environment and reduce production costs.
For more information on Fossil & Nuclear Power Generation: World Analysis & Forecast click on: http://www.mcilvainecompany.com/brochures/energy.html#n043