Power Water Insights No

				Power Water Insights No. 2 January 6, 2012

WELCOME

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· “Silica Scale Issues” Will be a “Hot Topic” Discussion on January 25

· 81 Percent of Planned Power Plants in the U.S. are Within Ten Miles of a Municipal Treatment Plant with Discharge Capacity to Meet Cooling Needs

· Xylem Gravity Media Filters are used to Treat Municipal Effluent Prior to use by Florida Power & Light

· Combined Cycle Plant Burning Sewage Sludge to Provide Additional Heat for HRSG

Join us on Wednesday, January 25 at 10 a.m. central time to hear and participate in a discussion of silica scale issues and answers for the power industry. Silica scale can cause problems in cooling towers and other equipment based on:

· Concentration mechanisms such as cooling water evaporation and RO concentrate

Bill Harfst of Harfst Associates will co host the session along with Bob McIlvaine of McIlvaine. Power plants with problems will be encouraged to ask questions. Suppliers of chemicals and equipment will be encouraged to provide answers. We will also encourage the experts from the consulting companies to join in as well.

There are three types of silica scale causing problems, Magnesium Silicate (is the most common), Aluminum Silicate and Iron Silicate.

The improvement in filtration and the need for chemical treatment go hand in hand. The number of cooling tower cycles can be increased with better side stream filtration, but the greater the number of cycles, the greater the concentration of silica. So preventing or dissolving the silica scale is needed to enjoy the benefit of better filtration.

For those involved in power plant water issues, the conference hosted at the University of Illinois each year is high on the list of events.

The 2012 workshop will offer talks on the following topics, along with other topics:

-A Comparison of Wet vs. Dry Scrubbing
-Advanced Gray Water Treatment System for Power Plant Makeup
-Boron Removal
-Cation Conductivity Monitoring in Cycling Plants
-Chemistry Data Collection for Statistical Analysis
-Compliance Plans for the Utility MACT
-Do Amines Have a Role in the Treatment of High Purity Boiler Feedwater?
-Effects of Dissolved Oxygen on FAC and Corrosion Product Transfer
-High Purity Boiler Water Production Using Municipal Wastewater
-How to Control Oxygen
-Low Level Oxygen Detection in Power Plants
-Make-Up Contamination
-Mercury Deposition Monitoring
-Mercury Removal
-Optical Dissolved Oxygen Measurement
-Power Plant Waste Stream Assessments
-Proper Care and Maintenance of pH Sensors
-Protective Coatings for Use in BOP Heat Exchangers and Condensers
-Reduction of Hazardous Waste Generation on Boiler Cleaning Waste
-RO Membrane Operations and Failures

Here are some of the ways that water and power technologies can be combined to achieve environmental and production goals in an optimum manner:

· Combust sewage sludge to increase HRSG temperatures in combined cycle operations

These technologies are already being utilized around the world. Examples are provided below. But let us not limit ourselves to the tried and true combinations. We should come up with novel ways to improve the synergy. Here is one idea from left field.

Why not send untreated municipal wastewater to the power plant? The reasoning is that if you are trucking the sewage sludge to the plant for use in the boiler and are simultaneously pumping the treated wastewater, why not combine the two and save the trucking cost.

One important factor in the practicality of this idea is geography. If the town is north and the power plant and municipal facility are south, then there is not much transport to be saved by combining the two facilities. If, on the other hand, the municipal plant is south, the town is in the middle, and the power plant is north, then the geography makes sense. Why transport sludge and water south and then separate them and truck and pipe them north. You can just pipe the sewage from the middle to the north.

Another important factor is the future demand for water and power in the area. If an addition to the wastewater plant is contemplated, then there is an incentive to consider the combination scheme. If a new power plant is under consideration, then the various synergies need to be considered.

One of the factors affecting the value is whether the treatment scheme itself can be customized to take advantage of the combination location. One possibility would be to use the biosolids in one form or another for fuel reburn. Gasified sewage or even sewage slurry could be injected above the primary firing zone to result in a NO_x reduction of up to 20 percent. There would be an offsetting reduction in coal usage if the gasification route is chosen. If the slurry route is chosen, then the coal usage will be a function of the amount of water injected. At some point the evaporation requirement exceeds the fuel value of the biosolids.

Gasification can be accomplished with partial combustion or by anaerobic digestion. Both technologies are well established. Gasification through partial combustion is possible with either solids or slurries.

There is a big push on creating liquid manure and piping to biogas plants. Liquid manure could become a supplemental fuel to the municipal sludge. This liquid flow could enter the pipeline from farms and even industrial plants in the area.

The environmental aspects make lots of sense. Combustion of sewage in a coal-fired boiler results in less dioxin production than from a dedicated combustor. The new rules for air toxic emissions from power plants assure high purity flue gas exiting the stack.

Let us know your thoughts on this matter. You can e-mail Bob McIlvaine at: rmcilvaine@mcilvainecompany.com. You can also stop by our stand at EUEC at stand 938. We covered the show in depth in our Power Water Insights #1. You can obtain registration details at: http://euec.com/index.aspx.

81 Percent of Planned Power Plants in the U.S. are Within Ten Miles of a Municipal Treatment Plant with Discharge Capacity to Meet Cooling Needs

A study sponsored by the U.S. Department of Energy entitled, “Reuse of Treated Internal or External Wastewaters in the Cooling Systems of Coal-Based Thermoelectric Power Plants,” showed that treated municipal wastewater is the most common and widespread source in the United States. Data analysis revealed that 81 percent of power plants proposed for construction by the Energy Information Administration (EIA) would have sufficient cooling water supply from one to two publicly owned treatment works (POTW) within a 10-mile radius, while 97 percent of the proposed power plants would be able to meet their cooling water needs with one to two POTWs within twenty-five miles of these plants. Thus, municipal wastewater will be the impaired water source most likely to be locally available in sufficient and reliable quantities for power plants. Results of initial studies indicate that it is feasible to use secondary treated municipal wastewater as cooling system makeup. The biodegradable organic matter, ammonia-nitrogen, and phosphorus in the treated wastewater pose challenges with respect to enhanced biofouling, corrosion, and scaling, although current research is demonstrating that these problems can be controlled through aggressive chemical management.

Xylem Gravity Media Filters are used to Treat Municipal Effluent Prior to use by Florida Power & Light

The East Central Regional Waste Reclamation Facility (ECRWRF) in West Palm Beach uses Xylem (Leopold) tertiary FilterWorx filters to purify its effluent for delivery to the Florida Power & Light power plant. Six filters are utilized with a total area of 4212 ft².

Each Leopold^® FilterWorx™ tertiary filter is engineered to achieve the specific performance requirements. Based on over 40 years of experience treating wastewater, more than 200 Leopold tertiary filter systems are installed worldwide. The tertiary filters employ an upflow water wash with full bed cleaning. To ensure thorough cleaning of the filter media, the filters also employ air scour.

Ismat Kamal, Principal Technical Specialist, Fluor makes a convincing argument for combining seawater desalination with power generation.

The economic benefits of integrating seawater desalination with power plants are discussed, starting from the first principles of thermodynamics. The concepts of the "fuel-use performance ratio" and the "power loss" method are described in the context of their usage for thermal cycle evaluation and desalination process selection, both with conventional steam cycles and with combined cycle power plants. A thermo-economic model is introduced to evaluate water and power costs, and rates of return in dual-purpose power/desalination applications. The future of integrated power and desalination plants is discussed with reference to the growing role of seawater reverse osmosis (SWRO) in the desalination area. A case study is presented to evaluate the benefits of integrating SWRO with existing power/desalination plants in the Middle East. Repowering and retrofitting could result in a nearly three-fold increase in the power generating capacity and an over six-fold increase in the water output, without requiring any expansion of the seawater intake system. Based on natural gas fuel, the repowered plant could also result in a 70 percent increase in the fuel efficiency of the station and a drastic reduction in the cost of water production.

For a privatization scenario, an economic analysis is used to show that attractive rates of return could be obtained if a developer were to purchase and refurbish the existing plant, selling the products on a build own and operate (BOO) basis. In preparation for this promising application, the need for pilot plant testing at existing power/desalination stations, together with research and development work in membrane technology for high temperature operation is emphasized.

Combined Cycle Plant Burning Sewage Sludge to Provide Additional Heat for HRSG

The 850 MW gas combined cycle power plant was added to the Mellach power complex in Austria. The plant was built for ATP by Siemens and cost an estimated €400 million. It also provides 250 MW of district heating for the Greater Graz Region, so generating around 5,000 GWh a year.

The existing Mellach power plant already had an installed electrical power of 245 MW and 230 MW district heating. The plant is powered by hard coal. It is burning up to 6t/h or 99t/d of wet sludge, so 34,900t/a. With dry matter, the amount is about 10,500t/a.

The tightening of the regulations of the Austrian Federal Waste Management Act has greatly reduced the extent to which sewage sludge can be used on agricultural ground. Since January 1, 2004, no untreated and only drained sludge from commercial sewage plants has been allowed to be deposited.

The simultaneous combustion of sewage sludge at Mellach is a way of disposing of this. CO₂emissions are reduced as the sewage sludge is used as a substitute for coal. At the Fast Forward Awards 2005, ATP won the special prize for eco-technology for the project.

A test operation was performed in Mellach in December 2003 on sludge burning. The drying capacity of the coal mills was sufficient for an average water content of coal and a maximum sludge amount of 1.5t/h per mill. If the coal water content rises, the sludge amount has to be reduced. The chemical and physical properties of fly ash and gypsum are similar to those without burning sludge.

Steam is generated in a steam generator through the combustion of coal, natural gas, crude oil, biomass and substitute fuels. The steam leaves the steam generator and flows through the guide and rotor blades of the turbine, which drives the generator via gear transmission. Electricity from the generator is fed into the interregional grid.

The steam that exits the turbine is converted back into water in the condenser unit. This water is then fed back into the steam generator and the water-steam cycle starts again. In co-generation plants that produce heat and electricity, part of the steam is taken from the turbine and used to heat the water of the district heating network.

In August 2002, PSEG Power, the energy producing subsidiary of Public Service Enterprise Group (PSEG) awarded USFilter, acquired by Siemens Water Technologies in 2004, a US$1.2 million contract for a system to filter reclaimed water for reuse in the cooling towers at its Linden combined cycle plant in New Jersey.

The 1,220 MW project began commercial operations in May 2006. The plant uses about 12 mgd (8,100 gpm) of reclaimed water from the Linden and Roselle Sewage Authority (LRSA) for its cooling tower make-up.

PSEG Power utilizes reclaimed water which is treated effluent from local municipal wastewater treatment plants at the Linden combined cycle plant.

Hydro-Clear pulsed bed sand filters treat an average flow of 4,200 gpm of reclaimed water from the Linden-Roselle Sewerage Authority wastewater treatment plant. The filtration system consists of seven cells in concrete tanks located on the sewerage authority property.

The installation has increased the water reuse capacity to around 10,000 gpm, while use of recycled treated wastewater for cooling tower make-up and the closed loop cooling systems has reduced the municipal water consumption of the plant by about 10 million gallons per month.

Reclaimed water from LRSA wastewater treatment plant is piped to an auxiliary treatment facility where the water is chlorinated and filtered. After filtration, the reclaimed water is pumped approximately one mile to the Linden power station and further treated.

The treatment includes the addition of hypochlorite to kill selected biological organisms and the sand filters to remove grease, residual oil and suspended solids from the treated water. It is then pumped at 8,100 gpm via a 24 inch pipe to the plant's cooling tower basins. The water is conventionally treated in the cooling basins.

The process prevents scaling and foaming of the two ten-cell mechanical draft-cooling towers. Excess water is returned to the wastewater treatment plant where it is stored in tanks and discharged maintaining the flow. The beneficial reuse of reclaimed water reduces the power station's dependence on potable water while assuring a reliable, continuous source.

Of the 200 people interviewed at Power-Gen in Las Vegas last month, nearly half had insights on water. In the western U.S., Mexico, China and many other parts of the world, the reduction in use of water for power generation is high on the priority list. SPX has just signed an agreement with Shanghai Electric to jointly offer dry cooling systems for Chinese power plants. Since this approach is more expensive than wet cooling, it is apparent that China is setting an even higher priority on water conservation than is the U.S. Here are a few of the other Power-Gen exhibitors who were focused on water:

Pictured below is Jose Gutierrez, Director of Business Development for ITT Industrial Process. Jose is responsible for vertical pumps and is photographed with one of those pumps on display at Power-Gen.

Pictured below from left to right is Daniel Mahanor, Vice President, Utility Sales, Rachel Sagiroglu, Trade Show & Event Manager and Douglas Rountree, Vertical Account Manager for Clean Harbors. Clean Harbors is a provider of environmental, energy and industrial services, including hazardous and non-hazardous waste recycling, treatment and disposal, field services, emergency response and disaster recovery.

Pictured below from Buckman USA is David Herndon, District Manager, Water Technologies, Mark Harbison, Buckman Power Group Leader, Robert Byers, Buckman Power Group Leader and Debbie French, Market Analyst and PT Project Coordinator Global Marketing Communications. Buckman is a supplier of specialty chemicals through a network of associates who identify, prevent and solve problems.