Showing posts with label feedwater. Show all posts
Showing posts with label feedwater. Show all posts

Saturday, September 14, 2019

Minimize Controllable Feedwater Heater Losses Through Heat Rate Awareness


A feedwater heater is a device used in a power plant to pre-heat water being delivered to a steam generating boiler. Preheating the feedwater prior to steam generation improves the thermodynamic efficiency of the system. Heat rate is a measure of how efficiently a power plant uses heat energy. You can measure heat rate by the number of BTUs the power plant requires to generate a kilowatt hour of energy. As your heat rate goes up, so do your fuel costs. Considering fuel expenditures account for 70 to 80 percent of production costs and millions of dollars per year, improving heat rate one percent could generate five hundred thousand dollars in annual savings for a 500 megawatt power plant.

To contain fuel costs, power plants must maximize the efficiency of their feedwater heaters. That's why many companies today are focusing on improving heat rate as a way to use their feedwater heaters more effectively and significantly reduce their fuel costs.

The video above (courtesy of Magnetrol) explains ways to focus on heat rate awareness to minimize controllable losses from the feedwater system.

For more information, contact M.S. Jacobs and Associates. Call them at 800-348-0089 or visit their web site at https://msjacobs.com.

Wednesday, October 12, 2016

Conductivity Controller For Boiler Applications

Multivariable water quality controller
Conductivity controller for boiler applications
Lakewood Instruments
Modern boilers using the Rankine cycle require feedwater and make-up feedwater quality maintained within certain limits with respect to alkalinity, conductivity, and other factors in order to maintain boiler operating efficiency and minimize maintenance requirements.

Controlling the feedwater quality can be accomplished with the addition of controlled amounts of the right chemicals to regulate various aspects of water quality. Another method is to purge, or blowdown, the boiler in a measured fashion that allows fresh feedwater to replace overly contaminated water. Filtration, which I generally deem to include ion exchange, reverse osmosis, and mechanical filtration, is a third method. All deal specifically with a limited scope of contaminates that have an impact on boiler operation and longevity.

Boiler blowdown can be used to limit the amount of total dissolved solids in the boiler drum water. As water boils, the dissolved solids in the water concentrate in the remaining liquid water. Blowdown purges a portion (or all) of this water, allowing the addition of water, presumably treated, with substantially lower total dissolved solids.

Boiler blowdown has an energy cost, since the replacement water must be heated to the design condition. It follows that executing this procedure should be undertaken when necessary, but not more frequently. A conductivity monitor and controller can accomplish properly timed blowdown cycles. The system consists of a conductivity sensor and a control unit that provides all the necessary functionality in a single integrated package. A data sheet is included below for one such unit from Lakewood Instruments.

Share your boiler operation challenges with an instrumentation specialist an explore how a properly instrumented steam system can provide operational savings and extended time between failure.