Balancing Chemistry Helps Control Costs

Kurt Bayburt explains in Power Magazine a few ways Apache Station remains competitive

The concept of how we generate electricity can sound simple. Burning fuel boils water to turn a steam turbine which then spins a generator to create electricity. But containing that process of combustion and the steam created by it requires costly maintenance. Kurt Bayburt, AzGT chemistry manager, recently wrote in Power Magazine about many small things can get overlooked and create major maintenance expenses.

“In my previous job as an industrial water treatment sales representative, we focused on communicating the value of proper water treatment chemistry to customers. This way, water treatment was not viewed as a cost, but rather as a savings,” Bayburt explained, and added that good water treatment can prolong the life of plant equipment and improve its efficiency. “I continue to operate with that mindset as an AzGT employee, and so I wanted the focus of the article to be in relation to this, but taking it a step further and showing how, within the water-side of the boiler, there is an intertwined relationship between boiler chemistry, auxiliary equipment condition, and boiler efficiency.”

This picture by Kurt Bayburt, AzGT chemistry manager, is of a vacuum pump and seal water heat exchanger at Apache Station, which help protect the boiler system from outside elements and play a significant role in the efficiency of the steam units.

Bayburt used several specific examples from Apache Station to illustrate his point. Much of the auxiliary equipment that he mentioned has pumps and valves that help carry water to and steam from the boiler. When outside air gets into these systems, it can dissolve into the water that they carry, corrode the metals of the equipment and reduce the efficiency of how it operates.

“The primary influencing factor that increases the corrosion transport levels is oxygen ingress into the condensate water, or anywhere that is under vacuum, like the condensate pumps or turbine steam extraction lines, which are examples I gave in the article,” Bayburt explained. “Oxygen is particularly damaging to the feedwater heaters that have copper alloy tubes; this is a ‘double whammy’ in that the tubes lose material from the corrosion process, which results in tube leaks that cause reduction in efficiency and increased maintenance for leak repairs, and the copper ends up in the boiler drum, which makes the boiler less efficient.”

Decreased efficiency ultimately means burning more fuel for the same amount of electricity. Chemical cleanings to remove iron and copper from the boiler drum during outages can cost hundreds of thousands of dollars. While the cleanings are eventually necessary, the preventative measures that Bayburt described and that are used at Apache Station extend the time between these cleanings. Back to his main point, the equipment he described that helps seal the system from outside elements and the sensors that indicate changes in chemistry at critical locations can reduce the need for costly repairs and can help extend maintenance periods. The money and time saved can help reduce the cost of generating electricity at Apache Station.

“The advancements in water treatment technology have definitely allowed more thorough monitoring and detection, which then have in turn allowed more robust solutions,” Bayburt said. “There have been quite a few instrumentation advancements over the past 10 to 15 years that have allowed plants to detect and quantify issues real-time, so that adjustments or fixes can be made before an outage.”

As for his own position, Bayburt points out that the number of power plants with an on-site chemist is falling. But like the equipment that helps protect and monitor the generation process, he said that having a chemist is an investment in the longevity and efficiency of the facility and its operations.

“Many plants with conventional boilers still have one, but the newer gas plants, with HRSGs or heat recovery steam generators, typically do not. They’ll relinquish the chemistry program management to the water treatment vendor,” Bayburt explained. “Being that there’s a significant amount at stake related to chemistry, and that Apache Station is AzGT’s only facility, I feel that the company has made a good investment in having a chemist.”

You can read Kurt Bayburt’s article in Power Magazine online at:

The Steam Cycle Mechanical Relationship to Chemistry and Its Influence on Heat Rate and Reliability