Case Study | CPV (PSM – Direct Customer)

Background:

CPV – Valley, a power plant operating two Siemens gas turbines in New York, was interested in adding an inlet heating system to their gas turbine, as their inlet filters often became clogged with snow and ice. The clogged filters required the turbine to shut down or derate at a time of typically high electrical demand. A solution was required to keep their filters protected during the harsh winter months.

Problem:

Due to its northern location, CPV – Valley often experiences heavy snow, freezing rain, and ice combinations. Because of these conditions, the inlet filters would become clogged, or partially clogged, increasing the pressure drop.

Once a certain differential pressure is reached, it is then determined whether the power plant needs to be turned down – so less power is being generated – or if the plant must face an entire shutdown. Fines also pose a threat to the plants if they are not able to supply the amount of power agreed upon in their electrical contracts.

To ensure that neither a fine nor shutdown would happen, CPV – Valley, required a reliable, productive solution that would raise the temperature of the air on average by 30oF, concentrated at the lower portion of the inlet filter house where more snow and ice accumulated the most and have it installed before the next winter season.

Solution:

Nederman Pneumafil worked in partnership with PSM, a company that provides parts & services for gas turbines. Nederman Pneumafil would design the inlet heating system, whereas PSM would handle any internal issues that may occur when connected to the turbine and the field installation on site. It was determined that the best option for CPV – Valley’s problem was compressor bleed inlet heating where a portion of the hot air from the turbine compressor is piped back into the inlet upstream of the filters.

As air moves through the turbine, it travels through a multi-stage compressor where it is then squeezed before fuel is injected. Once the air has been compressed enough, it can reach temperatures of ~700oF. A small amount of this hot air can be extracted, bleeding off through a pipe and control valve, where it is then rerouted to the front of the inlet filter house. The hot air is then injected with a manifold system of piping and nozzles so that it is spread smoothly and evenly across the entire face of the inlet filter house, eliminating hot spots and other potential damages.

Nederman Pneumafil designed an inlet bleed heat system, sizing the piping and nozzles to handle the higher mass flow of air that CPV – Valley wanted to pull from the turbine. PSM was in agreement that the total air flow rate, normally between 2% to 3%, would be increased to 5%+. The temperature had to be hot enough to melt the snow and ice, but not over what the filters could withstand. With specific temperature limits applied, Nederman Pneumafil adapted their design to provide more space between the air distribution nozzles and the filters to allow for the air to mix more evenly while ensuring no hot spots would occur, resized all piping to handle higher air flow in accordance with ASME pipe design regulations, and concentrated the number of nozzles in the lower portion of the inlet filter house.

Results:

New inlet bleed heating units were installed on each of the two turbine inlets, at the CPV – Valley power plant; PSM handled the installation of the systems on site. The Pneumafil design saved existing weather hoods which were removed and re–installed upstream of the heating systems. In September 2023, the new inlet heating units were installed, tested, and ran smoothly, right on time before the freezing weather hit.

By the end of 2023, CPV – Valley experienced their first significant snowstorm of the season. What would have previously caused them to turn down and derate the turbines, or to shut down altogether, now was not the case. Due to the new inlet heating system that Nederman Pneumafil designed and supplied and PSM installed, CPV– Valley could remain online throughout the winter season and continue with their uninterrupted, smooth production.