Mitsubishi-Hitachi Power Systems – GVEA Healy NOx Compliance Project SCR System Unit 2 – Coal-Fired Power Plant

Gas analyzer system for a NOx compliance SCR systemGVEA Healy Site Details/Project Background:

On December 4, 2013 the purchase of Healy Unit 2 was finalized. Golden Valley Electric Association paid $44 million to the Alaska Industrial Development and Export Authority (AIDEA) for the power plant. The purchase of the power plant is being financed by the Cooperative Finance Corporation (CFC).

Before Healy Unit 2 can be restarted, certain systems had to be upgraded. These upgrades, or restart activities, include installing new mill exhauster fans and environmental analyzers as well as upgrading the pulverizer, electrical and coal handling systems.

Healy Unit 2 is expected to come online by the second quarter of 2015.

The coal-fired power plant is expected to help stabilize electric rates which have fluctuated with the oil market over the past several years.

The project specification covers the minimum requirements for the design, documentation, materials, fabrication, examination, and testing etc. for NOx, SO2, and CO2 monitors at the inlet and outlet of each SCR with probes, sampling grids, sample conditioning units, sample pumps, analyzer shelter and accessories for GVEA Healy Power Plant, Unit-2 SCR System. The NOx monitoring system shall be used to measure NOx concentrations at the inlet and outlet of the SCR reactor. These measurements shall be used as part of the control of the ammonia injection system.


Cemtrex Scope of Supply:

Cemtrex provided analyzer systems of the dilution extractive type to measure NOx concentration at the SCR reactor inlet and outlet. Two (2) NOx monitoring system are dedicated to measuring SCR inlet NOx emissions and Two (2) are dedicated to measuring SCR outlet NOx emissions. The SCR design consists of one reactor and each SCR inlet and SCR outlet has its own monitoring system(s).

Also, Two (2) CO2 & SO2 monitors at the outlet were provided.

The analyzers and system controller are located in a shelter. Shelter is complete skid-mounted, factory assembled enclosure specifically designed to house the analyzers. Shelter is complete with lighting, air conditioning, and heating, and is of adequate size to house all of the monitoring system. All Cabinets are NEMA 12 classification.

Cemtrex provided all power distribution equipment or transformers required to distribute power at the proper voltage level to the monitoring equipment. All necessary voltage regulating transformers and filtering devices are furnished and installed to provide 120 volt AC auxiliary power suitable for the system controller and all other electronic equipment.

A single system controller is provided for data logging and control of each of the NOx monitoring system. The response time of an extractive type NOx monitoring system is less than 2 minutes. The response time is defined as the time needed for the system to go from measuring zero emissions to measuring 95 percent of the full scale span from when the flue gas is sensed by the probe in the duct until the time when the NOx concentration is communicated to the SCR ammonia control system which is part of the DCS furnished by others.

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