Malath Ibrahim Arar

Gas Turbine Corrected Parameters Control: Humidity Correction – Sensors Evaluation and Selection

Gas Turbine, GT, control methodology applied to power generation is being evaluated. Corrected parameter control methodology has been adopted for this purpose. This method uses the corrected physical ambient conditions such as pressure, temperature and humidity in controlling the GT operations. Humidity correction becomes increasingly important in this control scheme. The following are the reasons for accurate and robust humidity measurement: (1) Humidity measurement is important to the operation control of the dry low NOX , DLN, combustor system. (2) GT inlet performance enhancing devices, such as evaporative coolers and inlet foggers, depend upon the accurate humidity measurement to determine the amount of water needed for inlet temperature depression. (3) Humidity measurement is used to determine the amount of water to be injected in the combustor for NOX abatement when running on liquid fuel as an alternative to natural gas fuel. In order to obtain accurate and reliable humidity readings, several commercially available humidity sensors were extensively tested and evaluated in a controlled laboratory environment. The sensors were tested for their measurement accuracy, saturation conditions, power interruption and surge, sudden temperature changes and medium air speed. Test ambient temperature ranges from −30 °C to 50 °C. This covers the operating ambient conditions range for the Gas Turbine. The test criterion is that the error in the response of the sensor shall not exceed ±1 °C from the test reference for all the tests conducted on the sensors. The combustion requirements for Dry Low NOX operations and mode transfer dictate this criterion. Also, as a DLN requirement, error in specific humidity shall not exceed 0.904 g/g of air. This test criterion also satisfies the water injection requirements for NOX abatement and inlet performance enhancing devices. The results show that for ±1 °C error in the sensor measurement, the resulting error in NOX calculation is less than 0.2 ppm. The test results show that all sensors except the current one in use have met the test criterion. The current sensor, General Eastern DT-2, has a large measurement error in the order of ±5 °C. Programs have been launched to field test and evaluate these sensors in order to replace the current one.Copyright

Redesign of N2 Injection System for Gas Turbines in Integrated Gasification Combined Cycle Applications

Gas Turbines (GT) applied to integrated gasification combined cycle (IGCC) power plants utilizing Nitrogen injection to reduce emission and increase power output. This redesign process reduced the customer’s equipment and the operational cost for GT’s with Nitrogen injection. This project focused on reducing nitrogen supply pressure required by the GT. Customer’s cost of electricity (COE) is reduced, translating to additional potential revenue of

High pressure inlet bleed heat system for the compressor of a turbine

3.0MM over the life of the plant. This has been achieved through six sigma methodology of design optimization of the Nitrogen injection manifold, reduced combustion chamber pressure entry loss and optimizing the control system. Statistical analysis combined with various engineering tools was used to optimize, validate and verify the new design. The new design is applicable to all GT frame sizes. It also, can be applied as an upgrade to existing units.Copyright