It is an established fact that higher efficiency of fossil power plant equipment results in reduced carbon emission and reduction in cost of generation. NETRA is developing technologies for improving efficiency and reducing costs.
NETRA is engaged in the following key activities of research and technology development:
Recovery of water and utilisation of waste heat from flue gases for improving heat rate of the plants or additional power
Flue gases contain around 10 – 12% moisture besides CO2, acidic gases, nitrogen & suspended particulate matter. NETRA is working on technology to extract the moisture from the flue gas and also reduce load on ID fan besides reducing acidic gases by condensation. The waste heat can be utilised for either heat rate improvement of the plant or for generation of additional power using aqueous ammonia cycle.
Development of Multi-composition Ammonia Liquor Absorption Engine (MALAE Cycle) for power generation from flue gases
For efficient utilisation of low grade/waste heat from flue gases, low pressure steam and solar energy a power cycle using aqua ammonia as working fluid can be used instead of water as working fluid. It has been established that by use of binary fluid in place of steam in power generation cycle at low temperature range of around 200 degrees celsuis increases the cycle efficiency. In this advantage is taken of the fact that the boiling and condensation of the binary fluid takes place at variable temperature.
A test loop is being developed to study various aspects of design, operation, control and safety. Based on success of this test loop scale up pilot plant shall be developed.
Integrated Polarisation Depolarisation Current – Recovery Voltage (PDC-RV) measurement apparatus for insulation condition monitoring of transformers
NETRA has developed jointly with Jadavpur University, an integrated PDC-RV instrument for condition monitoring of transformers. Field trials are in progress. An expert system will be developed for condition monitoring of transformers.
Flue Gas Heat Recovery System for Air-conditioning (FGHR-AC)
FGHR-AC process is designed to recover waste heat from exiting flue gas to produce air conditioning effect. Flue gas is drawn from the bulk flow going to the chimney, using a slip stream fan and passes over the gas to water heat exchanger (GWH) to heat the water. The hot water serves as an input to the Vapour Absorption Machine (VAM) driving Li-Br cycle & may produce up to 100 tons of refrigeration effect.
Robotic based inspection systems for inspection of plant components such as boiler tubes, generator stator etc.
For faster inspection of plant components NETRA is developing robotic devices. These will help in reducing the overhaul duration and will provide more reliable data on the health of the components.
Thermosyphon Heat Pipe based Air Pre Heater (THPAPH)
Thermal power plants are generally provided with Rotary Air Pre-heaters of Ljungstrom design where considerable fan power is lost due to seal leakage. To overcome the problem, NETRA is considering to set up an experimental facility of Thermosyphon Heat Pipe based Air Pre Heater (THPAPH) as an alternate option. Depending on the learning, the experimental facility shall be suitably scaled up.
Development of technique for online monitoring of colloidal silica in steam water cycle
Colloidal silica is difficult to be analysed and causes severe problems in boilers and turbines. NETRA is developing an online method for detection of colloidal silica in DM water so that preventive measures can be taken.
Development of Artificial Intelligence (AI) based advisory system
NETRA has developed the artificial intelligence based real time plant advisory software system, which provides real-time online operator advisory to run the plant in the most efficient manner and thereby leads to on the spot improvement in unit heat rate.
The system has been developed based on data collected from one of the power stations. This software based system will take the real time plant data and provide the online advisory for optimisation of the operational activities. The system is a self learning type and can adapt to newer plant conditions. The system has real time data validation and reconciliation for detecting and reproducing plausible value for any corrupted value due to sensor random error or gross error. The system is currently deployed at one of the power stations in testing mode.
Existing motor modification to retrofit VFD with suitable rewinding and other measures
Variable Frequency Drive (VFD) usage in power plant helps in saving auxiliary power and reduced wear & tear of the rotary system. A VFD environment poses higher thermal and dielectric stress on motor which severely affects the reliability of the motor. Up-gradation of motor into inverter duty motor is the economic retrofitting solution rather than the usually higher frame size inverter duty motor.
NETRA has upgraded a standard induction motor into an inverter duty motor by refurbishment and tested it at a power station for its dielectric and thermal behavior. Presently this set up is in operation at NETRA premises and is being tested for varying cable length.
Development of nano coating material for HV insulators
To prevent corona discharge on insulators, NETRA is developing super-hydrophobic nano coatings for the insulators. Once developed these coatings will help in reducing the possibility of corona discharge during foggy seasons.
Real Time monitoring of chemical parameters of boiler water chemistry
To improve the performance of the boiler systems it is necessary that proper control on plant chemistry is maintained. Presently all water chemistry parameters are monitored manually, NETRA is developing software for an integrated monitoring and advisory of chemical parameters of plant chemistry.
Computational Fluid Dynamics (CFD) studies on plant boiler systems
Computational Fluid Dynamics (CFD) allows visualisation of process parameters throughout the process domain and has become an ideal tool for process understanding and analysis, problem solving, process/design development. A validated CFD model has the potential of replacing costly pilot plant studies by cost and time effective lab-based “what-if” analysis for process/design/efficiency improvement.
NETRA is involved in 3D modeling, flow and energy simulation of power plant equipments such as steam generators and flue gas ducts. Currently work is under way on modeling steam generators at selected power stations.