Coal Audit

CPRI   is  in the area of energy efficiency in the generation sector through energy audit, performance evaluation, component testing for a number of years. CPRI has specialized in energy audits of hydro and coal fired thermal power plants of the complete range of ratings from as low as 20 MW to 500 MW. It also plans to take up supercritical units of 660 MW and above. CPRI has a track record of conducting over energy audits in thermal (coal, gas and nuclear) thermal stations and hydro power stations besides a number of R & M studies.

Energy Efficiency & Renewable Energy Division (ERED) of CPRI has taken up a prestigious consultancy work for Maharashtra Energy Regulatory Commission for benchmarking of the unit heat rates and station heat rates of coal fired units of MSPGCL (Maharashtra State Power Generating Company Ltd.), thermal stations through conducting performance tests on coal fired thermal power plants, computing the present performance indices and suggesting performance norms for the immediate term, medium term and long term. The performance indices cover unit heat rates (UHR), station heat rates (SHR), specific oil consumption (SOC), auxiliary power (AP), etc. for 32 units (ranging between 30 MW to 500 MW) of MSPGCL spread over different geographic regions of Maharashtra. The consultancy work was awarded by the Maharashtra Electricity Regulatory Commission (MERC), Mumbai.

The scope of activities which is based on a comprehensive scope of work and terms of reference given by MERC, involves an in-depth look at the processes and procedures of the seven TPS- Koradi, Khaperkheda, Chandrapur, Nashik, Bhusawal, Paras & Parli in complete transparency. The primary processes of receipt, handling and management of fuels (imported, indigenous and washed coals, fuel oils) and water (DM, soft, potable and raw) which are accounting for major cost components of the stations have been analyzed and technologies for supply chain optimization and raw material management have been proposed.

The principles of accounting of coal quantity and its heating values at various points; and computation of station heat rate have been reviewed in depth and procedures and instrumentation have been suggested to answer to the observations of MERC –'the coal consumption should be dependent on the unit heat rate and not vice versa'. The suggestions also encompass the break-up of the accountability and responsibility for coal from the mine to the station entrance, from the tipplers to the bunkers and from the mills to the furnace.

In preference over analog, stand alone, incompatible measuring equipment, the change over to digital instrumentation and tracking devices which can be seamlessly integrated into a central server and which have provision for downloading data into a data base has been advocated. Need for technical auditing of Information and communication system for obtaining a holistic picture of its structure and efficacy on one hand and the change over to Intelligent electronic devices (IEDs) preferred instrumentation systems has been highlighted.

The study encompasses capture and dissemination of tacit operational knowledge, maintenance knowledge and forced outage knowledge which is essential for progress in performance. It assesses and validates the internal knowledge sharing processes. It reviews the maintenance philosophy, maintenance organization structure, tooling techniques, maintenance performance mapping, maintenance delivery system, maintenance planning, standardization of procedure, benchmarking of timing of outages caused by BTL (boiler tube leaks), etc. Performance orientation linked with knowledge based maintenance, condition based guidelines, component reliability and risk evaluation procedures are part of the study. The benefits of 5 year rolling plans for pressure parts replacements (like ECO coils, primary SH coils, WW tubes, etc.), heat exchanger replacements (like lube oil coolers, feed water heaters, vent condensers, etc.), thermal skin insulation replacement, 20 %/year painting and upkeep plan have been brought out.

The study points out that R & M must be a continuous activity and the plans must not be equipment centric but must be aligned with benefits of improvements in unit heat rate and/or other unit performance parameters.

The stress on performance optimization, cleanliness and leakage control being a round the clock activity with ISO objective focus to achieve the required results is a part of the study.

On the financial side, a critical re-look through audits for the simplification and modification of administrative and accounting processes to bring down the lead times for the procurement cycle (which has an impact on inventory carrying costs and overall business cycle) is studied. Analysis of decision making processes is also a part of the study.

Coming to HRD, the study revisits job functions, both operation and maintenance, re-orientation towards performance and accountability at all levels, job rotation system, alternative ways of augmenting the shortage of manpower, reward of invention talent, support of quality circles, mid career educational intervention, reduction of attrition rate, etc., are studied. A critical review of training needs in the present day context such as operational optimization, maintenance methodologies, regulatory requirements, etc., is undertaken.

The performance tests give the Test TG heat rate (UHR) (boiler, turbine & generator only) at 80 % load against the Design heat rate (DHR). The Test station Overall Station heat rate (considering besides the boiler and turbo generator other factors such as DM water make up; rejects; consumptions due to hot, warm and cold starts; heat in MS & RH pipelines, seasonal deviations (if any) at 80 % load which accounts for all the coal at the bunker. The life time degradation rates are computed. The capacity adequacy is also checked.

The tests include total electrical system audit including transformer load management, power factor management and load balancing. The performance evaluation of auxiliary equipment like boiler feed pumps, condensate extraction pumps, induced daft fans, forced draft fans, primary air fans, mills, etc. Energy efficiency also covers the common station auxiliaries like coal handling plant, ash handling plant, DM plant, circulating water system, air compressors, etc. Suggestions for improving the energy efficiency of these equipments with techno-economic feasibility study are also proposed.

Suggestions for measures to improve the KPI (key performance indices) like station heat rate, auxiliary power consumption and specific oil consumption with time bound action plans are given. Objective oriented Monsoon management plan is required to be in place for maintaining the KPI within regulatory limits as the deviations in station load, monthly SOC and monthly PLF are predominant during monsoon seasons.

The study benchmarks the performance, identifies undone works which were historically ignored but which are of current importance and proposes changes leading to reliability, transparency and cleanliness in an environment of competitive cutting edge power generation. In short the study encompasses the business process re-engineering for enhancing station performance to maintain market leadership. If the existing plant processes and procedures are made more effective, the improvement of performance will be a natural consequence.