Coal Usage and Optimization in Thermal Power Plant

Coal Usage and Optimization in Thermal Power Plant

Coal Usage and Optimization in Thermal Power Plant

Opportunity for coal usage optimization is technically and economically achievable but will require leadership from power plant owner and operators.

  • Coal is the biggest source of energy used for generation of electricity
  • The efficiency of converting coal into electricity is a matter of serious concern since it emits carbon dioxide which damages climate
  • Reducing the carbon footprint of energy production activities has emerged as one of the defining environmental issues of the 21st century.
  • Long-term opportunities to reshape this are promising while near-term opportunities are limited because current coal-fired power station accounts for 80% of carbon emission from the power sector.
  • Improving the efficiency of existing coal-fired power plant fleet in India presents one of the most promising low-cost options for reducing near-term carbon emission by way of coal usage optimization.
  • Improvement in knowledge of operators with training can definitely optimize the coal usage in thermal power plants
  • Coal usage optimization process starts with an assessment of current operational practices of both managerial and technical including various technical subsystems.
Overall phases are:
  1. Awareness phase 
  2. Identification phase
  3. Evaluation phase
  4. Implementation phase
Coal usage optimization can be achieved by following:
  1. Enhancement of operational practices
  2. Enhancement of maintenance practices
  3. Plant optimization
Enhancement of operational practices
  • To make available well documented operating procedures to every engineer working in shift such as
  • Signature checklist for starting and shutdown of equipment of various systems
  • Equipment change over guidelines
  • Key process diagrams
  • Heat balance diagram
Key logic diagram of interlocks, protection and associated C & I details
  • Technical parameter handbook which includes designed parameters of various systems at various loads, process parameter limits and critical alarm values for all equipment
  • O & M manuals of OEM to be available with shift charge engineer and respective maintenance head
  • Training on procedures, manuals, and instructions
  • Refresher course for adherence by experienced people
  • To create the central technical library
  • Good housekeeping practices to be developed
  • Good safety practices to be adopted to achieve the target of zero accident
  • The computer-based system for online monitoring of energy efficiency such as unit heat rate, boiler efficiency, turbine efficiency, the performance of condenser and regenerative heaters, coal consumption and to take immediate action for reduction of controllable losses.
  • Installation of reliable coal flow devices
  • System-wise monitoring of auxiliary power consumption for all equipment
  • Formation of specialized and focused operation and efficiency cell 
  • Formation of a trip committee
  • Formation of energy audit committee
  • Knowledge management through E.R.P. (Enterprise resource planning)
  • To standardize report for M.I.S. (Management information system)
  • Generation planning for the year is to be done analyzing partial loss occurrences of the previous year for improved generation level
  • The focus is to be kept on monitoring of tariff parameters during operation
  • Greater focus should be kept on operation efficiency such as a shortfall in generation analysis, partial loss analysis, inputs from energy audit reporter
  • To integrate MIS policy to cover operation, maintenance, stores, purchase, HR, safety, environment etc.
  • To establish quality assurance system with suitable quality manuals covering quality assurance plan, customer hold point for inspection, material acceptance criteria 
  • To establish vendor management system covering procurement procedure, vendor performance appraisal system
  • To prepare material management manual covering stores and inventory, proper identification and codification of store items, a method of physical verification of assets, the automatic procurement process for fast moving items and consumables by fixing minimum and maximum reorder level 
  • To keep common high-value spares for the organization
  • To develop material preservation manual
  • Systematic mapping of skill requirement and training need assessment
  • To develop a mechanism that captures training needs and establish proper linkage between development needs and training imparted
  • To carry out post-training evaluation for up gradation of training methods, faculty, and curriculum
Enhancement of maintenance practices
  • Documentation of maintenance procedures to be developed
  • Equipment failure analysis to be recorded properly and history should be readily available for reference 
  • Dedicated team for maintenance planning to be formed
  • Long-term planning for an overhaul to be done in many advances
  • Systematic spares planning to be done
  • Maintenance decision-making process should appreciate commercial linkage of plant level availability and reliability of individual equipment and impact on fix cost recovery
  • To establish decision support system to facilitate proactive maintenance
  • To carry out day to day maintenance in coordination with operation and efficiency cell
  • To establish a database for the aging of equipment
  • To establish computerized maintenance management system having modules like plant performance, work planning material management, budget & cash flow, work permit, costing system, financial accounting, coal management, HR 

Optimization can be achieved in following areas:
  • Plant start-up time reduction and to reach full load in minimum time with minimum fuel consumption
  • The plant shut down time reduction and to shut down plant safely with minimum fuel consumption
  •  Plant heat rate optimization during normal operation by improving individual equipment performance and better process monitoring and control
  • Minimizing the plant aux. power consumption when the plant is not in operation by measures like switching of transformer, lighting, HVAC load
  • Studying the tripping and reduce energy loss due to it
  • Optimization of aux. power consumption during operation and shut down
  • Incorporating house load operation
  • Minimizing heat losses with proper insulation
  • Minimizing heat losses of steam leaks
  • Minimizing heat losses of seal leaks
  • Optimizing of excess air ratio to improve combustion and reduce ID, FD fan loading
  • To use VFD for PA and ID fan
  • To detect air, flue gas leakages by thermal vision monitoring and attend the leakages
  • Optimization of a level set point in HP/LP heater since heater drip level affects feed water outlet temperature
  • To charge APRS from CRH line instead of from MS line
  • To isolate steam line which is not in use
  • Timely replacement of BFP cartridge
  • To attend recirculation valves which are passing
  • To optimize ball loading in ball tube mill
  • To ensure proper blending of coal
  • To avoid idle running of conveyors, crusher in CHP
  • Optimize coal mill maintenance based on running hours, mill fineness, bottom ash unburnt particles, the degree of reject pipe chocking
  • To optimize voltage level of transformers since higher voltage causes more losses
  • To use energy efficient lighting
  • To use on load condenser cleaning system
  • To optimize instrument and service air compressor discharge pressure by tuning loading/ unloading cycle to save power
  • To use screw compressors instead of reciprocating compressors
  • To use absorption refrigeration system instead of vapor condensation system for HVAC system
  • To use wind turbo ventilators instead of the conventional motor-driven exhauster
  • To provide fabric expansion bellow from outside to cover metallic expansion bellow    
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