A method and a system for monitoring and on-line determining of a calorific value of solid fuel that is currently combusted in a boiler

A system for on-line monitoring and determining a calorific value of a solid fuel that is currently combusted in a boiler that comprises a combustion chamber with a steam production system to which the solid fuel is fed from at least one mill connected to a hopper, the system comprising:

• an interface to sensors for measuring operational data of the boiler and operational data of at least one mill;
• wherein the operational data of the boiler comprise at least one of:
• temperature, pressure, steam flow;
• and
• wherein the operational data of the at least one mill comprise at least one of:
• mill power, air pressure upstream of the mill, solid fuel feeder revolutions, air temperature upstream of the mill, temperature of the dust-air mixture downstream of the mill;
• an archive module for collecting historical data of solid fuel calorific value measurements and operational data of the power block, wherein the operational data of the power block include at least one of:
• lower heating value, mill characteristics, fuel flow rate and boiler efficiency, operational parameters of turbine, including flows, pressures and temperatures for live steam, superheated steam and secondary steam, operational data of the boiler, operational data of at least one mill, composition of exhaust gases, power of the block;
• a module for calculating energy balances of the steam production system on the basis of the historical data collected in the archive module and depending on the amount of thermal energy input to the turbine generator set divided by the boiler efficiency;
• a module for iterative determination of boiler efficiency on the basis of historical data, configured to:
• determine sets of mill characteristics depending on a calorific value of the solid fuel and operational data of the mill while combusting that solid fuel, wherein the mill characteristics include at least one operational parameter selected from the group consisting of:
• mill power, air pressure upstream of the mill, solid fuel feeder revolutions, air temperature upstream of the mill, temperature of the dust-air mixture downstream of the mill;
• determine the fuel mass flux on the basis of the set of mill characteristics;
• and
• determine the actual calorific value of the fuel for historical data;
• a model based on artificial intelligence algorithms for predicting calorific value, that is trained using historical data of fuel calorific value and measured operational data of the boiler, and once trained, configured to determine in real time the calorific value of the solid fuel that is currently combusted on the basis of the currently measured operational data of the boiler.