If lower grade coal is used instead of the prescribed quality for the design of the boiler, a substantial amount of impact may be seen in its working and efficiency.Vikram Singh
When we talk about thermal energy, coal is a crucial part of that discussion as thermal power is majorly dependent on this non-renewable resource. Thermal power plants invest money and time in coal testing because they understand how important it is in the working of a boiler design. The performance of a boiler design heavily relies on the fuel or in this case, coal analysis. If lower grade coal is used instead of the prescribed quality for the design of the boiler, a substantial amount of impact may be seen in its working and efficiency.
Coal quality is important for proper functioning of a boiler. Heat generated from burning coal in a thermal energy boiler is used for power generation, generating steam, and a variety of other applications. The chemical composition of coal determines many characteristics of a boiler design. For example,a boiler designed for fuel will have a smaller furnace in comparison to boilers designed for coals. Coal testing labs help with a complete analysis of the quality of coal so that you can gauge the performance of the boiler design.
Coal is a heterogeneous fuel. Fuel sources like gas, oil, coal etc. are made of hydrocarbons. While gases and oil fuel have pretty much defined hydrocarbon structure, coal has an assumed structure with varied C and H ratio which behave differently depending upon their reaction and formation. This ratio can only be known if you send the sample coal to coal testing company.
Consistency: Consistency in coal is very important for a boiler design as it governs factors like the quantity of combustion air, flame temperature, and combustion time. Inconsistency can lead to limitations in fuel handling systems. It also causes a loss in the capability when ash formation crosses the threshold of the fuel preparation system.
Oversized Pulverizing: Using lower grade coal can lead to over sizing of the firing equipment. This leads to impact on increased auxiliary power consumption and limits on the turn down. Both of these things are not desirable for a boiler designer. As a result, furnace size has to be increased and it also becomes difficult to manage the required outlet temperature.
Boiler Efficiency: Coal testing services also check the moisture content in coal. High moisture coal requires oversized pulverizes and heaters which will require excess tempering of air while handling coal with normal moisture content. All this results in higher gas outlet temperature which is responsible for decreasing the efficiency of a boiler.
Behavior of ash: One of the major issues that are faced while designing a boiler is the behavior of ash during the combustion process and management of coal ash. This can be curbed by testing a batch of coal and determining its properties.
Environmental regulations: Thermal plants must follow set environmental safety regulations while also minimizing the quantity of fuel they burn. Therefore, they need the guidance of a coal testing laboratory to provide them with coal quality analysis and help them comply with the guidelines too.
Coal blending: In case a thermal plant decides to mix more than one type of coal to achieve the desired outputs, they need to verify the combination from a coal testing lab. Before going ahead with the blend, it is necessary to understand what impact it will have on the performance and efficiency of a boiler design.
Unplanned shutdowns: While environment testing labs can help thermal plants to avoid an unplanned shutdown (in case thermal plants are majorly contributing to air pollution) coal testing labs can help in coal quality analysis to ensure improved fuel quality thus preventing a bad reputation and shutdown in the longer run. These analysis reports will come in handy to maintain the quality of the coal and help reduce air pollution levels and environmental impact.