A Study on Bituminous Coal Base Acid Ratio to the Slagging Factor at Large Scale Boiler

Abstract

Different types of coal have different characteristics and performances. In thermal coal plant, deposition of coal ash inside the furnace causes slag formation inside the boiler rear path and consequently reduces the heat transfer process and boiler efficiency. Besides, accumulation of ash on the boiler tube surfaces form layers of slags and blocks the flue gas flow out of the boiler. Therefore, the purpose of this study is to investigate the relationship between sub-bituminous coal base acid ratio towards the heat transfer process inside large-scale boilers. The base acid ratio for sub-bituminous coal is measured before firing inside large-scale boiler of studied the thermal plant which has a generation capacity of 700 MW. This study found correlation between high furnace rear path temperature (FRPT) that is observed to be above 800℃, with the build up of ash accumulation inside the boiler, for the studied coal. Thus, a high base acid ratio causes the accumulation of coal ash, thus reducing the heat transfer process which results in high FRPT of the boiler. Therefore, it proves that a base acid ratio is an indicator for coal performance during firing inside the boiler.

Hydrothermal dewatering of low-grade coal: Product evaluation and primary component analysis of ash deposition

“…Alternatively, by dividing these oxides into two groups, Al 2 O 3 is assigned to the acidic oxide group and Fe 2 O 3 to the basic oxide group [ 13 ]. The formation of slag is mainly influenced by Fe 2 O 3 , CaO, MgO, K 2 O, Na 2 O, SiO 2 , Al 2 O 3 , and TiO 2 [ 14 ]. For the prediction of ash deposition by slagging and fouling in boilers, most researchers measure the base-to-acid (B/A) ratio, bed agglomeration index (BAI), fouling index (Fu), slag viscosity index (SR), and Babcock index (RS) of coal [ [15] , [16] , [17] ].…”