Ash Evaluation of Indonesian Coal Blending for Pulverized Coal-Fired Boilers

Coal calorific value is one of the main considerations for using coal as a power plant fuel. In addition, the requirements for indications of slagging and fouling are also important to maintain combustion efficiency. However, coal power plants often experience problems in boiler operations due to the use of certain types of coal, even though they have a relatively high calorific value. This research investigates the effect of coal blending on ash fouling and slagging in an experimental investigation using a drop tube furnace with or without additives. Five different types of coal from different locations have been used in this study. Pulverized low-rank coal samples are burned in a drop tube furnace at 1,175°C with probe temperatures of 550°C and 600°C, corresponding to the combustion chamber of 600 MW power plants, including superheater and reheater areas. The ash particles’ characteristics and material composition were also analyzed using scanning electron microscopy with energy-dispersive X-ray (SEM-EDX) and X-ray diffraction (XRD), respectively. All coal mixture combinations demonstrated potential as a fuel for power plants that use pulverized coal-fired boilers. Because of its capacity to reduce slagging and fouling potentials, combining coal blending with the use of chemical additives yielded the greatest results.

Coal blending selection for CFPP fuel with slagging fouling prediction and procurement cost calculation

Most coal-fired power plants in Indonesia use medium and low-rank coal due to coal availability in the domestic coal market. Because of technical and economic reasons, single coal as fuel is rarely used in coal-fired power plants. Therefore the coal blending method is used. Here, the most dominant technical requirement of a coal-fired power plant is the calorific value and potential of slagging and fouling. For this reason, a selection method that involves the technical aspect of coal and coal procurement cost is carried out. This study found that from 42 types of alternative coal blend made, 18 types fulfill the potential of slagging and fouling criteria. 12 type coal blends could be prioritized as the main alternative because they fulfilled all technical aspects and coal procurement costs. The conclusion obtained from this study is the completion of the search for alternative coal blends based on technical aspects, especially slagging and fouling and procurement cost, to effectively obtain blending priority. This method can be developed for different coal-fired power plant technology and operation condition.

The performance of Pacitan Power Plant (pulverized boiler) toward the blending coal: an experimental

Coal blending testing of medium rank coal (MRC) and low-rank coal (LRC) in the Pacitan power plant with pulverized boiler type was conducted to increase the use of readily available coal. It was necessary to ensure the impact of the blending coal on the boiler performance. Therefore, this study was aimed to examine the performance of the plant. There were two coal blending configurations in testing; a) Combo #1: 75% of LRC and 25% MRC; b) Combo #2: 60% of LRC and 40% MRC. Each combination was held in 4 schemes of load at 165 MW, 210 MW, 255 MW, and 300 MW. Heat rate calculation was determined with the heat loss method (energy balanced approach). As a result, compared to the commissioning test (2,270 kCal/kWh), the power plant performance decreased. The performance of combo #1 obtained 2,517 kcal/kWh; meanwhile, combo #2‘s performance showed 2,360 kcal/kWh.

Types and Composition of Biomass in Biocoke Synthesis with the Coal Blending Method

The steelmaking industry requires coke as a reducing agent, as an energy source, and for its ability to hold slag in a blast furnace. Coking coal as raw coke material is very limited. Studying the use of biomass as a mixture of coking coal in the synthesis of biocoke is necessary to reduce greenhouse gas coal emissions. This research focuses on biomass and heating temperature through the coal blending method to produce biocoke with optimal mechanical properties for the blast-furnace standard. The heating temperature of biomass to biochar was evaluated at 400, 500, and 600 °C. The blending of coking coal with biochar was in the compositions of 95:5, 85:15, and 75:25 wt.%. A compacting force of 20 MPa was employed to produce biocoke that was 50 mm in diameter and 27 mm thick using a hot cylinder dye. The green sample was heated at 1100 °C for 4 h, followed by quenching with a water medium, resulting in dense samples. Increasing heating temperature is generally directly proportional to an increase in fixed carbon and calorific value. Biocoke that meets several blast-furnace criteria is a coal mixture with coconut-shell charcoal of 85:15 wt.%. Carbonization at 500 °C, yielding fixed carbon, calorific value, and compressive strength, was achieved at 89.02 ± 0.11%; 29.681 ± 0.46 MJ/kg, and 6.53 ± 0.4 MPa, respectively. This product meets several criteria for blast-furnace applications, with CRI 29.8 and CSR 55.1.

Evaluation of Grindability Behaviors of Four Different Solid Fuels Blending by Using the Hardgrove Mill

Grindability measurements are widely used in mineral and coal processing industry to determine resistance of materials to comminution.Grindability measurement as testing methods can be divided into two general categories; the Bond and the Hardgrovegrindabilities. Grinding characteristics of the mineral or coal blending have been studied by several researchers over many yearsand a wide range grinding variables has been investigated. In this study, because of the simplicity and the potential usage of themethod for the determination of the grindability of coals and their blending in a comparative scale, a Hardgrove mill were used toinvestigated the grinding behavior of four different solid fuels and their blending. Grindability of four different solid fuels such as;petroleum coke, coke coal, lignite and bituminous coal and their binary, ternary and quaternary blending were investigated by theHardgrove grindability test. The test results indicated that determine the existence of a very good relation between the Bond andthe Hardgrove grindability of the fuels, and relationship between experimental and calculated HGI values of the fuels blendingwere also shown as a very good. However, there is not obtain a good relation between proximate analysis results of the solid fuelsand HGI values of fuels blending.