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• Chlorine-rich RDF can cause corrosion of metal surfaces. • Ash deposition rate increases with addition of RDF to coal. • Biodegradable- and non-biodegradable-rich RDF separation has a beneficial on ash deposition. • Biodegradable-rich RDF potentially as co-firing fuel. • Blend of 5 wt% non-biodegradable-rich RDF with coal has medium to high risk. The potential impact of ash deposition during the combustion of separated biodegradable- and non-biodegradable-rich waste of refuse-derived fuel (RDF) was evaluated in this study. Theoretical prediction, drop tube furnace experimental combustion, and ash observation were performed to comprehensively investigate their ash deposit behaviour. The results show that high CaO and Cl in RDFs result in severe sintering and rust in the metal surface. The high ash deposit weight and aggregated sticky particles are observed during single-firing RDFs. Furthermore, adding 5 wt% of biodegradable-rich RDF or mixed RDF to coal has a less significant effect on ash deposition. However, several aggregate particles and metal degradation are observed during the combustion of mixed coal with the addition of 5 wt% non-biodegradable-rich RDF. The high Cl in non-biodegradable-rich RDF affects the ash deposition behaviour significantly. This research provides valuable insights into optimising coal-RDF co-combustion, especially with separating biodegradable- and non-biodegradable-rich RDFs. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

• The effect of ash deposits on corrosion resistance in high Cr material must be investigated. • The corrosion investigation is carried out on a laboratory scale and depends on observations of ash effects with material degradation. • The majority molten phase of alkali and chlorine has degraded the oxide layer. A high chromium concentration in the boiler material is believed to increase corrosion resistance, especially at high temperatures. It is related to the formation of a protective layer on the surface of the metal, called a chromium oxide (Cr 2 O 3) layer. However, the impact of alkali and chlorine from co-combustion coal with biomass in power plants can harm this protective layer, reducing its effectiveness and potentially leading to increased corrosion. Therefore, it is important to evaluate the impact of these factors on the corrosion resistance of high-chromium materials. This research investigates coal co-combustion with empty fruit bunch (EFB) and plastic waste on the corrosion resistance of austenitic stainless-steel material on a laboratory scale using drop tube furnaces. The investigation steps included probe observation, SEM-EDS on ash and probe material, and XRD. The analysis indicates that the ash from the coal sample did not affect the probe, unlike the coal with EFB or EPL (mixture of EFB and plastic crackles), which caused up to 14% oxide layer degradation. The existence of alkali chloride, sulfate, and silicate in the ash that is still adhered to the surface of the probe can reduce the corrosion resistance of the metal. [ABSTRACT FROM AUTHOR]

Indonesian coal reserves are dominated by medium and low-rank coals. Despite being economically profitable, low-quality coals can trigger ash-related problems in a boiler, such as slagging and fouling. Suitable additives can be useful to overcome the issue of high-alkali coals. The main objective of this study is to determine the effectiveness of the three additives in reducing slagging and fouling risks using a drop tube furnace. Aluminum silicate-based, aluminum-based, and magnesium-based additives were used in coal combustion to comprehensively evaluate ash fusion temperature, thermal properties, ash deposit, emission, and ash mineral morphology. The results showed that additives in high-risk coal/blended coal could reduce ash sintering during the combustion. It can lower the ash fusion temperature yet reduce slagging ash deposits and flue gas emissions. Si–Al, Al, and Mg minerals play a role in increasing the ash melting point. Among three additives, the aluminum-based additive can increase the R max value, resulting in more stable conditions during the combustion. • High impurities in the coal can trigger ash-related problems during combustion. • Additives can mitigate against slagging-fouling risks. • The effects of aluminum silicate, aluminum, and magnesium-based additives were evaluated. • The aluminum-based additive can indirectly help the stability during combustion. [ABSTRACT FROM AUTHOR]