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In the present work, feasibility to upgrade Indonesian low-rank coal by oil coating was investigated. The low-rank coal (LRC) was upgraded by addition of bio tar, tallow, crude cashew nutshell liquid, refined cashew nutshell liquid, and waste lubricant. Two types of Indonesian low-rank coal samples were pulverized, mixed, dried, coated and briquetted by mixing of the aforementioned materials. Heat calorific values, crossing point temperatures, and moisture re-adsorption characteristics of raw and upgraded coal were evaluated. Heat calorific values of upgraded coals were significantly improved compared to raw coal. Upgraded coals showed a medium tendency to spontaneous combustion and resistance to moisture re-adsorption. Isothermal oxidation characteristics of raw and upgraded coal were assessed by means of the carbon-dioxide-formation rate in the exhaust gas. Upgraded coal showed less susceptibility to isothermal oxidation due to the suppression of active functional groups to oxygen in air by oil coating. Results of the study indicate that these additives are potential candidates for upgrading Indonesian LRC. [ABSTRACT FROM AUTHOR]

In the present study, a method was developed to upgrade low-rank coal using palm oil residues. The upgrading process consisted of pulverization, mixing, drying, coating, and briquetting. A palm oil residue (palm fatty acid distillate [PFAD]) was used to upgrade an Indonesian low-rank coal. Pores generated in the low-rank coal due to the evaporation of moisture were coated with the PFAD. The inhibitory effect of the PFAD was investigated by measuring the crossing-point temperature (CPT) of the upgraded coal. The amount of moisture re-adsorbed by the upgraded coal was compared to the raw coal with several methods. The CPT of the upgraded coal increased 10°C, and the moisture re-adsorption decreased by less than 60% compared with the raw coal. The upgraded coal briquettes were hydrophobic and had high compressive strength. This makes the upgraded coal sufficiently stable for long-term storage and long-distance transportation. [ABSTRACT FROM PUBLISHER]

Process simulation and optimization for fry-drying of low-rank coal was carried out. The operating conditions of the evaporator was set so that the coal moisture would decrease from 33% to 10% during the drying process. Through process simulations, the heat duty supplied and power consumption were calculated under each operating condition. From the simulation results, the amount of enthalpy supplied and operating costs were calculated on the basis of prices in Indonesia as a coal-producing country and South Korea as a coal-importing country. Cases where thermal energy was reused through MVR showed an effect of reducing enthalpy and operating costs by around 50%. The results indicated that the amount of enthalpy supplied to fry-drying process was minimized at the evaporator pressure of 100 kPa and temperature of 120°C. However, the results of optimum operating conditions in terms of operating costs showed a different tendency to depend on the steam and electricity costs. The optimum operating conditions were evaporator pressure 500 kPa and temperature 168°C in Indonesia. On the other hand, the optimum operating conditions were evaporator pressure 250 kPa and temperature 138°C in South Korea. [ABSTRACT FROM PUBLISHER]

The wood processing industry produces a significant amount of wood waste. Biomass valorization through pyrolysis has the potential to increase the added value of wood wastes. Pyrolysis is an important thermochemical process that can produce solid, liquid, and gas products. This paper aims to review the pyrolysis of wood wastes from Indonesia, including teak wood (Tectona grandis), meranti (Shorea sp.), sengon (Paraserianthes falcataria (L) Nielsen), and rubberwood (Hevea brasiliensis). The review is based on an in-depth study of reliable literatures, statistical data from government agencies, and direct field observations. The results showed that pyrolysis could be a suitable process to increase the added value of wood waste. Currently, slow pyrolysis is the most feasible for Indonesia, with the main product of charcoal. The efficiency of the slow pyrolysis process can be increased by harvesting also liquid and gaseous products. The use of the main product of pyrolysis in the form of charcoal needs to be developed and diversified. Charcoal is not only used for fuel purposes but also as a potential soil improvement agent. [ABSTRACT FROM AUTHOR]

Indonesia is the world's largest palm oil producing country. The oil palm industry (plantation and milling) generates large amounts of solid waste in the form of empty fruit bunches (EFB), palm kernel shells (PKS), mesocarp fiber (MF), oil palm fronds (OPF), and oil palm trunks (OPT). This leftover waste, collectively termed oil palm biomass (OPB), causes severe environmental pollution, thereby threatening the sustainability of the oil palm industry. Upgrading OPB by thermochemical processes (torrefaction and pyrolysis) has attracted significant interest as a means of recycling the residues and mitigating the environmental damage. This study reviews the previous research on the environment-friendly utilization of OPB in Indonesia. First, general information is presented on OPB in Indonesia (availability, properties, and governmental policy). Second, the torrefaction of OPB for the production of upgraded solid fuel is summarized. Third, the pyrolysis of OPB to produce biochar is reviewed for use as a soil amendment and in carbon storage. The market perspective and life cycle assessment (LCA) of the thermally treated OPB are discussed, targeting the generation of electricity (OPB torrefaction) and agricultural soil enhancement (OPB biochar). The recycling of OPB is expected to contribute to the sustainability and economic success of the oil palm industry and also the net-zero 2060 in Indonesia. • Availability, properties, and policy on oil palm biomass (OPB) waste in Indonesia is outlined. • Torrefied OPB is discussed for the production of upgraded solid fuel. • OPB biochar is reviewed for soil amendment and carbon storage. • Market perspective of the thermally-treated OPB is described. [ABSTRACT FROM AUTHOR]