Herri Susanto

Palm oil industry generates substantial amount of biomass, which of them is palm kernel shell (PKS) that can be utilized by industries, as a renewable energy so

The palm oil industry is a promising biomass source, as the production generates wastes more than four times that of the main product. In 2020, for 45 MT of crude palm oil production in Indonesia, it was estimated that around 12 MT of palm kernel shell were generated or equivalent to 5.4 MTOE in net calorific value. This high calorific value of solid waste can be used by industries as a source of renewable energy, once it is proven to be technically, environmentally and economically feasible. In this comparative study, the life cycle assessment method was deployed to determine the environmental feasibility of palm kernel shell usage as an alternative renewable energy source to coal and natural gas in ceramic tile production through the application of combustion technology. The novelty of this study lies in a cradle-to-gate approach by comparing the carbon footprint of biomass from agriculture industrial waste with common fossil fuels as sources of energy for a highly energy-intensive industry. This research demonstrates that by evaluating the total life cycle of a fuel, the perspective on environmental impacts can be quite different when compared to looking solely at the end-use process. This study shows how the deployment of life cycle assessment would create managerial implications toward the decision making of fuel selection with carbon footprint considerations.

Potassium content in biomass ashes, especially empty fruit bunches was quite high and had not been utilized maximally. This research dealt with the development of a technique for recovering potassium salt from a solution of ash extraction. Experiments were carried out usung a solution model containing KCl, NaCl, MgCl₂, and CaCl₂ with concentrations of 164.19, 8.39, 7.44, dan 39.60 mg/L respectively. Results of a preliminary experiment indicated that the solubilities of KCl and NaCl were reversed: 280.4 and 280.4 (g/L in water) to 6.9 and 14.2 (g/L in absolute ethanol), while the solubilities of MgCl₂ and CaCl₂ were still high (68.7 and 383.5 g/L in ethanol). Using these values of solubility, a combined evaporation and adding ethanol was trialed firstly to increase the precipitation of KCl. Evaporation of KCl solution 164.19 g/L until an evaporation leves of 15% did not give any precipitation yet, while adding ethanol to the remaining solution (at solution ratios of 4/1 and 3/2 ethanol) yielded precipitations with the potassium recoveries of 60% and 48% respectively. At an evaporation level of 30%, the evaporation yielded a 5% potassium recovery, while the combined technique gave 60% and 50% recoveries for adding ethanol with ratios of 4/1 and 3/2 respectively. The application of the combined technique on the mixed salts solution was modified slightly. The precipitate from the evaporation (containing KCl and NaCl) was redissolved into water and followed by adding ethanol to precipitate only KCl. Thus, two precipitates were finally obtained: (i) precipitate from adding ethanol to filtrate of evaporation, and (ii) precipitate from dissolving precipitate from evaporation. At an evaporation level of 30%, the evaporation only gave a precipitate recovery of about 10%, while the application of combined technique gave bout 80% and 60% recoveries by adding ethanol with ratios of 4/1 and 3/2 respectively. Hopefully this technique could separate KCl from its mixture with NaCl, MgCl₂, and CaCl₂.

Conversion of fallen leaves and twigs from urban waste into pellets may be one of several options to reduce the amount of waste transported to the landfill. However, the production of pellet needs very high mechanical energy or electricity. A case study has been conducted to evaluate the advantages and disadvantages of integrating a gasification technique into the production unit. In this integrated unit, the source of electricity for the pellet production was based on the conversion of a portion of pellet product to gaseous fuel which was then used as substitute of diesel fuel for running an electricity generator set. Three scenarios for supplying the electricity were compared: (i) scenario-A: from PLN (national grid, coal fired power plant), (ii) scenario-B: diesel-generator set; and (iii) scenario-C: diesel-genset and gasification unit. Total CO₂ emissions in the production of pellet were as follows (kg CO₂ eq /ton pellet): 81.8, 47.2 and 16.3 for scenario-A, B and C respectively. Due to the addition cost of investment, the integrated pellet production and gasification unit needed a Payback Period of about 5.6 years, while those of diesel based electricity and PLN were 5.1 and 4.8 years respectively. Data for this study was obtained from experiments on a pellet production unit with a design capacity of about 9 ton/week. The diesel engine was run in dual fuel mode using producer gas from the gasification of pellet. The producer gas heating values were in the range of 3300-4600 kJ/Nm³. Oil saving in dual fuel operation was up to 70%.

National General Energy Plan of Indonesia 2017 (RUEN 2017) stated that dimethyl ether (DME) is appointed as a blending of LPG to reduce LPG imports. DME can be made with two reaction pathways, namely direct synthesis and indirect synthesis. The objective of this study was to determine the effect of pressure and syngas composition on the direct synthesis of DME using dual fixed bed catalyst. The research was carried out with two types of catalyst: M-xxx as a commercial catalyst for methanol synthesis and γ-Al2O3 as catalyst for dehydration of methanol to DME. The later was prepared in our Laboratory of Chemical Reaction Engineering and Catalysis, ITB. The dual catalyst experiment was carried out at 5 and 7 bars, and a fixed temperature of 240oC. The mass ratio of the M-xxx to γ-Al2O3, so-called M/D ratios, were varied from 1/9 to 9/1. Two type of syngas were used, i.e. SA containing only H2 and CO with a SN of 2,3 and SB containing 4% CO2 with SN of 1,8. The dual bed with a M/D ratio of 1/4 gave a CO conversion up to 62% at 5 bars and 240oC (SA). As pressure increased, the conversion of CO and H2 increases to 85% and 83% at 7 bar and 240oC (SA). The presence of CO2 (SB) decreases catalyst activity, as indicated by the decrease in conversion of CO and H2 to 56% and 54%, at 7 bar and 240oC.

Direct synthesis of DME catalyst was prepared using the co-precipitation method. The catalyst contained CuO/ZnO/Al₂O₃ about 40/27/33 (%-wt). Two types of catalyst were prepared, i.e. CZMA0 (Mg 0%-wt) and CZMA20 (Mg 20%-wt). Both of catalysts were activated using reducing gas (5% H₂ and N₂). The activity test was conducted by syngas model which contained (%-mole) 65% H₂, 28% CO and 7% N₂. The reaction was carried out in a fixed bed reactor at 5 bar, and temperature of 240, 250 and 260°C. Synthesis shown CZMA20 catalyst gave the highest catalytic activity with 73% of CO conversion and 66% of H₂ conversion (5 bar and 260°C). Direct synthesis of DME was also carried out using a dual-catalyst, i.e. catalyst for methanol synthesis (M151, the commercial catalyst of methanol synthesis) and methanol dehydration (γ-Al₂O₃-ITB). The activity of dual catalyst shown 93% of CO conversion and 91% of H₂ conversion. This activity was more stable than two other catalysts (CZMA0 and CZMA20).

Empty fruit bunch (EFB) is not yet utilized as a solid fuel for boiler due to their physical characteristics such as very bulky, high moisture and potassium contents. The hydrothermal treatment (HT) has been conducted in our research to overcome those problems. HT experiments were conducted in a 2 L digester, with 100 grams of EFB. The liquid to solid ratio was 5:1 mL/g. HT were conducted at temperature of 120, 150, 180, 200, and 220°C, and holding time of 60 minutes. The results indicated that the properties on solid products could be improved using HT, particularly its higher heating value (HHV) of 20.1 MJ/kg (obtained from HT at 180°C) compared to feedstock of 19.68 MJ/kg and commercial pellet of EFB of 13.03 MJ/kg. Pellets made of solid product from HT at 150°C and pelletized at 200 bar were considered to meet the characteristic of commercial pellets.

Experimental study on direct synthesis of DME (dimethyl ether) has been conducted using tubular reactor. The synthesis of DME was performed with two commercial catalysts, ie methanol synthesis catalyst (M151, Cu-based) and methanol dehydration catalyst (γAl₂O₃). A mixture of H₂, CO, and N₂ was used as a model for synthesis gas. Gas flow rate was set at 20 mL/min (5 bar and 240^oC). The reaction held at: pressure of 5 bar and a temperature of 240°C. This experiment was conducted by arranging a series of two types of catalysts in a fixed bed reactor. The methanol synthesis catalyst was placed in the upstream to ensure the reaction of methanol formation, then proceed with dehydration of methanol to DME. The objective of this experiment was to find out the best dual catalyst composition to produce a high concentration of DME. The experiment has shown that the best combination of methanol catalyst to dehydration catalyst was a mixture of 20% methanol catalyst (ratio 1/4). CO conversion was 62% and the product ratio of DME/methanol was 40%.

The study of rice husk charcoal utilization as gasification waste water treatment Our laboratory works showed that activated char with a specific surface area of 145 m2/g and adsorption capacity of 1.35 mg/g could be prepared by activating rice husk char using 0.5 M of NaOH solution, at 92 oC (boiling point at atmospheric pressure) for 3 hours. Using this simple process, a cheap activated char could be produced, so that the cost of wastewater treatment might be reduced. Base on common rice mill capacity of 6 tonnes/day in north part of West Java, a production of activated char with a daily capacity of 480 kg might be expected. With assumptions of a plant life time of 8 years, an activated char price is IDR 5,000/kg, and an investment of IDR 545 millions, a production unit of activated char based on rice husk was found to be economically attractive with estimated Net Present Value of IDR 1.22 billions and Return on Investment of 27%. Keywords: Rice Husk, Activated Char, Wastewater, Phenol Adsorption, Economic Feasibility AbstrakAdsorpsi dengan arang aktif merupakan salah satu cara pengolahan air limbah yang mengandung senyawa-senyawa turunan fenol. Pemanfaatan sekam padi diharapkan dapat menghasilkan arang aktif yang murah, sehingga penggunaannya dapat mengurangi biaya operasi di dalam pengolahan air limbah industri. Prosedur pembuatan arang aktif sederhana telah dikembangkan di laboratorium, yaitu aktivasi arang sekam padi dengan larutan NaOH 0,5 M, pada titik didih atmosferik dan selama 3 jam. Arang aktif yang diperoleh memiliki luas permukaan spesifik 145 m2/g dan kapasitas adsorpsi fenol sekitar 1,35 mg/g dari air limbah gasifikasi yang mengandung fenol antara 39-44 mg/L. Laju adsorpsi fenol sesuai dengan persamaan pseudo-orde 1 Lagergren, sehingga diduga proses adsorpsi yang dominan dalam percobaan ini adalah adsorpsi fisik. Atas dasar hasil percobaan ini, sebuah unit usaha kecil/menengah diusulkan untuk dikembangkan bersamaan dengan unit penggilingan gabah yang banyak terdapat di pantai utara Jawa Barat. Unit produksi ini dirancang untuk menghasilkan arang aktif dengan kapasitas 480 kg/hari atas dasar kapasitas penggilingan gabah 30 ton/hari. Dengan asumsi umur pabrik 8 tahun, harga arang sekam aktif sebesar Rp 5.000/kg, investasi sebesar Rp 545 juta menghasilkan NPV sebesar Rp 1,22 miliar dan ROI sebesar 27%. Kata Kunci: Sekam Padi, Arang Aktif, Air Limbah, Adsorpsi Fenol, Kelayakan Ekonomi