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Selective H2S Absorption Using the Mixture of NaOH-NaHCO3-Na2CO3 Buffer Solvent Solution Anggit Raksajati; Haditya Kukuh Purwanto; Ardian Nugra Baskoro; Antonius Indarto; Danu Ariono
Journal of Engineering and Technological Sciences Vol. 54 No. 5 (2022)
Publisher : Institute for Research and Community Services, Institut Teknologi Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/j.eng.technol.sci.2022.54.5.13

Abstract

Acid gas enrichment unit (AGEU) involves selective separation of H2S from acid gas mixture, for example using absorption with an NaOH solvent solution. Sodium carbonate (Na2CO3) and sodium bicarbonate (NaHCO3) buffer addition to NaOH solution suppresses CO2 absorption, thereby increasing the selectivity of H2S absorption. This study evaluated the effect of buffer addition to increase H2S absorption selectivity using an NaOH solution. It was shown that both buffer addition and L/G ratio decrease could increase H2S selectivity by limiting CO2 absorption. Based on the simulation results, in the 0.006 to 0.030 L/G ratio range and NaOH solvent concentration greater than 2%-mass, the addition of NaHCO3 with mass ratio greater than 1.5:1 to NaOH and the addition of Na2CO3 at 1.26 times NaHCO3’s mass increased H2S absorption selectivity up to 17.3%. The combination of an L/G ratio of 0.006 and solvent with a composition of 5%-mass NaOH, 15%-mass NaHCO3, and 18.9%-mass Na2CO3 produced the highest H2S selectivity of 23.1 (379.7% H2S selectivity increase).
Pengaruh Tekanan Dan Tahap Kompresi Dalam Pemurnian Biogas Menjadi Biometana Dengan Absorpsi CO2 Menggunakan Air Bertekanan Raksajati, Anggit; Adhi, Tri Partono; Ariono, Danu
Indonesian Journal of Chemical Research Vol 8 No 1 (2020): Edisi Bulan Mei (Edition for May)
Publisher : Jurusan Kimia, Fakultas Sains dan Teknologi, Universitas Pattimura

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.30598/ijcr.2020.8-ang

Abstract

Palm oil mill effluent (POME) from condensate stew, hydrocyclone water, and sludge separator contains organic carbon with a COD more than 40 g/L and a nitrogen content of about 0.2 and 0.5 g/L as ammonia nitrogen and total nitrogen. At present, the POME is converted into biogas using anaerobic ponds. Biogas produced contains 60% methane (CH4) and 40% carbon dioxide (CO2) and can be purified into biomethane through CO2 absorption using water. This study evaluates the optimum pressure and feed compression stage in biogas upgrading into biomethane. The results show the rate of circulation of water needed to separate CO2 from biogas feed decreases with increasing absorber pressure due to increased solubility of CO2 in water. Water circulation pumps and biogas compressor works increase due to the increase in pressure difference needed. The optimum pressure of the biogas biogas purification unit is within the range of 7-10 bar. At the same absorber pressure, the 1 stage feed compression unit is cheaper than that of 2 stages. However, the overall process with 1 compression stage might not be more economical than the 2-stage if consider the higher methane loss.
Life Cycle Assessment of Decaffeinated Coffee Beans Production Shofinita, Dian; Lestari, Dianika; Fiorine, Fiorine; Rochili, Andreana; Raksajati, Anggit; Achmadi, Amarthya
Journal of Engineering and Technological Sciences Vol. 57 No. 3 (2025): Vol. 57 No. 3 (2025): June
Publisher : Directorate for Research and Community Services, Institut Teknologi Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/j.eng.technol.sci.2025.57.3.3

Abstract

Life Cycle Assessment (LCA) analysis was conducted on the simulation of the production process of decaffeinated coffee beans using ethyl acetate (EA) and dichloromethane (DCM) solvents. The methods employed include the cradle-to-gate system, the ReCiPe 2016 midpoint method, and a hierarchic perspective on OpenLCA. The analysis used 320 kg of Robusta coffee beans per batch with the scope of analysis consisting of planting, postharvest, transportation, and decaffeination. The overall results of the hotspot analysis were human carcinogenic toxicity, marine ecotoxicity, global warming, freshwater ecotoxicity, and land use of 8 x 101  kg 1,4-dichlorobenzene eq, 1 x 101 kg 1,4-dichlorobenzene eq, 6 x 104 kg CO2 eq, 7 x 100 kg 1,4-dichlorobenzene eq, and 3 x 104 m2a crop eq for both EA and DCM. Comparison of the two solvents shows that the biggest environmental impacts were marine ecotoxicity, freshwater ecotoxicity, and human carcinogenic toxicity of 8.52 x 100 kg 1,4-dichlorobenzene eq, 5.44 x 100 kg 1,4-dichlorobenzene eq, 7.65 x 100 kg 1,4-dichlorobenzene eq for EA, and 8.52 x 100 kg 1,4-dichlorobenzene eq, 5.61 x 100 kg 1,4-dichlorobenzene eq, 8.03 x 100 kg 1,4-dichlorobenzene eq for DCM. Cultivation, extraction, and drying were the stages of considerable environmental impact. The application of agroforestry, reduction of inorganic and organic fertilizers, and the use of more environmentally friendly electricity sources serve as alternatives to reduce emissions.
IMPROVING HYDROCARBON RESIDUE FEED DEFINITION THROUGH VALIDATED SIMULATION MODELS Rinzan Akhirjulima; IGBN Makertihartha; Tri Partono Adhi; Anggit Raksajati
Scientific Contributions Oil and Gas Vol 48 No 1 (2025)
Publisher : Testing Center for Oil and Gas LEMIGAS

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29017/scog.v48i1.1683

Abstract

The conventional development of deasphalting processes relies on costly and time-consuming lab experiments. This study introduces a more efficient approach using simulation to tackle these challenges. The method identifies the composition of synthetic crude oil (SCO) feedstock, dividing it into four key molecular groups: Saturates, Aromatics, Resins, and Asphaltenes (SARA). These groups are pseudo-components in the simulation, characterized by parameters like boiling points and molecular weights. The simulated boiling points are then compared with actual crude oil to ensure accuracy. The framework is applied to model hydrocarbon residue in Lube Oil production, testing adaptability across various feedstocks. The strategy to improve the simulation's accuracy was adjusting molecular interactions for asphaltene separation and refining pseudo-components. This resulted in a boiling point curve with an RMSD of 2.689, closely matching the actual residue curve. This approach improves the precision of deasphalting while reducing dependence on resource-heavy lab work.
Analysis of CCS implementation in Indonesia’s coal fired power plants, economic optimization, and potential impact on Java-Bali grid for future decarbonization Anggit Raksajati; Sanggono Adisasmito; Veri Hendrayawan
International Journal of Applied Power Engineering (IJAPE) Vol 15, No 2: June 2026
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/ijape.v15.i2.pp927-941

Abstract

This study aims to evaluate impact of retrofitting carbon capture and storage (CCS) technology on coal fired power plants (CFPP) in Indonesia. Using a representative 3×330 MW CFPP, the integration of CCS increases the levelized cost of electricity (LCoE) to 124 USD/MWh. Key cost components include CO₂ capture (21.7%), energy penalty from steam extraction (18.5%), and CO₂ transport and injection (16.7%). Sensitivity analysis indicates that CCS becomes financially viable under a high carbon cap (0.9 tCO₂/MWh) and a carbon tax of 76 USD/tCO₂. Meanwhile, International carbon markets offer a potential revenue at 75 USD/tCO₂ can fully offset CCS costs. Additionally, CAPEX grants can reduce LCoE to 12.4%, serving to mitigate upfront investment for CCS deployment. Within the Java-Bali grid, CFPP account for 58.8% of the generation mix with 41% aged 10-20 years using predominantly subcritical technology while 28% are over 20 years old and follow natural retirement being replaced by renewable energy. CCS retrofitting is more economically and technically viable for mid aged plants with newer technologies and lower emission intensities, supporting grid stability with limited renewable base load availability. This strategy also serves as a transitional pathway toward long term renewable integration until the LCoE of PV+BESS falls below 50 USD/MWh.
Understanding the Potential of Bio-Carbon Capture and Storage from Biomass Power Plant in Indonesia Zefania Praventia Sutrisno; Attaya Artemis Meiritza; Anggit Raksajati
Indonesian Journal of Energy Vol. 4 No. 1 (2021): Indonesian Journal of Energy
Publisher : Purnomo Yusgiantoro Center

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.33116/ije.v4i1.99

Abstract

Indonesia is currently experiencing a significant increase in population, industrialization and energy demand. As the energy demand increases, so does the production of climate-altering CO2 emission. Biomass power plants have emerged as a low carbon power generation alternative, utilizing agricultural and industrial waste. Biomass power plants have the potential of being a carbon-negative power generation technology in the near future by integrating carbon and capture storage (bio-CCS). The objective of this paper is to analyze and map potential CO2 emission in the processes of biomass power plants from gasification and firing or co-firing technology, then recommend suitable carbon capture technology based on the biomass power plant characteristics in Indonesia. The CO2 emission to be captured in the gasification process is 11-15% of the producer gas, while in co-firing it is 7-24% of the flue gas stream. Using biomass instead of coal in power plants reduces the electric efficiency and increases the plant’s in-house emission, but when analyzed in a wider boundary system it is apparent that the net GWP and CO2 emission of biomass power plants are way smaller than coal power plant, moreover when equipped with carbon capture unit. Biomass power plant that uses firing technology can reduce CO2 emission by 148% compared to typical coal power plant. Installing carbon capture unit in biomass firing power plants can further reduce the specific CO2 emission by 262%. If carbon capture technology is implemented to all existing biomass power plants in Indonesia, it could reduce the greenhouse gas emission up to 2.2 million tonnes CO2 equivalent annually. It is found that there are 3 significant designs for gasification technology: NREL design, Rhodes & Keith design and IGBCC+DeCO2 design. The first two designs are not suitable to be retrofitted into existing biomass power plants in Indonesia since they are based on a specific BCL/FERCO gasifier. While IGBCC+DeCO2 design still needs further study regarding its feasibility. While for firing, the most promising technology to be applied in the near future is solvent-based absorption because it is already on commercial scale for coal-based power plants and can be implemented for other source, e.g. biomass power plant. Bio-CCS in existing biomass power plant with firing technology is likely to be implemented in the near future compared to the gasification, because it applies the post combustion capture as an “end-of-pipe” technology which is generally seen as a more viable option to be retrofitted to existing power plants, resulting in potentially less expensive transition.