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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.
Steam Supply Evaluation for Carbon Capture and Storage in a Subcritical Coal-Fired Power Plant Hendrayawan, Veri; Raksajati, Anggit; Adisasmito, Sanggono; Juangsa, Firman Bagja
Journal of Mechanical Engineering Science and Technology (JMEST) Vol 9, No 1 (2025)
Publisher : Universitas Negeri Malang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.17977/um016v9i12025p291

Abstract

The aim of this study is to analyze the implementation of carbon capture and storage (CCS) in coal-fired power plants (CFPP) in Indonesia by determining the reboiler energy demand through steam source analysis. The study uses a representative 3×330 MW subcritical coal-fired power plant (CFPP), with an emission intensity of 1.02 tCO₂/MWh and flue gas CO₂ concentration of 13.8%. CCS modeling shows the reboiler requires about 2.9×10⁹ kJ/h energy, supplied by steam extracted from the plant’s steam cycle. A steam cycle model was developed to evaluate the impact of steam extraction. Potential tapping points analyzed include main steam, cold reheat, intermediate-pressure (IP) extraction, low-pressure to intermediate-pressure LP-IP crossover, and low-pressure (LP) extraction. Main steam extraction with the highest energy content needs the lowest steam mass flow of 355 t/h but causes the highest energy penalty of 57% because of lost electricity production in HP and IP extraction. Cold reheat extraction requires moderate steam flow of 399 t/h and a penalty of 52% but risks overheating reheater tubes. The LP-IP crossover point needs the highest steam flow 414 t/h, yet achieves the lowest net energy penalty at 33.8% with minimal operational risk, making it the most favorable option for CCS integration.