1,720,975 research outputs found
Environmental analysis of methanol production from steel-making offgas
No full textLinz-Donawitz gas is currently used as a heat source for the steel-making process by combustion, which is a conventional pathway. In a resource-efficient and environment-friendly point of view, methanol can be produced from Linz-Donawitz gas with balancing hydrogen due to its high carbon monoxide contents. This study designs a large-scale process for the catalytic conversion of Linz-Donawitz gas to methanol based on the validated kinetic studies and performs a lifecycle assessment of the proposed process. A lifecycle assessment of the methanol production from Linz-Donawitz gas, a new pathway, is conducted by defining the "cradle-to-gate" system boundary and are compared with those of the conventional pathway based on the ReCiPe 2016 Midpoint level methodology. Consequently, the lifecycle assessment results show that three ones among eighteen environmental impact results, global warming, fossil resource scarcity, and water consumption, of the new Linz-Donawitz gas pathway are lower than those of the conventional pathway by 86.9%, 88.8%, and 75.5%, respectively. They are dominated by the displacement effect of the heat generation of Linz-Donawitz gas by the primary sources. Using wood chips as a primary source could reduce especially global warming, fossil resource scarcity, and water consumption than using hard coal or natural gas by 29.8-58.9%, 32.5-49.1%, and 50.0-91.7%, leading to an environmental-friendly Linz-Donawitz gas process. (c) 2022 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).11Ysciescopu
유기폐기물 기반 바이오에탄올 공급 네트워크 수학적 모델 개발 : 다중 기간 확률론적 모델
No full text바이오에탄올은 최근 화석연료 사용량을 줄이기 위한 가솔린 첨가제로써 주목을 받고 있으며, 미국 및 유럽의 여러 나라에서 가솔린과 혼합되어 수송용 연료로 사용되고 있다. 전 세계 바이오에탄올의 80% 이상이 식량자원을 활용하여 생산되고 있지만, 개발도상국 등 여러 나라에서 식량자원은 에너지원으로 활용되기 어려운 실정이다. 최근 유기폐기물로부터 생산되는 아세트산으로부터 바이오에탄올이 생산될 수 있는 연구가 발표됨으로써, 유기폐기물 처리 문제 해결과 더불어 새로운 바이오에탄올 생산 경로의 도입 가능성이 확인되었다. 본 연구에서는 유기폐기물을 활용한 바이오에탄올의 최적 공급 전략을 위해 경제성을 최소화 하는 수학적 모델을 제시한다. 제안된 모델은 다중 기간 확률론적 모델로, 시간에 따라 변화하고 불확실성이 높은 여러 파라미터들 (ex, 유기폐기물 발생량, 아세트산 및 바이오에탄올 수율, 바이오에탄올 수요)의 영향이 고려된다. 모델 타당성 검증으로 국내 바이오 연료 보급정책 데이터를 기반으로 한 사례연구를 진행하여, (1) 아세트산의 조달 위치 및 양, (2) 바이오에탄올 리파이너리 위치, (3) 바이오에탄올 공급 위치 및 양을 결정한다. 본 연구 결과를 통해 유기폐기물 활용 바이오에탄올 생산 경로의 국내 도입 가능성을 확인할 수 있다.2
Process optimization, economic and environmental analysis of biodiesel production from food waste using a citrus fruit peel biochar catalyst
No full textThe concept of sustainably reusing food waste to produce value-added byproducts, such as biodiesel, was studied. Food waste is an organic-rich source of lipids. An optimization study of the extraction of oil from food waste using a solvent for biodiesel production was undertaken. A biochar catalyst derived from citron (Citrus medica) peel containing a rich carbon source. A biodiesel yield of 96.3% was obtained under the optimized reaction conditions of a 1:10 oil to methanol molar ratio, 4 w% catalyst loading, reaction temperature of 55 degrees C, and a reaction time of 52 min. The conditions were optimized by response surface methodology with a central composite design. The biochar catalyst maintained a significant biodiesel yield for four cycles. This technoeconomic analysis found that the annual plant revenue was 55,017,000. A minimum biodiesel selling price of 0.46 $/kg was used, and the environmental sustainability of the produced biodiesel was assessed by a life cycle assessment. The impact of global warming potential on the FW-based biodiesel scenario was -3.967 kg CO2 equivalent.11Nsciescopu
Green Methane as a Future Fuel for Light-Duty Vehicles
No full textFood waste (FW) has traditionally been disposed by incineration or landfilling; however, it can be converted to green methane (GM) via anaerobic digestion, and GM can be used as fuel for light-duty natural gas vehicles (LDNGVs). A lifecycle assessment (LCA) of FW-based GM production and LDNGV operation in China, a new scenario, was performed. The LCA results were compared with those for the conventional FW treatment, where a “well-to-wheel” system boundary including FW collection, GM production from FW, and vehicle manufacturing, operation, and disposal was defined. The LCA results showed that the global warming impacts of the new FW scenario are 44.3% lower than those of the conventional option. The fine particulate matter formation impact of the new FW scenario was dominated by the displacement effect of electricity supply to anaerobic digestion, followed by CO2 adsorption by the primary source. The sensitivity analysis showed that hydroelectric power as the best primary source for electricity supply could substantially reduce both global warming and FRS in the new scenario. In the short term, the proposed FW scenario could be a feasible option for achieving sustainable society by minimizing environmental impacts of FW treatment
Design under uncertainty of carbon capture, utilization and storage infrastructure considering profit, environmental impact, and risk preference
No full textThis study presents a decision making tool for risk management of a carbon capture utilization and storage (CCUS) network under uncertainty among conflicting objectives. A two-phase-two-stage stochastic multi-objective optimization problem solving algorithm is formulated to balance environmental impact and various sources of uncertainty and corresponding risk by installing and operating a CCUS network. The algorithm allows decision makers to choose their own tolerance on risk. By conducting case studies that have different target profits for CCUS networks, the algorithm provides optimal results based on the decision maker's attitude to risk. To evaluate risks imposed by uncertain parameters, a concept of downside risk is introduced. By setting different target profit levels, the suggested tool enables decision makers to choose their own tolerance and preference for risk. In the model, the life cycle assessment is applied to evaluate all environmental contributions caused by installation and operations of the CCUS network. The model provides the trade-off relationship between total annual benefit with financial risk as well as corresponding environmental impact. The aim of this model to optimize CCUS supply chain networks is to provide an intuitive decision making algorithm to balance conflicting objectives within a single framework. This problem is formulated as a mixed integer linear program model. To illustrate the applicability of the model, four optimal CCUS network models for the various types of industrial complex of Korea in 2030 are presented. Results indicate that risk-averse cases with a low profit target are more reliable in stochastic uncertainty, and that risk-taking decision makers tend to invest more on capture facility and produce more product than do, risk-averse decision makers.11Nsciescopu
Advanced sensitivity analysis using automation simulation model: Towards digital twin
No full text현재 공정 운영에 있어서 스마트 팩토리와 같은 빅데이터 기반 인공지능 적용 기술이 발전함에 따라 Digital twin (DT) 기술이 대두되고 있다. DT 시스템을 통해 공정 설계를 위한 계획 수립부터 운영, 관리, 유지·보수 및 조기 대응 등에 대해 사전에 시뮬레이션 검증과 시스템 운영 중 최적화 수행, 미래 상황 예측, 사후 문제 분석 등이 가능하다. 이를 이용하여 디지털 차원에서 공정 조건 최적화 모델을 구축하고, 생산량 및 에너지효율과 같은 공정 효율을 극대화한 정교한 예측 및 분석을 수행할 수 있다. 본 연구에서는 Aspen plus 공정 모사 프로그램을 사용하여 모델링 된 고로가스 기반 메탄올 생산 공정에 Python 프로그래밍을 이용해 공정 내 recycle stream과 purge gas stream의 split ratio를 변수로 설정해 최적 공정 값을 찾는 DT 지향 automation simulation model for methanol production을 설계하였다. 설계한 모델은 최적 공정 값 도출뿐만 아니라 변수 범위에 따른 제품 생산량과 공정 에너지 데이터를 확인할 수 있으며 이를 시각화 하여 표현할 수 있다. 이 모델은 본 연구의 공정 이외에도 다양한 공정의 최적화 시뮬레이션 모델에 기여하며, DT 시스템 적용에 대한 가능성을 보여준다.2
Comparison of polylactic acid biodegradation ability of Brevibacillus brevis and Bacillus amyloliquefaciens and promotion of PLA biodegradation by soytone
No full textPolylactic acid (PLA), a biodegradable plastic, is used to substitute commercial plastics in various fields such as disposable packaging materials and mulching films. Although the biodegradation of PLA under submerged or composting conditions is accelerated, increasing the biodegradability of PLA under soil burial conditions is still a challenge. This study reviews and compares the PLA biodegradation ability of Bacillus amyloliquefaciens and Brevibacillus brevis, both PLA-degrading bacteria. The biodegradation ability of a single bacteria in non-composting conditions was evaluated. In addition, in terms of biostimulation, PLA biodegradation according to nitrogen sources was compared. As a result, a higher PLA biodegradation ability was found in B. brevis than in B. amyloliquefaciens. Moreover, it was confirmed that the biodegradation of the PLA film was increased by using soytone as a nitrogen source in both bacteria. Controlling the nitrogen source could be a new way to increase the biodegradation of PLA.11Nsciescopu
Highly selective, energy-free, and environmentally friendly one-pot production of linear α-olefin from biomass-derived organic acid in a dual-bed catalyst system
No full textLinear α-olefins (LAOs) such as 1-heptene and 1-octene are in high demand in the petrochemical industry. The increasing concerns about the environment and resource depletion have raised the importance of new technologies for producing LAOs from sustainable resources. We report for the first time the direct production of 1-octene from biomass-derived octanoic acid using a dual-bed catalyst system of RuSn/SiO2 and Al2O3. In this new catalyst system, the catalyst bed configuration and reaction temperature profile were found to be critical factors in controlling the 1-octene yield and purity. We obtained an unprecedented high 1-octene yield of 69.4% with 83.9% purity after optimization of the dual-bed catalyst system. Based on the experimental results, simulation models were developed to analyze the mass flow and energy efficiency of the new catalytic process that can convert 283 t per d of octanoic acid into 152 t per d of 1-octene. Life cycle assessment results proved that the newly-developed dual-bed catalyst system for 1-octene production from bio-based octanoic acid could be a key technology for producing environmentally sustainable LAOs with 56% lower CO2 emissions than conventional petroleum-based LAOs (6.51 vs. 14.95 kg CO2 eq.).11Nsciescopu
Techno-economic analysis of methanol production from joint feedstock of coke oven gas and basic oxygen furnace gas from steel-making
No full textThis paper presents a study of the techno-economic analysis of producing methanol (MeOH) from steel mill off-gases, especially coke oven gas and basic oxygen furnace gas. The mixed off-gases produce syngas with appropriate H2/CO ratio and are converted to MeOH. A detailed kinetic model over a commercial catalyst Cu/ZnO/Al2O3 is applied for MeOH synthesis reaction. Four process designs were analyzed; they are combinations of two syngas compositions and the presence or absence of an interim MeOH-separation unit. When production rate was 22.2–28.3 t MeOH h−1, the unreacted purged gas could be used to generate electricity or can be sold as a fuel. The energy efficiency was in the range of 54.6–55.9%, considering both MeOH and electricity as an energy output. A heat-exchanger network is designed to minimize energy usage in the process. We analyzed the proposed process techno-economically and calculated a minimum selling price. The best case gives $0.57 kg−1 which is slightly higher than the recent market price, although a sensitivity analysis suggests that the price can be decreased in some cases. This study can be a basis for further research on this process.11Nsciescopuskc
Design under uncertainty of carbon capture and storage infrastructure considering cost, environmental impact, and preference on risk
No full textWe present a stochastic decision-making algorithm for the design and operation of a carbon capture and storage (CCS) network; the algorithm incorporates the decision-maker's tolerance of risk caused by uncertainties. Given a set of available resources to capture, store, and transport CO2, the algorithm provides an optimal plan of the CCS infrastructure and a CCS assessment method, while minimizing annual cost, environmental impact, and risk under uncertainties. The model uses the concept of downside risk to explicitly incorporate the trade-off between risk and either economic or environmental objectives at the decision-making level. A two-phase-two-stage stochastic multi-objective optimization problem (2P2SSMOOP) solving approach is implemented to consider uncertainty, and the s-constraint method is used to evaluate the interaction between total annual cost with financial risk and an Eco-indicator 99 score with environmental risk. The environmental impact is measured by Life Cycle Assessment (LCA) considering all contributions made by operation and installation of a CCS infrastructure. A case study of power-plant CO2 emission in Korea is presented to illustrate the application of the proposed modeling and solution method.1113Nsciescopu
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