Sustainability and Safety Study of Tank to Propeller Process

Many public concerns have been brought to the increasingly intense greenhouse effects. The International Maritime Organization (IMO) has ambitious strategies to limit the air pollutant emissions from the merchant ships in a long run, especially for carbon, sulfur, methane and nitrogen oxides. To achieve IMO 2050 decarbonization objectives, more than one solution are required for maritime energy transition, from electric batteries for onboard activities to a variety of “green fuels” as well as safe and sustainable process design of onboard carbon capture, utilization, and storage (CCUS). Our work is focusing on screening promising marine fuels and providing safer and more sustainable carbon capture systems for maritime industry from the perspective of process safety and process systems engineering. This work can be divided into four major parts: Tank to propeller (TTP) sustainability study focuses on providing solutions on marine fuel consumption and TTP exhaust gas emission control, and a bottom-up emission inventory model was developed by analyzing and optimizing multiple parameters; Then an onboard carbon capture system called TTP post-combustion carbon capture (TTPPCC) system was proposed by integrating ship engine process modeling with chemical absorption/desorption process modeling techniques, this work covers a thorough sustainability evaluation based on emission reduction efficiency, energy penalty, and carbon cyclic capacity among two single aqueous amines, MEA and diisopropanolamine (DIPA), and one blended amine with a promoter, methyldiethanolamine (MDEA) with piperazine (PZ); The first TTP safety study aims at identifying the contributors influencing liquid aerosol flammability and solving their data deficiencies by developing quantitative structure−property relationship (QSPR) models, 1215 liquid chemicals and 14 predictors have been input to train the developed machine learning models via k-fold cross validation with the consideration of principal component analysis; The second TTP process safety study makes contributions on exploring inherently safer marine fuels by offering a liquid combustion risk criterion for ship compression ignition engines, two unsupervised machine learning clustering models were developed by considering liquid flammability flame propagation and aerosol formulation characteristics

Auto-ignition and heat release of alternative engine fuels.

Diversification of energy sources and transport decarbonisation are growing concerns of modern societies. Alternative fuels play an important role in addressing these challenges. For the spark ignition (SI) engine, the propensity of the fuel and fuel blends to auto-ignite is a critical characteristic that limits engine efficiency, which can be assessed by the ignition delays (τi). Severity of knock is also dependent upon the duration of heat release rate - the excitation time (τe). In this thesis, detailed evaluations of τi and τe are employed to study the tendency of methane to detonate in comparison with other fuels, employing the detonation peninsula on the ξ/ɛ diagram. The ξ parameter is the ratio of acoustic to auto-ignitive velocity, whereas ε is the ratio of the acoustic wave resistance time in a hot spot to the τe. It is shown that stoichiometric methane/air exhibits very good anti-knock properties in comparison with other fuels under turbocharged engine running conditions. The changes in the auto-ignition behaviour caused by the progressive addition of n-butanol (at 10%, 20%, 40% and 85% vol n-butanol) to gasoline (RON 95, MON 86.6) and its toluene reference fuel (TRF) are studied computationally and experimentally in a rapid compression machine (RCM) under stoichiometric condition at 2 MPa and at 678-916 K. At low temperatures, n-butanol acts as an octane enhancer, reducing low temperature heat release and increasing ignition delays, with marginal additional effects for blends above 40%. This is supported by the results from ξ /ɛ diagram, where higher n-butanol blends lie further away from the developing detonation region. A brute-force sensitivity analysis of the surrogate model suggests that the main reaction inhibiting ignition at low temperatures is H abstraction from the α-site of n-butanol, even for the 10% blend. At higher temperatures, the behaviour reverses as the chain branching routes from H abstraction by OH from the γ-site of n-butanol and from the α-site by HO2 become more dominant, promoting ignition. For the lower blends, the largest discrepancies between simulations and experiments are found in the negative temperature coefficient (NTC) region, where a larger number of reactions contribute to the uncertainty in predicting τi. For the higher blends, the largest discrepancies occur at low temperatures, indicating that uncertainties within the low temperature n-butanol chemistry need to be resolved. Regarding τe, the addition of n-butanol to the TRF blends has a negligible effect. Furthermore, τe, is not influenced by NTC chemistry

Molecular Dynamics Modelling on Utilisation of Lignocellulosic Biomass Derived Biofuels.

PhD Theses MedicalUtilisation of renewable biofuels (rapeseed oil, soy oil, dimethyl carbonate, cyclopentanone, methyl butanoate, dimethoxymethane and ethanol) is essential to achieving net-zero carbon emission and meeting the requirement of 2 ◦C scenario. Deployment of biofuels derived from lignocellulosic biomass such as agricultural wastes is expected to be scaled up substantially. Molecular dynamics simulation can provide in-depth understanding of the physiochemical properties of biomass and biofuels. Surface coking as the primary deactivation pattern of metal-based catalyst in biofuel reforming is investigated. Mass reduction of lignin pyrolysis in simulation is validated against experimental results. Mechanisms behind the effects of temperature, aromatic size and oxygen content on coke adsorption are revealed in molecular simulation considering the molecular collision dynamics, thermal dynamics and kinetics. It is identified that the modification of crystallinity of catalyst outer shell and the occurrence of seeping after coke adsorption would affect the subsequent catalyst regeneration. Insight into the chemical mechanism of soot inception in combustion has been gained from molecular dynamics simulation with reactive force field. The hydrocarbon structures of nascent soot in molecular simulation agree well with the experimental observation. Concurrently, the mechanisms of molecular structure of the oxygenated additives, i.e. the existence of ester, alcohol, carbonyl group and ether, on soot precursor mitigation are elucidated via evaluating the early formation of CO and CO2 quantitatively during the thermal decomposition. Prediction of fuel transport properties in high-pressure conditions is achieved. The phase transition of biodiesel at extremely high pressure is studied via morphology evolution to elucidate the experimentally observed solidification process. Viscosity and thermal conductivity are predicted over extended ranges of temperatures and pressures. Thermophysical properties like critical temperature, critical density and critical pressure are predicted for supercritical combustion. The capability of molecular simulation on thermophysical property prediction is evaluated after comparing with the experimental results

Book of abstracts of the 10th International Chemical and Biological Engineering Conference: CHEMPOR 2008

This book contains the extended abstracts presented at the 10th International Chemical and Biological Engineering Conference - CHEMPOR 2008, held in Braga, Portugal, over 3 days, from the 4th to the 6th of September, 2008. Previous editions took place in Lisboa (1975, 1889, 1998), Braga (1978), Póvoa de Varzim (1981), Coimbra (1985, 2005), Porto (1993), and Aveiro (2001). The conference was jointly organized by the University of Minho, “Ordem dos Engenheiros”, and the IBB - Institute for Biotechnology and Bioengineering with the usual support of the “Sociedade Portuguesa de Química” and, by the first time, of the “Sociedade Portuguesa de Biotecnologia”. Thirty years elapsed since CHEMPOR was held at the University of Minho, organized by T.R. Bott, D. Allen, A. Bridgwater, J.J.B. Romero, L.J.S. Soares and J.D.R.S. Pinheiro. We are fortunate to have Profs. Bott, Soares and Pinheiro in the Honor Committee of this 10th edition, under the high Patronage of his Excellency the President of the Portuguese Republic, Prof. Aníbal Cavaco Silva. The opening ceremony will confer Prof. Bott with a “Long Term Achievement” award acknowledging the important contribution Prof. Bott brought along more than 30 years to the development of the Chemical Engineering science, to the launch of CHEMPOR series and specially to the University of Minho. Prof. Bott’s inaugural lecture will address the importance of effective energy management in processing operations, particularly in the effectiveness of heat recovery and the associated reduction in greenhouse gas emission from combustion processes. The CHEMPOR series traditionally brings together both young and established researchers and end users to discuss recent developments in different areas of Chemical Engineering. The scope of this edition is broadening out by including the Biological Engineering research. One of the major core areas of the conference program is life quality, due to the importance that Chemical and Biological Engineering plays in this area. “Integration of Life Sciences & Engineering” and “Sustainable Process-Product Development through Green Chemistry” are two of the leading themes with papers addressing such important issues. This is complemented with additional leading themes including “Advancing the Chemical and Biological Engineering Fundamentals”, “Multi-Scale and/or Multi-Disciplinary Approach to Process-Product Innovation”, “Systematic Methods and Tools for Managing the Complexity”, and “Educating Chemical and Biological Engineers for Coming Challenges” which define the extended abstracts arrangements along this book. A total of 516 extended abstracts are included in the book, consisting of 7 invited lecturers, 15 keynote, 105 short oral presentations given in 5 parallel sessions, along with 6 slots for viewing 389 poster presentations. Full papers are jointly included in the companion Proceedings in CD-ROM. All papers have been reviewed and we are grateful to the members of scientific and organizing committees for their evaluations. It was an intensive task since 610 submitted abstracts from 45 countries were received. It has been an honor for us to contribute to setting up CHEMPOR 2008 during almost two years. We wish to thank the authors who have contributed to yield a high scientific standard to the program. We are thankful to the sponsors who have contributed decisively to this event. We also extend our gratefulness to all those who, through their dedicated efforts, have assisted us in this task. On behalf of the Scientific and Organizing Committees we wish you that together with an interesting reading, the scientific program and the social moments organized will be memorable for all.Fundação para a Ciência e a Tecnologia (FCT

Proceedings of the 10th International Chemical and Biological Engineering Conference - CHEMPOR 2008

This volume contains full papers presented at the 10th International Chemical and Biological Engineering Conference - CHEMPOR 2008, held in Braga, Portugal, between September 4th and 6th, 2008.FC