Assessment of Sustainability-Potential: Hierarchical Approach (original) (raw)
Related papers
In this work, fourteen synthetic routes of vinyl chloride are generated from ‘create-reactionset’ software that runs on MATLAB using the molar constraints of all the molecules of the reactants, products and the by-products involved in the manufacture of one unit of vinyl chloride. In order to quantitatively evaluate the energy performance and the potential profits of the process routes, comparison of the fourteen synthetic routes showed that eight synthetic routes is heat absorbing reactions requiring energy input, while six are heat generating reactions resulting to negative energy quality. Route〖 (R〗_9), with synthetic reaction Cl2+HCl+O2 + C2H4-->2H2O + 3C2H3Cl, and with exergy dissipation of -1370.1563Kcal/g-mol and a potential profit of 51c/lb is considered as being sustainable. The comparison rendered it possible to rapidly screen out synthetic routes that are highly unlikely to be sustainable at the earliest possible stage thereby preventing the enormous expenditure required for developing such processes. Definitions and calculation formulas of exergy and potential profits of a substance, a mixture, a stream, and a unit (process) are illustrated. KEYWORDS: Vinyl chloride, sustainability, process routes, software
In this work, fourteen synthetic routes of vinyl chloride are generated from 'create-reactionset' software that runs on MATLAB using the molar constraints of all the molecules of the reactants, products and the by-products involved in the manufacture of one unit of vinyl chloride. In order to quantitatively evaluate the energy performance and the potential profits of the process routes, comparison of the fourteen synthetic routes showed that eight synthetic routes is heat absorbing reactions requiring energy input, while six are heat generating reactions resulting to negative energy quality. Route , with synthetic reaction Cl 2 +HCl+O 2 + C 2 H 4->2H 2 O + 3C 2 H 3 Cl, and with exergy dissipation of-1370.1563Kcal/g-mol and a potential profit of 51c/lb is considered as being sustainable. The comparison rendered it possible to rapidly screen out synthetic routes that are highly unlikely to be sustainable at the earliest possible stage thereby preventing the enormous expenditure required for developing such processes. Definitions and calculation formulas of exergy and potential profits of a substance, a mixture, a stream, and a unit (process) are illustrated. INTRODUCTION Limiting energy utilization and achieving economically viable processes is one of the main challenges of chemical engineering at present for sustainable chemical process route development. To develop and design a less energy consuming processes and cost effective alternative to replace or retrofit a current inefficient process, it is essential to establish a method for quantitatively evaluating and comparing the energy performance and the potential profits of chemical processes.
A comparative life cycle assessment of internal combustion engine (ICE) based vehicles fueled by gasoline, diesel, LPG, methanol, CNG, hydrogen and ammonia; hybrid electric vehicles using 50% gasoline and 50% electricity; and electric only vehicles. Electric and hybrid electric vehicles result in higher human toxicity, terrestrial ecotoxicity and acidification values because of manufacturing and maintenance phases. In contrast, hydrogen and ammonia vehicles yield the most environmentally benign options. In this first section of the final report, a comparative life cycle assessment of internal combustion engine (ICE) based vehicles fueled by various fuels, ranging from hydrogen to gasoline, is conducted in addition to electric and hybrid electric vehicles. Various types of vehicles are considered, such as ICE vehicles using gasoline, diesel, LPG, methanol, CNG, hydrogen and ammonia; hybrid electric vehicles using 50% gasoline and 50% electricity; and electric only vehicles for comprehensive comparison and environmental impact assessment. The processes are analyzed from raw material extraction to vehicle disposal using life cycle assessment methodology. In order to reflect the sustainability of the vehicles, seven different environmental impact categories are considered: abiotic depletion, acidification, eutrophication, global warming, human toxicity, ozone layer depletion and terrestrial ecotoxicity. The energy resources are chosen mainly conventional and currently utilized options to indicate the actual performances of the vehicles. The results show that electric and hybrid electric vehicles result in higher human toxicity, terrestrial ecotoxicity and acidification values because of manufacturing and maintenance phases. In contrast, hydrogen and ammonia vehicles yield the most environmentally benign options. In the second section of this report, production of ammonia using conventional hydrocarbons is investigated by implying current technologies and developments. Hydrogen can be produced by dissociation of hydrocarbons which can be then converted to ammonia using a nitrogen supply. Decomposition of heavy fractions can bring some challenges because of various metal and sulfur contents, however, purification is possible and applicable. There are multiple pathways for decomposition namely; thermal, non-thermal, plasma, non-plasma techniques. An alternative method of hydrogen and ammonia production from hydrocarbons is their thermal decomposition which is accompanied by the formation of carbon deposits. Methane can be thermally or thermocatalytically decomposed (TCD) into carbon and hydrogen without CO or CO2 production. There are some research papers and patents in the literature regarding the application of microwave energy for hydrocarbons. They have shown that bitumen, which is the end product from oil sand, can be decomposed using microwave energy. Many of the inorganic particles in processed oil sands hold a charge, and could be influenced by electromagnetic radiation. They are excited at a different rate than the water and bitumen when irradiated, creating a temperature gradient between the different components of the oil sands. In the third section, detailed cost and feasibility analyses of various key scenarios for production, storage and transportation of ammonia in Ontario, Newfoundland and Labrador, and Alberta are performed. Renewable resources based ammonia is quite attractive supplying similar costs in some cases compared to conventional steam methane reforming route. The high hydroelectric and wind energy source potential of Newfoundland and Labrador make the energy storage attractive using ammonia. Ontario, with decreasing electricity prices, has potentials for hydropower especially in Northwestern region for on-site ammonia production. The hydrocarbon decomposition option is also considered for Alberta province and it is observed that the cost of ammonia can be lower than conventional steam methane reforming. Storage and transportation of ammonia brings additional costs after production which is a significant disadvantage for long distance transportation. The results imply that using appropriate renewable resources and cleaner hydrocarbon utilization paths, ammonia production can be cost-effective and environmentally friendly.
Bio-Based Solvents for Organic Synthesis
Available online at http://etheses.whiterose.ac.uk/4999/ Scrutiny over solvent selection in the chemical industry has risen in recent decades, popularising research into neoteric solvent systems such as ionic liquids and supercritical fluids. More recently bio-based solvent products have been considered as replacements for conventional petroleum derived solvents. Because they bear a close resemblance to existing solvent products, bio-based solvents can be readily absorbed into the fine chemical industries. This work develops a methodology for identifying reactions of concern with respect to current solvent selection practice, and then implementing a high performance bio-based solvent substitute. In this thesis, kinetic studies of heteroatom alkylation, amidation, and esterification are documented, and the solvent effect dictating the rate of each reaction ascertained. With the ideal properties for the solvent known, bio-based solvent candidates were screened for suitability in each ...
Biorefineries and Chemical Processes: Design, Integration and Sustainability Analysis
As the range of feedstocks, process technologies and products expand, biorefineries will become increasingly complex manufacturing systems. This book presents process modelling and integration, and whole system life cycle analysis tools for the synthesis, design, operation and sustainable development of biorefinery and chemical processes.