Industrial Separation Processes:Fundamentals

Separation processes on an industrial scale account for well over half of the capital and operating costs in the chemical industry. Knowledge of these processes is key for every student of chemical or process engineering. This book is ideally suited to university teaching, thanks to its wealth of exercises and solutions. The second edition boasts an even greater number of applied examples and case studies as well as references for further reading. - An authoritative introduction to industrial separation technology. - Contains exercises at the end of each subject as well as solutions. - Now with extended and updated examples and case studies

Equilibrium studies on butane-1,4-diamine extraction with 4-nonylphenol

BACKGROUND: The extraction of butane-1,4-diamine (BDA) from aqueous solutions with undiluted 4-nonylphenol (4NP) has been studied at three temperatures (298 K, 310 K and 323 K) in a batch system. A reactive extraction model based on mass action law was applied to describe the experimental data. RESULTS: The model developed describes the distribution of BDA between the 4NP phase and the aqueous phase, and the average stoichiometry of the complexation due to interactions between the two amine groups of BDA and 4NP, as well as the complexation constant were fitted to experimental data with good accuracy for each of the three temperatures, the largest error at the confidence limit of the estimated parameters being 6%. Using a Van't Hoff plot, the thermodynamic parameters of the equilibrium constant were determined and used to estimate that in a single stage with only S/F = 0.5, over 99% of the BDA can be extracted from a 1.146 wt% aqueous solution. High distribution ratios at low BDA concentrations hampered the effective recovery by back-extraction in a single stage, therefore multistage processing was considered and short-cut calculations revealed a maximum concentration factor of 3.6. CONCLUSION: Good agreement between single stage equilibrium data and the model was obtained and the model developed was used in short-cut calculation of a coupled multistage forward and back-extraction process showing a maximum concentration factor of only 3.6, therefore an alternative, more effective recovery strategy, e.g. through anti-solvent addition is suggested

Social and Environmental Life Cycle Assessment (SELCA) Method for Sustainability Analysis:The Jeans Global Value Chain as a Showcase

In this chapter the concepts of social life cycle assessment and combined social and environmental LCA were explored through the application of existing LCA methods to the global value chain of jeans. The social and environmental life cycle assessment (SELCA) method resulted from this explorative research that aims to contribute to the battery of impact assessment tools of products whose value chain scope is multinational (global). From a broader perspective, SELCA has a double-folded purpose to (i) identify opportunities for environmental and social improvement at any of the value chain phases of products, for remediation goals, and (ii) predict the environmental and social performance of different ways (scenarios) to produce the same product, using it as a product design tool. To simplify SELCA development, it was decided to use a single product (jeans) as a showcase from the global textile sector. In this showcase, four scenarios for jeans assembly were compared; three of them were defined under the circular economy principles by including recycled materials (cotton, PET and nylon 6) during the yarn production. During the application of the SELCA method, some new challenges were encountered related to inventory analysis, in particular during data acquisition for social inventories. This is later mainly due to the extensive list of key stakeholders for the showcase and the qualitative nature of social metrics. This list starts with cotton cultivators from different countries where regulations and codes of conduct seem to have contextualised interpretations and consequently different levels of implementation. In this regard, governmental intervention to instrument the transition towards suitable social/environmental performance along the global jeans value chain was also discussed in this chapter

Biomass offsets little or none of permafrost carbon release from soils, streams, and wildfire: an expert assessment

As the permafrost region warms, its large organic carbon pool will be increasingly vulnerable to decomposition, combustion, and hydrologic export. Models predict that some portion of this release will be offset by increased production of Arctic and boreal biomass; however, the lack of robust estimates of net carbon balance increases the risk of further overshooting international emissions targets. Precise empirical or model-based assessments of the critical factors driving carbon balance are unlikely in the near future, so to address this gap, we present estimates from 98 permafrost-region experts of the response of biomass, wildfire, and hydrologic carbon flux to climate change. Results suggest that contrary to model projections, total permafrost-region biomass could decrease due to water stress and disturbance, factors that are not adequately incorporated in current models. Assessments indicate that end-of-the-century organic carbon release from Arctic rivers and collapsing coastlines could increase by 75% while carbon loss via burning could increase four-fold. Experts identified water balance, shifts in vegetation community, and permafrost degradation as the key sources of uncertainty in predicting future system response. In combination with previous findings, results suggest the permafrost region will become a carbon source to the atmosphere by 2100 regardless of warming scenario but that 65%–85% of permafrost carbon release can still be avoided if human emissions are actively reduced

Leading Order Temporal Asymptotics of the Modified Non-Linear Schrodinger Equation: Solitonless Sector

Using the matrix Riemann-Hilbert factorisation approach for non-linear evolution equations (NLEEs) integrable in the sense of the inverse scattering method, we obtain, in the solitonless sector, the leading-order asymptotics as $t$ tends to plus and minus infinity of the solution to the Cauchy initial-value problem for the modified non-linear Schrodinger equation: also obtained are analogous results for two gauge-equivalent NLEEs; in particular, the derivative non-linear Schrodinger equation.Comment: 29 pages, 5 figures, LaTeX, revised version of the original submission, to be published in Inverse Problem