Thermodynamic optimization of steady-flow industrial chemical processes

© 2018, The Author(s). Industrial steady-flow chemical processes are generally organised as a sequence of individually optimised operations. However, this may not achieve overall optimization since material (as recycle), heat and work transfers overall may not be well balanced. We introduce the idea of a preliminary overall thermodynamic balance to produce a reversible process, with the objective of minimising, for both economic and environmental reasons, the quality and quantity of energy used. This balance may later require adjustment to account for the realities of available materials and equipment. For this purpose, we introduce (i) a Carnot temperature, TCarnot, by which a Carnot machine (an engine which can operate as either a heat pump or a turbine) can supply the required heat at the correct temperature for a process to operate reversibly, that is with least energy, and (ii) the GH Diagram on which Carnot temperature-based processes are plotted in ?G–?H space. We demonstrate the utility of this analysis by simple application to the Haber–Bosch process for ammonia synthesis and by a sequence of operations for the synthesis of methanol. We also briefly introduce the state function exergy, which uses the natural environment as the reference base for energy in place of pure elements under standard conditions

Informal Action—Adjudication—Rule Making: Some Recent Developments in Federal Administrative Law

Direct energy consumption of ICT hardware is only “half the story.” In order to get the “whole story,” energy consumption during the entire life cycle has to be taken into account. This chapter is a first step toward a more comprehensive picture, showing the “grey energy” (i.e., the overall energy requirements) as well as the releases (into air, water, and soil) during the entire life cycle of exemplary ICT hardware devices by applying the life cycle assessment method. The examples calculated show that a focus on direct energy consumption alone fails to take account of relevant parts of the total energy consumption of ICT hardware as well as the relevance of the production phase. As a general tendency, the production phase is more and more important the smaller (and the more energy-efficient) the devices are. When in use, a tablet computer is much more energy-efficient than a desktop computer system with its various components, so its production phase has a much greater relative importance. Accordingly, the impacts due to data transfer when using Internet services are also increasingly relevant the smaller the end-user device is, reaching up to more than 90 % of the overall impact when using a tablet computer.QC 20140825</p

Competition and Complementarity in Diffusion: The Case of Octane

The standard ontogenic (life-cycle) model of technological evolution can be characterized briefly as follows (Ayres, 1987): (1) a radical invention (birth) creates a new technology; (2) it is commercialized on the basis of performance and rapidly developed by a series of improvements and modifications (infancy); (3) it is successful enough in the marketplace to attract many variants and imitators who hope to exploit a growing market (adolescence); (4) the pace of technological change finally slows down enough to permit standardization and exploitation of economies of scale, and competition on the basis of price rather than performance (maturity); and finally a new and better technology supplants it (senescence)

CRITICAL ANALYSIS OF EXISTING RECYCLABILITY ASSESSMENT METHODS FOR NEW PRODUCTS IN ORDER TO DEFINE A REFERENCE METHOD

The designers of products subject to the European regulations on waste have an obligation to improve the recyclability of their products from the very first design stages. The statutory texts refer to ISO standard 22 628, which proposes a method to calculate vehicle recyclability. There are several scientific studies that propose other calculation methods as well. Yet the feedback from the CREER club, a group of manufacturers and suppliers expert in ecodesign and recycling, is that the product recyclability calculation method proposed in this standard is not satisfactory, since only a mass indicator is used, the calculation scope is not clearly defined, and common data on the recycling industry does not exist to allow comparable calculations to be made for different products. For these reasons, it is difficult for manufacturers to have access to a method and common data for calculation purposes. A critical analysis of the standard and the various calculation methods identified in scientific journals was performed. An initial discussion brought to light several possible scopes of calculation. Additional indicators, such as quality loss or economic value loss, would be complementary to the mass indicator. Case studies were performed to compare these different methods. A new method and its scope of calculation are proposed in order to develop a reference method.CREE

Agroecosystem energy transitions in the old and new worlds: trajectories and determinants at the regional scale

Energy efficiency in biomass production is a major challenge for a future transition to sustainable food and energy provision. This study uses methodologically consistent data on agroecosystem energy flows and different metrics of energetic efficiency from seven regional case studies in North America (USA and Canada) and Europe (Spain and Austria) to investigate energy transitions in Western agroecosystems from the late nineteenth to the late twentieth centuries. We quantify indicators such as external final energy return on investment (EFEROI, i.e., final produce per unit of external energy input), internal final EROI (IFEROI, final produce per unit of biomass reused locally), and final EROI (FEROI, final produce per unit of total inputs consumed). The transition is characterized by increasing final produce accompanied by increasing external energy inputs and stable local biomass reused. External inputs did not replace internal biomass reinvestments, but added to them. The results were declining EFEROI, stable or increasing IFEROI, and diverging trends in FEROI. The factors shaping agroecosystem energy profiles changed in the course of the transition: Under advanced organic and frontier agriculture of the late nineteenth and early twentieth centuries, population density and biogeographic conditions explained both agroecosystem productivity and energy inputs. In industrialized agroecosystems, biogeographic conditions and specific socio-economic factors influenced trends towards increased agroecosystem specialization. The share of livestock products in a region's final produce was the most important factor determining energy returns on investment

Relating industrial symbiosis and circular economy to the sustainable development debate

Industrial Symbiosis (IS) is a business-focused collaborative approach oriented towards resource efficiency that has been theorised and studied mainly over the last twenty-five years. Recently, IS seems to have found a renewed impetus in the framework of the Circular Economy (CE), a novel approach to sustainability and Sustainable Development (SD) that has been rapidly gaining momentum world-wide. This opening chapter of the book provides an introduction to the concepts of IS, CE and SD, and summarizes their complex evolutionary paths, recalling the rel-evant developments and implementation challenges. In addition, the authors point out the divergences and interrelations of these concepts, both among themselves and with other related concepts and research fields, such as industrial ecology, eco-logical modernization and the green economy. Furthermore, the potential contribu-tion of IS and the CE to SD is briefly discussed, also highlighting critical issues and trade-offs, as well as gaps in research and application, especially relating to the so-cial component of sustainability. Particular attention is given to the potential role of IS in the achievement of targets connected to the Sustainable Development Goals set in the UN Agenda 2030. The recent advances in the IS and CE discussion in the context of the SD research community are further explored, with particular empha-sis on the contribution of the International Sustainable Development Research So-ciety (ISDRS) and its 24th annual conference organised in Messina, Italy, in 2018. The programme of that conference, indeed, included specific tracks on the above-mentioned themes, the contents of which are briefly commented on here, after an overview on the whole conference and the main cross-cutting concepts emerged. In the last part of the chapter, a brief description of the chapters collected in the book is presented. These contributions describe and discuss theoretical frameworks, methodological approaches and/or experiences and case studies where IS and the principles of CE are applied in different geographical context and at different scales to ultimately improve the sustainability of the current production patterns

Energy conservation more effective with rebound policy

This article sketches the problem of indirect energy use effects, also known as rebound, of energy conservation. There is widespread support for energy conservation, especially when it is voluntary, as this seems a cheap way to realize environmental and energy-climate goals. However, this overlooks the phenomenon of rebound. The topic of energy rebound has mainly attracted attention from energy analysts, but has been surprisingly neglected in environmental economics, even though economists generally are concerned with indirect or economy-wide impacts of technical change and policies. This paper presents definitions and interpretations of energy and environmental rebound, as well as four fundamental reasons for the existence of the rebound phenomenon. It further offers the most complete list of rebound pathways or mechanisms available in the literature. In addition, it discusses empirical estimates of rebound and addresses the implications of uncertainties and difficulties in assessing rebound. Suggestions are offered for strategies and public policies to contain rebound. It is advised that rebound evaluation is an essential part of environmental policy and project assessments. As opposed to earlier studies, this paper stresses the relevance of the distinction between energy conservation resulting from autonomous demand changes and from efficiency improvements in technology/equipment. In addition, it argues that rebound is especially relevant for developing countries. © 2010 The Author(s)

Eco-efficiency measurement and material balance principle:an application in power plants Malmquist Luenberger Index

Incorporating Material Balance Principle (MBP) in industrial and agricultural performance measurement systems with pollutant factors has been on the rise in recent years. Many conventional methods of performance measurement have proven incompatible with the material flow conditions. This study will address the issue of eco-efficiency measurement adjusted for pollution, taking into account materials flow conditions and the MBP requirements, in order to provide ‘real’ measures of performance that can serve as guides when making policies. We develop a new approach by integrating slacks-based measure to enhance the Malmquist Luenberger Index by a material balance condition that reflects the conservation of matter. This model is compared with a similar model, which incorporates MBP using the trade-off approach to measure productivity and eco-efficiency trends of power plants. Results reveal similar findings for both models substantiating robustness and applicability of the proposed model in this paper

Cadmium-Induced Oxidative Stress and Apoptotic Changes in the Testis of Freshwater Crab, Sinopotamon henanense

Cadmium (Cd), one of the most toxic environmental and industrial pollutants, is known to exert gonadotoxic and spermiotoxic effects. In the present study, we examined the toxic effect of Cd on the testis of freshwater crab, Sinopotamon henanense. Crabs were exposed to different Cd concentrations (from 0 to 116.00 mg·L−1) for 7 d. Oxidative stress and apoptotic changes in the testes were detected. The activities of SOD, GPx and CAT initially increased and subsequently decreased with increasing Cd concentrations, which was accompanied with the increase in malondialdehyde (MDA) and H2O2 content in a concentration-dependent manner. Typical morphological characteristic and physiological changes of apoptosis were observed using a variety of methods (HE staining, AO/EB double fluorescent staining, Transmission Electron Microscope observation and DNA fragmentation analysis), and the activities of caspase-3 and caspase-9 were increased in a concentration-dependent manner after Cd exposure. These results led to the conclusion that Cd could induced oxidative damage as well as apoptosis in the testis, and the apoptotic processes may be mediated via mitochondria-dependent apoptosis pathway by regulating the activities of caspase-3 and caspase-9