35 research outputs found
Metal casting energy efficient metrics for material selection of automotive parts
The automotive sector is one of the main end-use markets for metal casting worldwide. The strong competitive pressure typical of this industry have been influenced in the recent years by sustainability as a new factor promoted by legislation, increased societal awareness of relevant instances and resource scarcity. Energy efficiency, although only a part of sustainability, is important for the metal casting practice because of its nature of large consumer of energy per unit product. Therefore, the effective use of appropriate energy efficient metrics in foundries is of great interest. In this work, a set of indicators developed by the authors (and derived by traditional metrics) to analyse the energy performance of foundries will be used to compare high pressure die casting processes producing car transfer cases with different suitable materials. On the basis of this analysis, it will be shown that the most energy efficient material can be identified whereas the traditional metrics cannot detect such opportunity
Access and allocation in earth system governance: Water and climate change compared
A significant percentage of the global population does not yet have access to safe drinking water, sufficient food or energy to live in dignity. There is a continuous struggle to allocate the earth's resources among users and uses. This article argues that distributional problems have two faces: access to basic resources or ecospace; and, the allocation of environmental resources, risks, burdens, and responsibilities for causing problems. Furthermore, addressing problems of access and allocation often requires access to social processes (science, movements and law). Analysts, however, have tended to take a narrow, disciplinary approach although an integrated conceptual approach may yield better answers. This article proposes a multi-disciplinary perspective to the problem of access and allocation and illustrates its application to water management and climate change. © The Author(s) 2010
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Energy use and energy intensity of the U.S. chemical industry
The U.S. chemical industry is the largest in the world, and responsible for about 11% of the U.S. industrial production measured as value added. It consumes approximately 20% of total industrial energy consumption in the U.S. (1994), and contributes in similar proportions to U.S. greenhouse gas emissions. Surprisingly, there is not much information on energy use and energy intensity in the chemical industry available in the public domain. This report provides detailed information on energy use and energy intensity for the major groups of energy-intensive chemical products. Ethylene production is the major product in terms of production volume of the petrochemical industry. The petrochemical industry (SIC 2869) produces a wide variety of products. However, most energy is used for a small number of intermediate compounds, of which ethylene is the most important one. Based on a detailed assessment we estimate fuel use for ethylene manufacture at 520 PJ (LHV), excluding feedstock use. Energy intensity is estimated at 26 GJ/tonne ethylene (LHV), excluding feedstocks.The nitrogenous fertilizer production is a very energy intensive industry, producing a variety of fertilizers and other nitrogen-compounds. Ammonia is the most important intermediate chemical compound, used as basis for almost all products. Fuel use is estimated at 268 PJ (excluding feedstocks) while 368 PJ natural gas is used as feedstock. Electricity consumption is estimated at 14 PJ. We estimate the energy intensity of ammonia manufacture at 39.3 GJ/tonne (including feedstocks, HHV) and 140 kWh/tonne, resulting in a specific primary energy consumption of 40.9 GJ/tonne (HHV), equivalent to 37.1 GJ/tonne (LHV). Excluding natural gas use for feedstocks the primary energy consumption is estimated at 16.7 GJ/tonne (LHV). The third most important product from an energy perspective is the production of chlorine and caustic soda. Chlorine is produced through electrolysis of a salt-solution. Chlorine production is the main electricity consuming process in the chemical industry, next to oxygen and nitrogen production. We estimate final electricity use at 173 PJ (48 TWh) and fuel use of 38 PJ. Total primary energy consumption is estimated at 526 PJ (including credits for hydrogen export). The energy intensity is estimated at an electricity consumption of 4380 kWh/tonne chlorine and fuel consumption of 3.45 GJ/tonne chlorine, where all energy use is allocated to chlorine production. Assuming an average power generation efficiency of 33% the primary energy consumption is estimated at 47.8 GJ/tonne chlorine (allocating all energy use to chlorine)