522 research outputs found

    Network Designs for LPG Tanks in the Netherlands

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    Closing Loops in Supply Chain Management: Designing Reverse Supply Chains for End-of-Life Vehicles.

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    In this thesis, the focus is on the design of reverse supply chains for end-of-life products, in particular end-of-life vehicles. For long-term success of end-of-life management, more economic stimuli are needed than is currently the case. Legislation as a single driving force is insufficient for companies to achieve closed loop supply chains. The key issue is to find eco-efficient solutions, i.e. design and operate an economically low cost network without violating applicable targets imposed by environmental legislation. In this thesis, a case study research methodology is adopted to develop design principles for network design and assess the consequences on the operations research models. Three case studies, which stem from the network of Auto Recycling Nederland, are described in detail.

    Advanced Planning Concepts in the Closed-Loop Container Network of ARN

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    In this paper we discuss a real-life case study in the optimization of the logistics network for the collection of containers from end-of-life vehicle dismantlers in the Netherlands.Advanced planning concepts like dynamic assignment of dismantlers to logistic service providers are analyzed by a simulation model.In this model, we periodically solve a vehicle routing problem to gain insight in the long-term performance of the system.The vehicle routing problem considered is a multi depot pickup and delivery problem with alternative delivery locations.We solve this problem with a heuristic based on route generation and set partitioning.Reverse logistics;Closed-loop supply chain mmanagement;vehicle routing;set partitioning;distribution planning

    Guidelines for small scale biochar production system to optimise carbon sequestration outcome : a thesis presented in partial fulfilment of the requirements for the degree of Master of Engineering in Bioprocessing Engineering at Massey University, Palmerston North, New Zealand

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    Figures 2.1, 2.2, 2.3, 2.4, 2.8 & 2.9 have been removed for copyright reasons but may be accessed via their source listed in the References. They correspond respectively with Equation 1 (Brownsort, 2009), Fig 1 (Brownsort, 2009), Fig 10 (Cimò, 2014), Fig 4 (Antal & Grønli, 2003), Fig 3 (Antal & Grønli, 2003) & Fig 1 (Neves et al., 2011).Biochar is made in a 60 kg batch pyrolysis reactor developed by Massey University in both prior work and during this project. This thesis details the design and control features necessary to produce biochar (charcoal) at temperatures ranging from 400-700°C. It also examines the emissions abatement necessary to achieve the best possible carbon footprint by combusting the gases to avoid release to the atmosphere. The feedstock for this work was Pinus radiata without bark. The biochar reactor is a vertical drum mounted on top of a combustion chamber containing two forced draft LPG burners. The combustion gases pass through an outer annular drum and so heat the biomass through the external wall. Evolving pyrolysis gases then move toward a central perforated core inside the drum, then descend into the combustion chamber where they are partially combusted. The range of highest treatment temperatures (400-700°C) was extended by controlling the partial combustion by varying a secondary air supply into the combustion chamber (previously only 700°C was achievable). Effective emissions abatement requires complete combustion. This work reveals that the flammability of the pyrolysis gases is not high enough to self-combust and so does not remove soot and other products of incomplete combustion, such as CO and CH4. Therefore, supplementary fuel is always needed. Here, this was achieved using modulated LPG burners at the flare. This system has the problem of batch pyrolysis reactors, where the release of volatiles from the reactor is uncontrolled, making the design of a variable rate flare system a non-trivial matter. Modifications made to the reactor design in this project include insulating the flare chimney, extending it to provide sufficient residence time, and installing adjustable vents to ensure sufficient air entrainment for complete combustion. This achieved emissions of CO and CxHy (hydrocarbon, mostly CH4) of 32 and 51 ppm respectively, which were well within the US EPA limits for both suspension and fluidised bed biomass burners(2.400 and 240 ppm respectively). The net environmental impact was determined for char made at 700°C, through carbon footprint analysis. An efficient system is needed to achieve a net sequestration benefit. Here, even with emissions abatement and the above mentioned very low CO and CxHy emissions, no net benefit was achieved. With the flare working, the net fractional sequestration was -0,14 (kg C sequestered)/(kg C in biomass). Then, when the flare is turned OFF, the net fractional sequestration was -1,2401 (kg C sequestered)/(kg C in biomass). Therefore, another frame of reference for well-operated systems is that the permissible emission should be less than 0.001 (kg C emitted as CO)/(kg C biomass), without considering methane or other GHGs

    E-business and circular supply chains : increased business opportunities by IT-based customer oriented return-flow management

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    This paper deals with the application of IT in circular supply chains (CSCs). We consider information on the installed base critical, and present an illustrative example. Next we discuss a framework of different kinds of value contained in a return, and IT-applications useful in supporting its recovery or neutralisation in case of negative externalities. Also we show which kind of CSC is needed for which kind of return. We illustrate our work by three real life case studies.reverse logistics;supply chain management;electronic commerce;product life cycle
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