Circular solar: Evaluating the profitability of a photovoltaic panel recycling plant

Photovoltaic (PV) panels have a crucial role in coping with the global warming mitigation and the energetic crisis currently affecting the European Community. However, from the circular perspective of end-of-life (EoL) management, there are still big issues to be solved in order to recover materials from this kind of e-wastes. Because of several reasons (e.g. type of embedded materials, illegal shipments, location of manufacturers) EoL businesses do not have the interest in approaching them. This poses a significant environmental concern in terms of their management. This work wants to assess the profitability of a specific PV module recycling plant, by evaluating several market contexts in which multiple scenarios of material price, investment and process costs will be considered. The results for a 3000 tonnes plant show that profitability is not verified in the absence of an avoided landfill cost. Instead, when a value of 200 euro/tonnes is applied, the net present value is positive in 35.2% of the scenarios and at 87.6% when a value of 350 euro/tonnes is considered. The policy choice of this value requires linking the PV module disposal fee to the circular benefits associated with its recovery

A feasibility study for a circular approach in oil refining: Metals recovery from hydrodesulphurization catalysts

The paper deals with a profitability analysis developed for a plant that recycles spent hydrodesulphurization (HDS) catalysts. Such catalysts contain molybdenum (Mo), nickel (Ni), and vanadium (V), supported by an alumina (Al2O3) carrier. The recycling process is based on a double thermal pre-treatment stage, followed by a series of hydrometallurgical steps that allow recovering Mo and V and a Ni concentrate that need further refining for separation and recovery of the metals. The economic analysis is based on the discounted cash flow method, and the baseline case analyses show that the net present value (NPV) is 14,877 thousand EUR. The selling price of vanadium pentoxide strongly influences the results. Alternative scenarios are also studied to strengthen the results obtained, considering the sensitivity, scenario and risk analyses. Profitability is confirmed in 87% of the considered scenarios, and in about 81.5%, the NPV of the baseline scenario is achieved. Circular economy models can be realized if products are recovered and if there are technologies that can recover metals. This study confirms that an example of a circular economy is met from the proposed viability analysis, and the economic benefits can be significant

Design of a mobile neutron spectrometer for the Laboratori Nazionali del Gran Sasso (LNGS)

Environmental neutrons are a source of background for rare event searches (e.g., dark matter direct detection and neutrinoless double beta decay experiments) taking place in deep underground laboratories. The overwhelming majority of these neutrons are produced in the cavern walls by means of intrinsic radioactivity of the rock and concrete. Their flux and spectrum depend on time and location. Precise knowledge of this background is necessary to devise sufficient shielding and veto mechanisms, improving the sensitivity of the neutron-susceptible underground experiments. In this report, we present the design and the expected performance of a mobile neutron detector for the LNGS underground laboratory. The detector is based on capture-gated spectroscopy technique and comprises essentially a stack of plastic scintillator bars wrapped with gadolinium foils. The extensive simulation studies demonstrate that the detector will be capable of measuring ambient neutrons at low flux levels (~$10^{-6}$ n/cm$^2$/s) at LNGS, where the ambient gamma flux is by about 5 orders of magnitude larger

3D Position Sensitive XeTPC for Dark Matter Search

The technique to realize 3D position sensitivity in a two-phase xenon time projection chamber (XeTPC) for dark matter search is described. Results from a prototype detector (XENON3) are presented.Comment: Presented at the 7th UCLA Symposium on "Sources and Detection of Dark Matter and Dark Energy in the Universe

First Dark Matter Results from the XENON100 Experiment

The XENON100 experiment, in operation at the Laboratori Nazionali del Gran Sasso in Italy, is designed to search for dark matter WIMPs scattering off 62 kg of liquid xenon in an ultra-low background dual-phase time projection chamber. In this letter, we present first dark matter results from the analysis of 11.17 live days of non-blind data, acquired in October and November 2009. In the selected fiducial target of 40 kg, and within the pre-defined signal region, we observe no events and hence exclude spin-independent WIMP-nucleon elastic scattering cross-sections above 3.4 x 10^-44 cm^2 for 55 GeV/c^2 WIMPs at 90% confidence level. Below 20 GeV/c^2, this result constrains the interpretation of the CoGeNT and DAMA signals as being due to spin-independent, elastic, light mass WIMP interactions.Comment: 5 pages, 5 figures. Matches published versio

Constraints on inelastic dark matter from XENON10

It has been suggested that dark matter particles which scatter inelastically from detector target nuclei could explain the apparent incompatibility of the DAMA modulation signal (interpreted as evidence for particle dark matter) with the null results from CDMS-II and XENON10. Among the predictions of inelastically interacting dark matter are a suppression of low-energy events, and a population of nuclear recoil events at higher nuclear recoil equivalent energies. This is in stark contrast to the well-known expectation of a falling exponential spectrum for the case of elastic interactions. We present a new analysis of XENON10 dark matter search data extending to E$_{nr}=75$ keV nuclear recoil equivalent energy. Our results exclude a significant region of previously allowed parameter space in the model of inelastically interacting dark matter. In particular, it is found that dark matter particle masses $m_{\chi}\gtrsim150$ GeV are disfavored.Comment: 8 pages, 4 figure

First Results from the XENON10 Dark Matter Experiment at the Gran Sasso National Laboratory

The XENON10 experiment at the Gran Sasso National Laboratory uses a 15 kg xenon dual phase time projection chamber (XeTPC) to search for dark matter weakly interacting massive particles (WIMPs). The detector measures simultaneously the scintillation and the ionization produced by radiation in pure liquid xenon, to discriminate signal from background down to 4.5 keV nuclear recoil energy. A blind analysis of 58.6 live days of data, acquired between October 6, 2006 and February 14, 2007, and using a fiducial mass of 5.4 kg, excludes previously unexplored parameter space, setting a new 90% C.L. upper limit for the WIMP-nucleon spin-independent cross-section of 8.8 x 10^{-44} cm^2 for a WIMP mass of 100 GeV/c^2, and 4.5 x 10^{-44} cm^2 for a WIMP mass of 30 GeV/c^2. This result further constrains predictions of supersymmetric models.Comment: accepted for publication in Phys. Rev. Let

A search for light dark matter in XENON10 data

We report results of a search for light (<10 GeV) particle dark matter with the XENON10 detector. The event trigger was sensitive to a single electron, with the analysis threshold of 5 electrons corresponding to 1.4 keV nuclear recoil energy. Considering spin-independent dark matter-nucleon scattering, we exclude cross sections \sigma_n>3.5x10^{-42} cm^2, for a dark matter particle mass m_{\chi}=8 GeV. We find that our data strongly constrain recent elastic dark matter interpretations of excess low-energy events observed by CoGeNT and CRESST-II, as well as the DAMA annual modulation signal.Comment: Manuscript identical to v2 (published version) but also contains erratum. Note v3==v2 but without \linenumber

Dark Matter Results from 100 Live Days of XENON100 Data

We present results from the direct search for dark matter with the XENON100 detector, installed underground at the Laboratori Nazionali del Gran Sasso of INFN, Italy. XENON100 is a two-phase time projection chamber with a 62 kg liquid xenon target. Interaction vertex reconstruction in three dimensions with millimeter precision allows to select only the innermost 48 kg as ultra-low background fiducial target. In 100.9 live days of data, acquired between January and June 2010, no evidence for dark matter is found. Three candidate events were observed in a pre-defined signal region with an expected background of 1.8 +/- 0.6 events. This leads to the most stringent limit on dark matter interactions today, excluding spin-independent elastic WIMP-nucleon scattering cross-sections above 7.0x10^-45 cm^2 for a WIMP mass of 50 GeV/c^2 at 90% confidence level.Comment: 5 pages, 5 figures; matches accepted versio