Accurate dose rate determination is crucial for trapped charge dating (TCD) applications, such as using optically stimulated luminescence (OSL), thermoluminescence (TL), and electron spin resonance (ESR). The μDOSE and μDOSE+ systems provide efficient solutions for this task through simultaneous α and β-counting along with 220Rn/216Po, 219Rn/215Po, 212Bi/212Po and 214Bi/214Po decay pair detection.This paper outlines practical guidelines and optimized laboratory procedures that enhance the performance and data reliability of these systems. We detail critical protocols, including sample homogenization methods to minimize α-particle overcounting, standardized calibration routines using International Atomic Energy Agency reference materials to ensure the reliability of instrument output data, and strategies for managing laboratory environmental conditions such as airborne 222Rn interference through automated measurement delays. Furthermore, we address the necessity of isolating the systems from external high activity sources, such as built-in β sources in luminescence readers, for obtaining the lowest systems backgrounds. While these systems are commercially available, this paper represents the comprehensive compilation of operational best practices derived from years of extensive experience since the first introduction of these systems in 2018.We show that adopting these practices reduces measurement uncertainty, optimizes the measurement time, and improves system stability to ensure high-precision dose rate results for TCD chronologies.
This study presents the energy consumption of an electrolyzer designed for the conversion of carbon dioxide (CO2) to carbon monoxide (CO), serving as an intermediate energy carrier for synthetic fuel production. A validated MATLAB model was used to conduct a comprehensive parametric sensitivity analysis, quantifying the impact of kinetic, operational, and geometric variables on system energy consumption. The results reveal that the dominant factors influencing energy consumption are strongly dependent on the operating current density. At low current densities (50 mA/cm2), performance is primarily governed by chemical kinetics. Conversely, at high current den sities (500 mA/cm2), membrane thickness emerges as the critical limiting factor due to ohmic losses; however, activation overpotentials remain significant, underscoring the importance of minimizing activation losses through catalyst optimization. The replacement of the oxygen evolution reaction at the anode substantially reduces the cell voltage, lowers energy consumption, and enables the use of waste-derived substances as substrates. In op timistic scenarios at low current densities, the electrolyzer achieves an energy consumption of approximately 2.5-3 kWh/kgCO2. This rises to over 5 kWh/kgCO2 under pessimistic conditions with high current densities. These findings provide critical insights for scaling this technology toward industrial applications in renewable energy storage and power-to-chemical conversion.
Producing grid-quality biomethane from sewage-sludge biogas is promising, yet selecting an upgrading route remains uncertain because mature technologies differ in energy use, cost, methane losses in off-gas or vent streams, and the fate of biogenic CO2. This study evaluates anaerobic digestion integrated with five commercial upgrading technologies: amine scrubbing, water scrubbing (WS), membrane separation (MEM), pressure swing adsorption (PSA), and cryogenic separation (CRYO), modelled for a municipal wastewater treatment plant. All configurations deliver grid-quality biomethane, while separated CO2 is compressed and liquefied where feasible; venting is assumed for the dilute CO2 stream from WS. Aspen Plus simulations were coupled with techno-economic analysis (TEA) and consequential life cycle assessment (LCA). The results show clear trade-offs. Amine scrubbing has the highest thermal demand (1207 kW), whereas CRYO and MEM have the highest upgrading-unit electricity demands (257 and 201 kW, respectively). Economically, without an additional emission charge, WS is the most attractive option, with the lowest levelized cost of biomethane (LCOM) of 436 €/t, while amine scrubbing is the most expensive (652 €/t). Hypothetical charges on vented biogenic CO2 and CH4 progressively increase the LCOM of WS above those of MEM, CRYO, PSA, and amine scrubbing at approximately 36.5, 37.7, 43.2, and 120.4 €/t CO2-eq, respectively. From an environmental perspective, consequential LCA shows that PSA, MEM, and CRYO outperform solvent-based routes in human health, ecosystem, and climate performance due to efficient CO2 liquefaction and avoidance of upgrading-stage venting. In the deterministic base case, PSA delivers the highest net human-health savings and the largest net GHG reduction, whereas WS shows the weakest climate performance. The economic preference for WS depends on emission-pricing assumptions, while PSA, MEM, and CRYO are more suitable for carbon-circular biorefineries.
