CIRIAF - Interuniversity Research Center on Pollution and Environment, University of Perugia, Via G. Duranti, Perugia, Italy; Department of Engineering, University of Perugia, Via G. Duranti, Perugia, Italy.
CIRIAF - Interuniversity Research Center on Pollution and Environment, University of Perugia, Via G. Duranti, Perugia, Italy.
Sci Total Environ. 2018 Feb 15;615:404-411. doi: 10.1016/j.scitotenv.2017.09.254. Epub 2017 Oct 5.
The present paper aims at assessing the carbon and energy footprint of an energy process, in which the energy excess from intermittent renewable sources is used to produce hydrogen which reacts with the CO previously separated from an innovative biogas upgrading process. The process integrates a hydrate-based biogas upgrading section and a CO methanation section, to produce biomethane from the biogas enrichment and synthetic methane from the CO methanation. Clathrate hydrates are crystalline compounds, formed by gas enclathrated in cages of water molecules and are applied to the selective separation of CO from biogas mixtures. Data from the experimental setup were analyzed in order to evaluate the green-house gas emissions (carbon footprint CF) and the primary energy consumption (energy footprint EF) associated to the two sections of the process. The biosynthetic methane production during a single-stage process was 0.962Nm, obtained mixing 0.830Nm of methane-enriched biogas and 0.132Nm of synthetic methane. The final volume composition was: 73.82% CH, 19.47% CO, 0.67% H, 1.98% O, 4.06% N and the energy content was 28.0MJ/Nm. The functional unit is the unitary amount of produced biosynthetic methane in Nm. Carbon and energy footprints are 0.7081kgCO/Nm and 28.55MJ/Nm, respectively, when the electric energy required by the process is provided by photovoltaic panels. In this scenario, the overall energy efficiency is about 0.82, higher than the worldwide average energy efficiency for fossil methane, which is 0.75.
本文旨在评估一种能源工艺的碳足迹和能源足迹，该工艺利用间歇性可再生能源的过剩能源来生产氢气，然后氢气与从创新沼气升级工艺中预先分离出来的 CO 反应。该工艺集成了基于水合物的沼气升级部分和 CO 甲烷化部分，从沼气富集中生产生物甲烷，从 CO 甲烷化中生产合成甲烷。包合物水合物是由气体包封在水分子笼中的结晶化合物，用于从沼气混合物中选择性分离 CO。从实验装置中分析数据，以评估与该工艺的两个部分相关的温室气体排放（碳足迹 CF）和一次能源消耗（能源足迹 EF）。在单级工艺中，生物合成甲烷的产量为 0.962Nm，通过混合 0.830Nm 甲烷富集沼气和 0.132Nm 合成甲烷获得。最终体积组成是：73.82%CH、19.47%CO、0.67%H、1.98%O、4.06%N，能量含量为 28.0MJ/Nm。功能单位是 Nm 单位生物合成甲烷的产量。当工艺所需的电能由光伏电池板提供时，碳足迹和能源足迹分别为 0.7081kgCO/Nm 和 28.55MJ/Nm。在这种情况下，整体能源效率约为 0.82，高于化石甲烷的全球平均能源效率 0.75。
