Cleaner production of cleaner fuels: wind-to-wheel - environmental assessment of CO2-based oxymethylene ether as a drop-in fuel
Cleaner production of cleaner fuels: wind-to-wheel - environmental assessment of CO2-based oxymethylene ether as a drop-in fuel
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DOI：
10.1039/c7ee01657c
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发表时间：
2018-02-01
影响因子：
32.5
通讯作者：
Bardow, Andre
中科院分区：
文献类型：
--
作者：
Deutz, Sarah;Bongartz, Dominik;Bardow, Andre
运输部门燃烧化石燃料是全球变暖的主要驱动因素，并导致氮氧化物和颗粒物的有害排放。为了减少运输部门的这些负面影响，目前正在开发合成燃料，这些燃料是由通过氢气（H-2）和二氧化碳（CO2）的催化转化储存的可再生能源生产的。一类有前途的合成燃料是甲醛醚（OME）。本研究使用生命周期评估（LCA）对基于OME的燃料进行了前瞻性环境评估。我们研究了OME 1-柴油混合物（OME 1-混合物），其中OME 1取代24质量%的柴油燃料。这种OME 1共混物可以是朝向OME过渡的第一步。对于从CO2基甲醇生产OME 1，我们考虑了通过与甲醛缩合的既定路线和基于与CO2和氢气的催化组合的新的直接途径。为了关闭碳循环，考虑通过沼气和直接空气捕获提供CO2。在最好的情况下，氢是通过电解水生产的，使用欧盟的风力发电作为输入。直接途径将所需的工艺步骤从三个减少到两个，并显示出允许提高氢提供的能量的利用率：火用效率从74%增加到86%。对于燃烧，我们在单缸发动机中进行了实验，以确定与发动机相关的排放物的全谱。发动机数据为中型乘用车在全球统一轻型车辆试验程序（WLTP）循环内的累积原始排放模拟提供输入。我们的油井到车轮的生命周期评估表明，OME 1有潜力作为一种几乎碳中性的混合组分：用OME 1取代24质量%的柴油可以将GW影响降低22%，NOx和烟尘排放甚至分别降低43%和75%。实现这些效益的关键是将可再生能源整合到氢气生产中。与化石柴油相比，生命周期内的累积能源需求（CED）增加了一倍。有了足够的可再生电力，OME 1混合物可能成为迈向更可持续交通部门的有希望的第一步。
The combustion of fossil fuels within the transportation sector is a key driver of global warming (GW) and leads to harmful emissions of nitrogen oxides (NOx) and particulates (soot). To reduce these negative impacts of the transportation sector, synthetic fuels are currently being developed, which are produced from renewable energy stored via catalytic conversion of hydrogen (H-2) and carbon dioxide (CO2). A promising class of synthetic fuels are oxymethylene ethers (OMEs). This study conducts a prospective environmental assessment of an OME-based fuel using Life Cycle Assessment (LCA). We investigate an OME1-diesel-blend (OME1-blend), where OME1 replaces 24 mass% of diesel fuel. Such an OME1-blend could be a first step towards an OME transition. For the production of OME1 from CO2-based methanol, we consider both the established route via condensation with formaldehyde and a novel direct pathway based on catalytic combination with CO2 and hydrogen. To close the carbon loop, CO2 supply via biogas and direct air capture is considered. In a best-case scenario, hydrogen is produced by water electrolysis using electricity from wind power in the European Union as an input. The direct pathway reduces the required process steps from three to two and is shown to allow for an improved utilization of the energy provided by hydrogen: the exergy efficiency is increased from 74% to 86%. For combustion, we conducted experiments in a single cylinder engine to determine the full spectrum of engine-related emissions. The engine data provide the input for simulations of the cumulative raw emissions over the Worldwide Harmonized Light Vehicles Test Procedures (WLTP) cycle for a mid-size passenger vehicle. Our well-to-wheel LCA shows that OME1 has the potential to serve as an almost carbon-neutral blending component: replacing 24 mass% of diesel by OME1 could reduce the GW impact by 22% and the emissions of NOx and soot even by 43% and 75%, respectively. The key to achieving these benefits is the integration of renewable energy in hydrogen production. The cumulative energy demand (CED) over the life cycle is doubled compared to fossil diesel. With sufficient renewable electricity available, OME1-blends may serve as a promising first step towards a more sustainable transportation sector.