SusChEM: Carbon Capture and Utilization by Controlled Carbonate Mineralization

1335694(多尔蒂)。我们这个时代的决定性问题之一是，大气中的二氧化碳水平已从1958年的315ppm增加到2012年的394ppm，这导致人们担心气候变化的速度将难以管理。在一系列工业过程(如发电、水泥、化学品、塑料的制造)中，固定来源的二氧化碳排放量稳步增加，这引起了人们对碳捕获和利用过程的极大兴趣，理想的情况是不会对世界各地的生活水平产生不利影响。但是，如果二氧化碳捕获要在经济和环境上长期可持续，关键是要找到方法，以经济的价格将有害废物中的二氧化碳转化为有用的产品。这个项目是实现这一目标的高风险、高回报的战略。将探索一种新的全面的二氧化碳捕获方法，该方法以科学和绿色工程基础为基础，有可能将二氧化碳转化为具有净正价值的有用固体产品。目前处理这一问题的标准方法是以高度压缩和几乎纯的液体的形式将二氧化碳从燃烧气体中分离出来，然后以几种方法之一进行处置，其中大多数方法需要仔细监测是否再次排放。相反，在这个项目中，燃烧气体将与试剂(钙、OH-、硅酸盐或糖类/磷酸盐)反应，形成一种在建筑行业中应用的良性且具有潜在价值的固体碳酸盐材料。提出者估计，碳酸盐成矿技术的能源惩罚明显低于目前的方法。他们建议建立和优化以地下地质卤水或活性矿物为原料捕获和利用固体碳酸盐和/或硅酸盐形式的二氧化碳的主导分子过程。这些原料具有较高的钙含量以及理想的碱度，这显著提高了碳化速率。提出的假设是，对亚稳态固体产物形成的深入分子理解，再加上最先进的概念性工艺设计和开发(系统方法)，将导致一种有效的二氧化碳捕获和利用技术的组合，该技术将在其方法和潜在的社会影响方面具有变革性。该方法的智力优势是在分子水平上的基础材料科学的新颖耦合，以建立活性亚稳态碳酸盐/硅酸盐固体的形成和稳定的分子设计规则与在宏观尺度上实施这些规则的过程设计(系统)策略。这将通过利用最先进的核磁共振光谱技术来实现，该技术直到最近才可用于碳酸盐和胶凝材料中关键的43Ca、25 mg、13C、31P和偶极耦合的29Si和1H物种。糖/磷酸盐或其他有机分子稳定活性碳酸盐的新用途有望提高它们的加工性、储存稳定性，并转化为有价值的结构材料。基于获得的分子洞察力，将评估和优化材料加工变量(例如，温度、压力、pH、组成和反应器/分离器配置)，以控制具有工程结构、颗粒形态和表面组成的碳酸盐固体的沉淀和结晶，包括技术经济考虑。这项研究的更广泛的影响包括(1)广泛地教育研究生和本科生了解最先进的结晶固体分子工程方法及其合成工艺设计策略，(2)培养人们对温室气体排放、其影响、二氧化碳利用的候选策略以及相关的能源和环境影响的广泛认识，以及(3)开发一种改变范式的方法的具体可能性，通过这种方法将二氧化碳转化为一种有价值的结构材料。从拟议的项目中获得的见解将是一般性的，使学生和更广泛的科学界能够开发将废品转化为潜在有价值的材料的新方法，并通过评估成本效益的系统方法来量化工艺设计和经济因素。

1335694 (Doherty). One of the defining problems of our time is that levels of CO2 in the atmosphere have increased from 315 ppm in 1958 to 394 ppm in 2012, leading to concerns about changes in climate occurring at a rate that will be difficult to manage. The steady increase in CO2 emissions from stationary sources across a spectrum of industrial processes (e.g., electricity generation, manufacturing of cement, chemicals, plastics) has raised tremendous interest in the process of carbon capture and utilization, ideally without adversely affecting living standards world-wide. But, if CO2 capture is to be economically and environmentally sustainable in the long-term, it is crucial to find ways of turning CO2 from harmful waste into a useful product at an economical price. This project is a high-risk high-reward strategy toward achieving this goal. A novel holistic approach for CO2 capture underpinned by scientific and green engineering foundations that has the potential to transform CO2 into a useful solid product with net positive value will be explored. The current standard approach to dealing with this problem has been to separate CO2 from combustion gases in the form of a highly compressed and almost pure fluid that is then disposed of in one of several ways, most of which will require careful monitoring for re-emission. Instead, pn this project, the combustion gases will be reacted with reagents (Ca2+, OH-, silicates, or saccharides/phosphonates) to form a benign and potentially valuable solid carbonate material with applications in the construction industry. The proposers estimate that the energy penalty for carbonate mineralization technology is significantly less than that for current approaches. They propose to establish and optimize the governing molecular processes that underlie the use of subsurface geological brines or reactive minerals as feedstocks to capture and utilize CO2 in the form of solid carbonates and/or silicates. These feedstocks have high Ca2+ contents, as well as desirable alkalinities, which significantly increase the carbonation rates. The proposes hypothesize that deep molecular understanding of the metastable solid products formed, coupled with state-of-the-art conceptual process design and development (a systems approach), will lead to an effective combined capture and utilization technology for CO2 that will be transformative in its approach and potentially in its societal impact.The intellectual merit of the approach is the novel coupling of fundamental materials science at a molecular level to establish the molecular design rules for the formation and stabilization of reactive metastable carbonate/silicate solids with process design (systems) strategies for implementing these rules at macroscopic scale. This will be achieved by exploiting state-of-the-art techniques of NMR spectroscopy, which have only recently become available for key 43Ca, 25Mg, 13C, 31P and dipolar-coupled 29Si and 1H species in carbonates and cementious materials. The novel use of saccharides/phosphonates or other organic molecules to stabilize reactive carbonates is expected to promote their processability, storage stability, and conversion into valuable structural materials. Based on the molecular insights obtained, materials processing variables (e.g., temperature, pressure, pH, composition, and reactor/separator configurations) will be assessed and optimized to control precipitation and crystallization of carbonate solids with engineered structures, particle morphologies, and surface compositions, including techno-economic considerations. The broader impacts of this research include (1) educating graduate and undergraduate students broadly in state-of-the-art methods of molecular engineering of crystalline solids and process design strategies for their syntheses, (2) fostering broad awareness of greenhouse gas emissions, their impacts, candidate strategies for CO2 utilization, and associated energy and environmental ramifications, and (3) the specific possibility for developing a paradigm-changing approach by which CO2 is converted to a valuable structural material. The insights gained from the proposed project will be general, enabling students and the broader scientific community to develop novel approaches for converting waste products into potentially valuable materials, along with quantifying process design and economic factors through a systems approach to evaluate cost-effectiveness.