EAGER: COMPUTER AIDED MOLECULAR DESIGN (CAMD) FOR NEW ADSORBENTS FOR NORM REMOVAL FROM NATURAL GAS FRACKING PRODUCED WATER

为了生产大量新发现的非常规天然气，通常在页岩气和煤层气开采盆地进行水力压裂。在油气勘探过程中，水力压裂会消耗大量的淡水，并产生大量的污染废水。在水力压裂后的30天内，约有15-25%的水作为返排水返回地面。采出水在油井生命周期内持续流动。除了高盐度和硬度外，水还可能含有大量的天然放射性物质（NORM）。要有选择地将NORM从这些水域移除是非常困难的。本工作将研究新型吸附剂。研究人员将与天然气技术研究所（GTI）合作，确定高性能吸附剂的简化功能清单，并将该清单与常见的吸附剂联系起来。该项目将使用计算机辅助分子设计（CAMD）方法开发用于去除NORM的新型环保吸附剂。CAMD通常是基团贡献法（GCM）的反向使用，GCM用于生成具有理想性质的分子。GCM已被用于预测状态属性，如选择性、相对挥发性、表面张力、密度、粘度和反应性。PI将基于热力学开发新的基团贡献方法来研究吸附剂的重要性质。用GCM进行物理吸附得到了初步结果。PI建议研究化学吸附和Langmuir等温线。GCM将确定环境无害吸附剂的基团。这些组将通过探索所有可能的组合来产生所有可能的分子。每组的性质和/或组之间的相互作用参数可以理论计算，实验获得，或统计回归。从这组基团中，可以通过基团组合产生所需的分子。可能会施加来自物理和化学性质的限制，以及来自法规限制的限制，因此可以减少组合的数量。然而，这是第一次提出这种方法来生成用于NORM分离的吸附剂。PI将从CAMD获得的新吸附剂名单中选择前30名进行进一步研究。为了确定可能需要的化学物质，使用了各种溶液算法。这些方法包括启发式计算、知识库方法、带有代数方程的分子性质聚类和基于优化的方法。PI将使用优化方法来完成这项工作。CAMD方法已应用于许多领域，如萃取溶剂、聚合物设计、脱脂溶剂、毯子洗涤溶剂、吸收溶剂、制冷剂设计、蒸馏溶剂、反应溶剂、催化剂、增值产品、结晶溶剂和发泡剂。本研究对天然气压裂行业具有重要的基础和现实意义。拟议的研究涉及开发新的和强大的工具，以确定在天然气压裂中去除NORM的新型吸附剂。除水力压裂外，吸附剂在许多应用中都有应用。因此，在这项工作中开发的框架具有更广泛的商业和社会影响。该团队正计划与来自行业和国家实验室的研究人员合作，以他们之前在其他项目上的互动为基础。

1434964DiwekarVishwamitra Reserach InstituteTo produce large volumes of newly discovered unconventional gas, hydraulic fracturing of wells is commonly practiced in basins where shale gas and coal bed methane are extracted. Hydraulic fracturing of wells during oil and gas (O&G) exploration consumes large volumes of fresh water and generates larger volumes of contaminated wastewater. About 15-25% of this water returns to the surface as flowback water within 30 days of hydraulic fracturing. Produced water continues to flow for the life of the well. In addition to high salinity and hardness, the water may also contain significant levels of natural occurring radioactive materials (NORM). It is very difficult to selectively remove NORM from these waters.New and novel model adsorbents will be researched in this work. The reserachers will collaborate of the Gas Tecnology Institute (GTI)to identify a simplified list of functions expected from high performance adsorbents and to correlate that list with the adsorbents commonly found. The PI will use computer aided molecular design (CAMD) methods for developing new environmentally benign adsorbents for NORM removal. CAMD is generally the reverse use of the group contribution method (GCM) that is used to generate molecules having desirable properties. GCM has been used to predict state properties like selectivity, relative volatility, surface tension, density, viscosity, and reactivity. The PI will develop new group contribution methods for important properties of adsorbents based on thermodynamics. Preliminary results have been obtained using GCM for physical adsorption. The PI proposes to study chemical adsorption and the Langmuir isotherm. GCM will identify the groups for environmentally benign adsorbents. These groups will be uniquely designed to generate all possible molecules by exploring all possible combinations. The properties of each group and/or the interaction parameters between groups can be theoretically calculated, experimentally obtained, or statistically regressed. From this set of groups, desired molecules can be generated by group combinations. Constraints from physical and chemical properties, as well as those from regulatory restrictions, may be imposed, and hence the number of combinations can be reduced. However, this is the first time such an approach is proposed for generation of adsorbents for NORM separation. The PI will select top 30 from the list of new adsorbents obtained by CAMD for further study. In order to identify potentially desirable chemicals various solution algorithms are used. These include heuristic numeration, knowledge-base approaches, molecular property clusters with algebraic equations and optimization-based methods. The PI will use optimization approach for this work. CAMD methods have been applied to many areas, such as extraction solvents, polymer designs, degreasing solvents, blanket wash solvents, absorption solvents, refrigerant design, distillation solvents, reaction solvents, catalysts, value added products, crystallization solvents and foaming agents. The proposed research is of considerable fundamental and practical significance to natural gas fracking industries. Proposed investigations concern the development of novel and powerfultools for identifying novel adsorbents for NORM removal in natural gas fracking. Adsorbents are used in numerous applications apart from hydraulic fracturing. Therefore, the framework developed in this work has a broader commercial and societal impact. The team is planning to collaborate with researchers from industries and national laboratories, building upon their prior interactions on other previous programs.