The rise in US natural gas supplied, tied to challenges/costs associated with natural gas logistics, point to the value of converting natural gas to liquid products. Indirect routes are generally energy inefficient and capital intensive. In contrast, direct non-oxidative natural gas conversion eliminates the syngas production step and required oxygen generation. However, these technologies have not been commercialized because of technical challenges such as low selectivity, coking, heat management, catalyst deactivation and catalyst regeneration. The goal of this project is to develop and demonstrate an innovative modular system intensified with microwave (MW) catalysis, which allows simultaneous production of high-value chemicals (e.g. aromatics) and hydrogen generation via direct non-oxidative natural gas conversion. Specifically, the technical merits consist of synergistically integrating microwave reaction chemistry with novel zeolite catalysts that selectively activate natural gas. The microwave catalysis will enable direct, non-oxidative natural gas conversion under mild conditions with high product yield.
Processing natural gas is the largest industrial application of gas separation membranes. Membranes occupy 10% of the ~$5 billion worldwide annual market for new natural gas separation equipment, with amine absorption accounting for most of the rest. While widely used, amine systems suffer from corrosion, complex process design, and equipment often unsuitable for offshore gas processing platforms. Amine systems are also less efficient than membranes at high CO2 concentrations. Current membrane systems are most commonly based on asymmetric cellulose acetate polymers and suffer from lower CO2/CH4 selectivity and lower fluxes than are needed for more general adoption. Low selectivity means that such systems are often multi-stage, requiring expensive recompression of exhaust gas to extract more hydrocarbon product from it or resulting in greater losses of hydrocarbon product to waste streams. Low fluxes impact the overall size and cost of membrane equipment to treat a given quantify of natural gas. This project will prepare and characterize novel nanocomposite membranes based on recently discovered metal organic framework (MOF) materials and related nanoparticles having outstanding separation properties for removal of acid gases (e.g., CO2) from natural gas. The project aims to demonstrate advanced nanocomposite membranes with much higher flux and selectivity than commercial state-of-the-art membranes when separating CO2 from mixtures with CH4 and mixtures containing aromatic contaminants. Membrane systems based on such membranes would be several times smaller than existing systems to process comparable amounts of gas and lower the hydrocarbon losses, thereby increasing energy efficiency and minimizing emissions/waste.
This project will develop chemical looping technology (CLT) into a general process intensification (PI) strategy for modular upgrading of natural gas to commodity chemicals. Nonoxidative upgrading of methane, ethane and propane to alkenes and aromatics is often limited by equilbrium. CLT is an effective PI strategy to circumvent such limitations by either reactive separation or selective oxidation of a subset of products from the reaction mixture to restore the thermodynamic driving force. CLT also allows for efficient heat utilization/management among different reaction steps, thus enhancing the overall energy efficiency of the process. The commercial potential of CLT is underexplored primarily because of the high cost in the design and prototyping of automated continuous systems. This project aims to demonstrate the generality of chemical looping technology (CLT) as a process intensification strategy by advancing chemical looping for methane dehydroaromatization (DHA) and alkane (ethane and propane) dehydrogenation (DH) at yields well in excess of one-pass thermodynamic limits. In each of these chemical looping processes, an increase in per pass conversion, a dramatic simplification of separation, and heat integration are all addressed in a single system, which makes them ideal for being deployed in standard reactors modules at remote natural gas extraction sites.
Low permeability natural gas reservoirs are being developed across the world using fracturing technologies. The most common approach for fracturing uses water with friction-reducing agents and thickening polymers. However, this approach requires approximately 400 tanker trucks to bring millions of gallons of water to a wellhead and results in millions of gallons of contaminated water that must be treated before going back into the natural water cycle. A second approach to fracturing uses high-pressure gases such as nitrogen or carbon dioxide. The use of energized fluids such as N2 or CO2 offers the potential to carry out fracturing without the negative aspects associated with water-based fracturing. This approach, however, often requires producers to divert initial gas production to a flare until N2 / CO2 gas concentrations in the “flow-back” drop below allowable limits for feeding into the natural gas pipeline network. This project aims to address the loss of hydrocarbon energy and the associated CO2 emissions related to N2 fracture operations by utilizing a new adsorbent developed by Praxair in a modular Pressure Swing Adsorption (PSA) system capable of recovering N2 from produced gas at wellhead locations. Technology development in this area will address the specific problem described above and will shed light on the challenges of modular processing of distributed resources in general.
