This projects aims to integrate mechanical vapor compression with membrane distillation (MVC-MD) to intensify the treatment of produced water resulted from hydraulic fracturing of shale oil and gas. In particular, membrane distillation offers a viable pathway to treat concentrated brine streams with high salinity brines, and it has the potential to be utilized for near-zero liquid discharge. However, MD in its current state is handicapped by significant energy intensity due to loss of heat of evaporation, and scaling (fouling). This project is looking into the energy intensity issue by integrating MD with MVC to recycle the latent heat of evaporation. It also proposes a facile aluminum electrocoagulation (EC) pretreatment to remove up to 95% of total suspended solids and organic compounds. The proposed aluminum EC can effectively mitigate membrane scaling for long-term applications.
This project addresses the demonstration of a low-cost and low-energy pathway for the separation of metals from mixed scrap based on ionic liquids. The goal of the project is to develop and demonstrate a novel electrochemical process for the separation of metals from mixed scrap using ionic liquids (ILs) at low temperatures. For example, conventional separation of aluminum involves scrap melting at 800 °C resulting in high losses in metal values, high energy consumption and the generation of greenhouse gases including CO2 and fluorides that require post-combustion and flue gas cleaning processes. In the proposed electrochemical separation process, the separation will be carried out at low temperatures (<120°C), high metal recovery (>99%), low energy consumption, and no greenhouse gases generation. The electrolyte and residue of the process are recycled. This project will take the technology from bench to pilot scale.
In conventional two-phase separation, mass transport between the two phases can be intensified via increased surface area, usually in the form of smaller droplets or bubbles. The increase in the interfacial surface area typically results in higher energy cost due to agitation or mixing and slower processing time as the smaller droplet phase requires more time to separate. One can increase processing speed in centrifugal extractors but this, in turn, increases energy requirements significantly. Often, microscale process intensification is at odds with macroscale energy efficiency in conventional systems. From a capital cost perspective, current separation methods are economically feasible at large scale due to the inherent cost scaling of hardware manufacturing for traditional unit operations. As a result, they can be prohibitively difficult to translate into smaller modular systems. This project is working on the development of a flexible yet standardized platform for multiphase separation utilizing microchannel processing technology (MPT). Multiphase Microchannel Separation in MPT systems directs flow of each phase by creating a capillary force gradient via size and spacing of micro-scale architectural features, thereby controlling interfacial curvatures and thus capillary forces. With a proper choice of surface properties, the system is designed so that a selected phase cannot overcome capillary forces in one direction of the gradient with inertial and viscous forces, guiding the fluid towards a selected outlet stream. Additionally, a flat plate design can accommodate a larger processing throughput per layer of the device and reduce manufacturing complexity compared to single microchannel devices.
This project is utilizing solid oxide membrane reactors for chemical transformations that are critical to the seamless integration of shale natural gas and liquids into the chemical industry supply chain. The project is particularly interested in the production of propylene from propane. Current propylene production occurs primarily via naphtha steam cracking, a highly energy-intensive process that is not amenable to distributed operations, which are highly desirable when shale natural gas and liquid is used as the carbon source. This technology can apply to centralized or distributed operation and can operate at dramatically lower temperatures than steam crackers. The technology will apply perovskite solid oxide membranes which can simultaneously conduct oxygen and hydrogen ions. On one side of the membrane reactor, air is used as an oxygen source to the perovskite. Oxygen anions are conducted across the membrane where they can react with propane at the interface of the perovskite and small Pt alloy catalysts in an exothermic partial oxidation process. In addition, the process of propane dehydrogenation takes place at the same side of the membrane yielding hydrogen ions, which are conducted by the same membrane to the other side. By adjusting the external conditions as well as the membrane and catalyst design, the flux of oxygen and hydrogen ions in the opposite directions of the membrane can be controlled. This control will allow to develop a highly selective thermo-neutral process operating at lower temperatures and drive equilibrium conversion forward while avoiding the deleterious further reaction to unselective combustion products.
This project will utilize microfibrous entrapment of small particulate sorbents or ion exchange (IX) resins to overcome physical barriers and identified technology gaps that currently prevent energy efficient and cost-effective wellhead CO2/CH4 separations through pressure swing adsorption (PSA) and Cs+ removal from nuclear fuel processing streams. Both commercial cyclic adsorption processes are currently limited by heat and mass transport restrictions occurring in large particle (1-4 mm diameter) packed beds. In this project, the use of smaller particles (10-150 μm diameter) eliminates previous intraparticle mass transport restrictions resulting in effectiveness factors near unity, while particulate entrapment within sinter-locked networks of micron-diameter metal fibers (microfibrous entrapped sorbent, MFES) provides packed bed thermal conductivities that are up to 250-fold higher than those of typical packed beds. Higher thermal conductivity allows for near-isothermal operation and results in more rapid and higher duty cycles, which reduces the required sorbent load and increases the overall output of the now smaller unit. The entrapment of particulates within a flexible fibrous structure eliminates shrink/swell problems and bed channeling while maintaining a low pressure drop. For IX processes, the reduction in particle size provides an order of magnitude enhancement in IX kinetics and allows new IX resin powders to be quickly adopted without having to undergo the lengthy, expensive, performance-limiting penalties associated with large bead formulations. For both applications, the process intensification and enhancement of fundamental rate phenomena decreases system size, increases energy efficiency, decreases cost, and promotes efficacy and modularity. This methodology is a transformative platform approach that is inherently modular and broadly applicable across a wide range of catalytic or sorbent-based processes.
