RAPID Funded Projects

Separation of liquid mixtures, frequently by distillation, consumes large amounts of energy in the chemical and process industries. This project proposes to develop, test, and demonstrate a continuous-flow, scalable, nonthermal, nonequilibrium liquid separation for the test case of ethanol + water that uses ultrasound, and avoids the heat transfer losses and azeotropic bottleneck of distillation. The basis of the separation is straightforward. When ultrasound passes through a nominally quiescent liquid with a free surface above, droplets are produced and form a mist. Previous work in this area shows that in aqueous ethanol solutions, removal of these droplets using a carrier-gas flow provides a liquid in which ethanol is significantly enriched relative to the initial bulk solution. Successful deployment of this technology could result in significant savings in energy and capital costs for this high-volume separation, and will lay the groundwork for similar separations in a broad class of other binary (and probably multi-component) systems, including those forming azeotropes.

Biofuels produced from fermentation processes have long been processed using decades-old distillation technology. Distilling a minor component of this broth to a high purity requires substantial amounts of energy that can lessen the net-energy and profitability of the fuel produced. This work will demonstrate a new technology concept developed by Mattershift, LLC that uses a carbon nanotube (CNT) membrane to selectively extract the biofuel, in this case ethanol, from a fermentation broth. Due to the unique chemical and structural features of the nanotubes, ethanol selectively permeates through the membrane, leaving water behind. Mattershift has developed the first-ever hollow fiber CNT membrane for this task, and this work will demonstrate its effectiveness at selectively removing ethanol directly from fermentation broths. These membranes are expected to take low concentration ethanol solutions (between 10 and 40%) and selectively extract it to above 80% ethanol in a single pass.

Renewable feedstocks, including triglycerides and lignocellulose-derived sugars, can be converted to a new class of ionic surfactants, called “oleo-furan sulfonates” (OFS) by multi-step solid acid catalysis. The renewable OFS surfactant exhibits superior properties relative to conventional fossil-derived materials with higher micelle-forming efficiency, stability in cold water, and resistance to hard water. The sequential synthesis process includes catalytic hydrolysis of triglycerides, fatty acid dehydration to anhydrides, and furan acylation with anhydrides to form alkylfuran ketones, the key precursor to OFS surfactants. This technology has been demonstrated as a three-step process with independent reactors. This project aims to more efficiently prepare oleo-furan sulfonate (OFS) surfactants by combining all three chemistries (hydrolysis, dehydration, and furan acylation) into a single reactor-separator that permits integrated separation of byproduct water. All three reactions will be conducted in a vertical column containing packed trays to promote selective vaporization of light components (i.e., water). Spatially distributed throughout the column will be three catalytic zones containing hierarchical solid acid zeolite catalysts, each of which promote the chemistry specific to the composition of that zone. Water liberated from the acylation and dehydration steps at the bottom of the reactor flow upward to promote triglyceride hydrolysis, while fatty acids and anhydrides flow down to promote furan acylation. At the conclusion of this project, a detailed design of a reactive distillation system will be developed permitting tunable extents of each of the three chemistries, such that various grades of OFS surfactants can be manufactured. The project is also looking into advancing the lab-scale demonstration to the pilot-scale production.

While tremendous progress has been achieved on creating routes for the production of chemicals and fuels from lignocellulosic biomass, many of these processes are not economic due to the number of process steps required and the requirement for significant inter-stage separations. This project is developing a modularized chemical process intensification technology for the production of bio-para-xylene (biopX) from glucose. This process has received significant attention as a route to meet the high growth rate of pX (CAGR = 7%) and at the same time as we are seeing declining petroleum-based pX production in North America due to the reduction of naphtha cracking. This approach also meets the rising consumer demand for sustainable feedstocks to manufacture materials. This project focuses on the significant reduction of biopX production costs (>20%) using a novel, biphasic, multifunctional, continuous flow microreactor to carry out a cascade of four reactions combined with reactive extraction and potential in-situ generated H2 – all in a single pot – followed by hydrophobicity-driven separation and a second multiphase microreactor. ‘Smart’ organic solvent selection as a common platform for all processes will also be explored to minimize separations. Fast and efficient microwave (MW)-based heating will also be implemented.

Black liquor (BL), also known as “spent pulping liquor”, is a high-volume byproduct of lignocellulosic biomass pretreatment (i.e., wood pulping by the kraft process). BL is a corrosive, toxic, and complex mixture. About 500 million tons/yr of BL are produced in more than 200 kraft process units worldwide (including 99 in the US, with about 0.2 quads/yr energy spent for BL concentration by multi-effect evaporation). Currently, BL concentration is performed by multi-effect evaporators and is one of the most energy-intensive industrial separation processes. Development of a more efficient BL concentration technology is a high priority for the forest products industry, with membrane technology being a particularly feasible alternative. However, membrane technology has been elusive because of the lack of a long-lived/stable, low-cost, high-performance membrane. This project will develop and demonstrate a bench-scale modular graphene oxide (GO)-based membrane system that substantially improves the energy efficiency of concentrating kraft black liquor (BL) from 15 wt% solids (lignin, organic molecules, and inorganic salts) to 30 wt% solids by removing water (maximum 0.1 wt% solids). The key innovation is the development of BL-stable, scaled-up, GO-based NF and RO membranes supported on macroporous polymeric (polyethersulfone, PES) supports for dewatering black liquor. The challenge is in developing and scaling up low-cost membranes that are long-lived in the corrosive conditions. The recent work on this project promises successful development and scale-up of BL-stable graphene oxide (GO) membranes. It would allow this technology to be quickly integrated into existing Kraft processing facilities to leverage existing assets.

Deconstruction of lignocellulosic biomass into fermentable sugars is among the major challenges in producing cellulosic biofuels and biobased products. Current pretreatment methods to liberate solid cellulose are expensive, accounting for as much as 30% of the cost of producing cellulosic biofuels. Most pretreatments do not completely fractionate cellulose and lignin, the latter of which interferes with enzymatic hydrolysis. The goal of this project is to develop a pyrolysis-based Modular Energy Production System (MEPS) for the thermal deconstruction of lignocellulosic biomass into cellulosic sugars and other value-added products. Thermal deconstruction uses thermal energy instead of enzymes or chemicals to fractionate lignocellulose into solubilized carbohydrate and phenolic oil. It has the prospects for intensifying and modularizing biorefineries, especially through pyrolysis innovations including biomass pretreatments to increase cellulosic sugar production and autothermal pyrolysis to simplify design and increase feedstock throughput. Modular Energy Production Systems configure unit operations as modules sized to fit in standard shipping containers, mass produced and integrated in the field to form fully operational biorefineries at a smaller and on-demand scale. Distributed processing with modular pyrolysis units deployed at multiple locations decreases logistical hurdles/costs for both feedstock and products.