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Jesse Hensley

Group Research Manager III-Chemical Engineering

| 303-384-7914

Research Interests

  • Production of premium fuels and chemicals from gasified biomass

  • Low temperature hydrodeoxygenation

  • Advanced equipment and laboratory design

  • Membrane separations

Production of Premium Fuels and Chemicals from Gasified Biomass

Plant materials contain complex chemical structures (see for instance Dr. Gregg Beckham's discussion of lignin), but through thermal heating in limited O2 (gasification), it can be converted to the simple building blocks of CO and H2, also known as "syngas." The challenge then becomes converting this syngas into something valuable (like fine chemicals) and/or something that can displace our major sources of greenhouse gases (like gasoline, diesel, and jet fuels). And of course, this must be done inexpensively so our bottom line is helped just as much as the environment.

I like to focus on single or dual-step processes that convert syngas to fuel products, and one of my career goals is to find a way to make diesel and jet fuel from biomass at a cost that competes with the market price of oil. Given the costs of producing and delivering biomass to a conversion facility and the energy costs associated with gasification (studied in detail by our Analysis team), we know that any such process must deliver a high yield and the product must be of better quality than petroleum analogues. So this is our target. My group has recently studied the direct conversion of syngas to mixed linear alcohols in partnership with The Dow Chemical Company, and we're currently developing catalysts and processes that convert methanol (made commercially from syngas) to ultra-premium gasoline and jet-range hydrocarbons (schematic below). The results to date are compelling. See our recent patent application and feature publications below for more detail on our current work in this area.

Schematic illustration of a reaction of dimethyl ether (shown by a molecular formula) on a zeolite (shown with an image of orange outlines of hexagonal shapes configured into a series of tubes on a black background) to form hydrocarbons (shown by molecular formulas) and a second reaction of the hydrocarbons on a sulfonic acid resin to form distillate-range hydrocarbons (all shown by molecular formulas).

Low-Temperature Hydrodeoxygenation

The catalytic removal of heteroatoms (e.g., covalently-bound sulfur in crude oil hydrocarbons) represents a major cost in oil refining, and catalyst scientists have been studying and improving the process for nearly a century. When biomass goes through a lower-temperature heating process to produce oil instead of a gas (pyrolysis), a diverse mixture of oxygenated products are formed, as shown in this plot from our recent review on bio-oil upgrading:

Bar chart showing the relative composition of oxygenated molecules in pyrolysis oil. The y-axis shows "Component wt%" and the x-axis lists "Acids," "Sugars," "Alcohols," "Ketones," "Aldehydes," "Furans," "Mixed Oxys," "Phenols," "Guaiacols," and "Syringols." Lignin is represented by red bars and Cellulose and Hemicellulose are represented by blue bars.

The oxygen in these products is heteroatomic, and because we want hydrocarbons as a finished product, we must get the oxygen out. Two ways to do this include hydrodeoxygenation and direct deoxygenation:

Schematic illustration (using hexagons showing molecular formulas) that shows two reaction pathways to remove oxygen from a phenol molecule.

The trouble with these pathways is that high temperatures and pressures are required due to high activation barriers. Principle investigator Dr. Joshua Schaidle, myself, and members of the Heterogeneous Catalysis for Thermochemical Conversion team are developing nanostructured metallic, carbide, nitride, and phosphide materials that are reducing the severity of reaction conditions, bringing us closer to an ability to transform pyrolysis oils into hydrocarbon fuels without costly high pressure processing. See our cover article in Green Chemistry below to learn more about the challenges in this area and where we see the future of catalysis in hydrodeoxygenation.

Advanced Equipment and Laboratory Design

Some things I've learned as a researcher are that collecting data is hard, having the right equipment means everything, and setting up your equipment for success is critical (and often time-consuming and expensive). Nothing is as frustrating as having a great idea to try in the reactor, only to be faced with three months of necessary system retrofits, calibrations, tuning, and safety evaluations. Well, I'm trying to change that. I am currently designing and helping to build a new state of the art catalyst reactor testing laboratory, to be completed in early 2016. I am setting up the lab to be plug and play. That means: You bring your system to the power, gases, and analytical, not the other way around. We will soon have the ability to operate 6 reactor systems (for internal use or for partner projects) 24/7, with direct automated measurements from two custom-built process chromatographs. We will not be limited by utilities, with up to 140A of power per system, direct connections to 13 gases (4 customizable) plus 5 connections to in-house custom-blended high pressure gases (for operation up to 14 MPa) plus direct connections to a bench-scale gasification system, full safety interlocks, and 2 dedicated reactor loading and cleaning stations. Reactor control will be at our fingertips, with remote operation via smartphone. By centralizing our safety control systems and offering a large range of options for connection, we expect to reduce the time needed to modify a system for a new project (or to set up a partner's system) by more than half.

CAD drawings of a reactor hood, heated regulator, and electrical distribution box.

I also spend some of my time solving some common issues in bench scale systems, like how to feed high melting point solids at high pressure, how to reliably introduce liquids at nanoliters per minute, how to get catalyst loaded and unloaded without exposure to air, and how to interface systems at high pressure and temperature to downstream analytical equipment. If you want to put eyes and hands on some of the high performance, custom systems my team and I have built in recent years, come visit!

Membrane Separations

I completed my Ph.D. in this area and I continue to find membrane separations both interesting and useful (though I have no current projects in this area). Separation processes often consume the majority of energy in a refinery or chemical plant, and they usually consume most of the space and demand most of the maintenance budget. Membranes offer the potential to reduce the amount of energy needed by supplementing or replacing operations like distillation, extraction, and centrifugation.

A membrane is simply a barrier that allows some molecules (or particles) to pass through it while excluding others. The type of membrane material you use dictates how the separation takes place, i.e., sieving or solution diffusion as shown in cartoon form:

Illustration of small (red dots) and large (blue dots) molecules passing through a membrane or being rejected from passing through. The top image is labeled "porous" and the membrane is represented by a green rectangle with white lines through it. The middle image is labeled "dense, glassy" and the membrane is represented by a dark brown rectangle. The top image is labeled "dense, rubbery" and the membrane is represented by a tan rectangle. The top of the image is labeled "Feed," "Driving Force" with a blue arrow pointing right), and "Permeate."

Biomass-derived chemicals (like ethanol) are perfect candidates for membrane separations because they are typically produced in a solvent medium (like water), often form azeotropes with other components, and may face equilibrium limitations in production (making them dilute in concentration). In theory, a process like distillation could be replaced with a membrane separation like pervaporation (e.g., for ethanol), with substantial energy savings, as shown:

Illustration representing a fluid contacting one side of a membrane and a sweeping gas contacting the other. A blue box at the top is labeled "liquid feed, atm P" with an arrow pointing right; this box sits on top of a narrow orange bar labeled "permselective membrane." Below this are two circular arrows with "air sweep or vacuum" labeled in between: the top green arrow is labeled "vapor permeate;" the bottom brown arrow sits on a blue sphere labeled "permeate condensed" with a blue arrow pointing right to "more separations or packaging".

I am interested in partnering with companies or institutions who want to tackle a membrane separation challenge. Contact me if interested.

Affiliated Research Programs

Areas of Expertise

  • Heterogeneous catalysis

  • Gas to liquids

  • Hydrodeoxygenation

  • C—C coupling

  • Zeolites

  • Metal sulfides, carbides, nitrides, and phosphides

  • Kinetics and reaction mechanisms

  • Physical and chemical characterization

  • Reactor scale-up and validation

  • Instrumentation and controls

  • Laboratory and equipment design and construction

  • Computer aided design

  • Membrane separations

  • Process safety

Education

  • Ph.D., Chemical Engineering, Colorado School of Mines, 2007

  • B.S., Chemical Engineering/Environmental Studies, University of Notre Dame, 2003

Professional Experience

  • Supervisor, Thermochemical Catalysis R&D, National Renewable Energy Laboratory (NREL), National Bioenergy Center (NBC), 2013–present

  • Adjunct Professor of Chemistry, Colorado School of Mines, Department of Chemistry and Geochemistry, 2013–present

  • Staff Engineer, Thermochemical Sciences, NREL, NBC, 2009–2013

  • Research Engineer, Range Fuels Inc., 2007–2009

Associations and Accreditations/Memberships

  • Professional Engineer registered with the State of Colorado

  • AutoCAD 2015 Certified Professional

  • American Institute of Chemical Engineers (AIChE)

  • American Chemical Society (ACS)

Patents

  1. "Catalysts and methods for converting carbonaceous materials into fuels," U.S. Patent No. 9,714,387 (2017)

  2. "Methods and apparatus for continuous removal of carbon dioxide from a mixture of reacting gases," U.S. Patent No. 8,026,290 (2011)

  3. "Methods for improving syngas-to-alcohol catalyst activity and selectivity," U.S. Patent No. 8,318,986 (2012)

Featured Publications

  1. "Conversion of dimethyl ether to 2,2,3-trimethylbutane over a Cu/BEA catalyst: Role of Cu sites in hydrogen incorporation," ACS Catalysis (2015)

    Illustration showing an orange hexagon labeled "metallic Cu outside pore" attached to a circle of Si, O, Al, and H molecules in a compound, also labeled "cationic Cu in pore"; these figures are under the label "Role of the Cu Species." To the right of the circle is bracketed information showing a graph with the x-axis labeled "Time on Stream (h)" and the y-axis labeled "Hydrocarbon Production"; H-BEA and H-Beak + H2 are shown with light blue and dark blue dots on the chart and the red dots represent Cu/BEA + H2. The curve of red dots runs parallel above the curve of blue dots. Below the graph are two arrow-circles labeled "aromatic cycle" and "olefin cycle" with a double arrow between them, labeled "Cu/BEA + H2."

  2. "Recent advances in heterogeneous catalysts for bio-oil upgrading via 'ex situ catalytic fast pyrolysis': catalyst development through the study of model compounds," Green Chemistry (cover article 2014)

    Illustration showing a photo of a farm field and labeled "Biomass Feedstock" on the left with a large green and orange arrow (labeled "Catalyst Structure-Function Relationships" including several green spheres connected by rods and formed into a rectangular shape and white, red, and blue spheres attached with rods into circular shapes) pointing to the right to a photo of a barrel with a filling nozzle attached to the top and labeled "Transportation Fuel."

  3. "Deactivation and stability of K-CoMoSx mixed alcohol synthesis catalysts," Journal of Catalysis (2014)

    Graph labeled "desulfurization observed by XPS" and showing an x-axis labeled "Binding Energy (eV)" and numbered 238 to 224 from left to right; three sets of curves (peaking at 236, 232, and 229) are shown with a red-dashed line, blue-dotted line, and black line. The graph also shows two green arrows pointing up and labeled "oxidation" and two purple arrows pointing right and labeled "carburization."

View all NREL Publications for Jesse Hensley.

Please contact me with research questions, ideas for collaborations, and questions about the Heterogeneous Catalysis for Thermochemical Conversion Program. For information on jobs, please see NREL's Director's Postdoctoral Fellowship program or on NREL Careers (search center 5100).

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