Engineering topics

Hensley, Jesse E

Publications and source records attributed to Hensley, Jesse E.

4 records

DOE OSTI2020

Experimental, Economic, and Environmental Assessment of Feedstock Gasification for High-Octane Fuel Production

Five economically advantaged biomass feedstocks identified in the US Department of Energy's 2016 Billion Ton Study were gasified and the syngas reformed at the bench scale to study the feedstock price-performance relationship. The distribution of reformed syngas compositions, heating values, and yields were similar across the different feedstocks and blends thereof, which ranged from inexpensive residual wastes to more expensive and higher quality biomass, revealing that feedstock performance was mostly insensitive to its price. Custom blended feedstocks produced syngas with characteristics resembling linear combinations of syngas from single-component feedstocks, supporting the ability to customize and predict blended properties based on single-feedstock data. A techno-economic analysis of specific feedstock costs for producing high-octane gasoline showed that miscanthus and forest residues were the most cost-effective. A field-to-wheels life-cycle assessment of greenhouse gas emissions showed that forest residues was the most environmentally benign feedstock of those studied.

09 BIOMASS FUELS↗

DOE OSTI2020

Gasification and Techno-Economic Analysis of High-Impact Biomass Feedstocks for the Synthesis of High-Octane Gasoline

Five economically advantaged biomass feedstocks identified in the US Department of Energy's 2016 Billion Ton Study were gasified and the syngas reformed at the bench scale to study the feedstock price-performance relationship. The distribution of reformed syngas compositions, heating values, and yields were similar across the different feedstocks and blends thereof, which ranged from inexpensive residual wastes to more expensive and higher quality biomass, revealing that feedstock performance was mostly insensitive to its price. Custom blended feedstocks produced syngas with characteristics resembling linear combinations of syngas from single-component feedstocks, supporting the ability to customize and predict blended properties based on single-feedstock data. A techno-economic analysis of specific feedstock costs for producing high-octane gasoline showed that miscanthus and forest residues were the most cost-effective with gas yields consistent with experimental gasification data. A field-to-wheels life-cycle assessment of greenhouse gas emissions showed that forest residues was the most environmentally benign feedstock of those studied.

09 BIOMASS FUELS↗

DOE OSTI2019

Shifting the Paraffin-to-Olefin Ratio and Gasoline Fuel Properties with Bimetallic BEA Zeolite Catalysts in Dimethyl Ether Homologation

Recent research on the production of HOG from DME over BEA zeolites suggests that this process offers an attractive alternative to traditional methanol-to-gasoline (MTG) technologies by operating at milder conditions and providing greater carbon efficiency 1. The HOG product is rich in branched olefins and paraffins, particularly triptane (2,2,3-trimethylbutane) which has high research- and motor-octane numbers (RON 112, MON 101), making it an ideal unleaded fuel or fuel additive for aviation or racing applications 2. RON and MON are important fuel metrics and research shows a correlation between them and paraffin and olefin content 3. Copper-modified BEA (Cu/BEA) is more active than HBEA . Research has identified that ionic Cu(I) species are active for alkane dehydrogenation whereas metallic Cu species responsible for hydrogenation chemistry 4. Here we report on the effect of including ionic Zn and Ni as a means of increasing the dehydrogenation activity of Cu/BEA in DME-to-HOG reactions. Bimetallic Cu-Zn/BEA and Cu-Ni/BEA catalysts were synthesized by first incorporating Ni or Zn by ion-exchange, followed by incipient-wetness impregnation of Cu. Similar metal loadings, acid site densities, and Bronsted/Lewis acid ratios were confirmed across all materials. All catalysts were tested in DME-to-HOG reactions with co-fed H2 at 200 degrees C and 15 psia with 1:1 DME:H-2 and DME weight-hourly space velocity of 2.2 gDME-gcat-1-h-1. Compared at similar turnover numbers (TON), Cu-Ni/BEA displayed similar activity to Cu/BEA however, exhibited greater hydrogenation activity as evidenced by the higher C5-8 P:O ratio. The Cu-Zn/BEA demonstrated decreased activity and the lowest P:O ratio, attributed to enhanced dehydrogenation activity at ionic Zn sites. For the HOG-range products (i.e., C5-8 hydrocarbon species), each catalyst had a 98-99 estimated RON, while the MON decreased with decreasing P:O ratio. Compared to Cu/BEA, these bimetallic catalysts demonstrate a unique balance of hydrogenation and dehydrogenation of the hydrocarbon products to access markedly different P:O product ratios without requiring a separate unit operation or a mixed catalyst bed.

09 BIOMASS FUELS↗

DOE OSTI2019

Evaluating Cu/BEA Catalyst Performance with Techno-Economic Analysis to Develop a Market-Responsive Biorefinery Concept Around the Conversion of Methanol to High-Octane Hydrocarbons

A recent advancement in the conversion of methanol to hydrocarbon fuels is the development of a Cu-modified beta zeolite catalyst (Cu/BEA) that exhibits a higher productivity and yield than the parent H-form BEA catalyst in the production of branched C4-C8 hydrocarbons. This Cu/BEA catalyst enables process improvements in the High-Octane Gasoline (HOG) pathway, which operates under lower severity conditions than traditional methanol-to-fuels processes, offering a lower coke formation rate, higher selectivity to C5+gasoline-range hydrocarbons, and subsequently, improved process economics based on a recent process model and techno-economic analysis (TEA). Here, a market-responsive biorefinery concept around methanol and the HOG pathway is presented, where the major C4 products, isobutane and isobutene, serve as versatile intermediates that can either be recycled to increase the yield of the HOG product or directed to jet-fuel range hydrocarbons. Based on simulated recycle experiments with 13C-labeled isobutane, the Cu/BEA catalyst achieved increased yield to the HOG products during DME homologation by activating the co-fed isobutane and incorporating it into the chain growth pathway, as evidenced by the presence of isotopically-labeled 13C in C5+ products. Olefin coupling of an isobutene-rich mixture was also investigated, and the fuel properties of the resulting synthetic kerosene product were within the specifications for a typical jet-fuel. These experimental results were incorporated into an updated Aspen-based process model and TEA to quantify their impact on a market-responsive biorefinery concept. The improvements offered by C4 recycling with the Cu/BEA catalyst result in a decrease in the methanol-to-fuel synthesis cost from 101 cents per gallon of gasoline equivalent (GGE) with the baseline BEA catalyst to 72 cents/GGE, due in part to a significantly increased HOG yield from 40 to 55 GGE/dry-ton biomass. Expanding the process model to direct C4 products to a jet-range hydrocarbon product demonstrated a yield of 42 GGE/dry-ton HOG with 12 GGE/dry-ton distillate, resulting in a minor increase in the fuel synthesis cost to 77 cents/GGE versus the HOG-only case. With continued development, these advancements in fuel yield and reductions in cost position a market-responsive biorefinery around the HOG pathway to be competitive against mature fuel-synthesis technologies from a variety of carbon sources through methanol.

09 BIOMASS FUELS↗