Hakan Olcay

Production of jet and diesel fuel range alkanes from waste hemicellulose-derived aqueous solutions

In this paper we report a novel four-step process for the production of jet and diesel fuel range alkanes from hemicellulose extracts derived from northeastern hardwood trees. The extract is representative of a byproduct that could be produced by wood-processing industries such as biomass boilers or pulp mills in the northeastern U.S. The hemicellulose extract tested in this study contained mainly xylose oligomers (21.2 g/l xylose after the acid hydrolysis) as well as 0.31 g/l glucose, 0.91 g/l arabinose, 0.2 g/l lactic acid, 2.39 g/l acetic acid, 0.31 g/l formic acid, and other minor products. The first step in this process is an acid-catalyzed biphasic dehydration to produce furfural in yields up to 87%. The furfural is extracted from the aqueous solution into a tetrahydrofuran (THF) phase which is then fed into an aldol condensation step. The furfural-acetone-furfural (F-Ac-F) dimer is produced in this step by reaction of furfural with acetone in yields up to 96% for the F-Ac-F dimer. The F-Ac-F dimer is then subject to a low-temperature hydrogenation to form the hydrogenated dimer (H-FAF) at 110–130 °C and 800 psig with a 5 wt% Ru/C catalyst. Finally the H-FAF undergoes hydrodeoxygenation to make jet and diesel fuel range alkanes, primarily C13 and C12, in yields up to 91%. The theoretical yield for this process is 0.61 kg of alkane per kg of dry xylose derived from the hemicellulose extract. Experimentally we were able to obtain 76% of the theoretical yield for the overall process. We estimate that jet and diesel fuel range alkanes can be produced from between

Production of renewable jet fuel range alkanes and commodity chemicals from integrated catalytic processing of biomass

2.06/gal to

Production of renewable petroleum refinery diesel and jet fuel feedstocks from hemicellulose sugar streams

4.39/gal depending on the feed xylose concentration, the size of the biorefinery, and the overall yield. Sensitivity analysis shows that the prices of raw materials, the organic-to-aqueous mass ratio in the biphasic dehydration, and the feed xylose concentration in the hemicellulose extract significantly affect the product cost.

Aqueous-phase hydrogenation of acetic acid over transition metal catalysts

This article presents results from experimental studies and techno-economic analysis of a catalytic process for the conversion of whole biomass into drop-in aviation fuels with maximal carbon yields. The combined research areas highlighted include biomass pretreatment, carbohydrate hydrolysis and dehydration, and catalytic upgrading of platform chemicals. The technology centers on first producing furfural and levulinic acid from five- and six-carbon sugars present in hardwoods and subsequently upgrading these two platforms into a mixture of branched, linear, and cyclic alkanes of molecular weight ranges appropriate for use in the aviation sector. Maximum selectivities observed in laboratory studies suggest that, with efficient interstage separations and product recovery, hemicellulose sugars can be incorporated into aviation fuels at roughly 80% carbon yield, while carbon yields to aviation fuels from cellulose-based sugars are on the order of 50%. The use of lignocellulose-derived feedstocks rather than commercially sourced model compounds in process integration provided important insights into the effects of impurity carryover and additionally highlights the need for stable catalytic materials for aqueous phase processing, efficient interstage separations, and intensified processing strategies. In its current state, the proposed technology is expected to deliver jet fuel-range liquid hydrocarbons for a minimum selling price of

Water consumption footprint and land requirements of large-scale alternative diesel and jet fuel production.

4.75 per gallon assuming nth commercial plant that produces 38 million gallons liquid fuels per year with a net present value of the 20 year biorefinery set to zero. Future improvements in this technology, including replacing precious metal catalysts by base metal catalysts and improving the recyclability of water streams, can reduce this cost to

Lifecycle greenhouse gas footprint and minimum selling price of renewable diesel and jet fuel from fermentation and advanced fermentation production technologies

2.88 per gallon.

Effects of hydrogen and water on the activity and selectivity of acetic acid hydrogenation on ruthenium

We demonstrate how hemicellulose-derived C5 sugars can be converted into a high-quality petroleum refinery feedstock by a four-step catalytic process. The substitute petroleum consists of normal, branched and cyclic alkanes up to 31 carbons in length and is similar in composition to feedstocks produced in a petroleum refinery today from crude oil. This process can be tuned to adjust the size of the liquid alkanes. In the first step furfural is produced from the acid-catalyzed dehydration of hemicellulose-derived sugar streams in a biphasic reactor. The second step is the aldol condensation of furfural with acetone in a THF solvent and using a NaOH catalyst to produce highly conjugated C13 compounds along with some oligomeric adducts formed through Michael addition reactions. These compounds are then hydrogenated with a Ru/Al2O3 catalyst forming both the fully hydrogenated form of the C13 oligomers and also forming larger oligomers by Diels–Alder reactions. The extent of Diels–Alder reactions can be tuned by changing the temperature and feed concentration, thereby adjusting the distribution of liquid alkanes that can be produced. The final step in this process is hydrodeoxygenation using a Pt/SiO2–Al2O3 bifunctional catalyst to produce the liquid alkanes. A simple biorefinery model has shown that about 55% of a furfural–acetone mixture (10 : 3 wt ratio) can be converted into cycle oils while also producing other refinery products such as gasoline and natural gas.

Techno-economic and environmental evaluation of producing chemicals and drop-in aviation biofuels via aqueous phase processing

Catalytic hydrogenation of acetic acid to ethanol has been carried out in aqueous phase on several metals, with ruthenium being the most active and selective. DFT calculations suggest that the initial CO bond scission yielding acetyl is the key step and that the intrinsic reactivity of the metals accounts for the observed activity.

Environmental and economic assessment of producing hydroprocessed jet and diesel fuel from waste oils and tallow

Middle distillate (MD) transportation fuels, including diesel and jet fuel, make up almost 30% of liquid fuel consumption in the United States. Alternative drop-in MD and biodiesel could potentially reduce dependence on crude oil and the greenhouse gas intensity of transportation. However, the water and land resource requirements of these novel fuel production technologies must be better understood. This analysis quantifies the lifecycle green and blue water consumption footprints of producing: MD from conventional crude oil; Fischer-Tropsch MD from natural gas and coal; fermentation and advanced fermentation MD from biomass; and hydroprocessed esters and fatty acids MD and biodiesel from oilseed crops, throughout the contiguous United States. We find that FT MD and alternative MD derived from rainfed biomass have lifecycle blue water consumption footprints of 1.6 to 20.1 Lwater/LMD, comparable to conventional MD, which ranges between 4.1 and 7.4 Lwater/LMD. Alternative MD derived from irrigated biomass has a lifecycle blue water consumption footprint potentially several orders of magnitude larger, between 2.7 and 22 600 Lwater/LMD. Alternative MD derived from biomass has a lifecycle green water consumption footprint between 1.1 and 19 200 Lwater/LMD. Results are disaggregated to characterize the relationship between geo-spatial location and lifecycle water consumption footprint. We also quantify the trade-offs between blue water consumption footprint and areal MD productivity, which ranges from 490 to 4200 LMD/ha, under assumptions of rainfed and irrigated biomass cultivation. Finally, we show that if biomass cultivation for alternative MD is irrigated, the ratio of the increase in areal MD productivity to the increase in blue water consumption footprint is a function of geo-spatial location and feedstock-to-fuel production pathway.

Energy return on investment for alternative jet fuels

Fermentation and advanced fermentation (AF) biofuel production technologies may offer a means to reduce the greenhouse gas (GHG) intensity of transportation by providing renewable drop-in alternatives to conventional middle distillate (MD) fuels, including diesel and jet fuel. To the best of our knowledge, this is the first peer-reviewed study of the environmental and economic feasibility of AF technologies. We find that the attributional lifecycle GHG footprint of AF MD from sugar cane, corn grain and switchgrass ranges from −27.0 to 19.7, 47.5 to 117.5, and 11.7 to 89.8 gCO2e/MJMD, respectively, compared to 90.0 gCO2e/MJMD for conventional MD. These results are most sensitive to the co-product allocation method used, the efficiency and utility requirements of feedstock-to-fuel conversion, and the co-generation technology employed. We also calculate the minimum selling price (MSP) of MD fuel produced from sugar cane, corn grain and switchgrass AF as a range from 0.61 to 2.63, 0.84 to 3.65, and 1.09 to 6.30