Location: Sustainable Biofuels and Co-products Research
2020 Annual Report
Objectives
1: Develop pyrolysis processes that enable the commercial production of marketable, partially-deoxygenated pyrolysis oil intermediates.
2: Develop post-pyrolysis technologies that enable the commercial upgrading of pyrolysis oils into marketable fuels and/or chemicals.
3: Develop scalable technologies that enable commercially-viable pyrolysis oil-based products and co-products.
Approach
A three-tier developmental approach at the analytical, pilot and field scales will be followed to overcome the scientific, engineering and economic barriers that have challenged production and blending of biomass pyrolysis oils (bio-oil) into hydrocarbon fuels. In doing so three specific thrust areas including catalytic pyrolysis, reactive/co-reactant assisted pyrolysis, and upgrading of pyrolysis oils produced from these processes, already advanced at ARS, will be strengthened. The step-wise approach includes (i) the quest for novel processing strategies that address bio-oil stability issues directly at the farm site; (ii) enabling robust catalytic deoxygenation processes that will allow for effective separation of critical (valuable or detrimental) chemical species present within bio-oils; (iii) production of an intermediate bio-oil product that can support interim markets (e.g. home heating oil) and; (iv) production of hydrocarbons suitable for refining into fuels and for manufacture of specialty chemicals. Additionally, extensive physical and chemical property data will be collected to enable operations from the farm to the refinery. Data will be used to demonstrate compatibility of the liquid hydrocarbon product with petroleum refining unit operations and for economic and environmental assessment of the process life cycle.
Progress Report
New NP306 OSQR approved project entitled “Thermo-Catalytic Biorefining” is currently being established.
Objective 1: (1) Successful demonstration scale experiments on both the non-catalytic and catalytic pyrolysis of switchgrass over HZSM-5 was reported in the previous reporting period as part of the 60 month milestone for the completed project. These experiments were performed on the mobile Combustion-Reduction Integrated Pyrolysis System (CRIPS) providing for continuous regeneration of the catalysts. Since then, three additional demonstration scale experiments have completed, generating gallon quantities of bio-oil with oxygen contents ranging from 5- 15 wt%. The feed rate achieved on the system for catalytic pyrolysis was increased to about 17 kg/h, an 70% increase over the previous maximum rate for catalytic pyrolysis. The bio-oil produced will be used in our ongoing objectives related to separations, refining and development of high value co-products from bio-oil. (2) Laboratory experiments on the solvent liquefaction of lignin were initiated. Lignin is the most difficult of lignocellulosic biomass components to convert to high value projects and is produced as a byproduct of the pulp, paper and cellulosic ethanol industries. The experiments evaluated role of pretreatments, solvents (low and high boiling) and temperatures on the depolymerization of lignin. In addition to yield and phenolic monomer content, the bio-oils were also subjected to analysis by diffusion ordered NMR spectroscopy. This allows for chemical structural analysis resolved by estimated MW. This is valuable for accessing the potential value of partially depolymerized lignin that makes up the majority of the liquid product. (3) We have initiated experiments on the analytical scale to further access the co-pyrolysis of biomass and waste plastic. In our previous work in this area we established that addition of polyolefin waste could enhance the conversion of biomass to aromatic hydrocarbons over HZSM-5. The current experiments seek to find alternative less expensive catalysts and conditions that also enhance the conversion of biomass and plastic waste, with higher overall conversion efficiency than previously found. So far bio-char and other carbon based catalysts have been preliminary shown to aid in the depolymerization of polyethylene. Interaction with biomass and other factors are still being accessed.
Objective 2: 1) In cooperation with an industrial partner, we continued research into production of renewable calcined coke from bio-oil distillation residues. The aluminum industry relies on electrically conductive carbon materials to produce aluminum. Oil refineries usually create these materials from coke derived from petroleum (pekcoke), but these crude oil residues contain a high concentration of metal impurities, which increases production costs and still puts more CO2 into the atmosphere. We blended the petcoke with renewable bio-oil distillation residues, and used that to make a better electrically conductive carbon. We used a process that imitates what the aluminum industry does on a large scale by using a continuous rotary calcination system (~200 g/hr) to convert blends of petcoke and biocoke (0 – 30 wt% biocoke) into calcined coke product. The product contains lower levels of metal impurities and is strong enough for use in aluminum metal production, which requires temperatures more than 1200 degree C, meeting most of the requirements for use in aluminum anodes (low S, Ni, V, Ca, etc.; high crystalline structure). If this method is adopted by the aluminum industry – even blending just 10% - would decrease non-renewable CO2 by 7.5 million tons per year. The work has led out industrial partner to commit to larger-scale testing of the material in conditions that mimic aluminum production. This marks the first known continuous production of renewable calcined coke. Our industrial partner plans to run pilot scale anode testing for us in the future. 2) We published work with a collaborator on the decontamination of pyrolysis waste water. Aqueous-phase catalysis converted the acidic components into low molecular weight olefins. 3) As part of a request from another industrial partner, we began development of renewable coal tar pitch, which is also a critical component of aluminum smelting anodes. Our experiments involved distillations and/or extractions of partially deoxygenated bio-oils, as well as isolating toluene-insolubles. We improved critical properties, such as the coking value, toluene-insolubles content, and softening point. 4) For our bio-phenolics work, we isolated larger amounts of bio-oil phenolics for use in bio-lubricant synthesis in collaboration with another ARS project. We also determined methods for isolation of phenolics from aqueous phases. This involved a combination of sodium bicarbonate treatment and solvent extraction.
Objective 3: With our pyrolysis demonstration plant (CRIPS) developed and constructed as part of the completed project, we continue to develop scalable downstream bio-oil refining processes. This includes continuous distillation, extraction and calcining processes as described above.
Accomplishments
Review Publications
Mullen, C.A., Strahan, G.D., Boateng, A.A. 2019. Characterization of biomass pyrolysis oils by diffusion ordered nmr spectroscopy. ACS Sustainable Chemistry & Engineering. 7:19951-19960. https://doi.org/10.1021/acssuschemeng.9b05520.
Davidson, S.D., Flake, M., Lopez-Ruiz, J.A., Cooper, A.R., Elkasabi, Y.M., Tomasi, M.M., Lebarbier, D.V., Albrecht, K.O., Dangle, R.A. 2019. Cleanup and conversion of biomass liquefaction aqueous phase to C3-C5 olefins over ZnxZryOz catalyst. Catalysts. 9(11):1-15.
Elkasabi, Y.M., Wyatt, V.T., Jones, K.C., Strahan, G.D., Mullen, C.A., Boateng, A.A. 2020. Hydrocarbons extracted from advanced pyrolysis bio-oils: characterization and refining. Energy and Fuels. 34(1):483-490. https://doi.org/10.1021/acs.energyfuels.9b03189.
Elkasabi, Y.M., Mullen, C.A., Boateng, A.A. 2020. Continuous extraction of phenol and cresols from advanced pyrolysis oils. Springer Nature Applied Sciences. https://doi.org/10.1007/s42452-020-2134-4.
Mcvey, M., Elkasabi, Y.M., Ciolkosz, D. 2020. Separation of BTX chemicals from biomass pyrolysis oils via continuous flash distillation. Biomass Conversion and Biorefinery. 10(1):15-23. https://doi.org/10.1007/s13399-019-00409-1.
Gurtler, J., Mullen, C.A., Boateng, A.A., Masek, O., Camp, M.J. 2020. Biocidal activity of fast pyroloysis biochar against E.coli 0157:H7 in soil varies based on production temperature or age of biochar. Journal of Food Protection. 83:1020-1029.
