THE SCIENCE AND ENGINEERING FOR A BIOBASED INDUSTRY AND ECONOMY

• Sponsoring Institution: National Institute of Food and Agriculture
• Project Status: COMPLETE
• Funding Source: HATCH
• Reporting Frequency: Annual
• Accession No.: 0229359
• Multistate No.: OLD S-1041
• Project Start Date: Apr 1, 2012
• Project End Date: Sep 30, 2014
• Program Code: [(N/A)]- (N/A)

Recipient Organization
OKLAHOMA STATE UNIVERSITY
(N/A)
STILLWATER,OK 74078

Performing Department
Biosystems & Ag Engineering

Non Technical Summary
Production of fuels, chemicals and power from biomass resources is considered sustainable since biomass can be produced in a short duration and biomass recycles carbon dioxide during its growth. Additionally, biomass has the potential to significantly reduce U.S. dependence on imported petroleum resources. Thermochemical conversions, such as gasification and pyrolysis, are flexible in accepting a variety of feedstocks, and the products can also be used for a variety of end-use application such as transportation fuels, chemicals and power. However, commercial production of transportation fuels, chemical and power using these technologies face several challenges in using biomass. Challenges faced by gasification technology include difficulty in gasifying biomass materials with low bulk density and low energy density at high efficiency, low quality of syngas generated form biomass materials, and difficulty in conditioning syngas. This project will investigate fundamental and applied research in biomass gasification to solve these challenges. It is expected that new gasifier design, optimized gasification conditions, and new low-cost gas conditioning system will be developed to bring these technologies closer to commercialization. It is also expected that new fundamental knowledge will be gained through this project about biomass gasification, syngas conditioning and syngas application.

Animal Health Component

(N/A)

Research Effort Categories

Basic

(N/A)

Applied

(N/A)

Developmental

(N/A)

Classification

Knowledge Area (KA)	Subject of Investigation (SOI)	Field of Science (FOS)	Percent
511	0699	2020	20%
511	1629	2020	40%
511	1630	2020	40%

Knowledge Area
511 - New and Improved Non-Food Products and Processes;

Subject Of Investigation
1629 - Perennial grasses, other; 1630 - Summer annual grasses; 0699 - Trees, forests, and forest products, general;

Field Of Science
2020 - Engineering;

Keywords

biomass

thermochemical conversions

gasification

biochar

syngas

producer gas

Goals / Objectives
Reduce costs of harvesting, handling and transporting biomass to increase the competitiveness of biomass as a feedstock for biofuels, biomaterials and biochemicals Improve biofuel production processes Identify, develop and evaluate sustainable processes to convert biomass resources into biochemicals, biocatalysts and biomaterials Identify and develop needed educational resources, develop distance based delivery methods, and develop a trained work force for the biobased economy

Project Methods
Several approaches will be used to improve yield and quality of syngas generated from diverse biomass feedstocks. The syngas qualities of interest are gas composition, and tar and particulates contents. Feedstocks will include switchgrass, sorghum, wheat straw, woody residue and carbon containing wastes. The feedstocks will be characterized to obtain their properties related to thermochemical conversions. These properties will include proximate and ultimate analysis, and heating value. Effects of feedstock composition on gas evolution profile will be analyzed using thermogravimetric techniques. Syngas will be generated from biomass in downdraft and fluidized-bed gasifiers with varying operating conditions such as steam to biomass ratio, air to fuel ratio to maximize energy efficiency for syngas production. Effects of biomass pretreatment such as densification and torrefaction on yield and quality of biomass- generated syngas will be investigated. Syngas tar continues to be detrimental to the use of biomass-generated syngas. Novel biochar-based catalysts will be used for conditioning syngas to reduce tar content as well as improve gas composition. Use of the syngas to produce drop-in fuels and power will also be explored. For development of trained workforce for the biobased economy, course materials will be developed on biomass thermochemical conversion.

Progress 04/01/12 to 09/30/14

Outputs
Target Audience: Target audiences include researchers, entrepreneur, policy makers and public interested in using biomass as a resource for producing renewable and sustainable fuels, chemicals and power. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? One student graduated with a MS degree in Biosystems Engineering and currently working for a bioenergy company. How have the results been disseminated to communities of interest? Several refereed journal articles (as indicated earlier) and conference presentations were made. What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? Gasification performance of switchgrass pretreated with torrefaction and densification The purpose of this study was to investigate gasification performance of four switchgrass pretreatments (torrefaction at 230 and 270°C, densification, and combined torrefaction and densification) and three gasification temperatures (700, 800 and 900°C). Gasification was performed in a fixed-bed externally heated reactor with air as an oxidizing agent. Switchgrass pretreatment and gasification temperature had significant effects on gasification performance such as gas yields, syngas lower heating value (LHV), and carbon conversion and cold gas efficiencies. With an increase in the gasification temperature, yields of H2 and CO, syngas LHV, and gasifier efficiencies increased whereas CH4, CO2 and N2 yields decreased. Among all switchgrass pretreatments, gasification performance of switchgrass with combined torrefaction and densification was the best followed by that of densified, raw and torrefied switchgrass. Gasification of combined torrefied and densified switchgrass resulted in the highest yields of H2 (0.03 kg/kg biomass) and CO (0.72 kg/kg biomass), highest syngas LHV (5.08 MJ m-3), CCE (92.53%), and CGE (68.40%) at the gasification temperature of 900°C. Synthesis and evaluation of biochar-derived catalysts for removal of toluene (model tar) from biomass-generated producer gas Challenges in removal of contaminants, especially tars, from biomass-generated producer gas continue to hinder commercialization efforts in biomass gasification. The objectives of this study were to synthesize catalysts made from biochar, a byproduct of biomass gasification and to evaluate their performance for tar removal. The three catalysts selected for this study were original biochar, activated carbon, and acidic surface activated carbon derived from biochar. Experiments were carried out in a fixed bed tubular catalytic reactor at temperatures of 700 and 800 °C using toluene as a model tar compound to measure effectiveness of the catalysts to remove tar. Steam was supplied to promote reforming reactions of tar. Results showed that all three catalysts were effective in toluene removal with removal efficiency of 69 to 92 %. Activated carbon catalysts resulted in higher toluene removal because of their higher surface area (~900 m2/g compared to less than 10 m2/g of biochar), larger pore diameter (19 A° compared to 15.5 A° of biochar) and larger pore volume (0.44 cc/g compared to 0.085 cc/g of biochar). An increase in reactor temperature from 700 to 800 °C resulted in 3 to 10 % increase in toluene removal efficiency. Activated carbons had higher toluene removal efficiency compared to biochar catalysts.

Publications

• Type: Journal Articles Status: Published Year Published: 2014 Citation: Wang, D., W. Yuan*, D. Wang, and A. Kumar. 2014. A char-supported nano-NIO catalyst for biomass syngas cleanup and conditioning. Transactions of ASABE. 57(1):93-101.
• Type: Journal Articles Status: Submitted Year Published: 2014 Citation: Sarkar, M., A. Kumar*, J. S. Tumuluru, K. N. Patil, and D. D. Bellmer. 2014. Gasification Performance of Switchgrass Pretreated with Torrefaction and Densification. Applied Energy. 127: 194-201.
• Type: Journal Articles Status: Published Year Published: 2014 Citation: Sarkar, M., A. Kumar*, Jaya Shankar Tumuluru, Krushna Patil, and Danielle Bellmer. 2014. Thermal Devolatilization Kinetics of Switchgrass Pretreated with Torrefaction and Densification. Special Collection: Advances in Biomass Pretreatment and Conversion. Transactions of ASABE. 57(4):1199-1210.
• Type: Journal Articles Status: Published Year Published: 2014 Citation: 2. Sharma, A. M., A. Kumar*, S. Madihally, R. Whiteley and R. L. Huhnke. 2014. Prediction of biomass-generated syngas using extents of major reactions in a continuous stirred-tank reactor. Energy. 72 (2014) 222-232.

Progress 10/01/12 to 09/30/13

Outputs
Target Audience: Target audiences include researchers, entrepreneur, policy makers and public interested in using biomass as a resource for producing renewable and sustainable fuels, chemicals and power. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? One student graduated with a MS degree and another student graduated with a PhD degree in Biosystems Engineering. How have the results been disseminated to communities of interest? Six refereed journal articles were published or accepted and six conference presentations were made based on results of this project. What do you plan to do during the next reporting period to accomplish the goals? During next reporting period, this project will investigate effects of pretreatments on thermochemical properties and performance of biomass feedstocks. Development of robustcatalysts will also be pursued.

Impacts
What was accomplished under these goals? During this reporting period, we focused, primarily, on three studies: (a) development and validation of a new process model for gasification, and (b) development of biochar-based catalysts for syngas cleaning. The objective of the first study was to develop and validate reaction kinetics-based gasification model using extents of major reactions in a continuous stirred-tank reactor (CSTR) to predict syngas composition and yield. Results showed significant improvement in the predictions of syngas composition and yield, and gasification efficiencies. The extents of gasification reactions indicated that at equivalence ratios (ERs) below 0.32, the water gas reaction contributed the most to the syngas CO and H2 yields. The char oxidation reaction was also the dominating reaction contributing to CO yield at ERs below 0.40. At ERs above 0.29, the Boudouard and methane oxidation reactions were the most dominating reactions contributing to the CO yield while the water gas shift reaction contributed to the H2 yield. The developed model corrected one of the key underlying assumptions that biomass decomposes into elemental forms (C, H, O, N and S), however gasification temperature, carbon conversion efficiency and tar yield were assumed to be given. The objective of the second study was to synthesize and evaluate catalysts derived from biochar, a byproduct of biomass gasification. Three catalysts, original biochar, biochar-derived activated carbon, and biochar-derived activated carbon with acidic surface were synthesized. Results showed that surface area of activated carbon (~900 m2/g) was significantly higher than that of its precursor biochar (~60 m2/g). Biochar, activated carbon, and acidic surface activated carbon showed toluene removal efficiencies of approximately 78, 88, and 88 %, respectively, when the catalysts were tested individually with toluene in the presence of producer gas at 800 °C. The toluene removal efficiencies increased to 86, 91, and 97 % using biochar, activated carbon and acidic surface activated carbon, respectively in the presence of NH3 and H2S in the producer gas. Ammonia adsorption capacities were 0.008 g NH3/g catalyst for biochar and 0.03g NH3/g catalyst for activated carbon, and acidic surface activated carbon. H2S adsorption capacities were 0.008 g H2S/g catalyst for all biochar-based catalysts. High surface area biochar-based catalysts have shown high efficiencies for simultaneous removal of toluene, NH3, and H2S. These demonstrate that biochar-derived catalysts can remove the syngas contaminants simultaneously.

Publications

• Type: Journal Articles Status: Accepted Year Published: 2014 Citation: Bhandari, Pushpak N., A. Kumar*, and Raymond L. Huhnke. 2014. Simultaneous removal of toluene (model tar), NH3, and H2S, from biomass-generated producer gas using biochar-based and mixed-metal oxide catalysts. Energy & Fuels.. DOI: 10.1021/ef4016872.
• Type: Journal Articles Status: Published Year Published: 2014 Citation: Bhandari, Pushpak N., A. Kumar*, Danielle Bellmer, and Raymond L. Huhnke. 2014. Synthesis and evaluation of biochar-derived catalysts for removal of toluene (model tar) from biomass-generated producer gas. Renewable Energy. 66:346-353.
• Type: Journal Articles Status: Published Year Published: 2014 Citation: Sharma, Ashokkumar, M. A. Kumar*, and Raymond L. Huhnke. 2014. Effect of steam injection location on syngas obtained from an air-steam gasifier. Fuel. 116:388-394.
• Type: Journal Articles Status: Accepted Year Published: 2014 Citation: Sarkar, Madhura, A. Kumar*, Jaya Shankar Tumuluru, Krushna Patil, and Danielle Bellmer (Accepted in 2013). Thermal Devolatilization Kinetics of Switchgrass Pretreated with Torrefaction and Densification. Special Issue of Transactions of ASABE.
• Type: Journal Articles Status: Published Year Published: 2013 Citation: Qian, Kezhen, A. Kumar*, Krushna Patil, Danielle Bellmer, Donghai Wang, Wenqiao Yuan, and Raymond L Huhnke. 2013. Effects of biomass feedstocks and gasification conditions on the physiochemical properties of biochar. Energies. 6: 3972-3986.
• Type: Journal Articles Status: Published Year Published: 2013 Citation: Sharma, A. M., A. Kumar*, K. N. Patil, and R. L. Huhnke. 2013. Fluidization characteristics of a mixture of gasifier solid residues, switchgrass and inert material. Powder Technology. 235: 661-668.
• Type: Conference Papers and Presentations Status: Published Year Published: 2013 Citation: Kumar, A*. 2013. Cleaning Biomass-Generated Syngas: Is Biochar a Cheaper Alternative to Expensive Catalysts? Annual State Conference of Oklahoma EPSCoR, Stillwater, OK, Apr 23, 2013. Invited Presentation.
• Type: Conference Papers and Presentations Status: Published Year Published: 2013 Citation: Sharma, A. M., A. Kumar*, Sundar Madihally, Rob Whiteley, Raymond L. Huhnke. 2013. Prediction of biomass-generated syngas using extents of major reactions in a continuous stirred-tank reactor. 23rd NSF EPSCoR National Conference, Nashville, TN. Nov 3-7, 2013.
• Type: Conference Papers and Presentations Status: Published Year Published: 2013 Citation: Sharma, A. M., A. Kumar*, and R. L. Huhnke. 2013. CFD-based gasification model incorporating fluidization hydrodynamics and reaction kinetics. 2013 ASABE Annual International Meeting. July 21-24, 2013 in Kansas City, MO. Oral Presentation.
• Type: Conference Papers and Presentations Status: Published Year Published: 2013 Citation: Sharma, A. M., A. Kumar*, and R. L. Huhnke. Reaction kinetics-based gasification model using a continuous stirred-tank reactor (CSTR). 24th Annual OSU Research Symposium and Research Scholar Conference, Stillwater, OK, Feb 20-22, 2013. Oral Presentation.
• Type: Conference Papers and Presentations Status: Published Year Published: 2013 Citation: Kumar, A.*, P. Bhandari, and R. L. Huhnke. 2013. Biochar-based and mixed-metal oxide catalysts for simultaneous removal of toluene (model tar), NH3, and H2S, from biomass-generated producer gas. 2013 ASABE Annual International Meeting. July 21-24, 2013 in Kansas City, MO. Oral Presentation.
• Type: Conference Papers and Presentations Status: Published Year Published: 2012 Citation: Bhandari, P. N., A. Kumar*, and R. L. Huhnke. Simultaneous Removal of Biomass-Generated Syngas Contaminants Using Biochar-Based Catalysts. 2012 AIChE Annual Meeting, Oct 28  Nov 2, 2012 in Pittsburgh, PA. Oral Presentation.

Progress 10/01/11 to 09/30/12

Outputs
OUTPUTS: The biomass feedstocks contain different amounts of cellulose, hemicellulose and lignin. Their polymer structure and length, and their cross-linkage vary substantially, resulting in different thermal decomposition characteristics and products during gasification and pyrolysis. For biorefineries to be feedstock flexible, understanding the effects of the major biomass components, cellulose, hemicellulose and lignin, on thermal decomposition of biomass and resulting products is crucial. The objective of this study was to investigate effects of biomass constituents (cellulose, hemicellulose and lignin) on biomass thermal decomposition and gas evolution profiles of four biomass materials. Switchgrass, wheat straw, eastern redcedar and dry distilled grains with solubles (DDGS) were selected as the biomass materials. Biochar is a low-value byproduct of biomass gasification and pyrolysis with many potential applications, such as for soil amendment, synthesis of activated carbon and carbon-based catalysts. Considering the high-value applications, biochar can provide economic benefit to the biorefinery. However, the properties of biochar depend heavily on biomass feedstocks, gasifier design and operating conditions. The effects on biochar properties must be better understood so that different biochars can be made suitable for various applications. In this paper, effectiveness of four catalysts (biochar, activated carbon, acidic surface activated carbon, and mixed metal oxide) for simultaneous removal of toluene, NH3, and H2S from biomass-generated producer gas was studied. NH3 (0.03 %), H2S (0.015 %), and toluene at a flow rate of 2 ml/h were mixed with a synthetic producer gas composition (H2: 8.5 %, N2: 58 %, CO: 17 %, CH4: 2 %, and CO2: 11 %) and passed over a catalyst bed in a fixed-bed reactor tube maintained at 800 degrees C. PARTICIPANTS: New graduate Students: Madhura Sarkar, and Kezhen Qian TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
No significant difference was observed in the weight loss profiles of switchgrass, wheat straw and eastern redcedar even though their cellulose, hemicellulose and lignin contents were considerably different. The weight loss kinetic parameters were also not significantly different except for activation energy of the eastern redcedar. However, biomass composition did significantly affect gas evolution profiles. The higher contents of cellulose and hemicellulose in switchgrass and wheat straw may have resulted in their higher CO and CO2 concentrations as compared to eastern redcedar. On the other hand, higher lignin content in eastern redcedar may have resulted in significantly its high CH4 concentration. This project presents the results of the physiochemical properties of biochar derived from gasification of switchgrass and forage sorghum at three equivalence ratios: 0.20, 0.25 and 0.28. The surface area results showed all biochar samples were less than 10 m2/g. The highest volatile content was obtained at an equivalence ratio of 0.28 while the lowest was at 0.25. As expected, ash content of biochar was much higher than that of the original biomass. Biochar ash content increased with the equivalence ratio. All samples showed large peaks in FTIR spectra where the silicon band vibration occurs. FTIR spectra showed that aliphatic structure was available in biomass but not in biochar. Among the four catalysts, acidic surface activated carbon resulted in the highest toluene removal efficiency (97.5 %) and highest breakthrough time for NH3 (145 min.). For H2S removal, mixed metal oxides resulted in the highest breakthrough time (105 min.) among the four catalysts. Activated carbon showed good simultaneous removal capacity (91 % toluene removal efficiency; NH3 adsorption capacity of 0.03g-NH3/g-activated carbon; H2S adsorption capacity of 0.008 g-H2S/g-activated carbon) for the contaminants whereas biochar had moderate removal efficiencies (86 % toluene removal efficiency; NH3 adsorption capacity of 0.008 g-NH3/g-biochar; H2S adsorption capacity of 0.008 g-H2S/g-biochar). Results indicate that simultaneous removal of contaminants from producer gas is feasible using biochar-based catalysts. High surface area mixed metal oxides synthesized using microwave and ultrasonication are also effective for simultaneous removal of contaminants.

Publications

• Pasangulapati, V., A. Kumar, C. L. Jones, and R. L. Huhnke. 2012. Characterization of switchgrass, cellulose, hemicellulose and lignin for thermochemical conversions. Journal of Biobased Materials and Bioenergy. 6(3):249-258.
• Pasangulapati, V., K. D. Ramachandriya, A. Kumar, M. R. Wilkins, C. L. Jones, and R. L. Huhnke. 2012. Effects of cellulose, hemicellulose and lignin on thermochemical conversion characteristics of the selected biomass. Bioresource Technology. 114: 663-669.
• Bhandari, P. N., A. Kumar, and R. L. Huhnke. Simultaneous Removal of Biomass-Generated Syngas Contaminants Using Biochar-Based Catalysts. 2012 AIChE Annual Meeting, Oct 28-Nov 2, 2012 in Pittsburgh, PA (abstract).
• K. Qian, A. Kumar, K.N. Patil, D.D. Bellmer and R. L. Huhnke. Sun Grant Initiative 2012 National Conference. Oct 2-5, 2012 in New Orleans, LA (abstract).
• A. M. Sharma, A. Kumar, R. L. Huhnke. Effect of steam injection location on biomass-generated producer gas in a fluidized-bed gasifier. 2012 S-1041 meeting and symposium. Aug 6-7, 2012 in Washington, DC (abstract).
• Huhnke, R.L., H. K. Atiyeh, A. Kumar, K. N. Patil, M. R. Wilkins, D. D. Bellmer, R. S. Tanner, B. S. Stevenson, and R. S. Lewis. 2012. Hybrid thermochemical-biochemical processing for biofuels, biochemical, and biopower. Biomass 2012: Confronting Challenges, Creating Opportunities. Hosted by the U.S. Department of Energy in Washington, DC. Jul 10-11, 2012 (abstract).