Progress 10/01/08 to 09/30/14
Outputs
Target Audience: Scientists, biofuels engineers, undergraduate and graduate students, and postdoctoral associates. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided? Training in laboratory research plus professional development were provided to research engineers and graduate students. Several of these trained persons had the opportunity to present their work at national and international conferences. How have the results been disseminated to communities of interest? The results have been disseminated through conference presentations at national and international meetings. What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
Biomass feedstock supply The following are preliminary outcomes for biomass harvesting, handling, and storage. Additional information will be made available in the final report of the BRDI project titled “Sustainable Feedstock Production Supply Systems to Support Cellulosic Biorefinery Industries”. - Rotary disk blades dull faster when harvesting switchgrass after the first freeze as compared to before the first freeze. - Raking is not generally required for harvests after a freeze in switchgrass and mixed grass, unless it is economically feasible to combine windrows prior to baling. - Forage sorghum can be naturally dried in the field and baled in Oklahoma with proper conditioning and cooperating weather conditions. Dry down times can be as little as five days under optimum conditions. - Better bales are produced when forage sorghum is properly conditioned. Bales made from forage sorghum with minimal mechanical conditioning are difficult to construct, have a higher failure rate, and are often misshapen. - Optimal harvesting would include three windrowers for every high density baler and four balers for every Stinger loader. The Stinger can handle between 100 to 150 bales per hour when moving the bales to the edge of the field. Older stands of high yielding switchgrass are extremely difficult on equipment tires. - In-bale moisture variability is a major issue, assuming biorefineries are going to purchase biomass based on dry weights. Thermochemical conversion Downdraft gasification of forage sorghum The performance of forage sorghum as a gasification feedstock was evaluated in a pilot scale down draft gasifier system. The effects of input air flow rate, equivalence ratio and air temperature on producer gas composition and lower heating value, and gasification efficiencies were studied. As the equivalence ratio increased from 0.15 to 0.30, net heating value of producer gas was increased from 4.8 to 5.6 MJ/Nm3 and hot and cold gas efficiencies were increased from 30 to 70%. Preheating gasifying air from 21 to 600°C increased the temperature levels by 6-fold in the twin-shell section of the reactor. This section is the region where biomass pyrolysis gases and tar vapors are released and mixed with the gasifying air, and tar cracking oxidation reactions occur. As the air temperature increased from 21 to 200°C, the hot and cold gas efficiencies were increased from 66 to 71% and 60 to 66%, respectively, while lower heating value of producer gas increased from 1217 to 1425 kcal/Nm3. As the input air temperature was further increased to 400 and 600°C, no significant improvements were observed. Air-steam gasification of switchgrass The effects of steam addition on gasifier performance were studied using a pilot scale down draft gasifier system with switchgrass as the feedstock. Four levels of steam injection (0, 1.8, 3.0, and 3.9 kg/h) were used. As the steam injection increased from 0 to 3.0 kg/h, the carbon monoxide and hydrogen concentration levels (by volume) in the producer gas increased from 12.4 to 17.8%, and 8.6 to 9.5%, respectively, while the lower heating value increased from 1267 to 1770 kcal/Nm3. Hot and cold gas efficiencies were increased from 85 to 91% and 59 to 75%, respectively, as the steam injection increased from 0 to 3.0 kg/h. A further increase in steam flow rate from 3.0 to 3.9 kg/h showed a decreasing trend due to the decrease in reactor temperature. Improving solubility of tar compounds in water Solubility of tar compounds (benzene, toluene, ethylbenzene, styrene and p-xylene) in water was improved using an ionic surfactant, i.e., sodium dodecyl sulfate (SDS). Solubility enhancement experiments were performed using a batch reactor. Effects of SDS concentration level (15 to 60 gm/L) and solvent temperature (20 to 50°C) on aqueous solubility improvement of tar compounds were studied. Solubilities of tar compounds improved significantly (p<0.0001) using SDS above the critical micelle concentration. Experimental results showed that the solubility of benzene, toluene, ethylbenzene, styrene and p-xylene was increased 4 to 14, 9 to 33, 19 to 69, 18 to 83 and 29 to 135 fold, respectively, as SDS concentration increased from 0 (water) to 15 gm/L and 0 to 60 gm/L, respectively, at a solvent temperature of 20°C. Results also showed that the solubility of tar compounds reduced significantly as the temperature increased from 20 to 50°C. For example, benzene solubility reduced from 14 to 9 fold as the solvent temperature increased from 20 to 50°C at a SDS concentration of 60 gm/L. Vegetable oil based wet scrubbing system A vegetable oil (soybean and canola oils) based bench scale wet packed bed scrubbing system was designed and constructed to study the removal of biomass producer gas model tar compounds (benzene, toluene and ethylbenzene). Effects of bed height (0.5, 0.8 and 1.1 m), solvent temperature (30, 40 and 50°C) and solvent flow rate (53, 63 and 73 ml/min) on the removal efficiency of tar compounds were studied. An equilibrium stage based process model of the wet packed bed scrubbing system was also developed and validated. Packing specific constants of Billet and Schultes (1999) correlations were determined using experimental data to predict the height equivalent to a theoretical plate (HETP) and pressure drop across the column. Experimental results showed that vegetable oils (soybean and canola oils) are potential candidates as solvents for the removal of tar compounds. Bed height and solvent temperature had highly significant (p<0.0001) effects on removal efficiency of tar compounds. Solvent flow rate did not have a significant (p>0.05) effect on the removal efficiency of model tar compounds. Packed bed height, solvent temperature and solvent flow rate had highly significant (p<0.0001) effects on the pressure drop across the packed bed column. Packing specific constants CV = 0.80 and CL = 2.40 of Billet and Schultes correlation were determined using experimental data to predict the height equivalent to a theoretical plate (HETP). Packing specific constants Ch =2.52 and CP,0 = 2.93 of Billet and Schultes correlation were found using experimental data to predict the pressure drop across the column. Model predictions showed best fits with the experimental data within 6% for benzene, 4% for toluene, and 2% for ethylbenzene at a 30°C solvent temperature. Maximum deviation of model prediction from experimental data was at the highest solvent temperature of 50°C.
Publications
- Type:
Theses/Dissertations
Status:
Published
Year Published:
2014
Citation:
P.R. Bhoi, Wet scrubbing of biomass producer gas tars using vegetable oil (Doctoral dissertation), Oklahoma State University, Stillwater, OK, 2014.
- Type:
Conference Papers and Presentations
Status:
Accepted
Year Published:
2014
Citation:
Craige, C., E.A. Miller, V. Schielack, M.D. Buser and R. Huhnke. 2014. Storage evaluation of plastic wrapped large format square bales with and without vents. ASABE 141910218. Presented at the Annual International Meeting of ASABE, Montreal, CN.
- Type:
Journal Articles
Status:
Published
Year Published:
2014
Citation:
Sharma, A.M., A. Kumar, and R.L. Huhnke. 2014. Effect of steam injection location on syngas obtained from an air-steam gasifier. Fuel, 116:388-394.
- Type:
Journal Articles
Status:
Published
Year Published:
2014
Citation:
Bhandari, P. N., A. Kumar, D. Bellmer, and R.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, A.M., A. Kumar, S. Madihally, J.R. Whiteley, and R.L. Huhnke. 2014. Prediction of biomass-generated syngas using extents of major reactions in a continuous stirred-tank reactor. Energy. http://dx.doi.org/10.1016/j.energy.2014.05.027.
- Type:
Journal Articles
Status:
Under Review
Year Published:
2014
Citation:
Bhoi, P.R., R.L. Huhnke, A. Kumar, K.N. Patil and J.R. Whiteley. Design and development of a bench scale vegetable oil based wet packed bed scrubbing system for removing producer gas tar compounds. Fuel Processing Technology. (In review.)
- Type:
Journal Articles
Status:
Under Review
Year Published:
2014
Citation:
Bhoi, P.R., R.L. Huhnke, A. Kumar, M.E. Payton, K.N. Patil and J.R. Whiteley. Vegetable oil as a solvent for removing producer gas tar compounds. Fuel Processing Technology. (In review.)
- Type:
Journal Articles
Status:
Under Review
Year Published:
2014
Citation:
Bhoi, P.R., R.L. Huhnke, J.R. Whiteley, S. Gebreyohannes, A. Kumar. Equilibrium stage based model of a vegetable oil based wet packed bed scrubbing system for removing producer gas tar compounds. Separation and Purification Technology. (In review.)
- Type:
Conference Papers and Presentations
Status:
Accepted
Year Published:
2013
Citation:
Patil, K.N., D. Iyer, P. Bhoi, and R.L. Huhnke. 2013. Simulation of natural gas co-firing with producer gas mixtures using Aspen Plus. ASABE 131595946. Presented at the Annual International Meeting of ASABE, Kansas City, MO.
- Type:
Conference Papers and Presentations
Status:
Accepted
Year Published:
2014
Citation:
Bhoi, P.R., K.N. Patil, A. Kumar, and R.L. Huhnke. 2014. Performance of vegetable oil based wet scrubbing system for the removal of producer gas tars. ASABE 141895914. Presented at the Annual International Meeting of ASABE, Montreal, CN.
- Type:
Conference Papers and Presentations
Status:
Accepted
Year Published:
2014
Citation:
Bhoi, P.R., K.N. Patil, A. Kumar, and R.L. Huhnke. 2014. Design, fabrication and evaluation of vegetable oil based wet scrubbing system for the removal of biomass producer gas tars. ASABE 141895904. Poster presented at the Annual International Meeting of ASABE, Montreal, CN.
- Type:
Conference Papers and Presentations
Status:
Accepted
Year Published:
2014
Citation:
Craige. C., E.A. Miller, M.D. Buser and R. Huhnke. 2014. Stinger stacker 6500 time and motion studies for large format square bales. ASABE 141913131. Presented at the Annual International Meeting of ASABE, Montreal, CN.
- Type:
Conference Papers and Presentations
Status:
Accepted
Year Published:
2014
Citation:
Moore, T., M.D. Buser, E.A. Miller, V.P. Schielack III and R.L. Huhnke. 2014. Bale Sampling Tools Used in OSUs BRDI Project. ASABE 141913549. Presented at the Annual International Meeting of ASABE, Montreal, CN.
- Type:
Conference Papers and Presentations
Status:
Accepted
Year Published:
2014
Citation:
Sutterfield, D.H., M.D. Buser, C.C. Craige, R.L. Huhnke, E.A. Miller and W. Smith. 2014. Large format square switchgrass bale storage study: OSU BRDI project update. ASABE 141914228. Presented at the Annual International Meeting of ASABE, Montreal, CN.
- Type:
Conference Papers and Presentations
Status:
Accepted
Year Published:
2014
Citation:
Qian, K., A. Sharma, A. Kumar, and R. Huhnke. 2014. Conditioning of biomass-generated syngas using biochar and biochar-based catalyst. ASABE 141830177. Poster presented at the Annual International Meeting of ASABE, Montreal, CN.
|
Progress 10/01/12 to 09/30/13
Outputs
Target Audience: Scientists, biofuel engineers, undergraduate and graduate students, postdoctoral associates,farmers interested in growing biofuel crops, bioindustry personnel, policy makers and the general public. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided? Training in field and/or laboratory research plus professional development were provided toundergraduate andgraduate studentsinvolved in related project. Graduate students had the opportunity to present their work at national and international conferences. How have the results been disseminated to communities of interest? The results have been disseminated throughconference presentations at national and international meetings. What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
Biomass storage As a component of our current BRDI projects,the team is conducting a fully wrapped versus fully wrapped with slits storage study on switchgrass and forage sorghum to determine if the slits would allow the excess moisture to escape. The switchgrass study is a continuation of the study conducted in 2011 using bales from the late winter harvest. Each test stack was three bales tall and three columns long. There were three replications of both fully wrapped and fully wrapped with slits for a total of 54 bales per feedstock. Approximately 6,700 core samples were collected from the stacks in July 2013. The research team is also continuing the in-bale moisture variability after reviewing their preliminary storage study results. In 2012, the team focused on pre- and post-storage bales. After the physiological maturity harvest, sixty-two core samples were collected from five forage sorghum and five switchgrass bales after baling. After the early winter harvest, the team collected sixty-two core samples from five forage sorghum and five switchgrass bales and five mixed grass bales after baling. The team repeated the process after the late winter harvest. For the post-storage portion of the test, the five test bales that are pulled out of one of the late winter harvest uncovered storage stacks for switchgrass, mixed grass, and forage sorghum stacks that are part of the baseline storage study were more extensively sampled. The number of core samples from each of these bales was increased to sixty-two. Approximately 8,700 moisture samples were collected. This data will be combined with all other moisture data to generate a significant dataset to answer the team’s questions on in-bale moisture variability and recommended sampling schemes. Co-firing biomass producer gas with natural gas A model biomass producer gas mixture, representing the gasification of switchgrass, was investigated for co-firing with natural gas using a bench-scale, air-swirled burner unit. The effects of co-firing rates (CF), which is the percent natural gas energy in the mixture with syngas (0%, 50%, 75% and 100%), and equivalence ratios (ER from 0.9 to 1.15), defined as the actual air supplied to the stoichiometric air on flame characteristics and exhaust emissions, were studied. RGIBBS reactor-based Aspen simulations were conducted and used for comparison purposes. The NOx level of 54 ppm at 100% CF, i.e. natural gas only, was reduced to about 15 ppm at 0% CF, i.e. producer gas only. With increase in ER, NOx and flame temperatures showed direct correlation with ER. As the flame temperatures increased, NOx levels in the flue increased. At a typical ER of 1.1, reduction in CO2 levels from 18.5% at 0% CF to 12.3% at CF level of 75% was observed. The simulation model over predicted CO2 by 12% and NOx by 36% compared to experimental values at ER=1.1 and CF=75%. NO emissions significantly increase as flame temperatures increase above 800oC.
Publications
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2013
Citation:
Bhoi, P., K.N. Patil, and R.L. Huhnke. 2013. Downdraft gasification performance of forage sorghum. ASABE 131595877. Presented at the American Society of Agricultural and Biological Engineers, Kansas City, MO.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2013
Citation:
Miller, E., M.D. Buser, R.L. Huhnke, and V. Schielack. 2013. Initial Moisture Variability in High Density Biomass Bales. ASABE 131619970. Poster presented at the American Society of Agricultural and Biological Engineers, Kansas City, MO.
- Type:
Websites
Status:
Published
Year Published:
2012
Citation:
http://bioenergycenter.okstate.edu/videos/BRDI/logistics
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2013
Citation:
Buser, M.D., E.A. Miller, and R.L. Huhnke, and K.L. Kenney. 2013. Performance of large bale switchgrass and energy sorghum storage stacks: Oklahoma State University BRDI project overview. ASABE 131621076. Presented at the American Society of Agricultural and Biological Engineers, Kansas City, MO.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2013
Citation:
Patil, K.N., D. Iyer, P. Bhoi, and R.L. Huhnke. 2013. Simulation of natural gas co-firing with producer gas mixtures using Aspen Plus. ASABE 131595946. Presented at the American Society of Agricultural and Biological Engineers, Kansas City, MO.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2013
Citation:
Buser, M.D., E. Miller, and R.L. Huhnke. 2013. Field-scale switchgrass and energy sorghum harvesting: OSU BRDI project update. ASABE 131621074. Presented at the American Society of Agricultural and Biological Engineers, Kansas City, MO.
|
Progress 10/01/11 to 09/30/12
Outputs
OUTPUTS: Steam injected into a high temperature zone of the fluidized bed gasifier favors hydrogen forming reactions, yielding hydrogen-rich syngas. Whereas, steam injected at a low temperature zone can reduce reactor temperature, adversely affecting gasification reactions. Additionally, the formation of hydrogen depends on the residence time of reactants involved during gasification. Residence time can be optimized for efficient operation by changing location of steam injection. Since reaction conditions inside the gasifier vary along the height of the gasifier reactor, we hypothesized that the location of steam injection influences syngas quality. A study was initiated to determine the effect of steam injection location on syngas quality from air-steam gasification of biomass using an auto-thermal lab-scale fluidized bed gasifier. Co-firing of fossil fuels with biomass syngas has potential for reduction in energy costs and emission levels. Two model syngas fuels, equivalent to switchgrass and forage sorghum downdraft gasification, were investigated for co-firing with natural gas using a bench-scale air-swirled burner unit. For each syngas mixture, effects of co-firing rates, which is the percent natural gas energy in the mixture with syngas (0, 50, 75 and 100%), and equivalence ratio, defined as the actual air supplied to the stoichiometric air (0.9, 1.0, 1.10 and 1.15) on flame characteristics and exhaust emissions, were studied. All syngas co-firing test results were compared to the performance of burner with 100% natural gas. Water is commonly used as a biomass producer gas scrubbing solvent. However, water can remove only polar compounds. Water solubility for non-polar compounds is relatively low. Therefore, a study on improving solubility of tar compounds in water using sodium dodecyl sulfate (SDS) surfactant was taken-up. SDS is an anionic-type surfactant. Aqueous scrubbing solutions were made with water by adding SDS in the range of 15-60 g/L to study the solubility of tar compounds. Four levels of temperatures ranging from 20 to 50C were evaluated. Biomass can be converted to ethanol through a gasification-syngas fermentation process using acetogenic bacteria, such as Clostridium ragsdalei. The fermentation medium supplies minerals, metals and organic co-factors needed to build cell mass and activate the enzymes that conducts the production reactions. Commercial deployment of producer gas fermentation must consider using economically viable medium. The cost and function of fermentation medium components compared to an approximate elemental composition of common microbial cells was used to assess potential of the medium for commercial use. This assessment was used to develop production medium for producer gas fermentation to produce ethanol with C. ragsdalei. Producer gas fermentation transforms carbon monoxide and hydrogen into ethanol through a set of discrete elementary chemical reactions. Description of the producer gas fermentation in a mathematical model provides a tool for study and analysis of fermentation to allow design and analysis of equipment, flows and controls in laboratory, pilot plant and commercial scale. PARTICIPANTS: Nothing significant to report during this reporting period. TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Gasifier steam injection: Syngas composition, tar and particulates yields, and conversion efficiency were determined to analyze the effects of steam injection location on syngas quality and gasification performance. Statistical analysis showed that syngas carbon monoxide content, and cold gas and hot gas efficiencies were significantly influenced by injection location. Syngas hydrogen content and tar and particulates contents were not significantly influenced by injection location. Location of 254 mm above the air distribution plate and steam-to-biomass ratio of 0.1 resulted in the maximum hydrogen (9.8%) and carbon monoxide (17.9%) contents, and hot (80%) and cold (75%) gas efficiencies. The maximum carbon conversion efficiency of 98% was observed at 254 mm location and steam-to-biomass ratio of 0.3. Biomass producer gas-natural gas co-firing: For a model switchgrass and forage sorghum syngas mixtures and using a typical equivalence ratio of 1.10, the NOx level of 54 ppm at 100% co-firing rate was reduced to 15 ppm for switchgrass and 11 ppm for sorghum at 0% co-firing rate. With increase in equivalence ratio, NOx and flame temperatures showed direct correlation with equivalence ratio. As the flame temperatures increased, flue NOx levels increased. Sorghum model syngas mixture co-firing showed comparatively low concentration levels for NOx and carbon dioxide. Flame temperatures were also higher in case of switchgrass model gas due to its higher concentration levels of carbon monoxide and hydrogen in the syngas mixture. At a typical equivalence ratio of 1.1, carbon dioxide levels decreased from 18.5% at 0% co-firing rate to 12.3% at co-firing rate of 75%. Producer gas wet scrubbing: The major tar compounds selected for solubility studies in aqueous sodium dodecyl sulfate (SDS) surfactant solution are benzene, toluene, ethyl benzene, styrene and p-xylene. The experimental solubility values of selected tar compounds showed a linear correlation with the concentration levels of sodium dodecyl sulfate. It was also observed that as the temperature increases the solubility of tar compounds reduces. For example, the solubility of benzene increased from 4.6 to 15.9 g/L as the SDS concentration increased from 15 to 60 g/L at 20C. Similar trends of solubility improvement have been observed at other temperatures (30, 40, and 50C). Solubility of benzene reduces from 6.1 to 4.6 g/L as the temperature increases from 20 to 50C at SDS concentration level of 15 g/L. Similar trends were observed at SDS concentrations of 30, 45, and 60 g/L. Syngas fermentation: Cost of medium was reduced from $9.36/L to $0.25/L. The estimated growth potential for producer gas remained at 0.57 g/L of cell mass. Projected cost savings from use of syngas components as nutrients and recycle of fermentation broth after recovering ethanol can reduce the medium cost below $0.01/L. The model showed that reducing potential and pH affect the ratio of ethanol to acetic acid produced by Clostridium ragsdalei, which was also observed experimentally. The in silico description of producer gas fermentation is a powerful tool in interpretation of results and in process design.
Publications
- Liu, K., Atiyeh, H.K., Tanner, R.S., Wilkins, M.R., and Huhnke, R.L. 2012. Low cost medium for ethanol production using novel moderately alkaliphilic alkalibaculum bacchi CP15, ASABE Annual International meeting (abstract), Dallas, TX.
- Patil, K.N., Bhoi, P.R., and Huhnke, R.L. 2012. Biomass-based model syngas co-firing with natural gas in a laboratory air-swirled burner: Effects of co-firing rates, combustion air-to-fuel ratios and burner port area on flame and exhaust characteristics. Sun Grant Initiative National Conference (abstract), New Orleans, LA.
- Wilkins, M., Kundiyana, D., Ramachandriya, K.D., Terrill, J., Zhu, X., Liu, K., Atiyeh, H.K., and Huhnke, R. 2012. Biowinol: Capturing renewable electricity and carbon dioxide for transportation fuel. US-DOE Biomass 2012 Conference (abstract), Washington, DC.
- Zhu, X., Kundiyana, D., Ramachandriya, Liu, K., Terrill, J., Huhnke, R., Atiyeh, H., and Wilkins, M. 2012, Biowinol: Capturing wind energy and carbon dioxide for renewable fuel. ASABE Annual International meeting (abstract), Dallas, TX.
- Atiyeh, H., Liu, K., Tanner, R.S., Wilkins, M.R., and Huhnke, R.L. 2012. Hybrid thermochemical-biochemical processing for biorenewable alcohol production using Alkalibaculum bacchi. S-1041 The Science and Engineering for a Biobased Industry Annual Meeting and Symposium (abstract), Washington, DC.
- Atiyeh, H.K., Orgill, J.J., Devarapalli, M., Phillips, J.R., Lewis, R.S., and Huhnke, R.L. 2012. Comparison of syngas fermentation reactors for ethanol production. AIChE Annual Meeting (abstract), Pittsburgh, PA. Bhoi, P.R., Patil, K.N., and Huhnke, R.L. 2012. Experimental determination of solubility of major biomass producer gas tar compounds in the selected organic solvents and bio oils. ASABE Annual International meeting (abstract), Dallas, TX.
- Devarapalli, M., Atiyeh, H.K., Phillips, J.R., Orgill, J.J., Lewis, R.S. and Huhnke, R.L. 2012. Comparison of syngas fermentation reactors for biological alcohol production. Sun Grant Initiative National Conference (abstract), New Orleans, LA.
- Devarapalli, M., Atiyeh, H.K., Lewis, R.S., and Huhnke, R.L. 2012. Semi-batch syngas fermentation in a trickle bed reactor using Clostridium ragsdalei. ASABE Annual International meeting (abstract), Dallas, TX.
- Gao J., Phillips, J.R., Atiyeh, H.K., Wilkins, M.R., and Huhnke, R.L. 2012. Medium design for ethanol production through syngas fermentation. AIChE Annual Meeting (abstract), Pittsburgh, PA.
- Gao J., Phillips, J.R., Atiyeh, H.K., Wilkins, M.R., and Huhnke, R.L. 2012. Cost-competitive medium design for ethanol production through syngas fermentation. ASABE Annual International meeting (abstract), Dallas, TX.
- Huhnke, R.L., Atiyeh, H.K., Kumar, A., Patil, K.N., Wilkins, M.R., Bellmer, D.D., Tanner, R.S., Stevenson, B.S., and Lewis, R.S. 2012. Hybrid thermochemical-biochemical processing for biofuels, biochemicals, and biopower. US-DOE Biomass 2012 Conference (abstract), Washington, DC.
- Liu, K., Atiyeh, H.K., Tanner, R.S., Wilkins, M.R., and Huhnke, R.L. 2012. Fermentative production of ethanol from syngas using novel moderately alkaliphilic strains of Alkalibaculum bacchi, Bioresource Technology, 104:336-341.
- Phillips, J.R., Atiyeh, H.K., and Huhnke, R.L. 2012. Computer model for synthesis gas fermentation. ASABE Annual International meeting (abstract), Dallas, TX.
- Phillips, J.R., Atiyeh, H.K., Lewis, R.S., and Huhnke, R.L. 2012. Mass transfer analysis for synthesis gas fermentation in CSTR. ASABE Annual International meeting (abstract), Dallas, TX.
- Sharma, A.M., Kumar, A., Patil, K.N., and Huhnke, R.L. 2012. Fluidization characteristics of a mixture of gasifier solid residues, switchgrass and inert material. Powder Technology (in press).
- Sharma, A.M., Kumar, A., and Huhnke, R.L. 2012. Effect of steam injection location on biomass-generated producer gas in a fluidized-bed gasifier (abstract). S-1041 The Science and Engineering for a Biobased Industry Annual Meeting and Symposium, Washington, DC.
|
Progress 10/01/10 to 09/30/11
Outputs
OUTPUTS: Gasification: Effective fluidization of materials present in the gasifier reactor bed is very important for optimizing reaction conditions in a fluidized-bed gasifier. A study was performed to investigate the effect of reactor bed composition on fluidization using a 0.25 m inside diameter transparent column. Materials used were switchgrass, inert material, and gasifier solid residue. In this cold-flow study, the amount of inert material (silica sand) in the bed was held at 20 kg. The percentage of the switchgrass in the mixture ranged from 0.035 to 5% of the sand quantity while the percentage of the solid residues ranged from 5 to 35% of the switchgrass. The particle geometric sizes by mass of sand, solid residues and switchgrass averaged 336 micrometers, 80 micrometers, and 10 mm, respectively. Research on wet scrubbing processes for removal of biomass producer gas impurities like tars and particulates has been initiated. Commonly, water is used as a solvent for the tar removal in most of the scrubbing systems applied in the biomass gasification applications. A study is underway to identify potential scrubbing solvents and to investigate their solubility characteristics for major producer gas tar compounds. Syngas fermentation: Fermentation medium was designed for production of ethanol and acetic acid from synthesis gas (mainly CO, H2 and CO2) by Clostridium ragsdalei strain P11. The medium was developed by serial deletion of components from the standard medium used for isolation and growth of strain P11. Cost and purpose of individual components in the designed medium were considered to guide the revision of the medium recipe. A simple model was developed to describe syngas fermentation to produce ethanol and acetic acid. The model, coded in a new spreadsheet, provides a theoretical basis that incorporates the fermentation stoichiometry, calculation of mass transfer, and thermodynamic departure from standard conditions. Thermodynamics at standard conditions are most often used to describe biological reactions. This spreadsheet model was used to predict and simulate fermentation outcomes. PARTICIPANTS: Nothing significant to report during this reporting period. TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Gasification: For all conditions, an increase in gas superficial velocity, i.e. ratio of volumetric gas flow and bed cross-sectional area, corresponded to an increase in pressure drop across the bed, reaching a maximum at the minimum fluidization condition. When the bed consisted of only sand and solid residues, with an increase in solid residues, superficial velocity and bed pressure drop remained constant at the minimum fluidization conditions. When the bed consisted of sand, solid residues, and switchgrass, with an increase in switchgrass from 0.035 to 5%, the superficial velocity at the minimum fluidization decreased when solid residues were below 15%, and increased when solid residues were above 15%. However, the corresponding bed pressure drop remained constant. Results also showed that the gasifier bed with more than 25% solid residues can result in improper fluidization. Databases, such as NIST-IUPAC and DECHEMA, provided data on solubility of major producer gas tar compounds including benzene, toluene, phenol, ethyl benzene, methyl phenol, styrene, xylene, naphthalene, dimethyl naphthalene and methyl naphthalene in water. It revealed that water, a commonly used syngas scrubbing solvent, can only remove polar tar compounds. Potential solvents have been identified which include: bio oils, nitro benzene, isopropanol, isobutyl methyl ketone, 1-methoxy-2-propanol, acetone, and methanol. A static cell-based experimental technique is identified from the literature for the experimental determination of major tar compounds in various organic and bio oil solvents. Theoretical prediction of solubility of tar compounds in various solvents through Aspen plus is also underway. Syngas fermentation: The newly designed medium reduced production cost by 95% compared to the standard medium. This process resulted in the elimination of morpholinoethanesulfonic acid (MES), a buffer used to maintain the pH near 6.0. Instead, a buffer was formed from the acetic acid produced during the fermentation and addition of bicarbonate, keeping the pH around 4.75 to enhance ethanol production. Performance of fermentation without MES, with pH control using acetate buffer was similar to that from the original rich medium. Additionally, yeast extract, an undefined growth promoter, was eliminated. Fermentation without yeast extract resulted in lower growth, but comparable initial substrate uptake and production rates. Further, omission of cysteine from the medium and dependence on sulfide as nutrient sulfur source enhanced ethanol production, but did not sustain growth of P11. For the designed medium, pH control and appropriate selection sources of elemental nutrients are expected to enhance fermentation performance and further decrease cost. The model showed dependence of products on dissolved gas concentrations inside the cell. Preliminary results from the model were found to agree with experimental data. Further development and testing against experimental data, and packaging with more sophisticated calculation techniques promise a tool for analysis and control of the syngas fermentation that can be licensed commercially, as a market develops.
Publications
- Huhnke, R., and Kumar, A. 2010. Bioconversion Pathways: Thermochemical Options and Developments. Pacific Rim Summit (abstract), Honolulu, HI. December, 2010.
- Kumar, A., Mudinoor A., Atiyeh, H., Bellmer, D., and Huhnke, R. 2010. Development of a Catalytic Reactor for Conditioning of Biomass Generated Producer Gas and Evaluation of Selected Commercial Catalysts. AIChE Annual Meeting (abstract), Salt Lake City, UT. November, 2010.
- Liu, K., Atiyeh, H., Tanner, R., Wilkins, M., and Huhnke, R. 2011. Fermentative production of ethanol from syngas using novel moderately alkaliphilic strains of Alkalibaculum bacchi. Bioresource Technology, doi: 10.1016/j.biortech.2011.10.054.
- Maddipati, P., Atiyeh, H., Bellmer, D. and Huhnke, R. 2011. Ethanol Production from Syngas by Clostridium Strain P11 Using Corn Steep Liquor as a Nutrient Replacement to Yeast Extract. Bioresource Technology, 102:6494-6501.
- Mudinoor, A., Bellmer, D., Marin, L., Kumar, A., and Huhnke, R. 2011. Conversion of toluene (model tar) using selected steam reforming catalysts. Transactions of ASABE, 54(5):1819-1827.
- Pasangulapati, V., Kumar, A., Jones, C., and Huhnke, R. 2011. Characterization of switchgrass using TGA-FTIR for thermochemical conversion. Annual State Conference of Oklahoma EPSCoR (abstract), Norman, OK, April, 2011.
- Patil, K.N., Bhoi, P.R., Huhnke, R., and Bellmer, D. 2011. Biomass downdraft biomass gasifier with internal cyclonic combustion chamber: Design, construction, and experimental results. Bioresource Technology 102:6286-6290.
- Ramachandriya, K., R. Wilkins, M., Delorme, J., Zhu, X., Kundiyana, D., Atiyeh, H., and Huhnke, R. 2011. Reduction of acetone to isopropanol using producer gas fermenting microbes. Biotechnology and Bioengineering, 108:2330-2338.
- Sharma, A.M., Kumar, A., and Huhnke, R. 2011. Fluidization characteristics of a mixture of chopped switchgrass, gasifier solid residues and silica sand. Annual State Conference of Oklahoma EPSCoR (abstract), Norman, OK, April, 2011.
- Sharma, A.M., Kumar, A., and Huhnke, R. 2011. Fluidization-hydrodynamics of a mixture of gasifier residues, chopped switchgrass and bed materials. 22nd Annual OSU Research Symposium and Research Scholar Conference (abstract), Stillwater, OK. February, 2011.
- Sharma, A.M., Kumar, A., Patil, K.N., and Huhnke, R. 2010. Performance of a laboratory-scale fluidized-bed biomass gasifier. Symposium on Thermal and Catalytic Sciences for Biofuels and Biobased Products (abstract), Ames, IA. September, 2010.
- Sharma, A.M., Kumar, A., Patil, K.N., and Huhnke, R. 2011. Design, development and performance of a lab-scale fluidized bed biomass gasifier. Transactions of ASABE (in press).
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Progress 10/01/09 to 09/30/10
Outputs
OUTPUTS: Gasification: Air-steam gasification tests are being conducted on chopped forage sorghum using a laboratory-scale downdraft gasifier. To date, three levels of air-to-steam mixtures obtained by mixing a constant steam flow rate of 4.3 kg/h with three levels of air flow rates (18, 23, and 26 kg/h) have been evaluated. Study investigated the effects on gasifier performance in terms of gas composition, reactor temperatures, producer gas tar, producer gas yield, producer gas lower heating values, and gasifier efficiencies. A study was conducted to investigate effects of air temperature on composition and lower heating value of the dry producer gas, and gasifier efficiency for forage sorghum using an exploratory downdraft gasifier system. Four levels of input air temperatures (21, 200, 400 and 600C) were evaluated. Syngas fermentation: Two new methods were established to measure enzyme activities in ethanol production from syngas. This will allow a better understanding of how different process conditions affect the activity and expression of various enzymes involved. These tools will be used to generate data that will guide our future process development efforts. A system of measuring gene expression was developed using the sequenced genome for the syngas fermenting bacteria Clostridium carboxidivorans. This system will help in determining which genes are expressed during different parts of the fermentation as well as in response to various environmental factors. Additionally, this system can be expanded to other syngas fermentors as their genomes are sequenced. Yeast extract (YE) at a concentration of 1 g/L and corn steep liquor (CSL) at a concentration of 10 g/L were investigated as the primary media constituents in syngas fermentation. Growth and product profiles of Clostridium strain P11 in YE and CSL media were followed during fermentation. Bottled syngas composed of 20% CO, 15% CO2, 5% H2, and 60% N2 (by volume) was used. The effect of dithiothreitol (DTT) on enhancing ethanol production from syngas using Clostridium strain P11 was investigated. Reducing agents help in regeneration of NADH from NAD+. NADH is utilized in the production of alcohol from aldehydes. Strain P11 was fed with syngas every 24 h and samples were collected to measure pH, cell mass and product concentrations. Various concentrations of DTT were examined. PARTICIPANTS: Nothing significant to report during this reporting period. TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Gasification: As air-to-steam ratio increased from 4.2 to 6 in the downdraft gasifier, H2 and CO2 concentrations in the producer gas increased while CO level decreased. Cold gas efficiency increased from 55 to 61% and the producer gas tar content also increased from 44 to 67 g/Nm3. Maximum hot and cold gas efficiencies of 87 and 61%, respectively, were obtained at the air-to-steam ratio of 5.3. Preheating the air in the downdraft gasifier from 21 to 400C increased temperatures in twin-shell section (TSS) by 6-fold. Overall reactor temperatures were not changed significantly. As the air temperature increased from 21 to 200C, hot and cold gas efficiencies increased from 66 to 71% and 60 to 66%, respectively. Gas yield remained constant at 1.5 Nm3/kg of dry biomass, while lower heating value increased from 1217 to 1425 kcal/Nm3. As the input air temperature was further increased to 600C, TSS temperature increased to 612C and the gas lower heating value decreased to 1313 kcal/Nm3. Syngas fermentation: In studies to determine the effect of syngas composition on enzyme hydrogenase activity in Clostridium strain P11, hydrogenase activity is inhibited by CO. Hydrogen composition did not have a major effect on hydrogenase activity. Also, ethanol production did not occur when hydrogenase activity was not present. Hydrogenase activity must be maintained in order to continue production of ethanol in Clostridium strain P11. It was determined that the media used for Clostridium strain P11 can be completely replaced by addition of 0.5 g/L of cotton seed extract (CSE). Average ethanol concentrations after 15 days in batch bottle fermentations were 2.67 g/L when using 0.5 g/L CSE media, but only 0.60 g/L when the original media was used. Also, it was observed that the onset of ethanol production during fermentation was earlier when no buffer was used in the media than when buffer was used. Comparing product profiles of Clostridium strain P11 using the primary media component as either yeast extract (YE) and corn steep liquor (CSL), ethanol concentrations in 250-mL serum bottles with 1 g/L YE, 10 g/L and 20 g/L CSL were 1.3 g/L, 1.5 g/L, and 2.7 g/L, respectively, after 600 h of fermentation. However, the maximum ethanol concentrations after 360 h of fermentation in 7.5-L fermentor with 10 g/L and 20 g/L CSL media were 8.6 g/L and 9.6 g/L, respectively, which represent 57% and 60% of the theoretical ethanol yields based on CO consumed. Only about 6.1 g/L of ethanol was obtained in the medium with 1 g/L YE after 360 h, which represents 53% of the theoretical ethanol yield based on CO consumed. Results on the effect of dithiothreitol (DTT) on enhancing ethanol production from syngas using Clostridium strain P11 showed more than a 350% increase in ethanol concentration in media that contained at least 7.5 g/L of DTT after 360 h of fermentation compared to the control (without DTT) in 0.1% (w/v) yeast extract medium. However, only a 35% increase in ethanol production was measured in 1% (w/v) CSL in the presence of 2.5 and 5.0 g/L of DTT compared to the control medium.
Publications
- Babu, B.K., H.K. Atiyeh, M.A. Wilkins and R.L. Huhnke. 2010. Effect of the reducing agent Dithiothreitol on ethanol and acetic acid production by Clostridium strain P11 using producer syngas obtained from gasifying switchgrass. ASABE 1009107. American Society of Agricultural and Biological Engineers, St. Joseph, MI.
- Bhoi, P.R., K.N. Patil, R.L. Huhnke and D.D. Bellmer. 2010. Air-steam gasification of switchgrass in a downdraft gasifier. ASABE 1009030. Poster presented at the American Society of Agricultural and Biological Engineers, St. Joseph, MI.
- Kumar, A., K.N. Patil, D.D. Bellmer, & R.L. Huhnke. 2009. Effects of biomass and air flowrates on fluidized-bed gasification of switchgrass: Preliminary analysis. Poster presented at Bioenergy Engineering, Bellevue, WA.
- Kundiyana, D., M. Wilkins and R. Huhnke. 2009. Syngas fermentation in a 100 L pilot scale fermentor: design and process considerations. Journal of Bioscience and Bioengineering. doi:10.1016/j.jbiosc.2009.10.022
- Kundiyana, D.K., M.R. Wilkins and R.L. Huhnke. 2010. Scale-up of solventogenic Clostridium stain P11 fermentation in a pilot scale fermentor. ASABE 1009127. American Society of Agricultural and Biological Engineers, St. Joseph, MI.
- Kundiyana, D.K., R.L. Huhnke, P. Maddipati, H.K. Atiyeh and M.R. Wilkins. 2010. Feasibility of incorporating cotton seed extract in Clostridium strain P11 fermentation medium during synthesis gas fermentation. Bioresource Technology 101(24): 9673-9680.
- Maddipati, P.B., H.K. Atiyeh and R.L. Huhnke. 2010. Evaluation of corn steep liquor as an inexpensive nutrient for ethanol production from syngas using Clostridium strain P11. ASABE 1009548. American Society of Agricultural and Biological Engineers, St. Joseph, MI.
- Mudinoor, A., D. Bellmer, R. Huhnke, A. Kumar and H. Atiyeh. 2010. Reduction of toluene from syngas using steam reforming catalysts. Poster presented at the Oklahoma EPSCoR Annual State Conference, Norman.
- Panneerselvam, A., M.R. Wilkins, M.J.M. DeLorme, H.K. Atiyeh, R.L. Huhnke. 2010. Effect of reducing agents on syngas fermentation by Clostridium ragsdalei. Biological Eng. 2:135-144.
- Patil, K.N., P.R. Bhoi, R.L. Huhnke and D.D. Bellmer. 2010. Downdraft gasification of forage sorghum. ASABE 1009023. Poster presented at the American Society of Agricultural and Biological Engineers, St. Joseph, MI.
- Rowland, S., D. Bellmer, R. Huhnke, A. Kumar and K. Patil. 2010. Gasification of Eastern Redcedar using a small-scale updraft gasifier. Poster presented at the Oklahoma EPSCoR Annual State Conference, Norman.
- Sharma, A.M., A. Kumar and R.L. Huhnke. 2010. Design, development and performance of a laboratory scale fluidized bed biomass gasifier. ASABE 1009578. Poster presented at the American Society of Agricultural and Biological Engineers, St. Joseph, MI. Sharma, A.M., A. Kumar and R.L. Huhnke. 2010. Recent trends and advancements in fluidized bed biomass gasification technology - A literature review. ASABE 1009580. Poster presented at the American Society of Agricultural and Biological Engineers, St. Joseph, MI.
- Sharma, A.M., A. Kumar and R.L. Huhnke. 2010. The effect of air-steam injection on performance of laboratory-scale fluidized bed biomass gasifier. ASABE 1009579. Poster presented at the American Society of Agricultural and Biological Engineers, St. Joseph, MI.
- Wilkins, M.R., D. Kundiyana, and R.L. Huhnke. 2009. Effects of nutrient limitation on ethanol and acetic acid production by Clostridium strain P11. Poster presented at the Society of Industrial Microbiology Meeting, Toronto, ON, Canada.
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Progress 10/01/08 to 09/30/09
Outputs
OUTPUTS: Gasification: Several potential bioenergy feedstocks were gasified using an exploratory downdraft gasifier system. Preliminary research trials were conducted on switchgrass, chopped forage sorghum and sweet sorghum bagasse. One of the major objectives is to generate biomass syngas high in carbon monoxide and hydrogen concentrations and low in tars and particulate content suitable for applications like producing ethanol through syngas fermentation. Syngas fermentation: Several experiments were conducted with the Clostridium strain P11 fermentation media in an effort to improve the productivity, and possibly improve the fermentation process economics. Standard Clostridium strain P11 media was used in all fermentations with corn steep liquor replacing yeast extract. Fermentations were conducted in 250 mL serum bottles with 100 mL working volume. Syngas source was customized gas mix containing 5 percent hydrogen, 20 percent carbon monoxide and 15 percent carbon dioxide. PARTICIPANTS: Nothing significant to report during this reporting period. TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Gasification: For switchgrass at 12 percent moisture content (wet basis), air-blown gasification tests resulted in oxidation zone temperatures in the range of 1000 to 1110C. Gas components of greatest interest (volume basis) were carbon monoxide: 19-24 percent, hydrogen: 10-12 percent, carbon dioxide: 8-14 percent and methane: 2.5-4.5 percent. Dry product gas yield ranged approximately 1.7 normal cubic meters per kg dry biomass. Specific gasification rates varied from 507 to 736 cubic meters per hour of dry gas per square meter combustion zone area. Air-blown gasification tests on forage sorghum at 8 percent moisture content (wet basis) resulted in gas components (volume basis) of carbon monoxide: 11-14 percent, hydrogen: 11-13 percent, carbon dioxide: 14-20 percent and methane: 1-2.5 percent. Dry product gas yield ranged from 1.4 to 3 normal cubic meters per kg dry biomass. Hot gas and cold gas efficiencies varied from 61 to 75percent and 55 to 67 percent, respectively. Preliminary gasification test results with air-steam mixtures (using a steam to biomass ratio at 0.4) yielded carbon monoxide concentrations of 13-17 percent, while hydrogen concentrations were 14-16 percent. Compared to air-blown, steam gasification resulted in a slight decrease in CO concentration while the methane concentration slightly increased. Gas yield increased from 2.2 to 2.5 normal cubic meters per kg dry biomass. Hot gas and cold gas efficiencies were increased from 71 to 77 percent and 62 to 69 percent, respectively. Air-blown gasification tests on sweet sorghum bagasse at 12percent moisture content (wet basis) resulted in gas components (volume basis) of carbon monoxide: 15-19 percent, hydrogen: 10-13 percent, carbon dioxide: 14-16 percent and methane: 2.2-3.1 percent. Dry product gas yield ranged from 1.3 to 1.7 normal cubic meters per kg dry biomass. Hot gas and cold gas efficiencies varied from 42 to 60 percent and 38 to 54 percent, respectively while the mass balance varied from 85 to 91 percent. Syngas fermentation: Low temperature (30C) fermentation using Clostridium strain P11showed higher ethanol, acetic acid, and cell densities compared to the 37C control. A low temperature fermentation can further improve the overall process cost economics by reducing the operation cost associated with the higher process requirements. Lowering the initial pH from 6.0 to 5.0 did not enhance the ethanol production or cell density. Tests revealed that adding corn steep liquor (CSL) can have a pronounced effect on ethanol production, while the incorporation of yeast extract will aid acetic acid production. The effect of pre-treating CSL before its addition as a media component was also evaluated and compared to yeast extract as the control fermentation. The CSL pretreatment method had no effect on ethanol production.
Publications
- Atiyeh, H.K., B. Kubandra Babu, M.R. Wilkins and R.L. Huhnke. 2009 Effect of the Reducing Agent Dithiothreitol on Ethanol and Acetic Acid Production by Clostridium Strain P11 Using Simulated Biomass-Based Syngas. ASABE BIO-097917. American Society of Agricultural and Biological Engineers, St. Joseph, MI.
- Kundiyana, D. P. Maddipati, M. Wilkins, and R. Huhnke. 2009. Feasibility of incorporating cotton seed extract (CSE) as a fermentation media component during Clostridium strain P11 synthesis gas fermentation. Poster presented at 2009 Bioenergy Engineering, Bellevue, WA.
- Kundiyana, D. K., M. R. Wilkins, R. L. Huhnke and I. M. Banat. 2009. Effect of Furfural Addition on Xylose Utilization by Kluyveromyces marxianus IMB4 under Anaerobic and Microaerobic Conditions. Biological Engineering 2(1):3-15.
- Kundiyana, D., M. Wilkins and R. Huhnke. 2009. Syngas Fermentation in a 100 L Pilot Scale Fermentor: Design and Process Considerations. ASABE 096554. American Society of Agricultural and Biological Engineers, St. Joseph, MI.
- Kundiyana, D., P. Maddipati, M. Wilkins and R. Huhnke. 2009. Optimization of process parameters for synthesis gas fermentation using Clostridium P11. ASABE 096573. American Society of Agricultural and Biological Engineers, St. Joseph, MI.
- Patil, K.N.., R. Huhnke and D. Bellmer. 2009. Downdraft gasification of sweet sorghum for syngas generation. ASABE 095884. American Society of Agricultural and Biological Engineers, St. Joseph, MI.
- Suryawati, L., M.R. Wilkins, D.D. Bellmer, R.L. Huhnke, N.O. Maness and I.M. Banat. 2009. Effect of hydrothermolysis process conditions on pretreated switchgrass composition and ethanol yield by SSF with Kluyveromyces marxianus IMB4. Process Biochemistry 44:540-545.
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