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Robert C. Brown
Department of Chemical and Biological Engineering, Iowa State University, Ames, IA, U.S.A

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Journal article
Published: 20 August 2021 in Chemical Engineering Journal
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Passivation of naturally occurring AAEM in biomass enhances sugar yields from the fast pyrolysis of biomass by preventing these metals from catalyzing the fragmentation of pyranose rings in cellulose and hemicellulose. However, because AAEM also catalyzes lignin depolymerization, its passivation can be accompanied by undesirable char agglomeration. Pretreatment of biomass with ferrous sulfate both passivates AAEM and substitutes ferrous ions as lignin depolymerization catalysts. This pretreatment has been particularly successful for high ash biomass like corn stover, but of limited value for low ash biomass like wood. This study explores the reasons for this discrepancy and offers a combined pretreatment of ferrous sulfate and ferrous acetate pretreatment to overcome char agglomeration in wood. This new pretreatment increased sugar yields from 4.4 wt% to 15.5 wt% and 5.4 wt% to 19.0 wt% for hardwood and softwood biomasses, respectively. This pretreatment produces an iron-rich biochar that catalyzes oxidation of the biochar under the oxygen-rich conditions of autothermal pyrolysis, which is preferentially consumed to provide the enthalpy for pyrolysis, preserving bio-oil as a more desirable energy product. Instead of producing carbon monoxide, which dominates oxidation of biochar from untreated biomass, the iron catalyzes oxidation to carbon dioxide, producing more energy per mole of oxygen consumed. In fact, oxygen demand to support autothermal pyrolysis of red oak and southern yellow pine was reduced 15% by the presence of iron in the biochar.

ACS Style

Sean A. Rollag; Jake K. Lindstrom; Chad A. Peterson; Robert C. Brown. The role of catalytic iron in enhancing volumetric sugar productivity during autothermal pyrolysis of woody biomass. Chemical Engineering Journal 2021, 427, 131882 .

AMA Style

Sean A. Rollag, Jake K. Lindstrom, Chad A. Peterson, Robert C. Brown. The role of catalytic iron in enhancing volumetric sugar productivity during autothermal pyrolysis of woody biomass. Chemical Engineering Journal. 2021; 427 ():131882.

Chicago/Turabian Style

Sean A. Rollag; Jake K. Lindstrom; Chad A. Peterson; Robert C. Brown. 2021. "The role of catalytic iron in enhancing volumetric sugar productivity during autothermal pyrolysis of woody biomass." Chemical Engineering Journal 427, no. : 131882.

Research article
Published: 08 July 2021 in Energy & Fuels
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The oxidation kinetics for products of fast pyrolysis at low temperatures (<600 °C) are not well-known. These will be important in an effort to model autothermal pyrolysis, which has been recently developed to intensify the process but which occurs at much lower temperatures than combustion. This study determines global oxidation rates at 400–600 °C for three important products of fast pyrolysis: levoglucosan, xylose, and acetic acid. Experiments were performed in a fluidized bed pyrolyzer with the reactor modeled as a series of continuously stirred reactors and plug flow reactors to determine reaction rates. Oxidation rates at 500 °C for the three model compounds varied by a factor of 10.

ACS Style

Chad A. Peterson; Robert C. Brown. Global Gas-Phase Oxidation Rates of Select Products from the Fast Pyrolysis of Lignocellulose. Energy & Fuels 2021, 1 .

AMA Style

Chad A. Peterson, Robert C. Brown. Global Gas-Phase Oxidation Rates of Select Products from the Fast Pyrolysis of Lignocellulose. Energy & Fuels. 2021; ():1.

Chicago/Turabian Style

Chad A. Peterson; Robert C. Brown. 2021. "Global Gas-Phase Oxidation Rates of Select Products from the Fast Pyrolysis of Lignocellulose." Energy & Fuels , no. : 1.

Communication
Published: 28 June 2021 in Atmosphere
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The risk of inhalation exposure to elevated concentrations of hydrogen sulfide (H2S) and ammonia (NH3) during the agitation of stored swine manure is high. Once or twice a year, farmers agitate manure before pump-out and application to fields. Agitation of the swine manure causes the short-term releases of highly toxic levels of H2S and NH3. In our previous pilot-scale studies, the biochar powder showed significant mitigation of H2S and NH3 emissions when it was surficially applied to manure immediately before agitation. However, fine biochar powder application poses hazards by itself and may not be practical to apply on a farm scale, especially when livestock and workers are present. We hypothesized that applying pelletized biochar to manure surfaces is just as effective as applying powder to protect farmers and animals from excessive exposure to H2S and NH3. This work reports on the lab-scale proof-of-the-concept trials with biochar pellets on the lab scale. The objective was to compare the biochar pellets and biochar powder on their effectiveness of mitigation on H2S and NH3 gases during 3-h-long swine manure agitation. Three scenarios were compared in (n = 3) trials: (i) control, (ii) 12.5 mm thick surficial application to manure surface of biochar powder, and (iii) an equivalent (by mass) dose of pelletized biochar applied to the manure surface. The biochar powder was bound with 35% (wt) water into ~5 × 10 mm (dia × length) pellets. The biochar powder was significantly (p< 0.05) more effective than the biochar pellets. Still, pellets reduced total H2S and NH3 emissions by ~72% and ~68%, respectively (p = 0.001), compared with ~99% by powder (p = 0.001). The maximum H2S and NH3 concentrations were reduced from 48.1 ± 4.8 ppm and 1810 ± 850 ppm to 20.8 ± 2.95 ppm and 775 ± 182 ppm by pellets, and to 22.1 ± 16.9 ppm and 40.3 ± 57 ppm by powder, respectively. These reductions are equivalent to reducing the maximum concentrations of H2S and NH3 during the 3-h manure agitation by 57% and 57% (pellets) and 54% and 98% (powder), respectively. Treated manure properties hinted at improved nitrogen retention, yet they were not significant due to high variability. We recommend scaling up and trials on the farm-scale level using biochar pellets to assess the feasibility of application to large manure surfaces and techno-economic evaluation.

ACS Style

Baitong Chen; Jacek Koziel; Myeongseong Lee; Samuel O’Brien; Peiyang Li; Robert Brown. Mitigation of Acute Hydrogen Sulfide and Ammonia Emissions from Swine Manure during Three-Hour Agitation Using Pelletized Biochar. Atmosphere 2021, 12, 825 .

AMA Style

Baitong Chen, Jacek Koziel, Myeongseong Lee, Samuel O’Brien, Peiyang Li, Robert Brown. Mitigation of Acute Hydrogen Sulfide and Ammonia Emissions from Swine Manure during Three-Hour Agitation Using Pelletized Biochar. Atmosphere. 2021; 12 (7):825.

Chicago/Turabian Style

Baitong Chen; Jacek Koziel; Myeongseong Lee; Samuel O’Brien; Peiyang Li; Robert Brown. 2021. "Mitigation of Acute Hydrogen Sulfide and Ammonia Emissions from Swine Manure during Three-Hour Agitation Using Pelletized Biochar." Atmosphere 12, no. 7: 825.

Research article
Published: 08 June 2021 in ACS Sustainable Chemistry & Engineering
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Nitrogen (N) is an essential macronutrient for plant growth; however, excessive use of N fertilizers and complexities of the N cycle in soil cause negative environmental impacts. This imposes several challenges in controlling the N availability timing and losses. The objective of this study was to develop a biochar-based slow-release fertilizer (SRF) to reduce N loss and increase N use efficiency in crop production. We provided a laboratory-based assessment of several H3PO4 activated (5 and 15%) biochar-based SRFs, produced from different combinations of biochar to urea (1:2, 1:3, 1:4, and 1:6), calcium lignosulfonate (5%), and paraffin wax (10%). Characterization analyses (SEM–EDS, XRD, FTIR, and XPS) of developed SRFs suggest successful urea grafting onto biochar through both the urea amine N and carbonyl C═O modes, without urea crystal structure disruption. The SRFs were more efficient than uncoated urea (control): (1) urea released in aqueous medium was 61–90% in 4320 min for the SRFs versus 99.6% in 12 min for the control; (2) cumulative N leached from soil columns was 68–71% after 41 leaching events for SRF versus 99.9% after four leaching events for the control; and (3) NH3-N volatilization from soil was 0.2–0.9% for the SRFs versus 2% for the control. Inclusively, our results suggest that the developed SRFs are effective for reducing N loss from soil and provide larger quantities of NH4+-N to plants for a longer time (improved N use efficiency). We attribute this to that the developed SRFs are optimal for synchronizing with plant N uptake for providing better sustainability in modern agriculture.

ACS Style

Santanu Bakshi; Chumki Banik; David A. Laird; Ryan Smith; Robert C. Brown. Enhancing Biochar as Scaffolding for Slow Release of Nitrogen Fertilizer. ACS Sustainable Chemistry & Engineering 2021, 9, 8222 -8231.

AMA Style

Santanu Bakshi, Chumki Banik, David A. Laird, Ryan Smith, Robert C. Brown. Enhancing Biochar as Scaffolding for Slow Release of Nitrogen Fertilizer. ACS Sustainable Chemistry & Engineering. 2021; 9 (24):8222-8231.

Chicago/Turabian Style

Santanu Bakshi; Chumki Banik; David A. Laird; Ryan Smith; Robert C. Brown. 2021. "Enhancing Biochar as Scaffolding for Slow Release of Nitrogen Fertilizer." ACS Sustainable Chemistry & Engineering 9, no. 24: 8222-8231.

Research article
Published: 02 June 2021 in Energy & Fuels
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Biomass pyrolysis is a promising approach for producing economic and environmentally friendly fuels and bioproducts. Biomass pyrolysis experiments show that feedstock properties have a significant impact on product yields and composition. Scientists are developing detailed chemical reaction mechanisms to capture the relationships between biomass composition and pyrolysis yields. These mechanisms can be computationally intensive. In this study, we investigate the use of a machine learning reduced order model (ROM) for assessing the costs and emissions of a pyrolysis biorefinery. We developed a Kriging-based ROM to predict pyrolysis yields of 314 feedstock samples based on the results of a detailed chemical kinetic pyrolysis mechanism. The ROM is integrated into a chemical process model for calculating mass and energy yields in a commercial-scale (2000 tonne/day) biorefinery. The ROM estimated biofuel yields of 65 to 130 gallons per ton of dry biomass. This results in biofuel minimum fuel-selling prices of $2.62–$5.43 per gallon and emissions of −13.62 to 145 kg of CO2 per MJ. The ROM achieved an average mean square error of 1.8 × 10–20 and a mean absolute error of 0.53%. These results suggest that ROMs can facilitate rapid feedstock screening for biorefinery systems.

ACS Style

Olumide Olafasakin; Yahan Chang; Alberto Passalacqua; Shankar Subramaniam; Robert C. Brown; Mark Mba Wright. Machine Learning Reduced Order Model for Cost and Emission Assessment of a Pyrolysis System. Energy & Fuels 2021, 35, 9950 -9960.

AMA Style

Olumide Olafasakin, Yahan Chang, Alberto Passalacqua, Shankar Subramaniam, Robert C. Brown, Mark Mba Wright. Machine Learning Reduced Order Model for Cost and Emission Assessment of a Pyrolysis System. Energy & Fuels. 2021; 35 (12):9950-9960.

Chicago/Turabian Style

Olumide Olafasakin; Yahan Chang; Alberto Passalacqua; Shankar Subramaniam; Robert C. Brown; Mark Mba Wright. 2021. "Machine Learning Reduced Order Model for Cost and Emission Assessment of a Pyrolysis System." Energy & Fuels 35, no. 12: 9950-9960.

Review
Published: 18 May 2021 in Processes
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The International Panel on Climate Change and the 2015 Climate Summit in Paris have recommended that efforts to reduce carbon emissions be coupled with carbon removal from the atmosphere. Carbon negative energy combines net carbon removal with the production of energy products or other revenue-generating products beyond sequestered carbon. Even though both biochemical and thermochemical approaches to carbon negative energy can be envisioned, this paper considers the prospects for the latter including pyrolysis and gasification. The fundamentals of these two processes are described to better understand how they would be integrated with carbon removal. Characteristics of pyrolysis and gasification are related to the kinds of sequestration agents they would produce, the scale of their deployment, the fraction of biomass carbon that could ultimately sequestered, the challenges of effectively sequestering these different forms of carbon and the economics of thermochemical carbon negative energy.

ACS Style

Robert Brown. The Role of Pyrolysis and Gasification in a Carbon Negative Economy. Processes 2021, 9, 882 .

AMA Style

Robert Brown. The Role of Pyrolysis and Gasification in a Carbon Negative Economy. Processes. 2021; 9 (5):882.

Chicago/Turabian Style

Robert Brown. 2021. "The Role of Pyrolysis and Gasification in a Carbon Negative Economy." Processes 9, no. 5: 882.

Journal article
Published: 11 January 2021 in Atmosphere
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Rural communities are affected by gaseous emissions from intensive livestock production. Practical mitigation technologies are needed to minimize emissions from stored manure and improve air quality inside barns. In our previous research, the one-time surficial application of biochar to swine manure significantly reduced emissions of NH3 and phenol. We observed that the mitigation effect decreased with time during the 30-day trials. In this research, we hypothesized that bi-weekly reapplication of biochar could improve the mitigation effect on a wider range of odorous compounds using a larger scale and longer trials. The objective was to evaluate the effectiveness of biochar dose and reapplication on mitigation of targeted gases (NH3, odorous, volatile organic compounds VOCs, odor, greenhouse gases (GHG)) from stored swine manure on a pilot-scale setup over 8-weeks. The bi-weekly reapplication of the lower biochar dose (2 kg/m2) showed much higher significant percentage reductions in emissions for NH3 (33% without and 53% with reapplication) and skatole (42% without and 80% with reapplication), respectively. In addition, the reapplication resulted in the emergence of a statistical significance to the mitigation effect for all other targeted VOCs. Specifically, for indole, the percentage reduction improved from 38% (p = 0.47, without reapplication) to 78% (p = 0.018, with reapplication). For phenol, the percentage reduction improved from 28% (p = 0.71, without reapplication) to 89% (p = 0.005, with reapplication). For p-cresol, the percentage reduction improved from 31% (p = 0.86, without reapplication) to 74% (p = 0.028, with reapplication). For 4-ethyl phenol, the percentage emissions reduction improved from 66% (p = 0.44, without reapplication) to 87% (p = 0.007, with reapplication). The one-time 2 kg/m2 and 4 kg/m2 treatments showed similar effectiveness in mitigating all targeted gases, and no statistical difference was found between the dosages. The one-time treatments showed significant percentage reductions of 33% and 42% and 25% and 48% for NH3 and skatole, respectively. The practical significance is that the higher (one-time) biochar dose may not necessarily result in improved performance over the 8-week manure storage, but the bi-weekly reapplication showed significant improvement in mitigating NH3 and odorous VOCs. The lower dosages and the frequency of reapplication on the larger-scale should be explored to optimize biochar treatment and bring it closer to on-farm trials.

ACS Style

Baitong Chen; Jacek Koziel; Chumki Banik; Hantian Ma; Myeongseong Lee; Samuel O’Brien; Peiyang Li; Daniel Andersen; Andrzej Białowiec; Robert Brown. Mitigation of Gaseous Emissions from Stored Swine Manure with Biochar: Effect of Dose and Reapplication on a Pilot-Scale. Atmosphere 2021, 12, 96 .

AMA Style

Baitong Chen, Jacek Koziel, Chumki Banik, Hantian Ma, Myeongseong Lee, Samuel O’Brien, Peiyang Li, Daniel Andersen, Andrzej Białowiec, Robert Brown. Mitigation of Gaseous Emissions from Stored Swine Manure with Biochar: Effect of Dose and Reapplication on a Pilot-Scale. Atmosphere. 2021; 12 (1):96.

Chicago/Turabian Style

Baitong Chen; Jacek Koziel; Chumki Banik; Hantian Ma; Myeongseong Lee; Samuel O’Brien; Peiyang Li; Daniel Andersen; Andrzej Białowiec; Robert Brown. 2021. "Mitigation of Gaseous Emissions from Stored Swine Manure with Biochar: Effect of Dose and Reapplication on a Pilot-Scale." Atmosphere 12, no. 1: 96.

Research article
Published: 04 January 2021 in ACS Sustainable Chemistry & Engineering
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Biochars have been suggested to have P capture potential from effluent streams and to recycle the captured P to agricultural soils. However, most biochars have low P sorption capacity. The objective of this study was to engineer biochar for enhanced P sorption affinity. Biochar was produced from corn stover biomass pre-treated with FeSO4 (ISIB) using autothermal (air-blown) pyrolysis at 500 °C. Point of zero charge (pHZPC) shifted from 8.48 to 4.31, indicating that Fe treatment increased the dominance of acid functional groups. Batch equilibration isotherm study showed that ISIB had 11–12 times more P sorption capacity (3763 versus 46,300 mg kg–1 and 6704 versus 48,821 mg kg–1 for non-oxidized and oxidized conditions, respectively), while P desorption rate was ∼1/3 relative to the control biochar. A column leaching study also shows that ISIB was effective for removing P from simulated agricultural effluent. XRD (X-ray diffraction) and SEM-EDS (scanning electron microscopy–energy-dispersive X-ray spectrometry) analyses showed the P sorption was predominately through inner-sphere surface complexation followed by surface precipitation and that P is preferentially sorbed by hematite (α-Fe2O3) relative to magnetite (FeIII2O3 + FeIIO) or maghemite (γ-Fe2O3). This study demonstrates that ISIB can be produced by pyrolyzing corn stover with FeSO4, and the resulting ISIB is effective for adsorption and recycling of P. When loaded with P, the ISIB can potentially be used as a slow-release P fertilizer.

ACS Style

Santanu Bakshi; David A. Laird; Ryan G. Smith; Robert C. Brown. Capture and Release of Orthophosphate by Fe-Modified Biochars: Mechanisms and Environmental Applications. ACS Sustainable Chemistry & Engineering 2021, 9, 658 -668.

AMA Style

Santanu Bakshi, David A. Laird, Ryan G. Smith, Robert C. Brown. Capture and Release of Orthophosphate by Fe-Modified Biochars: Mechanisms and Environmental Applications. ACS Sustainable Chemistry & Engineering. 2021; 9 (2):658-668.

Chicago/Turabian Style

Santanu Bakshi; David A. Laird; Ryan G. Smith; Robert C. Brown. 2021. "Capture and Release of Orthophosphate by Fe-Modified Biochars: Mechanisms and Environmental Applications." ACS Sustainable Chemistry & Engineering 9, no. 2: 658-668.

Review article
Published: 04 December 2020 in Energy & Fuels
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As the field of fast pyrolysis has matured, it has been accompanied by a kind of orthodoxy in its practice. Among these orthodoxies are the following: (1) oxygen should be excluded from the pyrolysis process; (2) little sugar is produced during pyrolysis; and (3) the major product of pyrolysis is a low-value emulsion in water. Adherence to these tenets is an impediment to the commercial development of fast pyrolysis. Over the past 15 years, research at Iowa State University’s Bioeconomy Institute has challenged these tenets with what might be called heterodoxy in the science and engineering of fast pyrolysis: adding oxygen, producing sugars, and fractionating bio-oil into valorized products. This paper reviews these new approaches to pyrolysis and concludes with an outlook for further developing them.

ACS Style

Robert C. Brown. Heterodoxy in Fast Pyrolysis of Biomass. Energy & Fuels 2020, 35, 987 -1010.

AMA Style

Robert C. Brown. Heterodoxy in Fast Pyrolysis of Biomass. Energy & Fuels. 2020; 35 (2):987-1010.

Chicago/Turabian Style

Robert C. Brown. 2020. "Heterodoxy in Fast Pyrolysis of Biomass." Energy & Fuels 35, no. 2: 987-1010.

Journal article
Published: 01 November 2020 in Atmosphere
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Environmental impact associated with odor and gaseous emissions from animal manure is one of the challenges for communities, farmers, and regulatory agencies. Microbe-based manure additives treatments are marketed and used by farmers for mitigation of emissions. However, their performance is difficult to assess objectively. Thus, comprehensive, practical, and low-cost treatments are still in demand. We have been advancing such treatments based on physicochemical principles. The objective of this research was to test the effect of the surficial application of a thin layer (¼ inches; 6.3 mm) of biochar on the mitigation of gaseous emissions (as the percent reduction, % R) from swine manure. Two types of biochar were tested: highly alkaline and porous (HAP) biochar made from corn stover and red oak (RO), both with different pH and morphology. Three 30-day trials were conducted with a layer of HAP and RO (2.0 & 1.65 kg∙m−2, respectively) applied on manure surface, and emissions of ammonia (NH3), hydrogen sulfide (H2S), greenhouse gases (GHG), and odorous volatile organic compounds (VOCs) were measured. The manure and biochar type and properties had an impact on the mitigation effect and its duration. RO significantly reduced NH3 (19–39%) and p-cresol (66–78%). H2S was mitigated (16~23%), but not significantly for all trials. The phenolic VOCs had relatively high % R in most trials but not significantly for all trials. HAP reduced NH3 (4~21%) and H2S (2~22%), but not significantly for all trials. Significant % R for p-cresol (91~97%) and skatole (74~95%) were observed for all trials. The % R for phenol and indole ranged from (60~99%) and (29~94%) but was not significant for all trials. The impact on GHGs, isobutyric acid, and the odor was mixed with some mitigation and generation effects. However, larger-scale experiments are needed to understand how biochar properties and the dose and frequency of application can be optimized to mitigate odor and gaseous emissions from swine manure. The lessons learned can also be applicable to surficial biochar treatment of gaseous emissions from other waste and area sources.

ACS Style

Zhanibek Meiirkhanuly; Jacek Koziel; Baitong Chen; Andrzej Białowiec; Myeongseong Lee; Jisoo Wi; Chumki Banik; Robert Brown; Santanu Bakshi. Mitigation of Gaseous Emissions from Swine Manure with the Surficial Application of Biochars. Atmosphere 2020, 11, 1179 .

AMA Style

Zhanibek Meiirkhanuly, Jacek Koziel, Baitong Chen, Andrzej Białowiec, Myeongseong Lee, Jisoo Wi, Chumki Banik, Robert Brown, Santanu Bakshi. Mitigation of Gaseous Emissions from Swine Manure with the Surficial Application of Biochars. Atmosphere. 2020; 11 (11):1179.

Chicago/Turabian Style

Zhanibek Meiirkhanuly; Jacek Koziel; Baitong Chen; Andrzej Białowiec; Myeongseong Lee; Jisoo Wi; Chumki Banik; Robert Brown; Santanu Bakshi. 2020. "Mitigation of Gaseous Emissions from Swine Manure with the Surficial Application of Biochars." Atmosphere 11, no. 11: 1179.

Journal article
Published: 30 October 2020 in ACS Sustainable Chemistry & Engineering
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ACS Style

Arna Ganguly; Irene M. Martin; Robert C. Brown; Mark M. Wright. Application of Hydroprocessing, Fermentation, and Anaerobic Digestion in a Carbon-Negative Pyrolysis Refinery. ACS Sustainable Chemistry & Engineering 2020, 8, 1 .

AMA Style

Arna Ganguly, Irene M. Martin, Robert C. Brown, Mark M. Wright. Application of Hydroprocessing, Fermentation, and Anaerobic Digestion in a Carbon-Negative Pyrolysis Refinery. ACS Sustainable Chemistry & Engineering. 2020; 8 (44):1.

Chicago/Turabian Style

Arna Ganguly; Irene M. Martin; Robert C. Brown; Mark M. Wright. 2020. "Application of Hydroprocessing, Fermentation, and Anaerobic Digestion in a Carbon-Negative Pyrolysis Refinery." ACS Sustainable Chemistry & Engineering 8, no. 44: 1.

Preprint
Published: 26 October 2020
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Environmental impact associated with odor and gaseous emissions from animal manure is one of the challenges for communities, farmers, and regulatory agencies. Microbe-based manure additives treatments are marketed and used by farmers for mitigation of emissions. However, their performance is difficult to assess objectively. Thus, comprehensive, practical, and low-cost treatments are still in demand. We have been advancing such treatments based on physicochemical principles. The objective of this research was to test the effect of the surficial application of a thin layer (¼"; 6.3 mm) of biochar on the mitigation of gaseous emissions (as the percent reduction, % R) from swine manure. Two types of biochar were tested: highly alkaline and porous (HAP) biochar made from corn stover and red oak (RO), both with different pH and morphology. Three 30-day trials were conducted with a layer of HAP and RO (2.0 & 1.65 kg∙m-2, respectively) applied on manure surface, and emissions of ammonia (NH3), hydrogen sulfide (H2S), greenhouse gases (GHG), and odorous volatile organic compounds (VOCs) were measured. The manure and biochar type and properties had an impact on the mitigation effect and its duration. RO significantly reduced NH3 (19-39%) and p-cresol (66-78%). H2S was mitigated (16~23%), but not significantly for all trials. Significant (66~78%) reductions for p-cresol were observed for all trials. The phenolic VOCs had relatively high % R in most trials but not significantly for all trials. HAP reduced NH3 (4~21%) and H2S (2~22%), but not significantly for all trials. Significant % R for p-cresol (91~97%) and skatole (74~95%) were observed for all trials. The % R for phenol and indole ranged from (60~99%) & (29~94%) but was not significant for all trials. The impact on GHGs, isobutyric acid, and the odor was mixed with some mitigation and generation effects. However, larger-scale experiments are needed to understand how biochar properties and the dose and frequency of application can be optimized to mitigate odor and gaseous emissions from swine manure. The lessons learned can also be applicable to surficial biochar treatment of gaseous emissions from other waste and area sources.

ACS Style

Zhanibek Meiirkhanuly; Jacek A. Koziel; Baitong Chen; Andrzej Białowiec; Myeongseong Lee; Jisoo Wi; Chumki Banik; Robert C. Brown; Santanu Bakshi. Mitigation of Gaseous Emissions from Swine Manure with the Surficial Application of Biochars. 2020, 1 .

AMA Style

Zhanibek Meiirkhanuly, Jacek A. Koziel, Baitong Chen, Andrzej Białowiec, Myeongseong Lee, Jisoo Wi, Chumki Banik, Robert C. Brown, Santanu Bakshi. Mitigation of Gaseous Emissions from Swine Manure with the Surficial Application of Biochars. . 2020; ():1.

Chicago/Turabian Style

Zhanibek Meiirkhanuly; Jacek A. Koziel; Baitong Chen; Andrzej Białowiec; Myeongseong Lee; Jisoo Wi; Chumki Banik; Robert C. Brown; Santanu Bakshi. 2020. "Mitigation of Gaseous Emissions from Swine Manure with the Surficial Application of Biochars." , no. : 1.

Perspective
Published: 08 October 2020 in Joule
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Summary Autothermal operation of a chemical reactor involves coupling exothermic and endothermic chemical reactions for the purpose of thermal management without resorting to external energy sinks or sources. Often this is accomplished through regenerative or recuperative heat exchange between spatially or temporally separated exothermic and endothermic reactions. However, it is also possible to directly couple these reactions simultaneously within the same reactor volume, eliminating the heat-transfer bottleneck that characterizes much of chemical manufacture. It is not widely recognized that directly coupled autothermal operation allows dramatic process intensification. This perspective defines autothermal operation and contrasts it with conventional heat transfer for thermal management of chemical processes. The intensification and cost savings that can be achieved are quantified, and the implications to modular chemical process intensification are presented. Guidelines are proposed for designing directly coupled autothermal processes. Diverse examples are presented. Several challenges to expanding the field are critically discussed.

ACS Style

Robert C. Brown. Process Intensification through Directly Coupled Autothermal Operation of Chemical Reactors. Joule 2020, 4, 2268 -2289.

AMA Style

Robert C. Brown. Process Intensification through Directly Coupled Autothermal Operation of Chemical Reactors. Joule. 2020; 4 (11):2268-2289.

Chicago/Turabian Style

Robert C. Brown. 2020. "Process Intensification through Directly Coupled Autothermal Operation of Chemical Reactors." Joule 4, no. 11: 2268-2289.

Paper
Published: 15 September 2020 in Green Chemistry
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Increasing the selectivity of lignin oxidation toward phenolic monomers by enhancing oxygen mass transfer using perfluorocarbon media.

ACS Style

Parinaz Hafezisefat; Jake K. Lindstrom; Robert Clinton Brown; Long Qi. Non-catalytic oxidative depolymerization of lignin in perfluorodecalin to produce phenolic monomers. Green Chemistry 2020, 22, 6567 -6578.

AMA Style

Parinaz Hafezisefat, Jake K. Lindstrom, Robert Clinton Brown, Long Qi. Non-catalytic oxidative depolymerization of lignin in perfluorodecalin to produce phenolic monomers. Green Chemistry. 2020; 22 (19):6567-6578.

Chicago/Turabian Style

Parinaz Hafezisefat; Jake K. Lindstrom; Robert Clinton Brown; Long Qi. 2020. "Non-catalytic oxidative depolymerization of lignin in perfluorodecalin to produce phenolic monomers." Green Chemistry 22, no. 19: 6567-6578.

Communication
Published: 16 August 2020 in Catalysts
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Acute releases of hydrogen sulfide (H2S) are of serious concern in agriculture, especially when farmers agitate manure to empty storage pits before land application. Agitation can cause the release of dangerously high H2S concentrations, resulting in human and animal fatalities. To date, there is no proven technology to mitigate these short-term releases of toxic gas from manure. In our previous research, we have shown that biochar, a highly porous carbonaceous material, can float on manure and mitigate gaseous emissions over extended periods (days–weeks). In this research, we aim to test the hypothesis that biochar can mitigate H2S emissions over short periods (minutes–hours) during and shortly after manure agitation. The objective was to conduct proof-of-the-concept experiments simulating the treatment of agitated manure. Two biochars, highly alkaline and porous (HAP, pH 9.2) made from corn stover and red oak (RO, pH 7.5), were tested. Three scenarios (setups): Control (no biochar), 6 mm, and 12 mm thick layers of biochar were surficially-applied to the manure. Each setup experienced 3 min of manure agitation. Real-time concentrations of H2S were measured immediately before, during, and after agitation until the concentration returned to the initial state. The results were compared with those of the Control using the following three metrics: (1) the maximum (peak) flux, (2) total emission from the start of agitation until the concentration stabilized, and (3) the total emission during the 3 min of agitation. The Gompertz’s model for determination of the cumulative H2S emission kinetics was developed. Here, 12 mm HAP biochar treatment reduced the peak (1) by 42.5% (p = 0.125), reduced overall total emission (2) by 17.9% (p = 0.290), and significantly reduced the total emission during 3 min agitation (3) by 70.4%. Further, 6 mm HAP treatment reduced the peak (1) by 60.6%, and significantly reduced overall (2) and 3 min agitation’s (3) total emission by 64.4% and 66.6%, respectively. Moreover, 12 mm RO biochar treatment reduced the peak (1) by 23.6%, and significantly reduced overall (2) and 3 min total (3) emission by 39.3% and 62.4%, respectively. Finally, 6 mm RO treatment significantly reduced the peak (1) by 63%, overall total emission (2) by 84.7%, and total emission during 3 min agitation (3) by 67.4%. Biochar treatments have the potential to reduce the risk of inhalation exposure to H2S. Both 6 and 12 mm biochar treatments reduced the peak H2S concentrations below the General Industrial Peak Limit (OSHA PEL, 50 ppm). The 6 mm biochar treatments reduced the H2S concentrations below the General Industry Ceiling Limit (OSHA PEL, 20 ppm). Research scaling up to larger manure volumes and longer agitation is warranted.

ACS Style

Baitong Chen; Jacek Koziel; Andrzej Białowiec; Myeongseong Lee; Hantian Ma; Peiyang Li; Zhanibek Meiirkhanuly; Robert Brown. The Impact of Surficial Biochar Treatment on Acute H2S Emissions during Swine Manure Agitation before Pump-Out: Proof-of-the-Concept. Catalysts 2020, 10, 940 .

AMA Style

Baitong Chen, Jacek Koziel, Andrzej Białowiec, Myeongseong Lee, Hantian Ma, Peiyang Li, Zhanibek Meiirkhanuly, Robert Brown. The Impact of Surficial Biochar Treatment on Acute H2S Emissions during Swine Manure Agitation before Pump-Out: Proof-of-the-Concept. Catalysts. 2020; 10 (8):940.

Chicago/Turabian Style

Baitong Chen; Jacek Koziel; Andrzej Białowiec; Myeongseong Lee; Hantian Ma; Peiyang Li; Zhanibek Meiirkhanuly; Robert Brown. 2020. "The Impact of Surficial Biochar Treatment on Acute H2S Emissions during Swine Manure Agitation before Pump-Out: Proof-of-the-Concept." Catalysts 10, no. 8: 940.

Correction
Published: 12 August 2020 in Reaction Chemistry & Engineering
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Correction for ‘Tetrahydrofuran-based two-step solvent liquefaction process for production of lignocellulosic sugars’ by Arpa Ghosh et al., React. Chem. Eng., 2020, DOI: 10.1039/d0re00192a.

ACS Style

Arpa Ghosh; Martin R. Haverly; Jake K. Lindstrom; Patrick A. Johnston; Robert C. Brown. Correction: Tetrahydrofuran-based two-step solvent liquefaction process for production of lignocellulosic sugars. Reaction Chemistry & Engineering 2020, 5, 1 .

AMA Style

Arpa Ghosh, Martin R. Haverly, Jake K. Lindstrom, Patrick A. Johnston, Robert C. Brown. Correction: Tetrahydrofuran-based two-step solvent liquefaction process for production of lignocellulosic sugars. Reaction Chemistry & Engineering. 2020; 5 (9):1.

Chicago/Turabian Style

Arpa Ghosh; Martin R. Haverly; Jake K. Lindstrom; Patrick A. Johnston; Robert C. Brown. 2020. "Correction: Tetrahydrofuran-based two-step solvent liquefaction process for production of lignocellulosic sugars." Reaction Chemistry & Engineering 5, no. 9: 1.

Paper
Published: 22 July 2020 in Reaction Chemistry & Engineering
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THF-based solvent liquefaction demonstrates a new economic and sustainable approach for fractionating, saccharifying biomass with simple and efficient solvent recovery.

ACS Style

Arpa Ghosh; Martin R. Haverly; Jake K. Lindstrom; Patrick A. Johnston; Robert Clinton Brown. Tetrahydrofuran-based two-step solvent liquefaction process for production of lignocellulosic sugars. Reaction Chemistry & Engineering 2020, 5, 1 .

AMA Style

Arpa Ghosh, Martin R. Haverly, Jake K. Lindstrom, Patrick A. Johnston, Robert Clinton Brown. Tetrahydrofuran-based two-step solvent liquefaction process for production of lignocellulosic sugars. Reaction Chemistry & Engineering. 2020; 5 (9):1.

Chicago/Turabian Style

Arpa Ghosh; Martin R. Haverly; Jake K. Lindstrom; Patrick A. Johnston; Robert Clinton Brown. 2020. "Tetrahydrofuran-based two-step solvent liquefaction process for production of lignocellulosic sugars." Reaction Chemistry & Engineering 5, no. 9: 1.

Journal article
Published: 27 June 2020 in Chemical Engineering Journal
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The goal of this study was to determine oxidation kinetics for biochar produced from fast pyrolysis of various biomass feedstocks. In particular, the role of inherent ash content on the oxidation rate was evaluated. Thermogravimetric analysis (TGA) and fluidized bed combustion experiments were used to explore oxidation kinetics of six fast pyrolysis produced biochars with diverse ash content. Reaction rates varied by a factor of three under chemical kinetic-limited conditions, demonstrating inorganic content impacts oxidation rate. Chemical kinetic rate coefficients were proposed as a function of compositional parameters to determine overall fit and impact. Potassium content was found to have a positive correlation, best describing the differences in the oxidation kinetic rate coefficients. Additionally, feedstocks were subjected to a 1 M HCl acid wash mitigating the catalytic activity of the metals. Acid washed biochars had lower oxidation kinetic rates compared to their unwashed counterparts, indicating the removal of catalytically active metals reduced oxidation rate. Gas composition (CO/CO2) was measured during fluidized bed experiments for both acid-washed and unwashed biochars, which varied between the six biochars. Formation of CO2 was greatly affected by catalytic metals, finding potassium content to correlate well with a higher percentage of CO2 formation as compared to CO. Comparison of oxidation rates were made between the two experimental apparatuses to measure the effect of attrition on biochar oxidation.

ACS Style

Chad A. Peterson; Robert C. Brown. Oxidation kinetics of biochar from woody and herbaceous biomass. Chemical Engineering Journal 2020, 401, 126043 .

AMA Style

Chad A. Peterson, Robert C. Brown. Oxidation kinetics of biochar from woody and herbaceous biomass. Chemical Engineering Journal. 2020; 401 ():126043.

Chicago/Turabian Style

Chad A. Peterson; Robert C. Brown. 2020. "Oxidation kinetics of biochar from woody and herbaceous biomass." Chemical Engineering Journal 401, no. : 126043.

Preprint
Published: 07 June 2020
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Hydrogen sulfide and ammonia are always a concern in the livestock industries, especially when farmers try to clear their manure storage pits. Agitation of manure can cause dangerously high concentrations of harmful agents such as H2S and NH3 to be emitted into the air. Biochar has the ability to sorb these gases. We hypothesized that applying biochar on top of manure can create an effective barrier to protect farmers and animals from exposure to NH3 and H2S. In this study, two kinds of biochar were tested, highly alkaline, and porous (HAP, pH 9.2) biochar made from corn stover and red oak biochar (RO, pH 7.5). Two scenarios of (6 mm) 0.25” and (12 mm) 0.5” thick layers of biochar treatments were topically applied to the manure and tested on a pilot-scale setup, simulating a deep pit storage. Each setup experienced 3-min of agitation using a transfer pump, and measurements of the concentrations of NH3 and H2S were taken in real-time and measured until the concentration stabilized after the sharp increase in concentration due to agitation. The results were compared with the control in the following 3 situations: 1. The maximum (peak) flux 2. Total emission from the start of agitation until the concentration stabilized, and 3. The total emission during the 3 min of agitation. For NH3, 0.5” HAP biochar treatment significantly (p<0.05) reduced maximum flux by 63.3%, overall total emission by 70%, and total emissions during the 3-min agitation by 85.2%; 0.25” HAP biochar treatment significantly (p<0.05) reduced maximum flux by 75.7%, overall, total emission by 74.5%, and total emissions during the 3-min agitation by 77.8%. 0.5” RO biochar treatment significantly reduced max by 8.8%, overall total emission by 52.9%, and total emission during 3-min agitation by 56.8%; 0.25” RO biochar treatment significantly reduced max by 61.3%, overall total emission by 86.1%, and total emission during 3-min agitation by 62.7%. For H2S, 0.5” HAP biochar treatment reduced the max by 42.5% (p=0.125), overall total emission by 17.9% (p=0.290), and significantly reduced the total emission during 3-min agitation by 70.4%; 0.25” HAP treatment reduced max by 60.6% (p=0.058), and significantly reduced overall and 3-min agitation’s total emission by 64.4% and 66.6%, respectively. 0.5” RO biochar treatment reduce the max flux by 23.6% (p=0.145), and significantly reduced overall and 3-min total emission by 39.3% and 62.4%, respectively; 0.25” RO treatment significantly reduced the max flux by 63%, overall total emission by 84.7%, and total emission during 3-min agitation by 67.4%.

ACS Style

Baitong Chen; Jacek A. Koziel; Myeongseong Lee; Hantian Ma; Zhanibek Meiirkhanuly; Peiyang Li; Andrzej Białowiec; Robert C. Brown. Can Biochar Save Lives? The Impact of Surficial Biochar Treatment on Acute H2S and NH3 Emissions During Swine Manure Agitation Before Pump-out. 2020, 1 .

AMA Style

Baitong Chen, Jacek A. Koziel, Myeongseong Lee, Hantian Ma, Zhanibek Meiirkhanuly, Peiyang Li, Andrzej Białowiec, Robert C. Brown. Can Biochar Save Lives? The Impact of Surficial Biochar Treatment on Acute H2S and NH3 Emissions During Swine Manure Agitation Before Pump-out. . 2020; ():1.

Chicago/Turabian Style

Baitong Chen; Jacek A. Koziel; Myeongseong Lee; Hantian Ma; Zhanibek Meiirkhanuly; Peiyang Li; Andrzej Białowiec; Robert C. Brown. 2020. "Can Biochar Save Lives? The Impact of Surficial Biochar Treatment on Acute H2S and NH3 Emissions During Swine Manure Agitation Before Pump-out." , no. : 1.

Journal article
Published: 20 May 2020 in Journal of Analytical and Applied Pyrolysis
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Fast pyrolysis is traditionally defined as the rapid decomposition of organic material in the absence of oxygen to produce primarily a liquid product known as bio-oil. However, the introduction of small amounts of oxygen to the process holds prospects of internally generating the energy needed for pyrolysis. The present study investigates the partial oxidation of lignin-derived compounds during pyrolysis, which generates both carbon oxides and aromatic carbonyl compounds. Analysis of lignin derived phenolic compounds was performed to determine if the composition had changed under oxidative conditions. NMR analyses indicates aromatic carbonyls increased under oxidative conditions, with a corresponding decrease in phenolic hydroxyl groups. Model phenolic compounds were pyrolyzed to help understand the role of partial oxidation during autothermal pyrolysis of lignocellulosic biomass.

ACS Style

Chad A. Peterson; Jake K. Lindstrom; Joseph P. Polin; Sarah D. Cady; Robert C. Brown. Oxidation of phenolic compounds during autothermal pyrolysis of lignocellulose. Journal of Analytical and Applied Pyrolysis 2020, 149, 104853 .

AMA Style

Chad A. Peterson, Jake K. Lindstrom, Joseph P. Polin, Sarah D. Cady, Robert C. Brown. Oxidation of phenolic compounds during autothermal pyrolysis of lignocellulose. Journal of Analytical and Applied Pyrolysis. 2020; 149 ():104853.

Chicago/Turabian Style

Chad A. Peterson; Jake K. Lindstrom; Joseph P. Polin; Sarah D. Cady; Robert C. Brown. 2020. "Oxidation of phenolic compounds during autothermal pyrolysis of lignocellulose." Journal of Analytical and Applied Pyrolysis 149, no. : 104853.