Source: IOWA STATE UNIVERSITY submitted to
VALORIZATION OF BIOCHAR: APPLICATIONS IN ANAEROBIC DIGESTION, LIVESTOCK ODOR CONTROL AND PLANT GROWTH
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
NEW
Funding Source
Reporting Frequency
Annual
Accession No.
1016836
Grant No.
2018-10008-28616
Project No.
IOWW-2018-03697
Proposal No.
2018-03697
Multistate No.
(N/A)
Program Code
BRDI
Project Start Date
Sep 1, 2018
Project End Date
Aug 31, 2020
Grant Year
2018
Project Director
Brown, R. C.
Recipient Organization
IOWA STATE UNIVERSITY
2229 Lincoln Way
AMES,IA 50011
Performing Department
Department of Mechanical Engineering
Non Technical Summary
The goal of this project is to advance the economic prospects for pyrolysis-based biofuels by developing value-added applications for the co-product biochar. Researchers at Iowa State University (ISU) have developed a new approach to providing energy to pyrolyzers based on autothermal processing, which simplifies the design and operation of pyrolyzers and preserves biochar for applications other than heating the pyrolyzer. The high ash content and high porosity of biochar produced by autothermal pyrolysis of herbaceous biomass compared to biochar from conventional (oxygen-free) pyrolysis of woody biomass suggest its use in two immediate markets: enhancing anaerobic digestion (AD) of grassy feedstocks and livestock odor control (LOC). The mixture of digestate and spent biochar or composted manure and spent biochar from these two applications has potential as fertilizer. Specific objectives of the project include: (1) Produce high alkalinity/porosity (HAP) biochar through autothermal pyrolysis of herbaceous feedstocks such as perennial grasses; (2) Assess the utility of HAP biochar in improving the quality of biogas from AD of herbaceous biomass; (3) Assess the utility of HAP biochar for LOC; (4) Assess the utility of HAP biochar to improve performance of AD digestate and composted manure as a fertilizer and to lower NH3 discharge from animal feeding operations; and (5) Determine how valorizing biochar affects the economic, environmental and societal impacts of pyrolysis-based biofuels. The objectives will be pursued through a combination of bench-scale and pilot-scale pyrolysis, AD and LOC experiments and technoeconomic and life cycle analyses over two years. The project will be managed and administered by ISU's Bioeconomy Institute (BEI), which has extensive experience in managing collaborative, multi-investigator federally funded projects. Collaborating organizations include Argonne National Laboratory and Roeslein Alternative Energy.
Animal Health Component
0%
Research Effort Categories
Basic
(N/A)
Applied
100%
Developmental
(N/A)
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
40217992020100%
Knowledge Area
402 - Engineering Systems and Equipment;

Subject Of Investigation
1799 - Fiber crops, general/other;

Field Of Science
2020 - Engineering;
Goals / Objectives
The goal of this project is to advance the economic prospects for advanced biofuels from the pyrolysis of herbaceous biomass by creating high-value markets for biochar (a co-product of pyrolysis) for: 1) livestock odor control; 2) improved performance of anaerobic digestion and composted manure fertilizers from anaerobic digestion; and, 3) minimized NH3 discharge from animal feeding operations. Specific objectives include:Produce biochar with high alkalinity and porosity through autothermal pyrolysis of herbaceous feedstocks such as perennial grasses;Assess the utility of the biochar in improving the quality of biogas from anaerobic digestion of herbaceous biomass;Assess the utility of the biochar for livestock odor control;Assess the utility of the biochar to improve performance of digestate from anaerobic digestion and composted manure as a fertilizer and to lower NH3 discharge from animal feeding operations;Determine how increasing the market value of biochar affects the economic, environmental and societal impacts of pyrolysis-based biofuels.
Project Methods
Task 1. Production of HAP biochar via autothermal pyrolysis: Biochar will be produced from bales of prairie grass provided by Roeslein Alternative Energy (RAE). Two autothermal pyrolyzers will be used. The 8 kg/h system will produce kilogram quantities of biochar for bench-scale studies with the goal of optimizing HAP biochar for the three applications being investigated. The 45 kg/h system will produce hundreds of kilogram quantities of biochar for pilot-scale studies. Milestones: Produce HAP biochar with alkalinity and porosity suitable for AD and LOC applications (Qtr 3); Produce sufficient quantities of HAP biochar for field-scale trials (Qtr 7).Task 2. Characterization of HAP biochar: Particle size distribution of the biochar samples will be determined by sieving the pre-weighed (10 g) biochar using a micro sieve set (Scienceware, Wayne, NJ). Surface morphology and textural properties of the biochar will be characterized with an FEI Quanta 400F environmental scanning electron microscope (SEM) (FEI, Hillsboro, OR) operated at high vacuum mode at ambient temperature. Brunauer-Emmet-Teller (BET) surface area, total pore volume and pore size will be determined utilizing argon or nitrogen gas adsorption analysis at 77.35 K. The pH value of the biochar will be measured by mixing 5 g of biochar sample in 100 mL deionized water (Milli-Q, Millipore) stirred at 180 rpm for 24 h at room temperature. Proximate, ultimate and ash elemental analyses will be conducted in triplicate using ASTM methods. Milestones: Complete characterization of HAP biochar synthesized in Task 1 (Qtr 8); determine 2-3 HAP biochar candidates for evaluation in Task 3 (Qtr 2).Task 3. Laboratory-scale anaerobic digestion experiments with HAP biochar: Lab scale AD tests will be conducted in 500 milliliters digesters to evaluate the effects of biochar on AD process including: 1) different raw materials for the digestion (swine manure, fescue grass, prairie grass, mixed manure and fescue grass, and mixed manure with prairie grass); 2) different types of anaerobic digesters (CSTR vs plug flow); 3) water content of the digestion system (liquid AD vs solid AD) and 4) AD temperature (mesophilic, thermophilic, and temperature-phased). Milestones: Bench-scale AD produces biogas with CH4 content exceeding 90 vol% when digested in the presence of HAP biochar (Qtr 4); in the presence of HAP biochar, bench-scale AD achieves 20% reduction in H2S, NH3, and selected odorous VOCs when treating manure and manure-grass mixtures; and 50% reduction when treating grass samples, without a significant increase in GHGs emissions, at a cost that is less than 0.5% of market price of targeted livestock (Qtr 6).Task 4. Pilot-scale anaerobic digestion experiments with HAP biochar: Laboratory results will be scaled-up by Roeslein Alternative Energy (RAE) in a 500-gallon mesophilic AD pilot plant at its Ruckman Farm facility in northern Missouri. The manure substrate at 2% TS is fed into the first stage reactor which has a capacity of 120 gallons resulting in a hydraulic retention time (HRT) of seven days. The substrate is then fed from the first stage reactor to both second stage reactors in equal proportions, with one second stage reactor being used to evaluate the effects of adding biochar, and the other reactor used as a reference. The second stage reactors have a capacity of 275 gallons each, and an HRT of fourteen days. All reactors are submerged in a heated water bath that is temperature controlled at the mesophilic range. Biogas production rate and composition are measured by flow meter totalizers and gas analyzers. Milestones: Establish baseline performance for digestion of grassy feedstock (Qtr 5); Establish optimal operating conditions for AD with HAP biochar (Qtr 8).Task 5. Odor control experiments with HAP biochar: Laboratory scale odor control: A lab-scale apparatus will be used for testing the effects of HAP biochar dose and time on odor, NH3, H2S, key odorous VOCs responsible for downwind swine barn odor, and GHGs (CO2, CH4, N2O) on emissions from simulated swine manure storage treated surficially with HAP biochar. At least three doses and three trials will be conducted using the recent work with conventional biochar as an initial dose. Pilot-scale odor control: An existing pilot-scale setup will be used for testing the effects of surficial HAP biochar treatments on odor and gaseous emissions from simulated (100 L) swine manure storage as functions of dose and time. Milestone: 50% reduction in odor, H2S, NH3, and selected odorous VOCs from the use of HAP biochar without a significant increase in GHGs emissions, at a cost that is less than 0.5% of market price of targeted livestock (swine) (Qtr 8).Task 6. Nutrient recycling with spent biochar: Composting trials will be conducted at the labs-scale in a series of three runs using a randomized complete block design. Twenty-five pounds of compost mixture without biochar and then two mixtures with biochar (at rates of 5, based on dry mass, and 10%) will be created. Generated materials will be mixed, subsampled (analyzed for C, N, and P), and then mixtures placed into forced air, temperature controlled composting vessels. Airflow and CO2 content into and from each composter will be monitored continuously. Ammonia in the air stream will be monitored daily during initial phases of composting (1-2 weeks), two times per week thereafter. Compost will be turned as necessary at which time the mass, moisture content, and pH will be monitored. Chemical analysis and mass balance will be conducted to determine impact on composting kinetics, N loss, and value as a certified compost. Soil incubation and leaching studies will be conducted to evaluate how biochar addition rates to manures impacts N and P leaching as well as how it influences nutrient loss from composted digestate solids. Milestones: Achieve 50% reduction in NH3 loss during poultry composting and 30% reduction in volume of composted material (Qtr 8); Achieve a 70% separation of P and 40% separation of N from manure onto biochar with biochar recovery > 80% (Qtr 7); NO3-N losses reduced by 15% during first two weeks of incubation and by 5% after two months (Qtr 8).Task 7. LCA and TEA evaluations of biochar valorization: A baseline scenario, where biochar is marketed as low-value boiler fuel ($20/tonne), will be compared to an enterprise based on value-added applications of HAP biochar. Process profitability, environmental footprint, and social impacts will form the basis of the comparison. Process profitability will be measured in terms of its payback period, and 20-year net present value. Environmental impacts will be characterized by several midpoint categories including: climate change, human toxicity, ecotoxicity, land use, energy use (efficiency and petroleum displacement), particulate matter/respiratory inorganics and others. Social impacts will be evaluated in terms of job creation, labor income, value added, and economic output. Milestone: Design of an integrated HAP biochar and AD system with a 7-year payback period, net reduction in GHG emissions, and net increase in rural economic impacts developed (Qtr 8).Evaluation: Benchmarks will be established for each metric upon which milestones are based. Metrics by task are: 1) Yield of HAP biochar from autothermal pyrolysis of grassy biomass; 2) Alkaline content and porosity of HAP biochar; 3) Concentration of CH4 and H2S in raw biogas from laboratory-scale AD tests; 4) Concentration of CH4 and H2S in raw biogas from pilot-scale AD tests; 5) Gas concentrations (ppm) and emissions rates for H2S, NH3, and selected odorous VOCs; 6) N loss from biochar amended compost; economic value of compost; N loss from soil applied compost; 7) Costs of renewable natural gas ($/MMBtu) and livestock odor mitigation (% market price of livestock).

Progress 09/01/18 to 08/31/19

Outputs
Target Audience:Audiences at technical conferences, including the International Biochar Initative in Ft. Collins, CO. The technical conference audiences include USDA technical and administrative representatives, researchers from universities and non-profits, company R&D and business development personnel, farmers and agricultural trade and commodity groups. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?This project provides graduate and undergraduate students an opportunity to work in the area of chemical, agricultural and biological engineering. Graduate students are expected to conduct experiments and present results in written reports and oral presentation. They receive training on experimental design, data collection and analysis, as well as environmental monitoring. Graduate students and post docs will also have opportunities to prepare manuscripts for technical journals and present at technical conferences attended by universities, federal agencies including the USDA, and companies. Undergraduate students were involved in data collection and utilization and received training on measurement methods, soil analysis, and water analysis. An international student (Zhanibek Meiirkhanuly) was trained to work in this project, graduated and received his M.S. degree Environmental Science at Iowa State University in August 2019. How have the results been disseminated to communities of interest?Objective 1. An oral presentation has been presented at the Biochar & Bioenergy annual conference in 2019. Another oral presentation will be presented at the American Chemical Society Spring meeting in 2020. A scientific journal publication is under preparation for submission in early 2020. Objective 2. A manuscript was published in Water. Additional manuscripts focused on the effect of biochar addition on pH in the air-manure interface is in preparation. Objective 3. A manuscript is being completed and is nearly ready for submission. Objective 4. A manuscript is in preparation for Transactions of the ASABE. Objective 5. A scientific journal publication is under preparation for submission in 2019. A poster and oral presentation are planned for delivery in 2020. What do you plan to do during the next reporting period to accomplish the goals?Objective 1. Efficacy of the FeSO4 impregnated biochar towards phosphate recycling using both agricultural and industrial effluents by performing benchtop leaching trials. Objective 2. Year 2 pilot-scale evaluation of the effects of HAP biochar dose and time on odor, NH3, H2S, key odorous VOCs responsible for downwind swine barn odor, and GHGs (CO2, CH4, N2O) on emissions from simulated swine manure storage treated with a surficial application of biochar. Objective 3. AD of the fibrous feedstock materials (grasses): The fescue grass, prairie grass, and mixtures of manure and these grasses will be used as feedstock for AD. A CSTR will be used for digesting grasses, while a plug flow reactor (PFR) will be used to digest the manure/grass mixtures due to the difficulty of processing these heterogeneous mixtures in CSTRs. AD will be performed in both liquid (>85% moisture content) and solid (<85% moisture content) phases to accommodate the nature of grassy biomass. In addition to mesophilic AD, we will also use a temperature-phase method, i.e., thermophilic stage first to hydrolyze the recalcitrant fiber and produce volatile fatty acid, followed by the mesophilic stage for the CH4 production, to treat the materials with efficient raw material degradation and process stability. Objective 4. A follow up experiment is being conducted to evaluate the impact of biochar addition rate to both swine manure and poultry manure. We developed and refined our methodology for composting analysis and plan to evaluate how adding biochar to compost impacts both compost processes and ammonia loss of bedded pack cattle manure and herbaceous material separated from anaerobic digesters. Objective 5. Process models will be updated with experimental data gathered from the project. Economic assumptions will be updated when the model is modified to account for new performance metrics. Process design will be optimized to minimize costs. Lifecycle analysis results will be updated when the model is modified to account for new performance metrics. Process design will be optimized to minimize environmental impacts.

Impacts
What was accomplished under these goals? Objective 1. Biochar Production Autothermal (air-blown) pyrolysis of ferrous sulfate treated corn stover was carried out to produce FeSO4 impregnated biochar. Autothermal pyrolysis of untreated corn stover was conducted to produce control biochar (CS-control). Characteristics of these biochars are shown in Table 1. Phosphate sorption tests in solution with 0, 100, 400, 1000 and 4000 mg L-1 phosphate concentration at 48 hours with solid loading of 5 g/L and pH 7.5-8.2 were conducted. Phosphate sorption capacity of CS-FeSO4 biochar was 88.7 mg of phosphate per g biochar. Phosphate sorption capacity of CS-control biochar was only 59.8 mg of phosphate per g biochar. Desorption isotherms with three washings of water and Mehlich-III solution were done to test release of phosphate from the biochar. Desorption rates for CS-control biochar in water and Mehlich-III solution were 52.28% and 69.48%, respectively. Desorption rates for ferrous sulfate treated corn stover biochar were 15.15% and 26.19% in water and Mehlich-III solution, respectively. The combination of autothermal pyrolysis and ferrous sulfate treatment dramatically increases phosphate sorption capacity, and dramatically decreases desorption rates. Table 1: Biochar properties Figure 1: Phosphate sorption and desorption data of (a) biochar from untreated corn stover and (b) biochar from ferrous sulfate treated corn stover. Blue - water desorption; Gray - Mehlich-III desorption. Numbers in the dark portion of each bar represent the % phosphate desorbed. The number below each bar (PO43- aq mg L-1) is the phospate concentration remaining in the aqueous phase. The number above each bar (PO43- ads mg g-1) indicates indicates concentration of adsorbed phosphate. The four pairs of bars in each chart from L-R are results from 0, 100, 400, 1000 and 4000 mg L-1 phosphate-concentrated solutions. Objective 2. Biochar amended anaerobic digestion Anaerobic digestions (AD) experiments were conducted using municipal sludge. A control group (A0) without biochar addition and groups amended with biochar from untreated corn stover (A1), and biochar from sulfuric acid treated corn stover (A2) at three different dosages (L, M, and H) were investigated. The three dosages of biochar from low to high included 3.6g/g TSsludge (L), 7.2 g/g TSsludge (M) and 15 g/g TSsludge (H). Each digester contained inoculum (0.44g TS), sludge (0.36g TS), biochar (varies) and deionized (DI) water to total 80mL. Each condition was conducted in duplicate. Fig. 2 shows the time course of cumulative biogas production, cumulative methane production and daily methane content. Untreated corn stover biochar addition increased cumulative biogas and methane production proportional to biochar dosages. Sulfuric acid treated corn stover biochar increased the biogas production (Fig. 2B) but only significantly (p<0.05) with high dosage (A2-H). All of the three dosages resulted in significant higher methane production than that of the control group A0 (p<0.05). Contrary to the trend of biogas production in Fig. 2B, addition of sulfuric acid treated corn stover biochar decreased the methane production. Figure 2. Time-course profiles of AD experiments. Cumulative biogas production with: (A) untreated corn stover biochar; (B) sulfuric acid treated corn stover biochar. Cumulative methane production with: (C) untreated corn stover biochar; (D) sulfuric acid treated corn stover biochar. Methane content with: (E) untreated corn stover biochar; (F) sulfuric acid treated corn stover biochar. Objective 3. Livestock odor control Experiments to study biochar pH impact on the liquid-air interface were completed. Small doses of biochar were surficially-applied on water and swine manure to study the temporal and spatial (with depth) changes that regulate emissions of pH-sensitive odorous compounds from liquid to air. The impact of HAP corn stover biochar (pH 9.2) was compared with red oak (RO) biochar (pH 7.5). Both experiments showed OH- ions from biochar gradual movement from the surface into the water and manure. Both experiments support the hypothesis that biochar pH can be used to control the odorous compound emissions by buffering the H+/OH- ion concentrations. Table 2. Physicochemical properties of two manures sourced from a lagoon and pit used in this experiment. Lab-scale experiments were completed to evaluate the impact of HAP and RO biochar surficial application on mitigation of NH3, H2S, odorous VOCs and GHGs (CO2, CH4, N2O) emissions from swine manure. Both biochars showed the highest reduction of NH3 emissions on the day after application. Surficial biochar addition to manure reduced odorous VOCs emission up to 90% depending on the type of manure. Biochar application reduced the CH4 emission for the first two weeks after the surficial application then enhanced the CH4 emissions compared to untreated manure. High ash content and porosity is likely reducing the biochar floatability and therefore its ability to control the odorous compounds and their emissions in the long term. Green font represents significant reduction vs. control. Red font represents significant increase vs. control. Table 3. Efficacy of surficially-applied HAP biochar in mitigating NH3 emissions (mg/h/m2) from swine manure (lab-scale trials). Table 4. Efficacy of surficially-applied HAP biochar in mitigating H2S emission emissions (mg/h/m2) from swine manure (lab-scale trials). Table 5. Efficacy of HAP biochar in mitigating CH4 emission flux (mg/h/m2) from swine manure (lab-scale trials). Table 6. Efficacy of HAP biochar in mitigating odor emission (OUe.m-3) from swine manure Table 7. Efficacy of HAP biochar in mitigating odorous VOC emissions from manure over three lab-scale trials. Objective 4. Biochar amended digestate and manure composting The relationship between biochar and liquid swine manure application and its effect on total nitrogen loss was investigated. For eight weeks, soil columns were leached to determine total NO3-N loss of soil alone, biochar amended soil, swine manure, and a combination of biochar and swine manure. In this study, it was determined that swine manure increased the amount of nitrogen lost from the soil, the addition of biochar to swine manure treated soil decreased total nitrate loss. It is suggested that biochar has the ability to increase water and nutrient retention, reducing the risk of nitrogen loss. Figure 3: Cumulative Nitrate Loss by Treatment; Shared letters show no significant difference. Figure 4: Progressive Nitrate Loss by Treatment; Shared letters show no significant difference. Objective 5. Economic analysis and life cycle assessment Aspen PlusTM process models have been developed simulating gasoline and power production via pyrolysis-hydroprocessing-anaerobic digestion (Scenario I), and ethanol and power production via pyrolysis-fermentation-anaerobic digestion (Scenario II). Both scenarios assume conversion of 2000 metric tonnes per day of corn stover and 430 dry tonnes per day of manure to liquid transportation fuels, electricity, phenolic compounds, and biochar products. Total capital costs were estimated at $642 and $719 million for the gasoline and ethanol production scenarios, respectively. Preliminary minimum fuel selling prices for scenarios I and II were $2.71 per gallon and $2.31 per gallon (or $3.46 per gallons of gasoline equivalent). Corn stover and return on investment (ROI) contributed the most towards the MFSP in both scenarios. Preliminary life cycle analysis results showed negative greenhouse gas emissions for both scenarios. Life cycle emissions were estimated at -9.6 gm CO2,eqv. /MJ for scenario I and -80 gm CO2,eqv. /MJ for scenario II. Figure5. Cornstoverfast pyrolysis to gasoline or ethanol and manure anaerobic digestion to power Table 8:Comparison of gasoline and ethanol production scenario costs, fuel yield, minimum fuel-selling price, and greenhouse gas emissions GGE: gallons of gasoline equivalent

Publications

  • Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Bakshi, S.; Gable, P.; Brown, R. C., 2018. Phosphate sorption onto modified biochar surface. Biochar & Bioenergy, International Biochar Initiative, Fort Collins, CO, June 30-July 3, 2019 (Oral presentation).
  • Type: Journal Articles Status: Published Year Published: 2019 Citation: Meiirkhanuly, Z., J.A. Koziel, C. Banik, A. Bialowiec, R. Brown. 2019, The-proof-of-concept of biochar floating cover influence on water pH. Water, 11(9), 1802; doi: 10.3390/w11091802.