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What are the different types of gasification systems for generating energy from manure?


Gasification Systems Requiring Relatively Dry Biomass

Fixed Bed Gasifier

Fixed Bed types produce low Btu gases and can use updraft or downdraft approaches. The updraft pulls hot air up from the bottom through the fuel where pyrolysis (decomposition of organics by heat in the absence of oxygen) occurs first, followed by reduction and oxidation. The syngas is not considered “clean” because it contains tars, un-combusted solids, and moisture. An advantage of updraft systems is that they are very scalable; they can be made for small or large systems. Downdraft gasifiers differ in that the oxidation step occurs after pyrolysis. This sequence creates a system where the char filters the gas. This is also a very scalable system that produces clean gas that can go right into a pipeline. A disadvantage in manure management is that manure needs to be pelletized which greatly increases the cost of using a downdraft system.

Fluidized Bed Gasifier

Fluidized bed gasifiers produce a more energy-dense syngas than fixed bed systems. A fluidized bed consists of heated inert materials through which combustion air rises upward and creates a mass of suspended solids through which the fuel can intermingle. When the temperature is high enough, the gasification reaction occurs. These systems are generally more complex than fixed bed systems and require more careful attention to operation and maintenance.

Gasification Systems That Can Process Relatively Wet Biomass

Catalytic Wet Gasification or Hydrothermal Gasification

One of the areas of great interest and research in research years is in developing gasification system that can handle wet biomass, such as raw pig manure, algal biomass, or municipal sewage. These systems require a metallic catalyst and are referred to as catalytic wet gasification or hydrothermal gasification. In addition to a high-energy syngas, this system also produces ammonia, which can be recovered and utilized as a crop fertilizer. These systems require efficient heat-recovery components and monitoring for potential catalyst-poisoning materials (especially sulfur-containing compounds) for optimum performance.

To see an example of current research in this area, visit: auger reactor gasification

For more information:

Acknowledgements

Author: Jill Heemstra, University of Nebraska jheemstra@unl.edu

This information is part of the program “Integrated Resource Management Tool to Mitigate the Carbon Footprint of Swine Produced In the U.S.,” and is supported by Agriculture and Food Research Initiative Competitive Grant no. 2011-68002-30208 from the USDA National Institute of Food and Agriculture. Project website.

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What Is Gasification of Manure?

green stylized pig logoWhen looking at ways to improve the environmental impact of pig production, renewable energy generation is a popular topic. One such technology, gasification, is a series of chemical reactions (see image at bottom) that involve heating a suitable organic material in a controlled, low-oxygen environment to the point that the hydrocarbons (simple organic compounds that contain only hydrogen and carbon) are converted to synthesis gas (‘syngas’). Syngas is composed of hydrogen and carbon monoxide with smaller amounts of methane and carbon dioxide, all of which can be collected and utilized for heat and energy generation.

This manure treatment technology also produces mineral-rich bio-char and ash. Since this bio-char is less bulky than raw manure (and contains most, if not all, of the nutrients) it is much easier to handle and more cost effective to transport long distances. This can be beneficial in areas where nutrients are becoming concentrated on crop fields and contributing to water quality problems. The use of bio-char as a topically applied  soil amendment is currently being  explored for its potential at reducing ionization and thus aiding in the retention of nutrients by impeding chemical transformations and volatilization.

a two ton per hour fluidized bed biomass gasifierMany different organic materials can be used in gasification; wood, plant residues, certain types of manufacturing or household waste, and manure, among other biomass sources. Standard gasification systems utilizes materials that are dry (not pump-able) like beef feedlot manure, poultry litter, or manure that has undergone solids separation. Pig or dairy cattle manure tends to be a wet material and either require drying or a system designed to handle materials like these – wet gasification systems.  Related: Different types of manure gasification systems.

For more information:

chemical representing thermochemical conversion of manure to energy and other products

Image above provided by Dr. Samy Sadaka, University of Arkansas

Authors: Rick Fields, University of Arkansas and Jill Heemstra, University of Nebraska jheemstra@unl.edu

Acknowledgements

This information is part of the program “Integrated Resource Management Tool to Mitigate the Carbon Footprint of Swine Produced In the U.S.,” and is supported by Agriculture and Food Research Initiative Competitive Grant no. 2011-68002-30208 from the USDA National Institute of Food and Agriculture. Project website.

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Farm Manure-to-Energy Initiative in the Chesapeake Region Report January 2016

From 2012-2015, the Farm Manure-to-Energy Initiative conducted a study of thermal, farm-scale systems that produce energy from poultry litter. The technologies were installed on working farms in the Chesapeake region, in places where manure management is especially important for protecting water quality. The technologies were evaluated for technical, environmental, and financial performance. This report details the findings.

Download the full report and appendices. (252 pages; PDF)

Download a section of the report:

  1. Executive Summary (6 pages)
  2. Main Body of the Report (26 pages)
  • Background and Objectives
  • Process: Getting Projects on the Ground
  • Performance Evaluation
  • Summary of Results
  • Fertility Value and Market Potential of Poultry Litter Co-Products
  • Summary of Lessons Learned
  • Communicating Results
  • Summary and Next Steps
  1. Appendix A: Technical Performance Global Re-Fuel
  2. Appendix B: Technical Performance Ecoremedy ® Gasifier
  3. Appendix C: Technical Performance LEI Bio-Burner 500
  4. Appendix D: Technical Performance Total Energy Blue Flame Boiler
  5. Appendix E: Air Emissions and Permit Compliance
  6. Appendix F: Nutrient Availability from Poultry Litter Co-Products
  7. Appendix G: Nutrient Balance: Fate of Nitrogen and Phosphorus Nutrients
  8. Appendix H: Financial Assessment of the Farm Manure-to-Energy Initiative
  9. Appendix I: North Carolina State University’s Pyrolysis Technology
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Thermal-Chemical Conversion of Animal Manures – Another Tool for the Toolbox


How Can Thermo-Chemical Technologies Assist in Nutrient Management?

Livestock operations continue to expand and concentrate in certain parts of the country. This has created regional “hot spot” areas in which excess nutrients, particularly phosphorus, are produced. This nutrient issue has resulted in water quality concerns across the country and even lead to the necessity of a “watershed diet” for the Chesapeake Bay Watershed. To help address this nutrient concern some livestock producers are looking to manure gasification and other thermo-chemical processes. There are several thermo-chemical conversion configurations, and the one chosen for a particular livestock operation is dependent on the desired application and final by-products. Through these thermo-chemical processes manure Factory processingvolumes are significantly reduced. With the nutrients being concentrated, they are more easily handled and can be transported from areas of high nutrient loads to regions of low nutrient loads at a lower cost. This practice can also help to reduce the on-farm energy costs by providing supplemental energy and/or heat. Additional benefits include pathogen destruction and odor reduction. This presentation will provide an overview of several Conservation Innovation Grants (CIG) and other manure thermo-chemical conversion projects that are being demonstrated and/or in commercial operation. Information will cover nutrient fate, emission studies, by-product applications along with some of the positives and negatives related to thermo-chemical conversion systems.

Exterior of factory processingWhat did we do? 

Several farm-scale manure-to-energy demonstration projects are underway within the Chesapeake Bay Watershed. Many of these receive funding through the USDA-NRCS Conservation Innovation Grant program. These projects, located on poultry farms, are being evaluated for the performance of on-farm thermal conversion technologies. Monitoring data is being collected for each project which includes: technical performance, operation and maintenance, air emissions, and by-product uses and potential markets. Performance of manure gasification systems for non-poultry operations have also been reviewed and evaluated. A clearinghouse website for thermal manure-to-energy processes has been developed.

What have we learned? 

The projects have shown that poultry litter can be used as a fuel source, but operation and maintenance issues can impact the performance and longevity of a thermal conversion system. These systems are still in the early stages of commercialization and modifications are likely as lessons are learned. Preliminary air emission data shows that most of the nitrogen in the poultry litter is converted to a non-reactive form. The other primary nutrients, phosphorus and potassium, are preserved in the ash or biochar co-products. Plant availability of nutrients in the ash or biochar varies between the different thermal conversion processes and ranges from 80 to 100 percent. The significant volume reduction and nutrient concentration show that thermal conversion processes can be effective in reducing water quality issues by lowering transportation and land application costs of excess manure phosphorus.

Future Plans    

Monitoring will continue for the existing demonstration projects. Based on the lessons learned, additional demonstration sites will be pursued. As more manure-to-energy systems come on-line the clearinghouse will be updated. Based on data collected, NRCS conservation practice standards will be generated or updated as necessary.

Author       

Jeffrey P. Porter, PE, Manure Management Team Leader, USDA-Natural Resources Conservation Service jeffrey.porter@gnb.usda.gov

Additional information                

Thermal manure-to-energy clearinghouse website: http://lpelc.org/thermal-manure-to-energy-systems-for-farms/

Environmental Finance Center review of financing options for on-farm manure-to-energy including cost share funding contact information in the Chesapeake Bay region: http://efc.umd.edu/assets/m2e_ft_9-11-12_edited.pdf

Sustainable Chesapeake: http://www.susches.org

Farm Pilot Project Coordination: http://www.fppcinc.org

National Fish and Wildlife Foundation, Chesapeake Bay Stewardship Fund: http://www.nfwf.org/chesapeake/Pages/home.aspx

Acknowledgements

National Fish and Wildlife Foundation, Chesapeake Bay Funders Network, Farm Pilot Project Coordination, Inc., Sustainable Chesapeake, Flintrock Farm, Mark Weaver Farm, Mark Rohrer Farm, Riverview Farm, Wayne Combustion, Enginuity Energy, Coaltec Energy, Agricultural Waste Solutions, University of Maryland Center for Environmental Science, Environmental Finance Center, Virginia Cooperative Extension, Lancaster County Conservation District, Virginia Tech Eastern Shore Agricultural Research and Extension Center, Eastern Shore Resource Conservation and Development Council, with funding from the USDA Conservation Innovation Grant Program and the U.S. EPA Innovative Nutrient and Sediment Reduction Program.

The authors are solely responsible for the content of these proceedings. The technical information does not necessarily reflect the official position of the sponsoring agencies or institutions represented by planning committee members, and inclusion and distribution herein does not constitute an endorsement of views expressed by the same. Printed materials included herein are not refereed publications. Citations should appear as follows. EXAMPLE: Authors. 2015. Title of presentation. Waste to Worth: Spreading Science and Solutions. Seattle, WA. March 31-April 3, 2015. URL of this page. Accessed on: today’s date.

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Ecoremedy Gasifier on Flintrock Farm, Lancaster County, Pennsylvania

The Technology

The Ecoremedy gasifier ® by Enginuity Energy was installed on Flintrock Farm in Lancaster County, PA, in 2014 as a demonstration project for the Farm Manure-to-Energy Initiative.

The gasifier is a fixed feed rate, chain-grate, air-blown system that uses poultry litter as a fuel. The system is designed to deliver between 0.8 and 1.2 MBtu/hr of heat via hot water to four poultry houses. Syngas generated from the gasification process enters a separate oxidation chamber where it is combusted and delivered to a boiler and used to heat water that is delivered to the poultry houses via a Landmeco hydronic heating system.

The Farm

Flintrock Farm has been in Dan Heller’s family since the 1940s. The 80-acre farm now includes 12 poultry houses with capacity for 330,000 birds. Mr. Heller was one of six poultry producers to receive the 2012 Family Farm Environmental Excellence Award from the U.S. Poultry & Egg Association.

Performance Evaluation

The Ecoremedy gasifier was evaluated for technical, environmental, and financial performance. An overview of the findings is available in the main body of the 2016 Final Report. Details are in Appendix B.

The report includes an evaluation of air emissions from this and other systems, as well as the potential for transporting and marketing the ash co-product as a crop fertilizer.

Related: Introduction to Thermal Technologies…

More Manure-Based Energy Case Studies

Farm Manure Energy Initiative logoThis case study was funded by the National Fish and Wildlife Foundation (NFWF), the USDA, U.S. EPA, and Chesapeake Bay Funders Network. The views and conclusions contained in materials related to the Farm Manure-to-Energy Initiative are those of the authors and should not be interpreted as representing the opinions or policies of NFWF, the USDA, U.S. EPA, or Chesapeake Bay Funders Network. Mention of trade names or commercial products does not constitute endorsement by project funders.

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Thermal Manure-to-Energy Systems for Farms

Using manure to generate energy is growing in popularity. Explore the topics below to learn more.

  1. Introduction to Thermal Technologies for Generating Energy from Manure (Combustion, Pyrolysis, Gasification)
  2. Benefits & Challenges of Manure-Based Energy
  3. Farm Manure-to-Energy Case Studies
  4. Start-Up Questions and Considerations (What should I know or ask before pursuing manure-to-energy technologies for my farm?)
  5. Additional Resources on Manure-to-Energy Technologies
Manure-to-Energy in the Chesapeake Region 2016 REPORT

Farm Manure Energy Initiative logoPortions of this information were funded by the National Fish and Wildlife Foundation (NFWF), the USDA, U.S. EPA, and Chesapeake Bay Funders Network. The views and conclusions contained in materials related to the Farm Manure-to-Energy Initiative are those of the authors and should not be interpreted as representing the opinions or policies of NFWF, the USDA, U.S. EPA, or Chesapeake Bay Funders Network. Mention of trade names or commercial products does not constitute endorsement by project funders.

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Introduction to Thermal Technologies for Generating Energy from Manure

Manure-to-Energy home | Case Studies | Start-Up | More…

There are two general methods for producing energy from manure: the use of heat and the use of bacteria. This page is focused on the use of heat – specifically, on relatively small thermal systems that can be used on a farm to produce energy from excess poultry litter or manure.

temperature and oxygen levels for thermal technologiesThe use of bacteria to produce energy from manure is called anaerobic digestion. For more information about anaerobic digestion, explore Anaerobic Digestion and Biogas. Related: Treatment Technologies for Manure

Types of Thermal Energy Production for Farm-Scale Systems

In scientific terms, the use of heat to produce energy from manure is a thermochemical process. Thermal systems are well-suited for manure that is relatively dry, such as poultry litter, because there is less need to dry out the manure prior to processing.

Thermal processes that can convert animal manure into fuel include pyrolysis, gasification, and combustion. These processes differ with respect to temperature and oxygen concentrations, but each converts solid material into combustible, gaseous components, which then creates a hot flue gas. The flue gas is directed through a heat exchanger where heat is captured and moved through a distribution system for use in the poultry houses.

Thermal processes also produce a range of potentially valuable co-products including liquid bio-oils, diesel fuel, and combustible gases. They also produce nutrient-dense products like ash and bio-charcoal (commonly referred to as “biochar”). The concentration of nutrients varies depending on the process, operating parameters, and system design.

Fate of Manure Nutrients in Thermal Energy Systems

In thermal systems, almost all of the phosphorus and potash are conserved in the ash or biochar. While biochar retains some nitrogen associated with organic carbon, much of the nitrogen from these systems is lost in atmospheric emissions. Most is released to the atmosphere in the form of non-reactive nitrogen gas, or N2. Reactive forms of nitrogen may also be released, including oxides of nitrogen (NOx) and ammonia (NH3).

The concentration of phosphorus in the ash or biochar provides a way to transport excess nutrients to phosphorus-deficient regions where the ash or biochar can be used as a fertilizer to replace inorganic, mined phosphorus. Reactive nitrogen, on the other hand, is largely lost from agricultural production. Biochar retains some nitrogen, while systems that produce ash (like gasification and combustion) generally convert almost all of the nitrogen to atmospheric emissions. Given that land application of poultry litter and manure can result in atmospheric emissions of far greater amounts of reactive nitrogen (from 50 to 90 percent of ammonia-nitrogen for surface-applied manure), well-designed thermal manure-to-energy systems can reduce overall atmospheric emissions of reactive nitrogen.

Environmental Impacts

Thermal manure-to-energy systems can help address nutrient imbalances in high-density animal production areas, but it is important to use clean technologies with low emissions in order to avoid transferring a surface and groundwater problem to the atmosphere.

Technologies evaluated by the Farm Manure-to-Energy Initiative resulted in atmospheric reactive nitrogen emissions that were generally better than or, at the very least, similar to land application of poultry litter that is immediately incorporated, a strategy recommended to reduce ammonia emissions.

equipmentequipment

Thermal manure-to-energy systems, like the examples shown here, use heat to produce energy from manure.

However, the Farm Manure-to-Energy Initiative project identified particulate matter as a pollutant of concern for some thermal manure-to-energy technologies. At high temperatures typical of gasification and combustion, potash (which is abundant in poultry litter) volatilizes and can produce fine particulate matter in the form of potassium chloride or potassium sulfates. While some technologies have achieved low particulate matter emissions, others need additional work before they will be eligible for installation in states that set strict limits for particulate matter emissions.

Depending on the location and the size of the installation, emissions of particulate matter and NOx are often a consideration for air permitting. Data on other criteria and hazardous air pollutants associated with the proposed technology may also be required. To learn more about air permitting associated with thermal energy production, see Start-Up Questions and Considerations.

Components of a Farm-Scale System

Thermal systems are adaptable to different scales, but the technologies vary widely in their design, effectiveness, and cost. Most are still in the early phases of commercial development, and many are still in the research and development phase.

Thermal, farm-scale systems typically include some combination of the following components. Each configuration differs depending on the vendor’s technology and the specific goals and needs of the farm where the system is installed:

    • Covered manure storage area
    • Feed hopper and conveyor belt
    • Thermal manure-to-energy unit (combustion, gasification, or pyrolysis)
    • Heat exchanger or boiler
    • Heat distribution unit (ductwork or piping)
    • Emissions control unit
    • Ash or bio-char collection unit

The Farm Manure-to-Energy Initiative conducted several case studies between 2012-2015 to document the performance of farm-scale systems in the Chesapeake region.

More Resources on Thermal Technologies

Farm Manure Energy Initiative logoDevelopment of this information were funded by the National Fish and Wildlife Foundation (NFWF), the USDA, U.S. EPA, and Chesapeake Bay Funders Network. The views and conclusions contained in materials related to the Farm Manure-to-Energy Initiative are those of the authors and should not be interpreted as representing the opinions or policies of NFWF, the USDA, U.S. EPA, or Chesapeake Bay Funders Network. Mention of trade names or commercial products does not constitute endorsement by project funders.

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Agronomic and Environmental Uses of Biochar (Part 2)

Technologies to treat animal manure are rapidly gaining more traction as producers search for ways to minimize environmental impact and maintain a profitable operation. In the conclusion of this 2-part webcast, the focus continues on a thermal technology, pyrolysis, and the resulting biochar. Biochar impacts on soil carbon and fertility is discussed as well as how biochar as a soil amendment affects microbial life within the soil. This presentation was originally broadcast on August 21, 2015. More… Continue reading “Agronomic and Environmental Uses of Biochar (Part 2)”

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Agronomic and Environmental Uses of Biochar – Part 1

Technologies to treat animal manure are rapidly gaining more traction as producers search for ways to minimize environmental impact and maintain a profitable operation. In the conclusion of this 2-part webcast, the focus continues on a thermal technology, pyrolysis, and the resulting biochar. In part 1 of this 2-part webcast, we will provide a general overview of the history of biochar use, how biochar is produced, and give examples of how biochar is being used for agronomic and environmental purposes. This presentation was originally broadcast on July 17, 2015. More… Continue reading “Agronomic and Environmental Uses of Biochar – Part 1”

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Thermal Conversion of Animal Manure to Biofuel

Continued advances in technology have facilitated new avenues to access and extract energy (in various forms) from materials such as animal manure and crop residues that have not traditionally been considered viable fuel sources. This presentation discusses the use of thermochemical processes, including gasification, to produce biofuels from animal manure and was originally broadcast on February 28, 2014. More… Continue reading “Thermal Conversion of Animal Manure to Biofuel”