Biosystems and Agricultural Engineering

Advancing Utilization of Manure Methane Digester Electrical Generation

Philip Goodrich, R. Vance Morey, David Schmidt, Paul Burns, Matt Drewitz, Dennis Haubenschild, Amanda Bilek, David Nelson

Richard Huelskamp

Advancing Utilization of Advancing Utilization of Manure Methane DigesterManure Methane Digester

Funding for this project was recommended by the Legislative Commission on Minnesota Resources

from the Minnesota Environment and Natural Resources Trust Fund ($204, 375)

Biosystems and Agricultural Engineering

BackgroundBackground

Have a well operating digester on an 800 cow dairy herd

Biogas is being converted to electricity by 130 kW engine generator

Digester is producing excess biogas

Biosystems and Agricultural Engineering

Haubenschild Dairy Farm Energy Haubenschild Dairy Farm Energy ProductionProductionPrinceton, MinnesotaPrinceton, Minnesota

Milk Production + Crop Production + Electrical Production + Future

Hydrogen Production

= Farm Income Diversification

Biosystems and Agricultural Engineering

View of digester, barn and engine generator building at time of installation in 1999.

Digester Winter 2005

Biosystems and Agricultural Engineering

Biosystems and Agricultural Engineering

Plug-Flow Digester - A small “plug” of slurry is pumped into one end each day, causing a comparable amount to flow out of the other end into the storage basin in the background.

Methane Digester: To breakdown organic matter in the absence of oxygen to biogas, which is primarily CH4/methane, CO2/carbon dioxide, H2S/hydrogen sulfide, and water vapor.

Biosystems and Agricultural Engineering

Engine Generator set:

Internal combustion

engine with 135 kW 240 VAC

electrical generator.

Caterpiller 3406

Biosystems and Agricultural Engineering

Biogas Production Used in Generator

0

10,000

20,000

30,000

40,000

50,000

60,000

70,000

80,000

90,000

09/17/99 09/16/00 09/16/01 09/17/02 09/17/03 09/17/04

Date

Biogas Produced

(ft3/day)

Biosystems and Agricultural Engineering

ObjectiveObjective

Evaluate the feasibility of a fuel cell to convert biogas (methane) to electricity.

Next step may be to produce hydrogen for farm use from biogas.

Biosystems and Agricultural Engineering

Procedures to Achieve ObjectiveProcedures to Achieve Objective

Develop biogas gas cleanup system

Install fuel cell on digesterTest the fuel cellMonitor systems for energy,

consumption and emissions

Biosystems and Agricultural Engineering

ChallengesChallenges

Hydrogen sulfide removal– Initial concentration ~3000 ppm– Need concentration < 25 ppb

Moisture removal– Need dry gas

Carbon dioxide removal– Need concentration < 5 %

Biosystems and Agricultural Engineering

Types of Fuel CellsTypes of Fuel Cells

Proton Exchange Membrane -Low temp

Solid Oxide -High temperature

Molten Carbonate -High Temperature

Biosystems and Agricultural Engineering

Biogas

Biosystems and Agricultural Engineering

A fuel cell is similar to a car battery in that it produces electricity through

electrochemical reactions. A fuel cell produces electricity as long as the hydrogen

fuel source and oxygen passes through it.

Heat is also produced and can be utilized for space heating and hot water needs.

Electricity conversion efficiency is around 25%

The energy resources for hydrogen can be biogas, natural gas, propane, methanol, ethanol, and other hydrogen based liquids or gases.

Biosystems and Agricultural Engineering

Biosystems and Agricultural Engineering

The building at the left houses the 135 kW engine generator and the building on the right houses the fuel cell and instrumentation. One barn is to the right rear of the picture

Biosystems and Agricultural Engineering

Fuel Cell: Uses hydrogen to

generate electricity without

combustion. Output is 5 kW at 120 VAC

Biosystems and Agricultural Engineering

Cost per kilowatt is very high.$10,000 -->20,000 per

kW

Biogas must be cleaned up to strict specifications. Adds cost and complexity while consuming energy.

Fuel cell is an emerging technology.

Comparing Electrical Generator Technologies

Engine Generator System

Cost per kilowatt is low. $500 -->1000 per kW

Biogas can be used directly from the digester with no cleanup.

ICE is mature technology.

Fuel Cell System

Biosystems and Agricultural Engineering

Greenhouse emissions and particulates are very low.

System is very quiet.

Few moving parts.

Cost of maintenance is unknown.

Fuel cell technology is continuously improving at a rapid rate.

Comparing Electrical Generator Technologies

Engine Generator System

Greenhouse emissions of CO2, SO2, CO and particulates are significant.

Noise level is very high and sound mitigation is necessary.

Many moving parts, most moving in a hot environment needing oil and cooling.

Maintenance is well known.

Technology is mature and changing slowly.

Fuel Cell System

Biosystems and Agricultural Engineering

Proton Exchange Membrane Fuel Cell (PEM)

Advantages•Could buy one from a vendor with experience•Less expensive than others•Made in lower capacity

Disadvantages•Low temperature water for heating•Critical on gas quality•Lots of gas cleanup needed

Biosystems and Agricultural Engineering

Biogas Clean UpBiogas Clean Up

Biosystems and Agricultural Engineering

Biogas Clean UpBiogas Clean Up

Biosystems and Agricultural Engineering

Biogas Clean UpBiogas Clean Up

Biosystems and Agricultural Engineering

Biogas Clean UpBiogas Clean Up

Biosystems and Agricultural Engineering

Gemini Gas Monitor

Biosystems and Agricultural Engineering

Biosystems and Agricultural Engineering

Emissions from Haubenschild Generator Emissions from Haubenschild Generator Compared to Plug Power™ Compared to Plug Power™ Proton Exchange Membrane (PEM) Fuel CellProton Exchange Membrane (PEM) Fuel Cell

( 800ppmv) 4.18 g/kWh

(2960ppmv) 25.5 g/kWh

(277ppmv) 3.34 g/kWh

(20460ppmv) 53 g/kWh

( <1 ppmv) 0.014 g/kWh

(<1 ppmv) <.0023 g/kWh

(<1 ppmv) <0.030 g/kWh

(1790 ppmv) 14.5 g/kWh

Fuel CellEngine Generator

CO

NOx

SOX

CX HY

Biosystems and Agricultural Engineering

Energy Production +

Organic Fertilizer +

Net Air Emissions

=

$nergy Income +

$avings +

Environment Impact Reduction

Biosystems and Agricultural Engineering

Environmental and Economic Benefits

1) reduced reliance on fossil fuels 2) reduced odors and emissions 3) reduced soil and water pollution 4) supports rural economy

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Funding Funding

Funding for this project was recommended by the Legislative Commission on Minnesota Resources from the Minnesota Environment and Natural Resources Trust Fund ($204,375)

Biosystems and Agricultural Engineering

Project Participants

Philip R. Goodrich PE, David Nelson PE, Richard Huelskamp, David Schmidt PE, R. Vance Morey from Department of Biosystems and Agricultural Engineering,

University of Minnesota.

Dennis Haubenschild from Haubenschild Farms, Princeton MN

Matthew Drewitz, Paul Burns, from Minnesota Department of Agriculture

Other participants in this project include:

• Amanda Bilik, The Minnesota Project, • Verlyn Johnson and Blanca Martinez, BAE • Henry Fischer, East Central Energy. • Rob Lowen, Plug Power, Inc. • Jamie Tooley, CES-Landtec Engineering• Don White, Donaldson Corp• David Thimsen, EPRI• Claudio Martinez & Stephan Becerra ,John Deere Co

Biosystems and Agricultural Engineering

Thank you

Advancing Utilization of Manure Methane Digester

Funding for this project was recommended by the Legislative Commission on Minnesota Resources from the Minnesota Environment

and Natural Resources Trust Fund