Progress Through Collaboration

Agreeing on The Goals Charting A Path Forward Open Communication At Every

Step Managing Timelines and Budgets

How Our Project Got Started

A big driver was our need to provide more funding for our city parks and recreation budget to help the children and youth of our community. Thought if we could save big in one area, we could put more funding into another without having to raise taxes. Always a good thing.

Looked at waste material going into the landfill, the huge money being spent there, and thought there must be a way to stop that process and turn “dirty into dollars” for the city….recycling it into energy.

Thoroughly researched disposal options, and ran a lot of numbers to arrive at a solid recommendation for the city.

Kissed (at least interviewed) a few frogs before I found a company with the technology, experience and high trust factor we had to have.

Complex Job All The Way Around

InnovationCollaboration

Innovative CollaborationCollaborative Innovation

Along with Some Collaborative and Innovative Cat Herding

Held together with a commitment to“Do the right thing, for the right reason, in the right way.”

The Technology

The following slides explain how the waste gasification technology works and the

benefits it is bringing to Covington.

After all this extra homework, I achieved nerd status. But not quite a geek…yet!

What is Gasification?

This is NOT Incineration.

Converts multiple types of feedstock to a consistent gas

A thermo-chemical process producing a clean fuel gas by breaking down solids at the molecular level.

About 95% of what goes in comes out as fuel gas. The other 5% is a charcoal biochar with many uses.

The clean conversion of biomass into a combustible fuel gas in an oxygen-starved

environment

1941 Adler Diplomat powered with a gasifier

Converting Solids To Fuel Gas

Evaporate moisture from the feedstock

Feedstock breaks down to gas and tars

3000 degree F heat layer cracks tarsCarbon reforms with steam to create CO and H2

Rotating Grate shaves biochar layerResidue box for biochar removal

Drying

Pyrolysis

High Heat

Reduction

Feedstock

Grate

Residue

Air

Air

Gas

Gas

Feedstocks Woodchips

Urban yard waste, ROW trimmings Bark or pulp operation waste wood Manufacturing scrap

WWTP Sludge Food processing residue

and manufacturing waste Scrap tires and rubber

products Agricultural and animal

waste No glass, metals, rock, slag

Using The Fuel GasCurrently Being Utilized Here and Worldwide

• Electricity: Gas or steam turbines and ORC

generators

• Steam: Boiler and community heating

systems

• Direct Thermal: Kiln Operations & Sludge

Dryers

• Combustion: Industrial thermal oxidizers

Based on a PHG Energy Downdraft Gasifier

50,000 Hours ofCommercial Production

How Our Plant Functions

Waste Material Is Feedstock

Sludge From Sewer Plant:2 tons per day utilized ratherthan trucked to landfill

City Wood Waste:10 tons per day chippedand used as fuel

Waste Combines

Wood Chip and Sludge are combined, dried and

sent to the top of the Gasifier by conveyor equipment

Clean Conversion To Fuel Gas

Thermo-chemical Gasification process converts feedstockto fuel gas without incineration

Electric Power Production

1. Fuel Gas is Combustedin a thermal oxidizer to cleanly produce heat

2. Oil Is Heated to 350 Degrees

3. Hot Oil DrivesGeneral ElectricOrganic Rankine CycleGenerator to make electricity(125 Kw)

Big Picture Flow Diagram

Feedstock Flexibility Mitigates Future Risk of Change

Covington SustainabilityAnnual Landfill Diversion:• 3,600 tons of wood waste not landfilled• 720 tons of sludge not landfilled• = Over 4,000 tons of waste put to work for the

community

Carbon Footprint Reduction:• Prevents release of 425 tons of carbon dioxide into

the atmosphere each year by reducing electrical use WWT, as well as fossil fuels previously used in transportation.

• According to DOE, that translates to GHG emissions expected annually from 80 automobiles or carbon dioxide emissions from over 35 homes.

Back to Collaboration

Many Moving Parts To Coordinate

Collaboration Partners (the cats)

City Council Members

Public Works Department & City Engineers

Waste Water Treatment Plant Operators

Tennessee Municipal League

Tennessee Department of Environment & Conservation

PHG Energy

General Electric

Innovation

• Technology: Deploying Gasification System In A New Configuration

• Feedstock: Utilizing WWTP Sewer Sludge, Prepping city wood waste

• Energy Production: Using General Electric ORC Generator with Thermal Oxidizer and Heat Exchanger

• Financing: TML Bond Funds

Formula For Getting Things Done

Start with a Real Need + Motivation + Innovation + Collaboration + Commitment= Success*

*As long as you’re doing the right thing, for the right reason, in the right way.

FAQ’s

• How do you start the gasifier? Using a standard bag of charcoal.

• How do you stop the gasifier? It uses a small amount of air to sustain the process….turning that air off stops the flow of gas. It can be turned off for up to 24 hours without having to do a cold start procedure.

• It looks complicated…how many people does it take to operate? The majority of operation lies on the feedstock preparation; processing feedstock has been a focus of our efforts recently to increase runtime.

• I see a flame in some of the pictures…isn’t this really incineration? Gasification is 2 step process to first break a biomass material down into simpler combustible molecules and then combusting this gas. The US EPA recognizes the difference in the processes and has started updating regulations with this in mind.

• What can the biochar be used for? We are currently investigating what makes the most sense for our biochar, but it has value as a soil amendment, charcoal filtration, or as a bio-charcoal.