elevating vam rto inlet concentration … elevating vam rto inlet concentration through cmm blending...

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ELEVATING VAM RTO INLET CONCENTRATION THROUGH CMM BLENDING FOR POWER GENERATION

DURR SYSTEMS, INC.

CLEAN TECHNOLOGY SYSTEMS

ICAC 09/18/13

Karl WalbySenior Key Account Manager734-536-3423, [email protected]

CONTENTS

Clean Technology Systems, ICAC Industrial Rountable, VAM - CCM Blending, 09/18/13 2

1. Ventilation Air Methane (VAM) Overview

2. Regenerative Thermal Oxidizer (RTO)

3. CMM Injection

4. RTO Excess Heat Utilization – Steam and Power

5. Durr Systems China VAM / Power Generation Project - Parameters

6. System Overview

7. CMM Injection System

8. Partner Patented CMM Mixer

9. Safety

10. Project Status

ICAC 2013


1. Ventilation Air Methane Overview

Coal mine vent shafts emit many tons of methane each year

21 times worse than CO2 for the atmosphere

Carbon credit program developed to push methane destruction rather than venting to atmosphere

US Mines typically operate at methane concentrations ranging from 0.6% to 1.1%

China mines typically operate at methane concentrations ranging from 0.3% to 0.4%.

At methane concentrations above 0.3% oxidation systems can generate a substantial quantity of excess heat

For the US current carbon market price levels and shaft locations make stand alone oxidation systems unattractive. Durr has only full scale system operating in the US.

In China shafts are more centrally located to cities and grids. The combination of VAM oxidation and power generation becomes very attractive. Power generation alone can finance projects.

Low methane concentration hurdle can be overcome with Coal Mine Methane (CMM) injection to increase methane concentration levels

ICAC 2013


Two Tower Regenerative Heat Exchange Oxidizer

142 °F

1750 °F

70 °F

1628 °F

2. Regenerative Thermal Oxidizer (RTO)

ICAC 2013


CMM pumped from underground methane pockets at coal mines

Typical concentration 10% to 25% methane

Commonly used in small gas turbines at coal mines

Method to increase methane concentration and therefore carbon credit generation

Mixed concentration at RTO inlet up to 1.2% methane

Also increases the amount of excess heat generated in an oxidation system

Injected and mixed with low concentration VAM prior to an oxidation system

3. Coal Mine Methane (CMM) Injection

ICAC 2013


At 0.3% methane an RTO can operate with no supplementary fuel gas – self sustain

Above 0.3% methane a system must be implemented to shed excess heat from the combustion chamber. Oxidized methane gives off more heat than required to maintain typical combustion chamber temperature of 1550F. Combustion chamber temperature will begin to rise.

A hot gas bypass from the combustion chamber allows excess heat to be evacuated and the combustion chamber temperature to be stabilized at 1750F.

The excess heat can be sent to a heat utilization device for use. In the case of VAM projects this is a steam boiler. Up to 30% of the RTO inlet volume can be bypassed from the combustion chamber.

Steam is generated and then sent to a steam turbine to generate power.

4. RTO Excess Heat Utilization – Steam and Power

ICAC 2013


VAM Volume – 1,040,000 Nm3/hr (700,000 scfm)

VAM Methane Concentration – 0.3%

Collection Point – 20 meter tall stacks, 10 meter x 10 meter collection hoods

CMM Injection Volume – 40,000 Nm3/hr (27,000 scfm)

CMM Injection Methane Concentration – Up to 25%

VAM plus CMM Methane Concentration – Up to 1.2%

6 Point CMM Injection System

12 RTO Oxidation System

Excess Heat Hot Bypass To Steam Boiler – 300,000 Nm3/hr (201,923 scfm) at 1750F

Steam Turbine for 20MW Electricity Production

5. Example - Durr Systems China VAM Power Generation Project

ICAC 2013


6. System Overview

ICAC 2013


CMM Injection Volume – 40,000 Nm3/hr (27,000 scfm)

1200mm (47”) diameter main supply pipe from CMM pumping station

Six 500 mm (20”) diameter injection pipes

Injection performed underground concrete mixing structure

Modulating control based on laser methane concentration system at downstream VAM +CMM control point

Partner patented CMM Mixers

Multi-level safety system

7. CMM Injection System

ICAC 2013


7. CMM Injection

ICAC 2013


7. CMM Injection – Overall System

ICAC 2013


Durr partnered with reputable design institute in China with extensive CMM experience

Partner supplying patented high efficiency mixer

98% mixed within 2 meters of the mixer exit

Low pressure drop design


ICAC 2013



ICAC 2013


1. Primary - Redundant LEL (Lower Explosive Limit) switches in VAM supply duct

a) Fault Settings – Resulting in RTO isolation, dilution and shutdown

1.8% Methane

High differential between redundant switches

Loss of beam signal

b) Response Time

Faster T90 response time (<1 second) than catalytic heat of combustion and infrared types

2. Primary – RTO Isolation and Dilution

a) High LEL faults results in RTO isolation and shutdown, opening of dilution air and fresh air dampers.

b) If isolation fails, RTO fans pull dilution air and fresh air to reduce concentration entering the RTO.

c) US MSHA regulates that VAM process air travel time from the LEL sensors to RTO isolation valves is greater than: LEL detection / reaction time + PLC / Instrument reaction time + RTO isolation damper closing time. See example.

9. Safety

ICAC 2013


3. Primary - Pressure Relief – VAM Capture Hood

a) Durr designed and flow modeled capture hood. Roof openings to vent VAM air to atmosphere.

4. Secondary – Methane Monitoring System

a) Normally used to measure methane concentration to each individual RTO for carbon credit reporting

b) Durr integrated an isolation and shutdown fault if methane concentration is above 1.4%

5. Secondary – RTO Standard Safeties

a) High mid bed temperature thermocouple – High temperature initiates RTO isolation and shutdown

b) High combustion chamber temperature thermocouple – High temperature initiates RTO isolation and shutdown

c) Large RTO ceramic heat exchange beds act as flame arrestors if there is an ignition in the combustion chamber

d) All instruments within the air stream intrinsically safe or explosion proof

e) Heat exchange bed thermocouples to maintain cool lower bed temperature

9. Safety

ICAC 2013


RTO system installed

Steam boiler 95% complete

Steam turbine onsite

CMM injection system underground concrete complete

CMM mixers onsite

10. Project Status

ICAC 2013


10. Project Status

elevating vam rto inlet concentration … elevating vam rto inlet concentration through cmm blending...

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