meus presentation-me 490
TRANSCRIPT
Energy Substitution of Electricity with Natural Gas for Industrial Dryers
Kumar Aanjaneya (graduate student) & Hayden Youngs (Senior)Completed the work
Danielle Kyser (graduated) & Karl Stimmel (graduated)Started the work
Advisors:Arvind Atreya ([email protected]) & Claus Borgnakke ([email protected])
Department of Mechanical EngineeringUniversity of Michigan, Ann Arbor 48109
1MEUS: ME 490 | 12/10/2015
Acknowledgements
• This work was sponsored by the DoE via the University of Michigan Industrial Assessment Center (IAC)
• Special thanks to:– Weiyu Cao, Yawei Chen (PhD Students), Dr. Jacek Szymczyk (Visiting
Researcher), Harald Eberhart (Glass Blower)
2MEUS: ME 490 | 12/10/2015
Inspiration• Currently electric dryers are used in the plant• Substitution with natural gas dryers, benefits:
– Cheaper to run– Lower Carbon footprint– Faster heating; thus increased production speed
3MEUS: ME 490 | 12/10/2015
Concerns• Temperature Control
• Factory Air Quality Issues
• Flame Stability
• Incomplete Combustion
• Pollutant Formation
4MEUS: ME 490 | 12/10/2015
Data from the Plant• The plant uses dryers rated at 15 kW (0.05 MMBtu/hr)
• Dryers are used for 3120 hrs/year
• Cost of Electricity: $0.08/kWh (=$23.5/MMBtu)
• Cost of Natural Gas: $5.5/MMBtu
5MEUS: ME 490 | 12/10/2015
Current Set-Up
6
AirBlower
Electric Heater
Air Knife
Conveyor belt
Dry hot air jet
MEUS: ME 490 | 12/10/2015
Proposed Set-Up
7
AirBlower
Conveyor belt
Dry hot air jet
Air Knife
Combustion Air Fuel
Burner
MEUS: ME 490 | 12/10/2015
Carbon Footprints• Combustion of Natural Gas:
– emissions per kg of Natural Gas = kg– Fuel rate for a 15 kW dryer = – production rate for the dryer = 1.08 x 2.75 = 2.97 kg/hr– Annual production = 2.97 x 3120 = 9.2 tons/year
• Similar Energy produced by a Power plant (~40% efficient ):– production rate = 23 tons/year
• A reduction of 13.8 tons/year
8MEUS: ME 490 | 12/10/2015
Design• Co-Annular tubes for the burner1.• High velocity stream of air entrains high temperature combustion
products.• Optimum mixing to achieve uniform temperatures.
9
1. Gillon, P., Chahine, M., Gilard, V., and Sarh, B. 2014. “Heat Transfer from A Laminar Jet Methane Flame in A Co-Annular Jet of Oxygen Enriched Air” Combustion Science and Technology.
MEUS: ME 490 | 12/10/2015
Experimental Design• Obstacles to induce turbulence and mixing2
• High levels of dilution to:– Achieve complete combustion– Achieve desired temperatures
• Burner tubes made of glass to optically determine flame color and soot formation
• Temperature measurements at three radial locations downstream
10
2. Guo, P., Zang, S., and Ge, B. 2010. “Predictions of Flow Field for Circular-Disk Bluff-Body Stabilized Flame Investigated by Large Eddy Simulation and Experiments” Journal of Engineering for Gas Turbines and Power.
MEUS: ME 490 | 12/10/2015
Experimental Design (contd.)• Current small-scale apparatus designed for 1kW capacity (0.016
g/s fuel inlet)
• Idea is to have low fuel momentum but high primary air flow momentum to promote fuel-air mixing2
• Secondary (dilution) Air Flow kept constant by using a computer fan– For 150 C (302 F) outlet temperature, flow is ~35 CFM
11
2. Guo, P., Zang, S., and Ge, B. 2010. “Predictions of Flow Field for Circular-Disk Bluff-Body Stabilized Flame Investigated by Large Eddy Simulation and Experiments” Journal of Engineering for Gas Turbines and Power.
MEUS: ME 490 | 12/10/2015
Experimental Design
12
Outer TubePrimary Tube
MEUS: ME 490 | 12/10/2015
FLUENT Calculations• FLUENT calculations were carried out for the design prior to
fabrication
• Simplifications made:– 2D Axisymmetric model– Neglect heat loss through walls
13MEUS: ME 490 | 12/10/2015
Temperature Contours using FLUENT
14MEUS: ME 490 | 12/10/2015
Laboratory Apparatus
15
• Outer Tube: 1.8” Dia
• Fuel Tube: 0.9” Dia
• Inner (Air) Tube: 0.125’ Dia
• Fuel and Inner Tubes: 2” Long
• Outer Tube: 1’ Long
MEUS: ME 490 | 12/10/2015
16
Thermocouple
Computer Fan
Primary Tube
Outer Tube
Apparatus (Contd.)
MEUS: ME 490 | 12/10/2015
Images
17MEUS: ME 490 | 12/10/2015
Temperature Plots
18MEUS: ME 490 | 12/10/2015
Cost savings/dryer• Considering a 15kW dryer, running for 3120 hrs/year
• For Electricity powered dryer, annual electricity cost:– Costelec dryer = Wel x HR x Ce=15 x 3120 x 0.08= $3,750
• For gas powered dryer, annual fuel cost:– CostNG dryer = Wel x HR x CNG= 0.05 x 3120 x 5.5= $858
• Cost Savings = $2892/dryer• Here:
– Wel : Power rating (kW or MMBtu/hr)– HR: Hours of use per year (3120 hrs)– Ce: Cost of electricity ($/kWh)– CNG: Cost of electricity ($/MMBtu)
19MEUS: ME 490 | 12/10/2015
Potential Cost Savings
20MEUS: ME 490 | 12/10/2015
Comments• Temperatures decreases with increase in primary air flow.
(Dilution)
• Actual temperatures are lower than predicted– Can be explained due to heat loss in the real case
• Actual mixing higher near the wall than FLUENT– Because of additional obstacles (spiders to hold the central tube)
• No evidence of soot on any surface
21MEUS: ME 490 | 12/10/2015
Comments (Contd.)• Flame was stable.
– No flame-blowout throughout the duration of the experiments for all cases
• Calculations suggest no significant increase in humidity.– Relative Humidity increases from 3% to 4% due to additional water in the
stream produced by combustion – air still suitable for drying
• Costs of implementation– Burners cost around $1000-$1500 (15kW)– Burners would require more maintenance than electrical heaters (around
$700 per year)– With savings of $2892 per year, these costs are reasonable
22MEUS: ME 490 | 12/10/2015
Future Work• Current prototype is a lab scale model
• Needs to be scaled up for usage in industry– Use of multiple fuel jets to achieve better mixing and combustion in higher
power regimes– Metallic burners with additional active/passive mixing enhancers
• Detailed gas analysis of exhaust
• Closer control of the flow rates
23MEUS: ME 490 | 12/10/2015
Future Work• Increased control of flow to:
– Achieve desired temperatures– Maintain flame stability (by maintaining stoichiometric ratio)
• Flame sensor and Ignitor– Ignite the fuel at start up – Reignite if the flame blows off or turn fuel off
24MEUS: ME 490 | 12/10/2015
Thank You!
Questions?
25MEUS: ME 490 | 12/10/2015