RTO UPGRADE Opportunity for cost savings & Performance Improvements
Overview Older systems were selected for a variety of reasons Technology has advanced beyond these older systems Analysis and planning of the replacement will prove beneficial for: Process improvements Cost reduction Reliability
Background BACT Technology Technology Selection Recuperative Oxidizer Regenerative Thermal Oxidizer Carbon Adsorption / Recovery system Condensation Recovery System Catalytic Oxidizer Flair Typical Pre heater System Lowest initial cost to come into compliance Air to Air Heat exchanger pre heat SLA air up prior to combustion Secondary A/A for Heat Recovery to Plant Thermal Efficiency of ~ 40% Exhaust temperatures over 1000 degrees Destruction Temperatures of 1400 degrees
Madico Process Recuperative Oxidizer System Silicone coatings Mixed solvents Space limited Capital Cost Single Exhaust Fan for all processes 2 Speeds, change for number of processes and heat solvent load Inlet damper adjustment on Fan for exhaust pressure setting Machines coming on and off line caused disruption Changing fan speeds could cause shutdowns Line speeds limited Outrageous Gas Consumption Heat recovery to run coaters Hot air fan: two speed fan w/ damper pressure control Cold airfan: single speed fan w/ damper pressure control
Air Systems P&I
Why Did this happen? Was simplest solution at the time Lowest capital cost solution Fit in the limited space Madico had available at the time Silicone contamination concerns Companies had to comply py Additional Processes Added Subsequent growth exposed the weaknesses Technology was not there yet VFDs, PLCs, HMIs, Instrumentation Low Energy Costs
THERMAL OXIDIZER REPLACEMENT PROJECT CRITERIA Energy Reduction Maintain Environmental Compliance 100% capture > 99% destruction efficiency Operating efficiency of individual machines improved and unlinked to Oxidizer Capacity Minimize installation disruption & shutdown requirements Allow for future Expansion
Design Considerations/Uncertainties Thermal Oxidizer is integral to the process due to heat recovery, how much heat is needed? Changes in Hot Air will change Cold Air requirements as well. How large of a unit is required, total CFM? What about future growth? At what cost? How to install with minimal disruption to the operation?
Engineering Study To Scope Project Interviewed RTO suppliers, Engineering g Firms, and Process Air Engineering Companies Several RTO Suppliers were not interested at the study phase Capabilities and familiarity with the process was not firm with some Engineering Companies Selected companies with a strong reputation Matrix of considerations Knowledge of process, detail of proposal, scope of proposed report, interview, costs, assistance in permitting (Massachusetts), credit towards equipment purchase
Study Methods Detailed P&I used to identify all points for measurement Direct measurement of all exhaust values Oven air demand determined through; Zone by Zone Air supply measurements Nozzle velocity Total exhaust flow Total LEL content within exhaust flow Entrance and exit slot velocities Oven Design Data (fans, etc.) Heat load calculations based upon hot and cold air temperatures Examine values for various product mixes andsolvent loads Analyze air flow requirements based upon solvent loading (%solids and speeds) Consider low end requirements as well
Machine Solvent Loading Design Criteria (Maximum) Line 1 Line 2 Line 3 Solvent Load 212 562 583 lb/hr Coat Weight Adhesive 5 gsm Coating 1 25 gsm Coating 2 23 gsm Coating 3 Line Speed 125 fpm 150 fpm 200 fpm Web Width 61 71 61 CFM 25% 5,000 10,500 10,000
Future Capacity Consideration Decision must be made at time of order FutureLC Machinewith ~1,100 100lbs./hr. Line Speed 250 fpm, 25 gsm PSA, 2.5 gsm top coat Requires 26,000 scfm additional Cost adder of $218,000 Added space requirements In the end, adjusted the scope to similar machine of 10,000000 scfm Opportunity with cold air for oven make and fugitive control for additional Capacity
Exhaust CFM Requirements Machine Load 25,500500 Enclosures 3,000 Mixing ii Areas 3,000 General Fugitives 1,500 Future Addition 10,000 Total Required ~40,000
Supply air requirements Cold Air Analysis CA was from fugitive emission control points PTE air flows Fugitive data analysis Hot Air Analysis Nozzle measures Infiltration Total air supply & temperature Empirically determined Planned supply air temperatures For Hot Air define the high temperature limits for dryers Change from 750 degree supply to 400 degree Cold Air based upon ambient
Key Design Features CFM Capacity Double to 40,000 cfm New Main Exhaust fan of 250 HP Exhaust Fans for each machine Various control options & Setpoints T Dampers on Each hmachine Pressure controlled VFD for all fans Main Exhaust Hot air Cold Air Machine exhaust fans Self Sustaining @ ~4 to 5% of LEL Shutdown in idle < $12.13 per hour
Key Design Features Heat Recovery For Process Ovens RTO Shutdown & Bottle Up In Idle Mode CRT Central Control System Panel View Improved diagnostics Improved process overview Cold Air Make Up from Outdoors Coater Enclosures separated from oven Fugitive exhaust to Oxidizer not Oven
Energy Comparison Thermal Recup Costs RTO Costs Thermal Recup Costs RTO Costs Air Flowrate Air Temp (F) Solvent Loading (btu/hr) Fuel (btu/hr) Electrical (kw/hr) Fuel (btu/hr) Electrical (kw/hr) Fuel ($/hr) Electrical ($/hr) Total Fuel ($/hr) Electrical ($/hr) Total 9,000 70 0 6,752,115 26 -- -- $50.64 $2.87 $53.51 -- -- -- 36,240 100 23,752,800 2,995,412 130 0 170 $22.47 $14.33 $36.80 $0.00 $18.66 $18.66 36,240 300 23,753,800 0 177 0 202 $0.00 $19.45 $19.45 $0.00 $22.20 $22.20 36,240 100 2,628,150 24,121,062 130 1,157,210 170 $180.91 $14.33 $195.24 $8.68 $18.66 $27.34 36,240 300 2,628,150 21,182,687 177 480,105 202 $158.87 $19.45 $178.32 $3.60 $22.20 $25.80 10,000 70 0 -- -- 1,433,249 28 -- -- -- $10.75 $3.03 $13.78 Assumptions - Both the Thermal Recuperative Oxidizer and Regenerative Oxidizer have no Heat Loss to Atmosphere - The Pressure Drop for the Recup is about 19 Inches Water Column - The Pressure Drop of the RTO system is about 22 Inches Water Column - The Fuel Costs $0.75/therm and $0.11 kw/h
Schedule Thermal Oxidizer Equipment pre install month prior to plant shutdown Unit running and tested prior to plant shutdown for cut over Permitting is on the criticalpath on theseprojects Advance work on ducts where possible 3 week tie in : full shutdown Insulation takes a long time.
Anticipated Return on Investment Increased capacity $ 200,000 low gas cost $ 370,000 000 present gas cost $ 550,000 high gas cost $ 735,000 Project will be under 2 year pay back.
The Results..
Heat Recovery System Primary Heat from stack air Modulate combustion chamber air to achieve temperature Change hot air temperature set point dependent upon heat load Fresh air make up modulated as required during self sustain Pressure controlled VFD for Hot Air supply Pressure plenum Pressure controlled VFD for Cold Air Supply Pressure Plenum Cold Air Make 100% fresh air
Machine Exhaust Variable Speed fan Closed loop pressure control for steady exhaust flow Ability to adjust pressure set point for solvent loads Ability to set exhaust fan to an idle mode during extended down periods T Damper to take line off line for testing/non hazardous emissions/oven Cool downs
Additional Benefits Advanced alarm and diagnostics Provide time and address tag for PLC checks Machine and production status reports RTO performance Idle/self sustain/heat up Coating on / off / idle Machine Speed dincreases Safely handle the solvent loads No Interplay between machines
Past 2 years Average Cost Per Therm$1.39 FY2000 Usage 1,221,901 Therms Cost of $1,704,000 Actual Cost for past 12 months was $187,412 Savings of $1,516,600 Pays for investment every year!!! Savings
Annual Gas Useage 1,400,000 1,200,000 1,000,000 800,000 600,000 Therms 400,000 200,000 0 1995 1996 1997 1998 1999 2000 2001 2002 2003 2006 2007
Monthly Comparison 120,000 100,000 80,000 60,000 40,000 Therms Old Therms New 20,000 0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
View of Installation
Summary Define your project objectives (correct the short comings) Analyze your requirements Define Air Flow Requirements Understand denergy And dheat Requirements Fully Specify Project Manage the project closely