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Why Use Protective Atmospheres? TTo PreventPtOOxidation,id tiLossLoff CarbonC b (Decarburizing),(Db i i )and Avoid Corrosion.– Most Gases Containingg Oxygenyg (i.e.(Air,, Water Vaporp[H2O], Carbon Dioxide [CO2] React With Iron, Carbonand Other Elements Present in Steel and Other Metals.– Reactivity Depends on Temperature and Mixture ofGases in Contact With Steel. To Avoid and Eliminate Formation of Flammable orE l i MixturesExplosiveMi t

Types of Process Atmospheres Protective– To Protect Metal Parts From Oxidation or Loss of Carbonand Other Elements From the Metal Surfaces. Reactive– To Add Non-metallic (i.e., Carbon, Oxygen, Nitrogen) orMetallic (i.e., Chromium, Boron, Vanadium) Elements tothe Base Metal. Purging– To Remove Air or Flammable Gases From Furnacesor Vessels.

Importance of Protective Atmospheresin Heat Treating Proper composition and concentration in a furnace is requiredto give the required surface properties for the heat treatedparts. Loss of atmosphere “control” can result in unacceptable partsand result in major economic penalty - it can cost a lot! Atmospheres contain potentially dangerous (explosive, lifethreatening) gases and must be treated with “respect”. New advances in measurement and control of atmospheres inheat treating allow precise control of atmospheres to producequality parts.

Commonly Used Atmospheres in Heat TreatingProtective and Purging– Endothermic gases Lean – high and lowdew point Rich - highg and lowdew point– Nitrogen– Mixture of N2 andsmall amount of COReactive– Exothermic gases– Mixture (or individual) ofgases: Hydrogen, CO,CH4 Nitrogen and otherCH4,hydrocarbons– Dissociated Ammonia(H2 N2)

Source of AtmospheresRequirement:A Mixture of Gases (CO, H2, CO2, H2O and N2) That Givethe RequiredqCompositionpfor the Processingg Atmosphere.p Natural Gas (Hydrocarbon) Air Reaction Natural Gas - Steam Reaction Ammonia Dissociation orAmmonia-air ReactionOr: Mixture of Commercial Gases(N2, H2 and Hydrocarbons)

Use of Atmospheres in a PlantRequirement:A Mixture of Gases (CO, H2, CO2, H2O and N2) That Givethe RequiredqCompositionpfor the Processingg Atmosphere.p Most plants have an in-house, centrally located,pgasg generatorsgfor different typesyp ofatmosphereatmospheres required in the plant In some cases one or more generators may bep or productionparealocated for each “shop” In many cases other gases (i.e. N2, H2, NH3)are piped from storage tanks located within theplant premisesppand distributed byy a pipingpp gsystem to furnaces. Gas flow is mixed, measured and controlled priorjin the furnace.to its injection

Electrical HeatingSystemsfor Heat Treating

Type of Electric HeatingResistance HeatingCost ComparisonElectric vs. Natural GasCent/Kwh /MM 33 9333.9337.01Induction HeatingDirect CurrentLaser HeatingElectron Beam HeatingPlasma HeatingArc HeatingBased on 90% efficiencyin distributionAdvantages Claimed By Electric System ProvidersMajor Applications of Electric Heating for Heat Treating Vacuum Heat Treating Furnaces Sintering (Powder Metal) Furnaces Plasma or Ion Nitriding, Carburizing or SurfaceCoatings Low Temperature Tempering or Draw Furnaces Liquid (Water, Quench Oils or Polymer) Heating inTanks Gas Generators (Endo Gas and AmmoniaDissociators) Salt Bath Furnaces Pit (Underground) Furnaces “100100 %”% Efficient Better Temperature Uniformity andControllability Can Be Used for Higher TemperatureProcessesHigher Operating Cost : 2 to 3 Times forHeat Treating Furnace Applications Capital and Operating Cost Heating Elements Burn-out, Short Lifeand Expensive to Replace Product Loss Danger of Elements Shorting Due toPossibilities of Metal Parts Drop Environmental, Safety and May Need Expenses for Substation,Transformer Etc. Corrosion, Soot Deposits Etc. ForApplications With Process Atmosphere Longer Furnace Length for the Same HeatInput, Particularly for Continuous Furnace Safe - No Explosion Hazards No Flue Gases to Deal With No Pollution or Emissions of NOx Etc. Lower Initial Cost for Furnace Easy to Install and Operate Can Be Easily AutomatedDi dDisadvantagest- DrawbacksDb kMajor Issues and ConcernsHealth Productivity and Quality Other factors

Electrical Heating Terms and CostCost of Electric HeatingCent/Kwh456789101112 Energygy is measured in terms of KilowattHour (Kwh). 1 Kwh 3,413 Btu/hr. Electricity production is approximately33% efficient based on energy requiredat the power plant. For an equivalent (delivered to the load)Btu basis electricity production emits 2to 5 times more NOx than the gas firedfurnaces. Actual efficiency of application of heatcould be in the range of 65% to 85%. /MM sed on 90% efficiency indistribution

Advantages Claimed By Electric System Providers “100100 %%” Efficient Better Temperature Uniformity and Controllability Can Be Used for Higher Temperature Processes Safe - No Explosion Hazards No Flue Gases to Deal With N PNoPollutionll i or EmissionsE i ioff NOx Etc.E Lower Initial Cost for Furnace Easy to Install and Operate Can Be Easily Automated

Disadvantages - Drawbacks Higher Operating Cost : 2 to 3 Times for Heat TreatingFurnace Applications Heating Elements Burn-out, Short Life and Expensive toReplace Danger of Elements Shorting Due to Possibilities ofMetal Parts Drop Ma Need EMayExpensespenses fofor SSubstation,bstation TTransformeransfo me EtcEtc. Corrosion, Soot Deposits Etc. For Applications WithProcess Atmosphere Longer Furnace Length for the Same Heat Input,Particularly for Continuous Furnace

Primary Applications ofElectric Heating for Heat Treating Vacuum Heat Treating Furnaces Sintering (Powder Metal) Furnaces Plasma or Ion Nitriding, Carburizing or Surface Coatings Low Temperature Tempering or Draw Furnaces Li id (Water,Liquid(W t QuenchQh OilsOil or Polymer)P l) HeatingH ti ini TanksT k Gas Generators (Endo Gas and Ammonia Dissociators) Salt Bath Furnaces Pit (Underground) Furnaces

Electrical Heating Systemsfor Heat Treating Resistance Electrical Heating Systems–– Electrically Heated Conventional FurnacesElectrically Heated Atmosphere FurnacesElectrically Heated Vacuum Furnace–Heating and heat treating–Plasma Nitriding–Plasma Carburizing–CVD CoatingsCCoa gsInduction Heating

Majorj Componentspof anElectrical Heating System Heating Elementsl Power Supply Power Control System Connected withth FtheFurnace TTemperaturetCControlt lSystem Water Cooling System

Electrically Heated Atmosphere FurnaceNotice: Electric heating elements connections Lack of burners, vents, airair-gasgas piping or flue gas vents or ducts

Features of anElectrically Heated Vacuum Furnace VVacuumVesselVl With WaterW t CooledC l d ShellSh ll– High Temperature Heating Elements(Graphite, Molybdenum, etc.)– Insulated Shield Between the Elementsand Water Cooled Shell Gas Circulating Fan With Water CooledHeat Exchanger and Gas AccumulatorWater Re-circulating and Cooling SystemVacuum Pumping SystemControlsMaterial Handling System

Primary Reasons for the Useof Vacuum Heat TreatingNegative:Ni Higher Capital Cost Higher Utility(Electricity) CostgOverall HigherOperating Cost Lower OverallCapacity Less FlexibilityPositive:Pii Process Repeatability Temperature Uniformity Reliability of Operations Better Operating Environment No or Low Environmental(Perceived Emission) Problems Automation - Better Applicationfor Computer Control

Induction HeatingforH TreatingHeatTi AApplicationsli i

What is Induction Heating?g Method of heating electricallyconductive objects. No contact requiredqbetweenthe object and source of heat. Heat can be applied to localizedareas or surface zones. High surface heat flux relatively short heating time.time

Applications of Inductionfor Metal Heating SpotSHHeatingi - Brazing,Soldering, Local Heating, SpotHardening. Surface Heating - SurfaceHardening, Curing, Shrink Fit ThroughThh HeatingH ti - Tempering,Forging, Annealing, ThroughHardening. Melting - Steel, Copper, Brass,Aluminum

Gas Fired Vacuum Furnaceswww.gasfiredvacuum.comPresented under Available / Emerging Technologies

Process Heating Tools and ModelsModels*These Toolswill help youProsper!Thanks forShowing UsHow!Understanding ISthe Key toObtain Results!*Content Partially Provided Through Dominion Participation in both the Energy SolutionsCenter’s Heat Treat Awareness Consortium and the DOE BestPractices Program

How to Use These Tools and Models1.Discuss the fundamental cost differences between natural gas andelectricityl t i it withith customers.tElectricEl t i costt isi usuallyll 3 tot 5 timestitheth gascost on the basis of the total BTU’s supplied to the process equipment.2.For most plants, a relatively small number of all installed processq pusuallyy consume the largestgamount of energy.gy Identifyy theequipmenttop-users and gather basic information on energy use for all majorenergy use equipment in the plant.3.For major energy using equipment, record name-plate data and analyzehow and when energy is usedused. ThenThen, estimate the efficiency of theprocess based on age of existing equipment (older is lower efficiencygenerally), actual data, referencing the charts included in these Toolsand Models or by contacting the original equipment supplier.44.The operation cost comparison for selected equipment can becompleted by entering efficiency and energy cost information in theCost Comparison Calculator Model cells OR by reading the generalresults, in certain cases, from the charts (see pg’s 4 & 5).Cost Comparisonfor Gas Comparedto Electrical HeatFactors affectingffenergy cost includel d 1)) Efficiencyffoff gas andd electricallylllheated furnaces 2) Cost of gas and electricity and 3) Number of hoursequipment is operated.

Factors affecting efficiency of gas-firedequipment1.22.3.4.Flue (exhaust) gas temperatureOxygen (or CO2) in flue gasesCombustion air temperature (to the burner)Oxygen injection or enrichment (if any) in theincoming combustion airFactors affecting efficiency of electric equipment1. Power factor2. Losses in distribution system (from meter touse)3. Water cooling of components4 Induction coil and load coupling4.

Process Heating Cost ComparisonGas Cost Equivalent for Electric Process*1: If Efficiency is different than the three shownhere use the Cost Comparison CalculatorGas Cost vs. Electric Cost(Electric Heating "Efficiency" at 6060, 75 or 85%) *1Gas Costt /MM Btuu35.0030 0030.00Electrical Equipm ent Efficiency - 60%25.0075%20.0015 ty Cost Cents/kW9.010.0

Process Heating Cost ComparisonElectric Cost Equivalent for Gas Process*1: If Efficiency is different than the three shownuse the Cost Comparison CalculatorElectric Cost vs. Gas Cost(Gas EquipEquip. Heating Efficiency at 40,40 60 and 80%) *11Electricity CCost Cents/kWW8.07.0Gas Equipmentq pEfficiencyy - 00Gas Cost /Million Btu10.0011.00

Cost Comparison CalculatorFind Equivalent Electric RateGas Equipment EfficiencyElectric Heating EfficiencyGas Cost60%85% 5.50% - Percent% - Percentper million Btu (Mcf)Gas equipment provides cost savingswhen electric power cost is equal to(or higher) than this power rate2.7Cents/kWNote: TNTo EEnter EffiEfficiencyi& Energy Cost Data,“Double-Click” on theGreen portion of the tablecell. Then “Click” againin the cell and makedesired entry. Finally,“Click” once outside thecell to view results. DoNOT Enter Informationin Blue Cells.Find Comparable Gas RateElectrical Equipmentq pEfficiencyyGas Equipment EfficiencyElectricity CostGas equipment provides cost savingswhen gas cost is equal to (or below)this gas cost85%60%4.59.31% - Percent% - PercentCents/kwh /MM Btu (Mcf)

Avaialbile Heat in Gas-Fired SystemsAssumption; 10% Excess air, or 2% O2 in flue gasesAvailable heat is the m axim um possible "efficiency".Generally, efficiency is 75% to 90% of the avaialble heatshown on this graph.Perccent Available Heat (%)908070605040306008001,0001,2001,4001,600E hExhaustt FlueFlGasGTemperatureTt(Deg.(DF)1,8002,000

Typical Electric System Available Heat forProcess Efficiency FactorsElectrically HeatedSystems has ALL the9 Vacuum – 60%same losses as gasgas-firedfired9 InductionI d ti UUnderd 22,000000 F – 65%systems except Flue Gas9 Induction Over 2,000 F – 40%Losses. Line losses from9 SCR - 75%metering to application9 ResistanceR itElElementst – 85%also exist.9 All Other - 75% If Unsure Of ActualNote: ContactCyour equipmentiEffi iEfficiencyuse 75% inisupplier to verify actualthe Cost ComparisonfactorsCalculator.

How to Use Two Models to Determine Base & Modified Energy Use1.In the Base Case model, enter measured data in Green Cells thatpertaint i tot ththe currentt combustionb ti systemtoperatingti condition.ditiIf ddatat iisnot known, a portable combustion flue gas analyzer and a thermocoupleis needed to obtain this the Excess O2 and Flue Gas Temp. information.2.For most non-recuperatednon recuperated combustion systems, the flue gas temperatureexiting the process will average between 100 and 200 F higher than theprocess temperature. Also, the flue gas oxygen content for many oldercombustion systems will range from 3 to 9%. Additionally, thecombustion air temperature will correspond to the ambient conditionsnear the equipment. Unless you know, use 100 F.3.For the Modified Case, recuperative combustion systems can provide arange of preheated combustion air temperatures. Most systems willpreheat air to at least 400400–600600 FF. Some will provide significantly more(as high as 200 F below operating temperature). If unsure, use 500 Fand assist the customer in confirming the possible temperature with aqualified burner company or equipment supplier representative.Cost Comparisonfor Gas Comparedto Electrical HeatFactors affecting energy cost include 1) Efficiency of gas and electricallyheated furnaces 2) Cost of gas and electricity and 3) Number of hoursequipment is operated.

Process Heat Cost ModelBaseBaseCaseFurnace FlueGasTTemperaturetOxygen in FlueGasesExcess AirDeg. F.%%Deg. F.% of grossHeating Value1 6001,600616.138 338.310043 5043.50Gas equipment provides savings when gascost is equal to (or below) this gas costPower Cost (Cents/kWh), enter in 0.045formatInput Data in Green Cells 30.310.045CombustionAirAvailable HeatTTemperaturetNote:NtAfter Entering GasCombustion Data, Inputthe Current Power Costto Determine the GasCost Point that ProvidesSavingsView Result

Process Heat Cost ModelM difi dModifiedModifiedCaseCombustionAirAvailable HeatTemperatureFurnace Flue GasTemperaturepOxygen in FlueGasesExcess AirDeg. F.%%Deg. F.% of grossHeating Value1 4001,400212.110 210.250066 1766.17Note:Gas equipment provides savings when gas costis equal to (or below) this gas costPower Cost (Cents/kWh)Input Data in Green Cells 19.930.045To Enter Data, “DoubleClick” on the Greenportion of the table cell.Then “Click” again inthe cell until the curserappears and makedesired entry. Finally,“Click” once outside thecell to view results.View Result

EEmergingi GasGasG -FiredFi d ProcessPHeatingH i EquipmentE i Gas Vacuumwww.gasfiredvacuum.com Fuel Based Nitrogenwww industrialcenter orgwww.industrialcenter.org Flame Treating Systemswww.flamesys@gte.net Composite Radiant TubesT beswww.griweb.gastechnology.orgwww.flox.comwww shunk-inexwww.shunkinex.comcom Fluidized Bedwww.rapidheattreat.com(available soon)

Gas-FiredGasFired Vacuum Furnaces (GFVF) (GFVF) are a credible and low maintenancealternative to electric vacuum furnaces.furnaces GFVF utilize innovate burner designs to treatmore parts at lower costs while meeting orexceeding temperature uniformity and surfacequality standards.standards There are many applications for thiscontinually advancing technology.A li tiApplicationsHeat treating to 1,850 F (higher temperatures available soon) includingNormalizing, Annealing, Stress Relieving and others Who to contact?Surface Combustion, Thermotech and AFC-Holcroft offer GFVF’s. Visit the“Resource Center” section of www.gasfiredvacuum.com to contact them.Web site: www.gasfiredvacuum.com

Fuel-Based Nitrogen (FBN)AAtmospherehGeneratorGSteamNOx and O2Reduction Produces BOTH high-quality processatmosphere and steam. Natural gas used forboiler and atmosphere use is combined. NOx reductions measured at over 90% comparedto standard systems. Reduces operating cost substantially.substantially Recentinstallations report annual natural gas,maintenance and labor savings exceed 250,000. 500,000 annual saving have rCompressorFuelPurificationOutputInput RaitoControl StorageTankA li tiApplicationsFerrous and NonFerrous Annealing, Sintering, Brazing andGalvanizing of Rod / Wire, Sheet, Tube and other parts / shapes Who to contact?Energy Resource Control Corp., Cleveland, OhioPhone: 440.734.2560 Fax: 440.779.9184Web site: www.industrialcenter.org (click on “TechnologyTechnology TourTour” button)

Flame Treating Systems, Inc. (FTSI) Natural gas FTSI units are efficient, economicaland easy to install. Versatile designs withpackaged and custom-designed options. PLCcontrolled for repeatable and reliable operation. FTSI reduces energy costs and can be installedin low and high temperature applications. Competes with induction at significantly lowercapital cost.A li tiApplicationsHardening surfaces of parts, through heating prior to forming or forging, andpreheating. Metals, plastics, and other process applications exist Who to contact?Flame Treating Systems, Inc. Durham, NC1.800.435.5312Web site: www.flamesys.com

Composite Radiant Tubes (CRT) Available since the late-1980’s, CRT’s increaseheat release, allow maximum processt

- Approx. 10% of All Heat Treating Production Is by Commercial HeatApprox. 10% of All Heat Treating Production Is by Commercial Heat Treaters. - Usually There Are 4 to 5 Captive Heat Treaters for Each Commercial Heat Treater Shop. Captive Heat Treaters - Usually a Part of Large Manufacturing Business.