Heaters Efficiency

Download Heaters Efficiency

Post on 02-Oct-2015

24 views

Category:

Documents

9 download

Embed Size (px)

DESCRIPTION

Heaters Efficiency

TRANSCRIPT

<p>Optimizing Fired Heaters</p> <p>New Approach to Optimizing Fired HeatersAshutosh Garg, Furnace ImprovementsSugar Land Texas, USA</p> <p>IETC, Houston- Save Energy in Fired HeatersMay 12-13, 1999by Ashutosh Garg,Furnace Improvements, Sugar Land, TX1Energy ConsumptionPetroleum Refining 7.5% of the total energy consumption in USA0.40 MMBtu/ BBL of oilTotal Energy consumed in refining- 7.1 Quadrillion BTU/yrEnergy cost -$6/MMBtuTotal Energy Cost- 42 Billion /yrFired heaters -40-70% of the energy </p> <p>IETC, Houston- Save Energy in Fired HeatersMay 12-13, 1999by Ashutosh Garg,Furnace Improvements, Sugar Land, TX2Energy ConsumptionA Typical refinery process 100,000 BPDConsumption of 0.40 MMBTU/BBL$6 per MMBTUEnergy bill of $ 87.6 million per year.</p> <p>Potential Saving</p> <p>1% Efficiency improve $876,000/Year3Fired HeatersEssential component in Petrochemical and Chemical Plants</p> <p>Each refinery has 20-50 fired heaters</p> <p>Design efficiency - 70-90%Operating efficiency is even less than design.</p> <p>4Maintaining Design OperationMaintain the design conditions (very difficult)</p> <p>In the field, heater loads change constantly due to variations in:Feed flow rateFeed temperatureFuel compositionAmbient temperature</p> <p>The heater will be operating a non-optimal conditionsRequires optimization 24/7</p> <p>5How to Maintain the Design Efficiency?When the heater conditions change, adjustments in the heater are required.Manual adjustments are provided- not adequateOptimizing the fired heater will:Reduce Energy ConsumptionIncrease run lengthMinimize maintenanceFIS has proposed two prong approachSoftware based- Heater Performance IndexHardware based- Draft &amp; Excess O2 Control</p> <p>6Fired HeaterHeat liberated by the combustion of fuels is transferred to fluids contained in coils</p> <p>Fired Heater:Radiant SectionConvection Section Stack</p> <p>www.heatflux.com</p> <p>7Typical heater efficiencyNatural Draft- 70-84%Balance Draft-90-92%Natural Draft heaters in Industry- 86%Balanced Draft heaters in Industy-12%Typical stack temperature 500-800 FTypical stack Oxygen- 2-10%Target Oxygen-2-3%Plenty of room for optimization</p> <p>8CombustionCombustion RequiresAir ( 0.21O2 + 0.79 N2)FuelIgnition source</p> <p>Complete CombustionExcess air</p> <p>Incomplete CombustionEnergy Loss CO and H2 are released</p> <p>9DraftPressure inside the heaterCombustion air is drawn inside the heater through the burners air registerHot Flue gas flows out of the heater through the stack</p> <p>Types of DraftNatural Draft (ND)&gt; 80%Forced Draft (FD) &lt; 1%Induced Draft (ID) 10%Balanced Draft 10%</p> <p>10DraftStack Dampers helps control the draft</p> <p>Arch is the highest pressure point in the heater</p> <p>Excess or shortage of draft is not acceptable</p> <p>11Burner OperationCorrect combustion in firebox include:The firebox is clearNo smoky appearanceBurners flames are steady and well-formedCheck burners regularly</p> <p>Adjusting burner registers to control air intake</p> <p>12Air LeakagesAir entering in to furnace from a number of places:</p> <p>PeepholesHeader box doorsTube guide openingFeed tubes entering and exitsNot pressure tight structure</p> <p>IETC, Houston- Save Energy in Fired HeatersMay 12-13, 1999by Ashutosh Garg,Furnace Improvements, Sugar Land, TX13Heater OptimizationTarget set 2-3% O2 in the flue gas.Operating conditions fluctuates :Manual control /adjustmentsOperators Number going downExperience going downNeed training </p> <p>IETC, Houston- Save Energy in Fired HeatersMay 12-13, 1999by Ashutosh Garg,Furnace Improvements, Sugar Land, TX14Optimisation Case Study -1FIS performed a tuning job for a refinery.</p> <p>Heater:Depentanizer reboiler heaterHorizontal tube box Absorbed heat duty - 87 MMBtu/hr 15 up fired burnersThe stacks is connected to a large common stackTwo off take ducts provided with manual dampers </p> <p>15Optimisation ApproachCheck draftAdjust using off-take dampers</p> <p>Check excess O2Adjust burner register</p> <p>Check burnersLight up all burnersCheck Flames/Firebox </p> <p>16</p> <p>17</p> <p>18</p> <p>19</p> <p>20Crude Heater TuningCase Study -2</p> <p>Natural Draft Crude Heater</p> <p>Horizontal tube</p> <p>Up-fired burners</p> <p>11 burners</p> <p>21 Before &amp; After TuningFuel gas flow, MSCFDFuel gas pressure, psig</p> <p>Fuel gas Flow and PressureFired Heaters Operation School - Crude and Coker UnitsMay, 200122Before &amp; After Tuning</p> <p>Tube Skin Temp </p> <p>23RecommendationsFurnace working off design conditionsPoor quality of dampersLower number of operatorsOperator without sufficient training</p> <p>SoftwareHeater Performance Index (HPI)</p> <p>Hardware Draft control systemExcess O2 control system</p> <p>Observations in Refineries24Heater Performance IndexAnalyzes the performance of Fired Heater 24/7Built into DCSGenerates guidelinesBuilt in intelligenceCustomized modeling</p> <p>Thermal EfficiencyFuel gas rate, Draft, Excess O2, Tube skin temperatures, Feed flow rate, Pressure drop, Coking rate, Air preheater performance </p> <p>25Crude Flow RatesTAG No.SERVICEUNITSSET POINT8/15/20098/16/20098/17/2009Data 1Data 2Data 3PROCESS57FC0009.PVTotal Crude FlowBPH4337.65249.14807.34637.757FC0001.PVCrude Flow to Pass 1BPH542.2709.5711.6668.057FC0002.PVCrude Flow to Pass 2BPH542.2676.5725.0725.057FC0003.PVCrude Flow to Pass 3BPH542.2670.8671.1635.657FC0004.PVCrude Flow to Pass 4BPH542.2729.1731.1686.357FC0005.PVCrude Flow to Pass 5BPH542.2729.1731.2686.357FC0006.PVCrude Flow to Pass 6BPH542.2695.1710.1680.257FC0007.PVCrude Flow to Pass 7BPH542.2737.4743.8711.8AverageBPH542.2706.7717.7684.726Coil Inlet PressureTAG No.SERVICEUNITSSET POINT8/15/20098/16/20098/17/2009Data 1Data 2Data 3PROCESS57PI0054.PVCrude Inlet Pressure (Pass 1)psig147.9278.9287.4286.057PI0055.PVCrude Inlet Pressure (Pass 2)psig147.9296.0309.6309.857PI0056.PVCrude Inlet Pressure (Pass 3)psig147.9275.9282.8284.857PI0057.PVCrude Inlet Pressure (Pass 4)psig147.9286.0294.8293.057PI0058.PVCrude Inlet Pressure (Pass 5)psig147.9281.7290.4288.757PI0059.PVCrude Inlet Pressure (Pass 6)psig147.9283.8292.4290.257PI0060.PVCrude Inlet Pressure (Pass 7)psig147.9298.2310.0306.8Averagepsig147.9285.7295.3294.127Fluids Cross-over Temperatures.TAG No.SERVICEUNITSSET POINT8/15/20098/16/20098/17/2009Data 1Data 2Data 3PROCESS57TI0583 Crude Inlet Temperature oF542557.2553.8555.357TI0590Cross-over Temp. (Pass-1)oF610585.1581.9583.657TI0591Cross-over Temp. (Pass-2)oF610589.7586.9587.957TI0592Cross-over Temp. (Pass-3)oF610592.0589.4590.357TI0593Cross-over Temp. (Pass-4)oF610597.1594.2595.857TI0618Cross-over Temp. (Pass-5)oF610594.5591.9593.257TI0619Cross-over Temp. (Pass-6)oF610590.9588.4589.757TI0620Cross-over Temp. (Pass-7)oF610594.4591.1593.0AVERAGE Cross-over Temp.oF610.0590.9588.0589.428Coil Outlet TemperaturesTAG No.SERVICEUNITSSET POINT8/15/20098/16/20098/17/2009Data 1Data 2Data 3PROCESS57TI0633Coil Outlet Temp. (Pass 1)oF730686.8687.0687.457TI0634Coil Outlet Temp. (Pass 2)oF730678.6678.3677.557TI0635Coil Outlet Temp. (Pass 3)oF730680.2680.6679.057TI0636Coil Outlet Temp. (Pass 4)oF730678.5678.6679.957TI0629Coil Outlet Temp. (Pass 5)oF730683.4683.5683.757TI0630Coil Outlet Temp. (Pass 6)oF730670.1670.0670.957TI0631Coil Outlet Temp. (Pass 7)oF730683.0682.2683.3AVERAGE Coil Outlet Temp.oF730.0679.9679.9680.129Heater Performance Index. Remarks</p> <p>30Heater Performance Index. Remarks</p> <p>31</p> <p>Heater Performance Index</p> <p>32Oxygen &amp; Draft Control System (Natural Draft Heater)</p> <p>33</p> <p>Draft Control System34Stack dampersReliableCorrectly sizedPneumatically operatedOpposed blades</p> <p>Reliable DampersOpposed blades vs. Parallel Blades</p> <p>36Excess O2 ControlControl air supply to burnersPneumatically operated dampers or registersProvide proper control schemeDamper opening is provided based on DraftExcess O2Firing rateOther parametersSavings realized through out the day</p> <p>SummaryManual controls are not adequateEnergy prices are highAdvanced Controls possibleUse DCS based or PLC basedProvide adequate safe guards Intelligent analysis of heater parametersSubstantial savings can be realizedPayout will be less than a year in most cases </p> <p>Thank you very muchQuestions and comments are welcome</p> <p>39Drag the side handle to change the width of the text block.CONVECTIONSECTIONSTACK________BURNERS0.05"- 0.1"W.G. DRAFTDRAFT AT RADIANT SECTION OUTLET, R0RADIANT SECTION(SE)a STACKEFFECTIN STACKPc(SE)cNEGATIVE PRESSURE 0.05"- 0.1" W.G. AT TOP OF RADIANT SECTIONPb(SE)rPaNEGATIVE PRESSUREPOSITIVEPRESSURE0STACK EXIT LOSSChart40.60352265370.61901813420.60674231820.59391874780.59998898240.61230636960.61826444610.61887395660.61260860170.60580666610.5844399760.61055521330.59905813620.60192180240.59563500110.58634293920.61482827490.62006065790.59897967960.58430709240.59801861620.60538014090.59840687430.59116159270.601359450.60154279570.59719686430.60144493520.59524247780.60443812090.61645952360.58068180840.58911985860.59383782810.59241413510.59972742040.59253013790.59194603870.60727529450.62670610080.59759103970.59541116550.59836677490.60257306440.60268612360.60540387010.61692101190.59821613940.59057917560.60620753970.61758690180.6105257770.60304395420.60604035390.60977641430.60169658510.61020612340.60997850310.59311519830.58796019070.59898796980.58925941050.58568669120.60074104850.59804564950.59439128970.57396043190.58142252040.58367445340.57589835820.57847222760.56315925180.57435343580.58029523230.59431049020.59098503530.59517717740.58327754460.58848739980.58266707290.57595446730.57186481150.56399403970.58741291680.59069127360.58254566340.58189356050.56538427160.56743471640.5621946440.58695112810.58305563140.57447724830.57455240080.55570875750.57459445260.56228938070.58807628360.56760893090.55350947940.59464552270.58590193620.57321851840.55636861010.58604695480.60037201410.59963592770.58203767790.57516791880.58505194960.5987623320.60571204960.61415685820.60631098710.59953743640.60493583380.59486437220.59898460570.57873445050.58675186280.58579794820.59809463980.60515035790.60782716410.59920946260.60774651470.59223151020.59818790470.60133043420.61142123970.61088694170.60017310920.62174615330.61015800420.58739020880.59603995980.59455324910.60006930130.60528282110.60224199670.59837467460.60595967450.60322684940.59633630470.60148506460.59603761690.58573871520.5938888910.60639899550.59141498480.59474860960.60594663850.5952922190.58394160230.5915670320.6206138190.59145877870.59368475970.60230267140.58789110560.57784944070.60077643210.60776940290.61451799290.60198854460.60666782650.6078961590.59448344310.59541639190.60873686420.60047900580.59306206290.60349261670.60465961370.60127228260.60927731970.59792844520.61455349660.61848179370.60458698420.60174548530.59041727620.60444647120.59101014630.58773461290.59134589970.60190870630.59399221830.59202010990.58294875980.58765525520.5842149990.60538038120.60128573920.60340490870.6113427230.58332608440.59623898480.600206270.60212701510.60351892910.60152807760.60712997560.61687298270.61923410010.61857776190.60748218930.59302430640.58886664680.58195820.5761182890.5799010870.58670945050.57338246020.57448866240.56776998930.59139089510.58024374890.58920690580.57828269420.56232969030.57471015510.56437304640.58392412080.60330104080.6193403710.61302161030.6129580520.58764360080.60287373460.6055288840.61699219950.60313589740.58747797690.60228825370.59635865220.58110677160.57633377440.57011215330.59238584020.58715778260.60050081270.59859003980.58756745710.60190396050.61266588230.59411278670.59847343630.59433277760.6110121960.57767726870.58357449030.56709529850.5753613570.60162233370.60058695880.57993334670.58304589940.57403804750.57413374530.56950462520.58762359620.5756107240.57339309330.5703523290.57974855920.56205887680.61664124740.62839039480.58320443460.44741785240.4475027370.42358836980.40752110520.421095360.42199046220.37851739120.40638102130.36043921040.30165700840.31426707590.32179236220.33490272580.35116276780.33598273570.3723403450.53886942230.57937411810.5897194570.58353183780.59675988630.60130322070.57336660070.58989967890.60654046970.60980882420.60525128220.60330827970.61274797330.59473737580.57339880030.5859748660.59060656930.58569822540.57163905350.59648859220.59966590460.59994458780.61163402170.60219015290.60802141320.60502414250.59304136740.59320999510.59877638930.59451600320.62180863030.60688307150.61941366120.59532291680.60199803630.61645099310.60269020860.60273610510.61331350970.59956353860.5934998520.60447416530.60718614470.59254173220.58294575610.58479074790.60386765850.5939635630.60091346080.59304226850.61407182350.59786098210.57855392820.5753946980.5816187220.56761776180.58363618630.57648119590.60436495080.60648007190.61104359590.61655440670.62140613470.6218449750.61768623410.61790472320.60852417230.60746855250.60807439850.60162143260.61677082690.60422515870.6203896230.61634237940.58793844390.59266854830.61280972940.61770738020.62886588030.63998653380.61809561480.61881694020.62746888450.61845927730.61118087710.62155950350.62574407620.64244403990.64001356710.62774928540.6259835010.61295036260.6055856840.62625092030.60819130240.5913696890.60451081040.59778252550.5979859360.5990311630.59798064950.59891672210.59595699760.60762558580.60709849680.59903867230.61416373670.59497653030.58353348980.58516014280.59060218390.60714481380.61607940550.58318130610.56988339160.59533487150.57832006020.6005733820.58759121630.59841125970.61039193220.60954002320.61092226520.59247631160.5846648930.58148710.57800407110.58218113460.58075750160.60337691420.60496911480.59889191150.60340731160.60012270710.57189665070.50786830870.53684108460.53790466430.53941501410.54596268660.56890418590.56123183840.50949306940.53547932780.5039241520.53793262870.55399833140.53161561020.53372048210.54675280950.52893540990.53775769330.51251977640.38889703220.35465042230.30279883440.28575452670.3109269030.25901680290.23504566580.22139547750.22661644640.26368563190.23965057610.22786922910.24106327570.26059014030.23856167530.26313811780.26914587550.24020932420.23602493170.26070145730.27454232040.24981052670.2449794980.26130363880.25642719420.24676952210.24826103870.26970678610.25501263240.26065375860.2676422840.26655368350.26738438640.23160456860.26462548920.26026688220.24884700020.23721848130.23440143250.23832534430.26051721050.2441382220.23511835530.24206963490.2459930660.26131517310.25976418320.24470297750.25747944990.26909277010.25599039630.24423277850.23112728090.23577790750.23082534910.24408962220.24305689050.24502371240.26692337880.26239536320.26490993950.25671771190.24681752120.23951961490.24216773570.23603388270.25577509120.33300032770.44907828890.45160725080.45848455950.46751487910.47005132240.45899669020.47140124460.49658605620.50686663530.51163849120.47249447080.49078297050.48272548890.482750780.46613245690.47428794260.47876074560.48218894190.48927829770.50642929680.48928604730.4848184060.49726699470.50690820650.53225257450.51159301520.51214293230.52885316860.51815723810.50378105580.49780045160.51542110890.49147111790.46519061710.49576586630.5020587350.49969097950.52578921580.52055497060.50859165940.47680844280.47145807460.44102844480.47371144930.47755396080.47413821480.48793065830.47067194660.47624038340.48408742590.46326290340.47274101440.48748653140.48050377310.50...</p>