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Heating Oiland Its Properties

Chapter 2

Chapter 2—Heating Oil and Its Properties 2-3

Introduction to petroleumPetroleum Fuels Our Modern Life Style

More than six thousand products aremade from petroleum. It is almost impos-sible to get through a day without usingdozens of petroleum products.

Oilheat is reliableOilheat has a remarkable reliability

record. Despite wars, embargoes, politicalunrest, and natural disasters, oilheat keepsits customers warm. This reliability ispartly due to the variety of places wherecrude oil is found, the resourcefulness ofeveryone from the refiners to the local oildealer, the flexibility of the deliverysystem, and the stability and safety inherentin heating oil.

Refining oilHeating Oil is a fossil fuel, as are natural

gas, propane, and coal. They are calledfossil fuels because they are all made fromthe prehistoric plants and animals that formfossils.

Fossil fuels are hydrocarbons. Hydrocar-bon molecules are the building blocks oflife. Everything that is or was ever alive ismade of molecules composed of hydrogenand carbon atoms. Carbon is normally asolid, which, if not totally burned, becomessmoke and soot. Bonded together, hydro-carbons can be a gas like propane, a liquidlike heating oil or a solid like candle wax.The hydrocarbon gases contain morehydrogen; the liquids and solids containmore carbon.

Some Petroleum Products

Gasoline, jet fuel, kerosene, diesel fuel, heating oil, propane,butane, lubricating oils, greases, waxes, asphalt, nylon, plastics,fertilizers, washing, cleaning and polishing products, medicinesand drugs, photographic film, pesticides, waxed paper, foodpreservatives, food flavorings, beauty products, Plexiglas®, vinyl,audio and video tape, synthetic rubber, synthetic fibers, textiles,explosives, solvents, wax for candles, candy, matches, and pol-ishes, toiletries, crayons, roofing materials, floor coverings, carbonfiber, paints, lacquers, printing inks, DVDs and CDs. Five percent ofour electricity generated is oil powered.

Chapter 2Heating Oil

2-4 Heating Oil and Its Properties

Petroleum comes out of the ground inthe form of crude oil and wet gas. Both area complex mix of compounds consistingmostly of the elements carbon and hydro-gen. Sulfur and nitrogen are bound to someof these hydrocarbon compounds. Thismixture of molecules is separated at therefinery by distillation into their variousboiling ranges. Heating oil, diesel fuel, jetfuel, and kerosene are classified as middledistillates because their boiling range is inthe middle of the sweep of petroleumproducts separated in the distillationprocess. Heating oil produced directly bythe distillation process is called “straightrun” product. Heating oil is also producedby catalytically and thermally crackingheavier, more complex molecules into thesmall heating oil hydrocarbon molecules.This is called “cracked” product. Blending

a mixture of various middle distillateproducts together also creates heating oil.(Figure 2-1).

Properties of heating oilAmerican Society for Testingand Materials (ASTM)

ASTM publishes industry specificationsfor many different materials includingpetroleum products. The specification forFuel Oils is ASTM D396. This standardsets the minimum specifications for thefuel.

Flash pointThe flash point of fuel oil is the maxi-

mum temperature at which it can be safelystored and handled without serious firehazard. The ASTM specified flash point

Figure 2-1:Refining oil


GasesPropane and Burate

Naphtha

Gasoline

Kerosene

No. 2 DistillateHeavy Gas Oil

Pitch

VacuumFlashing

FractionatingColumn

CrudeI n

Pump

AdditiveInjection

HydroTreater

Preheater

Hydrogen Gas

Catalyst

Sulfur, NitrogenWater, etc.Hydro

TreatedDistillate

CatalyticCracker

SlurryOil

Residual Fuel

HeavyCat-

CrackedGas Oil

LightCat-

CrackedGas Oil

Gasoline


for No.1 and No.2 oil is100°F minimum. When oilis heated to its flash point,some of the hydrogenflashes off but the fuel willnot continue to burn.

Ignition pointThe ignition or fire point

is lowest temperature atwhich rapid combustion ofa fuel will take place in air.It is the temperature atwhich all the fuel has beensufficiently heated andvaporized to the pointwhere it continues to burnfor at least 5 seconds. ForNo. 2 oil, the ignition point is over 500°F.

Pour pointPour point is the lowest temperature at

which fuel will flow. Below this, it turns towaxy gel. The ASTM standard for un-treated No. 2 oil is 17°F. Additives orkerosene are added to heating oil during thewinter to ensure that it flows.

Cloud pointCloud point is the temperature at which

wax crystals begin to form in the fuel—typically 10 to 20 degrees above the pourpoint. These crystals can clog filters andstrainers, restricting fuel flow. Raising thetemperature causes the crystals to go backinto solution. ASTM does not list aspecification for cloud point for heatingoil. Both pour point and cloud point affectwinter performance, and could causeproblems if the fuel is not properly treated.

ViscosityViscosity is the thickness of the fuel and

its resistance to flow. Grease has a highviscosity. Gasoline has a low viscosity—itflows easily. Heating oil’s viscosity changesdramatically with temperature. As the

Heating Oil’s Physical Properties (No. 2 oil)

ASTM Specification: D 396

Flashpoint: 100°F minimum (37.8°C)

Ignition Point: >500°F (260°C)

Pour Point: 17°F (8.3°C)

Cloud Point: Pour point temp. plus 10-20° (F)

Viscosity: Varies: increases as temp. drops

Water/Sediment: ASTM allowable amount of H2O: 0.1%(Water content is usually much lower in practice)

Sulfur Content: Ranges from 0.5% to 0.05% (5000 to 500 parts per million);ASTM maximum allowable amount is 0.5%.

Color: Colorless, but heating oil is dyed red for tax compliance reasons.Color resembles cranberry juice.

BTU Content: 139,000 (approx.)

temperature decreases, viscosity increases.Normally the temperature of oil in abasement tank is 60°F. In the winter, youmight get a delivery of 5°F oil. The colderoil will have a higher viscosity and burner



ColorHeating oil is dyed red to differentiate it

from on-road diesel fuel for tax compliancereasons. Problems with the fuel are notindicated by the darkness of the color. Amurky appearance, however, may indicate afuel quality problem.

Fuel related service callsThe oilheat industry’s top two service

priorities are improved reliability andreduced heating equipment service costs. Asignificant number of unscheduled no-heatservice calls are caused by inconsistent fuelquality, fuel degradation, and contamina-tion.

Heating oil varies during the season.Wholesalers get their product from aroundthe world, from Malaysia to Texas. Each ofthese products is slightly different; as aresult, the product in the customer’s tankmay be a mixture of a variety of fuels. Agreat deal of our product is created byblending various fuels together to meet therather loose definition for #2 heating oillaid out in the ASTM D 396 specification.Additionally, over time, fuel degrades—water may enter the system and bacteriahave an opportunity to grow. Good house-keeping, installing filters on all customers’burners, and an aggressive problem-tankreplacement program can cut fuel relatedservice calls dramatically.

Potential problems in the tankThe population of oil tanks in the field

is aging. As the tanks age, rust and sedi-ments build up in the tank. Secondly, oilhas a finite shelf life and breaks down overtime. The third problem is the size andspeed of delivery. Filling a tank kicks-upall the sediments and rust in the bottom ofthe tank, and that leads to plugged lines,filters and nozzles. The solutions here arenot to let the level of oil in the tank get toolow, to slow down the pumping speed of

Good housekeep-ing, installing filterson all customers’burners, and an

aggressiveproblem-tankreplacement

program can cutfuel related servicecalls dramatically.

performance will be affected untilthe fuel warms. As stated in theNozzle Chapter (Chapter 5), coldoil causes poor atomization, delayedignition, noisy flames, pulsation,and possible sooting.

Water and sedimentAccumulation of water in tank

bottoms is undesirable, since it leadsto the formation of sludge and ice.

Sludge is largely oil and water. Water andoil usually do not mix, but if organicsediment is present in the fuel, it acts as abinder to stabilize the mix of fuel and

water. This forms a white milky substancethat will not burn. The ASTM limit forwater is 0.1%, but most fuel sold has muchless water. Unfortunately, water can getinto the system from condensation, leaks inlines, or missing vent and fill caps.

Sulfur contentSulfur exists in varying degrees in all

fossil fuels. The sulfur content of heatingoil ranges from 0.5% to 0.05%; the ASTMmaximum is 0.5%.

When the sulfur burns, it mixes withoxygen and forms sulfuric dioxide. It alsocreates a small amount of sulfur trioxide.The sulfur trioxide reacts with the watervapor in the combustion gases to create asulfuric acid aerosol. If the acid condenses(at 150-200°) it adheres to the heat ex-changer, flue pipe and the inside of thechimney. It creates a scaly yellow to redcolored crust. Scale makes up 50% ofdeposits on the heat exchanger. It down-grades efficiency by 1% to 4% over theyear. It also blocks flue passages, restrictingair flow and increasing smoke and soot.

Using low sulfur fuel all but eliminatesscale and soot formation on heat exchangersurfaces. The efficiency does not degradeover the heating season, saving energy. Italso results in decreased appliance service.



the truck, and to use diverters on the “blowor whistle pipes” (underground fill pipes)when filling underground tanks.

Major factorsin fuel degradation

1. Chemistry of the fuel

• Heat causes the oxidationof organics

• The presence of sulfur andnitrogen hasten degradation

• Corrosion creates iron oxides(rust)

• Presence of Gels caused bymercaptan sulfur

• Incompatible fuels

2. Microbiological effects

3. The tank and its environment—moisture, fuel circulation due to tempera-ture differences

4. Lack of tank maintenance and poordesign and installation that prevent ad-equate tank inspection, withdrawal of waterand sediment, improper or no filtration,and lack of corrosion protection.

Fuel stabilityFuels degrade over time. If the fuels are

contaminated, they will degrade even morequickly. The stability of heating oildepends a great deal on the crude oilsources from which it was made, theseverity of the refinery process, the use ofadditives and any additional refinerytreatment. Fuels that are stored for longperiods of time and subjected to tempera-ture extremes may form excessive amountsof sediments and gums that can plug filters,strainers, and nozzles.

Detecting “out of spec” oilOccasionally, a bad batch of oil will be

delivered. When that happens, there will bemany service calls. If there is a spike incalls and they appear to be fuel related, youshould alert your service manager. A fuelsample might show that the fuel can befixed with additives, or the fuel may needto be replaced.

Water problemsThe worst fuel problem is water in the

oil tank. Water enters the tank in thefollowing ways:

1. Condensation

2. Broken tank gauge (outside tank)

3. Loose fill or vent fittings andmissing caps

4. Directly from delivery trucks

5. Leaking vent, fill pipes, or tank

6. Pumping old oil into a new tank

SludgeSludge is a combination of water,

colonies of bacteria, degraded fuel, andother contaminates like sand, grit and rust.The ability of bacteria to grow almostanywhere and reproduce amazingly fastmakes it an all too common problem. Thebacteria live in the water and eat the fuel.They break the fuel down into hydrogen,CO

2, and carbon rich residue. The bacteria

also create sticky slime or gum to protectthemselves. Scientists call this slime“biofilm.” This deterioration of fuel is anatural occurrence that will appear in alltanks unless proper maintenance is per-formed. The sludge grows at the oil-waterline and when stirred up can to lead seriousand recurring service problems—mostnotably plugged fuel lines, filters, strainers,and nozzles. Sludge is acidic and mayeventually destroy the tank from the inside.



To reduce sludge formation:

• Never pump oil from one tank toanother. You may be transferring tankkilling sludge.

• Slow down delivery rates—highpressure filling can stir-up existing sludgecausing it to be drawn into the oil line.

• Routinely check the tank for water—once you have removed the water, ifpossible, clean the sludge from the tank andtreat the tank with a fuel conditioningadditive.

• Draw the oil from the bottom of thetank—As water will condense andcollect in all tanks, it is best todraw off the water as if forms. Itwill burn off in the combustionprocess. Allowing water toaccumulate will create conditionsfavorable for the formation ofsludge.

• The exception to this rule is outdoorabove ground tanks. In cold weather, thewater in the bottom suction line mayfreeze, causing a blockage and no heat. Itappears that the best solution to thisproblem is to run the suction line into oneof the top tappings on the above groundtank, use a floating suction line device, andregularly remove the water that condensesin the bottom of the tank.

Low temperature performanceAs oil gets cold, several bad things

happen. First, any water in the fuel freezes,plugging lines and filters. Second, theviscosity of the oil begins to increase,causing burner operation problems. Third,wax crystals begin to form in the oil. Thiswax or paraffin is a natural component ofheating oil. Oil temperature is the mainfactor in changing oil viscosity. As the

temperature of the oil goes down, theviscosity goes up. The oil gets thicker,which can cause a smoky fire.

How to deal with “frozen”tanks and oil lines

Cold-flow additives, called Pour PointDepressants, can help avoid frozen lines,but once the tank or lines have frozen orwaxed, other solutions are needed.

The best solution is to top off the tankwith kerosene. The agitation of the fuel inthe tank caused by the kerosene deliveryand the solvency of kerosene break up and

dissolve the wax crystals. You may alsohave to remove the filter temporarily,convert to a one-pipe system and heat thesuction line with a hair dryer or heat lamp.

If you are unable to arrange for adelivery, some technicians report thatadding as little as five gallons of kerosenecan help.

Others report having success “shocking”the tank with a pour point depressant. Youmay have to build a temporary shelter forthe tank out of plywood or cardboard,whatever is at hand, and then use a heatlamp or hair dryer to warm up the linesenough to get the oil to flow. Be verycareful with heat tape. If you wrap a heattape over itself, it can burn through its owninsulation causing a short that can result ina fire. The insulation on the wires can alsocrack with age and exposure to the ele-ments creating potential for a fire.


good fuel. The purpose of this test isto visually determine the possiblepresence of contaminants and waterin the fuel.

Fill a clean white bucket half waywith fuel and let the sample stand fora minute to remove the air bubbles.Place the bucket on a level surfacewith good light in the bucket. Inspectthe fuel, it should be clear and brightwith no water, or solids. It should notbe hazy or cloudy, and there shouldbe no brown or black slime. Drop ashiny coin into the bucket. If you can easilyread the date, the fuel is probably OK. Thefuel should also smell “normal.” Strangeodors can indicate problems. With eitherthe ‘clear and bright’ or ‘white bucket’test, a haze caused by wax crystals mayappear in the fuel if it is too cold. A hazein fuel that is not too cold may be due tocontamination with water.

Visual detectionof bacterial contamination

The ‘clear and bright’ and ‘whitebucket’ tests can also be used for testingtank bottoms, filter cans, and fuel pumpdrainings for the presence of microorgan-isms and sludge. There will be evidencethat can be seen and smelled.

Put the fuel into a clean white bucket orclear glass jar. Allow the sample to settle fortwo minutes. Tip or swirl the containerfrom side to side, looking for any evidenceof dark colored solids, dark colored water,substances that cling to the side of thecontainer, or a scummy mucus like material.Hold the sample in front of a light. Check tosee if the solids are rust. Move a smallmagnet along the outside of the container.Rust particles will collect and follow themagnet. If the sample is a dark-colored,sludge-like material and it does not respond


Quick testsfor fuel quality:Clear and bright test

The purpose of this test is to detectpossible water or solid contaminants in thefuel by visual inspection. Using a cleanglass container, take the sample at the bleedport of the fuel unit. Be sure the fuelsample tap (the bleed valve) is clean andfree of loose contaminates by flushing itout at maximum flow before drawing asample.

Let the sample settle for a minute toremove the air bubbles. Observe the sampleagainst a light background for a clear

bright condition. The sample should lookmore like cranberry juice than red wine.Swirl the container to create a whirlpool.Free water and solids tend to collect at thebottom of the whirlpool. The term “clearand bright” does not refer to color. “Clearand bright” fuel has no floating or sus-pended matter, and no free water. Brightfuel tends to sparkle.

White bucket testThis is a good quick test for drivers to

be sure you are filling your truck with


Slight Haze

Ice

Base Fuel with WaterBelow Freezing Point

Base Fuel

one of two categories: spin-on filters andcartridge type filters. The spin on filter issimilar to the oil filter on your car. Thefilter container, or can, and filter element(resin-coated filter paper with large surfacearea folded into a filter housing) are all onepiece. The cartridge type has a replaceablefilter element cartridge that you place into afilter can that attaches to the filter head. SeeFigure 2-2.

Filter elements are made from a varietyof materials, including: wool felt, woundyarn, sintered plastic in a continuous micro-spun fiber, resin-coated paper, and stainlesssteel mesh. Filters are sized by flow rategallons per hour (GPH) and pressure drop(inches mercury Hg). Each filter also has amicron, or mesh rating. These ratingsrepresent the amount of pressure drop orfiltration capability. The rating means thefilter will remove 95% of the particles ofthat size or larger. A lower micron/meshrating indicates a tighter filter construction,able to remove finer particles.

Filter elements made from sinteredplastics with pore sizes in the range 30-75microns and large surface area or spin onfilters with resin-coated paper in the 10micron range seem to work best. Most fuelunits contain a 100 micron mesh strainer.

Nozzles also have a mesh or sinteredbronze filter nominally rated for filtration to40 microns. The tangential metering slots—the things that get plugged up in thenozzle—are typically 60 to 90 microns.Grease or dirt on your fingers can plug thenozzle, so they must be carefully handled.Felt and wound yarn filters may shed finefibers that may clog low firing rate nozzles.See Figure 2-3.

To be fully effective, a modern filtermust stop particles from reaching the


Figure 2-2:Filters: Cartridgetype and spin-on

to the magnet, then it is probably bacterialcontamination.

Other indicators of these microorganismsare a matty, lumpy, or stringy consistencyand a rank moldy odor.

Water detection pasteWater detection pastes determine the

depth of water at the bottom of the storagetank. Apply the paste in a thin coating on agauge stick from zero up to a couple inchesabove the suspected oil water interface.Carefully lower the stick into the tank untilit lightly touches bottom. Hold it in thisposition for 30 seconds to a minute. Removethe stick— the water level will be clearlyindicated by a definite color change wherewater contacts the paste. Water paste willnot detect an oil-water emulsion. You shouldcheck customers’ tanks for water once ayear, and then drain off the water if de-tected.

Oil filtrationThe installation of filters in burner fuel

suction lines is strongly recommended.Filters protect the pump and nozzle bytrapping contaminants before they reach

these components. Thereare passages in theoilburner nozzle that aresmaller than the diameterof a human hair. It takesvery little contaminationto plug up these passagesin the nozzle. This is whyit is critical to do every-thing to be sure clean oilis delivered to the burner.

There are a widevariety of filters avail-able, but they all fall into


Replaceable Element Spin-on Cartridge

Figure 2-3:Relative size ofmicronicparticles



biologically active sludge. There is alwayssome water dissolved in the fuel. This iswhy sludge can sometimes grow faster onfilters and strainers than it can in the tank.

The rate at which sludge grows dependson the temperature and the availability ofmoisture and nutrients. Filters may plug,even with new tanks and lines. The “seed”sludge particles can arrive with the fuelfrom a contaminated tank upstream in thedistribution system. They can be drawndirectly into the suction line before theyhave a chance to settle to the bottom of thetank. If the conditions are right, a filter canplug within weeks of installation, even with

nozzle. There are two approaches tohow a filter should react when it is full.Some filters allow oil to bypass thefilter when the element is full; othersare designed to stop the flow of oilwhen they are full.

While the filters that will notallow bypass will cause a no heatcall when they are full, they ensurethat no particles reach the nozzle.With the bypass type filter, once thefilter is full, it will allow the con-taminants to flow down stream andplug the pump strainer and nozzle.This will take longer to happen, butwhen it does, it will require work onthe burner.

Many service managers are nowadvocating the installation of twofilters on problem installations. Theyinstall a large standard cartridgebypass filter at the tank and a 10-micron no-bypass spin-on filter at theburner.

Filters and sludgeFilters may fail because they have

become blanketed with biologically activeslime or sludge. The resulting black or gray“ball of grease” is a tough service problem.This sludge is not material that has beensucked from the tank; it is alive andactually growing in the filter.

When small particles of sludge in the oiltank are drawn into the oil line, the bacteriain these particles look for moist places toreproduce. If there is any water pocketed inthe bottom of the filter canister or if thereis water emulsified in the fuel, they cangrow their biofilm. Contrary to popularbelief, there does not have to be a layer offree water in order to support the growth of

an immaculately clean tank. Also, sludge iscorrosive. Untreated sludge can attack thesteel filter housing, causing pinhole leaks.

The answers to sludge fouling of filtersis good housekeeping throughout thedistribution system, keeping water out oftanks, and removing existing water. Inproblem jobs, the use of an effective sludge-control additive may be required. If youtreat an already fouled system with aneffective sludge dispersant, tiny darkparticles are released from the biofilm as itbreaks down. These particles are similar tothose that result from fuel instability.Unstable fuel is usually dark in color—burgundy cherry to coffee colored. In bothcases, the double filter system describedabove seems to the best answer.

Replacing theoil filter element

Cartridge type filter—shut off the oilthen loosen the nut on the top of the filterhead and lower the can from the head. (Usecaution; the can is full of oil.) Remove theelement and the gasket and clean inside thecanister. Inspect the old element. Excessivesludge or evidence of water calls for action.Check the inside of the can for pitting andrust. Install the new element and newgaskets, reassemble, open the oil valve, andbleed the air out of the filter through thebleeder.

Spin-on type—shut off the oil and usinga filter wrench, loosen and spin off the oilcartridge. Cut and remove the old centerstud “O” ring and replace it with a new “O”ring. Remove the outside filter gasket on thenew filter and apply a thin coat of petro-leum jelly to both sides of the gasket.Carefully replace the filter gasket. Fill thecartridge with clean oil and spin it onto thefilter head. Bleed the air from the filter.


Steps to Better Fuel Performance

Before removing the fill cap for a buried tank, thedriver must be sure water, dirt, snow or ice cannot fallinto the tank. After delivery, drivers should check gas-kets and O-rings if needed on the fill cap to be sure theyare in good shape, reinstall the fill cap, and makecertain it is sealed tight.

While making a delivery, the driver should check tobe sure the vent cap is in place, there is no wateraround the fill, the vent pipe is solid, and there is nowater in tank.

On above ground outdoor tanks: are the tank legsstable on a solid foundation? Are there signs of rust,weeps, wet spots, deep scratches, or dents on the tanksurface, oil leaks, or signs of spills, and does the tankneed painting?

Sampling of tank bottoms should be done routinely(during the tune-up) for cleanliness and lack of water.

If excessive sludge and water are found, theyshould be removed as soon as possible.

Hold up on deliveries to problem tanks until thesludge and water problem is solved.

Once the sludge and water are removed from thetank: fill the tank with kerosene or specially treated fuel,tune-up the burner, hand-pump the oil lines thoroughly,then replace the filter, strainer, and nozzle. Schedule afollow-up call a month later to see to it that the tank andlines remain clean.

The tank’s fill boxes, fill pipes, vent caps and pipesand remote fills should be checked for cracks and leakson every delivery and tune-up. Often the problem is ahole in the vent pipe just below ground level. Dig a fewinches of soil away from the vent to check for rusting. Ifthe fill box is in a driveway, it should be a “mushroom-type” fill box with a watertight gasket rather than ametal-to-metal fit.

When additives are used, they should be addedbefore filling the tank, if possible, to facilitate propermixing.


Fuel additive treatmentAdditives are designed to prevent or

retard fuel deterioration. Numerous types ofadditives are available on the market. Asuccessful fuel treatment program requiresknowledge of the quality of the fuel in thetank and the specific service problems.Using an additive off the shelf withouttesting may be more harmful than doingnothing at all.

Selection of additives: The multifunc-tional aftermarket additives available forheating oil are proprietary products thatoffer a range of properties.

Guidelines:

• Define the problem and the additivethat is needed.

• Make sure the fuel sample being testedrepresents the fuel being treated.

• Will the additive be used once, or iscontinuous treatment required?

• Does the additive perform more thanone function?

• Does the additive supplier havetechnical support if there are questionsor problems?

• Can the supplier provide a way todetermine effectiveness in specificcases?

• Follow all safety and handling instruc-tions on the labels and Material SafetyData Sheets that should accompany thepackage.

• Follow the recommended treatmentrates.

• Properly dispose of the additive

containers. Know and follow the locallaws concerning disposal of sludge andwater bottoms.

Types of additives:

Cold flow improvers: Flow improversare designed to lower the cold temperatureoperability limit for the fuel, and to avoidwax plugging of the filters. Pour pointreducers or anti-gels lower the temperatureat which fuel gels or solidifies, and coldfilter plug point reducers lowers thetemperature at which wax plugs the filter.Once wax has formed in the fuel, anadditive will not change the waxes present.To dissolve wax, a solvent such as kero-sene, must be used.

Dispersants: Dispersants or detergentskeep the little chunks of junk floating infuel so they can slip through the fuelsystem and be burned, rather than lettingthem settle to the bottom of the tank. Initialuse of dispersant may cause filter pluggingas existing deposits, sludge, and dirt arebroken up, suspended in the fuel andpicked up by the pump.

Antioxidants and metal deactivators:Fuel degradation caused by oxidation oraging leads to gum deposits. Antioxidantadditives can slow this process. Dissolvedmetals, such as copper, can speed aging anddegradation, and produce mercaptide(sulfur containing) gels. To minimize theseeffects, metal deactivators combine withthe metals and render them inactive.Periodic monitoring of fuel stability isrecommended if these additives are beingused.

Biocides: Serious problems can arisefrom microbial proliferation, includingsludge formation, acid and surfactantformation leading to operational problems.(Translation: Critters can grow in the oil




tank. They create a sludgy mess that willcause lots of no heat calls.) Biocides kill orprevent the growth of bacteria and othermicroorganisms. They must be fuel-solubleand must be able to sink to the water in thebottom of the tank where all the microbeslive. Microbiological organisms in fuel arebacteria, molds, and yeast. Since biocidesare poisons, you have to very careful. Readthe label to determine product use, treat-ment rate, and human exposure hazardswarnings.

Preventative maintenanceGood housekeeping means doing

everything you can to minimize dirt andwater from entering tanks. Water promotesthe growth of microbes, which use the fuelas a food source, and accelerates the growthof sludge and internal corrosion of thetank. Water can enter the tank throughcracked or leaking fill pipes and vents.They should be checked periodically andwhenever water contamination is suspected.Varying air temperature and humidity cancause condensation within the tank. Dirt

and debris are generally introduced into thefuel through careless handling.

Use of rags for cleaning componentsThe rags used for cleaning can be a

source of trouble. Using a rag contaminatedwith sludge or microbes can introduce thesecontaminates to a clean system. Also, if theyare of a loose weave or have frayed edges,strings or fibers, lint from these rags can getinto the system and plug the nozzle.

Tank cleaningWith massive accumulations at the

bottom and on the sides of the tank,mechanical cleaning, fuel filtration, the useof additives and a preventative maintenanceprogram are the only way to effectivelyremove the sludge. Portable tank cleaning/filtration machines are available. Theireffectiveness depends upon the conditionof the tank, access to the interior, and theoperator’s skill. Before attempting to cleanthe tank, let the burner draw the oil down aslow as possible to minimize the amount offuel you will have to dispose. There arecompanies that offer tank-cleaning service.However, cleaning a residential heating oiltank is usually expensive and difficult, anda tank replacement may be more economi-cal and effective.

Tank replacementIf the tank has gone too far, tank and fuel

treatment remedies will only buy you sometime. A tank’s surface contains microscopicpits and craters where bacteria can ‘hide.”Once fresh fuel is added and a bit of watercondenses, the bacteria can reproduce at anastounding rate and sludge formationbegins. Often, the only solution is toreplace the tank and oil lines. Never pumpthe oil from the old tank into the new one.

Figure 2-4:Tank shedcovering anoutdoor, aboveground tank



You will be transferring contaminates thatcaused the problem in the first place. It willtake surprisingly little time to make the nicenew tank as dirty as the old one.

If you are installing (or maintaining) anoutdoor, above ground tank, it is recom-mended you paint it a light color to reflectthe light. This will help keep the tankcooler and minimize moisture condensationinside the tank. Also, there are severaltypes of tank sheds available, Figure 2-4.They minimize water build-up and frozenlines as the tank temperature is steadier.

Keep the tank fullTopping off oil tanks, especially outdoor

above ground tanks in the spring, helpsprevent condensation—the less air in tank,the less condensation.

Bioheat fuel®

Biofuel is a renewable, biodegradablecombustible liquid fuel. Biofuel is manu-factured by processing vegetable oils suchas soy and rapeseed (canola). It is alsomade from waste cooking oils and trapgrease, tallow, and animal fats such as fish

oil. Biofuel has an ASTM specificationD6751 for pure biofuel (B100). It has 10-12% oxygen, so it will increase excess airto the flame. Its heating value is 125,000Btu per gallon. It has a slightly higherdensity and higher cloud and pour pointsthan #2 oil.

Bioheat fuel® is a blend of 95% or more

If you are installing (or maintaining)

an outdoor, above ground tank, it is

recommended you paint it a light

color to reflect the light. This will help

keep the tank cooler and minimize

moisture condensation inside the

tank. Also, there are several types of

tank sheds available. They minimize

water build-up and frozen lines as the

tank temperature is steadier.

#2 oil and 5% or less B100 biofuel. We calla 5% blend B5. Bioheat can be used inoilburners with little or no modifications tothe equipment or operating practices.While flashpoint is higher, ignition withblends of 5% or less is no problem. Theviscosity is higher, yet still within ASTMlimits for heating oil; but flow rate andatomization are similar. Bioheat will createslightly less deposits on the heat exchangerthanks to the reduced sulfur levels.

Bioheat fuel® has strong public appeal asa renewable fuel. It has good lubricitythat will help with low sulfur fuels. Itincreases our fuel source diversity,reducing dependence on foreign crudeand is a potentially huge market forAmerican agriculture.

SummaryMost of our fuel problems are created in

the customer’s tank and heating systemlong after delivery. Oilheat reliability isdependent on the technicians in the field,keeping customer’s systems operating atpeak safety, dependability, and efficiency.


ready heating oil and its properties chapter · heating oil and its properties chapter 2 chapter...

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