Heating oil

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Heating oil is a liquid fuel . As the middle distillate of petroleum , it is made from gas oil .

Types of heating oil

DIN 51603 and the corresponding ÖNORM C 1109 differentiate between several types of heating oil. The heating oil qualities are designated according to increasing density , the ash and sulfur content and the ratio of carbon to hydrogen (C / H):

  • Tbsp (extra light)
  • Low-sulfur EL, mainly intended for use in condensing systems; Mandatory if the condensate is discharged into the sewage system without prior neutralization. The filling connection is usually closed with a green cover
  • L (light)
  • M (medium)
  • S (difficult)
  • ES (extra hard)

The types L and M usually come from tar oils and are only rarely used.

Extra light heating oil (HEL)

Heating oil
other names

HEL, IGO (Industrial Gasoil)

Brief description Fuel for private use; colorless to yellowish liquid with a characteristic mineral oil odor, turns red in color


CAS number


Physical state liquid

6.0 mm 2 / s (20 ° C) max


0.820-0.860 kg / l (15 ° C)

calorific value

36.0 MJ / l = 42.6 MJ / kg (at 0.845 kg / l) corresponds to 10 kWh / l = 11.8 kWh / kg

Calorific value

38.4 MJ / l = 45.4 MJ / kg (at 0.845 kg / l) corresponds to 10.7 kWh / l = 12.6 kWh / kg

Boiling range

141-462 ° C

Flash point

> 55 ° C

Ignition temperature > 225 ° C
Temperature class T3
Carbon dioxide emissions from combustion

2.65 kg / l

safety instructions
GHS labeling of hazardous substances
02 - Highly / extremely flammable 07 - Warning 08 - Dangerous to health 09 - Dangerous for the environment


H and P phrases H: 226-304-315-332-351-373-411
P: 210-260-273-280-301 + 310-331
UN number 1202
Hazard number 30th
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

DIN 51603-1 differentiates between two types of heating oil EL : Heating oil EL (abbreviated: HEL ) and heating oil EL low-sulfur . The designation "EL" stands for "extra light (liquid)". "Heating oil EL" differs from "Heating oil EL low-sulfur" in its maximum sulfur content. According to DIN 51603 Part 1, EL heating oil may contain a maximum sulfur content of 1000 mg / kg since January 1, 2008, and EL low-sulfur heating oil a maximum of 50 mg / kg. Both types of heating oil according to DIN 51603-1 are provided with a "refinery additive" for safe logistics:

  1. HEL standard with "refinery additive" (including additives to improve the filterability limit, see below)
  2. HEL low-sulfur with "refinery additive" (including additives to improve the filterability limit, see below)

However, the HEL Standard type of heating oil is no longer produced in Germany and has a negligible market share of less than 1% due to isolated imports. Low-sulfur heating oil was specially developed for use in condensing boilers , which represent the current state of the art. The neutralization of the condensate can be omitted when using low-sulfur heating oil.

Almost all dealers also offer heating oil in "premium" quality. This is characterized by a special additive package (stabilizers, metal deactivators, odor maskers, possibly combustion improvers), which is added to the heating oil by a metering device on the tanker during delivery. This "premium" heating oil EL has above all increased thermal stability and increased storage stability and thus meets the changing requirements for heating oil (longer storage time due to reduced annual consumption; higher thermal load in recirculation and evaporation burners).


HEL is a mixture of kerosene , various gas oil fractions and various additives (the latter in the mg / kg range). Kerosene and gas oil are mainly by fractionation of petroleum as middle distillate fractions obtained and for the HEL-producing - at least partially - in Hydrodesulfurierungsanlagen desulfurized. Middle distillate fractions from cracking plants are also used (for example hydrocracker (HCU) kerosene, HCU gas oil, hydrogenated light cycle oil ).

HEL is a mixture, a blend, tailored to the required specifications . The available components can vary greatly in quality (depending on the crude oil), so that each batch may have to be produced with different mixing ratios ( kerosene / light gas oil / heavy gas oil) in order to meet all specifications. Furthermore, the products are diesel fuel and jet for (almost) all components "in direct competition" to HEL (see also: combined production ). Different demand volumes of the middle distillate products therefore have an influence on the composition of HEL (see also: Production planning ).

In contrast to diesel, HEL has no seasonal specifications, so it does not require any seasonal blends .

In 2009, around 15.07 million tons of EL heating oil were produced in Germany.


Additives (Latin additivum added, enclosed) are defined as additives that are added to fuels, fuels and lubricants in order to achieve and improve the desired properties. The filterability limit ( Cold Filter Plugging Point , CFPP; a temperature specification) can be reduced for all HEL grades by using appropriate additives.

Antioxidants, metal deactivators, detergents and dispersants prevent the formation and "flocculation" of aging products and increase the thermal stability of the HEL. Such additives are added to the "Premium" HEL.

The lubricity of the low-sulfur HEL is adjusted by additives that improve the lubricating properties (see below). Ash-forming additives such as ferrocene are not permitted in low-sulfur heating oil.


The main components of the HEL are predominantly alkanes , cycloalkanes and aromatic hydrocarbons with about 9 to 22 carbon atoms per molecule and a boiling range between 150 ° C and 390 ° C. Further properties are determined by the specifications.


Logo of the German Institute for Standardization DIN 51603-1
Area -
title Requirements and test methods
Brief description: Specifications for minimum requirements and tests for EL heating oil
Latest edition -
Qualitative boiling processes

The specifications are regulated by the DIN 51603-1 standard.

The new version of DIN 51603-1, which has been in effect since September 2011, also allows paraffin fractions obtained from synthesis or hydrogenation, such as hydrogenated vegetable oils, in standard and low-sulfur heating oil . It must not contain reconditioned used oil, admixtures of chlorine-containing substances or inorganic acids. In addition, the limit value for the thermal sediment that may form in the method for determining thermal stability was set at 140 mg / kg and a test method for determining storage stability was defined.

The sulfur content is limited to 1000 mg / kg and, for HEL, to 50 mg / kg. In winter, the precipitation of paraffin crystals can lead to blockages in the fuel filter or - in the case of outdoor storage - the fuel supply may come to a standstill. Therefore, the lines between the external tanks and the burner must be laid in a frost-proof manner. This is the case with a minimum depth of 1 meter. Two test parameters describe the cold behavior of a fuel: the so-called cloud point (abbreviated CP) and cold filter plugging point (abbreviated CFPP). While the CP can be influenced by changing the production of HEL (kerosene admixture), the CFPP is often adjusted by adding additives. The CP may not exceed +3 ° C. The Cold Filter Plugging Point specification is tied to the current cloud point :

  • Max. –12 ° C with a CP of +3 ° C
  • Max. –11 ° C with a CP of +2 ° C
  • Max. -10 ° C with a CP <= +1 ° C

For example, if the CP = +3 ° C, the CFPP must be –12 ° C, if the CP is +2 ° C, the CFPP can be increased to –11 ° C. A lower CP means a higher proportion of kerosene in the blend, but - due to the lower CFPP - a lower consumption of CFPP improver additive. The manufacturer then decides which blending strategy is the best economical solution for him.

The so-called pour point (PP) no longer plays a role in the HEL specification.

Furthermore, the density specification (<= 860 kg / m³), ​​the calorific value (> = 45.4 MJ / kg), the viscosity (<= 6.0 mm² / s at 20 ° C) and the flash point (> 55 ° C) are worth mentioning . The low viscosity guarantees - even without preheating - sufficient atomization at the burner nozzle, the relatively high flash point safe handling and storage. In order to ensure the lubrication of the heating oil pumps , the lubricity is also specified for HEL with low sulfur content. It is determined using the HFRR method and should be a maximum of 460 µm (analogous to diesel).


Approx. 16.13 million tons of HEL were sold in Germany in 2015. The deficit compared to the lower domestic production volume is mainly covered by imports via Rotterdam. In 2001, 60% of the consumption was in private households, 30% in trade and 8% in industry (including non-energy consumption). The rest (2%) was used to generate electricity, district heating and gas.


Technically speaking, HEL can be used as a fuel in (older) diesel engines. Up to 1994 both products were almost identical, so that at that time diesel engines were able to burn HEL without any problems. However, using it as fuel for vehicles is a criminal offense as tax evasion . Furthermore, the operating license of the motor vehicle expires, with all the legal consequences resulting from this.

To avoid confusion, HEL (and HEL low in sulfur) are colored with a red dye. The German Mineral Oil Tax Act , in its original version from 1964, prescribed the dye Sudan Red 7B (Solvent Red 19) for marking tax-privileged mineral oils (e.g. heating oil) . The compound is a powder dye and its processing has known disadvantages, e.g. B. Risk of exposure in production and processing, high consumption of solvents for the manufacture of the "packages" and time-consuming dissolving processes. With the approval of modified dyes, the Mineral Oil Tax Act 1977 was adapted to the current technical and industrial hygiene requirements. Liquid dyes have been used and processed since then. According to the current ordinance and specification of the Federal Ministry of Finance in the Mineral Oil Tax Act and TRGS 614 (restrictions on use for azo dyes that can be split into carcinogenic aromatic amines) for marking mineral oil, a liquid dye is used that consists of two components (CAS numbers 56358-09-9 N - (2-Ethylhexyl) -1 - [{2-methyl-4 - [(2-methyl-phenyl) azo] phenyl} azo] naphthalen-1-amine and 57712-94-4 1 - [{2-methyl -4 - [(2-methylphenyl) -azo] - phenyl} -azo] - N -tridecylnaphthalene-2-amine). In addition, the dye Solvent Red 215 (CAS No. 85203-90-3) is used for mineral oil export . The liquid dye mentioned (CAS number 56358-09-9) is also imported into the Federal Republic of Germany for the same area of ​​application. In addition, to the knowledge of the AGS, mineral oils are imported from neighboring EC countries which, according to local regulations, contain the azo dyes Sudan IV (85-83-6), Solvent Red 164 (92257-31-3) or Solvent Red 215 (85203- 90-3) are colored. Since 2002, the EU has switched over to labeling with the yellow marker Solvent Yellow 124 (34432-92-3), the analytical detection of which is much less complex to carry out. Since Solvent Yellow 124 only insignificantly colors the heating oil, 4.1 to 4.9 mg / l of the azo dye mixture Sudan Red M 462 are added. Sudan red M 462 consists of the above-mentioned red dyes N -ethyl-hexyl- (tolylazotolylazo) naphthyl-2-amine and N- tridecyl-1- (tolylazotolylazo) naphthyl-2-amine and can split off the carcinogenic o-toluidine .

Neither the coloring nor the marking material impair the use in engines and heating systems. Small amounts of Solvent Yellow 124 in the fuel can be detected using simple methods. Targeted inspections leads inches regularly and in justified cases of suspicion.

Since 1995 the differences in quality between diesel and HEL have grown steadily. For example, HEL contains up to 1000 mg / kg sulfur, while diesel is available nationwide in Germany and Austria with 10 mg / kg sulfur content. Today's engines and downstream emission control systems would be permanently damaged by the high sulfur content. Furthermore, a (minimum) cetane number is guaranteed (specified) for diesel , HEL has no such specification. It can therefore have a cetane number well below the diesel specification, resulting in nailing and soot emissions ( fine dust ). The missing specifications, which limit the proportions of heavy components in diesel (diesel density, T95 ) , are even more serious . The relatively high proportion of heavy components in the HEL can lead to increased soot formation.

Friction guidance

Friction line is the name for an illegally installed return line in tank vehicles. After passing through the meter, part of the delivery is pumped back into the vehicle's tank through one or more friction lines. During the entire pumping process, part of the oil is counted several times, so to speak. The result is that the dial gauge shows more than has actually been pumped into the house tank. The name is derived from the Reibach won as the profit. These lines are uncovered by test runs by the TÜV or calibration office . A fuel gauge on the oil tank can indicate the application of the friction line. In Germany, the offense of fraud under Section 263 of the Criminal Code is already met when attempting to use fraudulent guidance. Tank trucks should only have a single line. Instead, air is sold instead of heating oil.


Heating oil prices in Germany since 1960
year price
(annual average in cents per liter)
Data source: de.Statista.com

The prices for HEL are based on the Rotterdam market (trade name: IGO = Industrial Gasoil). It is traded in US dollars per 1,000 kg (US $ / t). Various publications such as Platts , ICIS or OMR report (sometimes daily) on current trading prices and volumes. The reference density used in trade (to set the price of a current batch with a given density in relation to the quotation) is agreed to be 0.845 kg / dm³ (as with diesel fuel ).

Furthermore, transport costs, storage costs (+ various other costs) and the desired interest on the capital employed must be taken into account when determining the price.

The price of heating oil, like the prices of diesel and petrol, depends directly on the level of crude oil. This has deteriorated dramatically in recent years. Since 2012, the price of heating oil has fallen to a level comparable to that in 2005 and 2006 (see graphic). This confirmed that a prognosis for the price development of heating oil is hardly possible.

taxes and expenses

In addition to all these price contributions, there are also taxes and duties, such as the levy for contributions to the petroleum storage association of around € 3.50 / m³, the energy tax of € 61.35 / m³ (from 2009 for HEL-1000-ppm 76.35 € / m³) and - on the sum of all listed price contributions - 19% sales tax . (Situation in Germany)

Low-sulfur heating oil

The resolution passed by the Bundestag on October 26, 2006 states that from January 1, 2009, the extra-light (EL) low-sulfur heating oil will be introduced across the board as the new standard in Germany. With the help of a tax change, the EL standard heating oil is now taxed higher than the low-sulfur EL heating oil.


Compared to the standard heating oil, the low-sulfur heating oil offers fewer pollutant emissions during combustion (50 mg / kg sulfur content compared to the standard heating oil with up to 1000 mg / kg sulfur content).


The clean combustion of the low-sulfur heating oil means that hardly any combustion residues are deposited on the boiler walls. This increases the service life of boilers enormously; the heating system can be used more efficiently.

The significantly lower emissions of pollutants when burning low-sulfur heating oil is an important step forward in environmental protection and, especially in urban areas, helps to reduce the dangers of smog and acid rain .

When using low-sulfur heating oil, the resulting condensate should be treated as with gas fuel. The DWA worksheet A 251 from November 2011 regulates the handling.


The low-sulfur heating oil was actually specially developed for modern heating systems and oil condensing technology. Some manufacturers even prescribe the use of low-sulfur heating oil in their devices. However, the heating oil can also be used in most conventional low-temperature boilers. In case of doubt, the manufacturer should approve the use of the low-sulfur heating oil. All devices that have been manufactured since July 2005 have already been classified as suitable by the manufacturers.


Low-sulfur heating oil is available nationwide and in 2015 accounted for 99.9% of total sales. This makes the low-sulfur heating oil the standard heating oil in Germany.

Light fuel oil

Larger central heating systems for blocks of flats and businesses were e.g. B. 1968 designed for the slightly cheaper heating oil, which is thicker than HEL, but remains liquid even at cellar temperature. In Graz (as of 2005) many systems have been converted to HEL or district heating feed. In a statement from the Styrian Chamber of Commerce in 2012, the 3-year deadline for the conversion obligation according to the Plant Emissions Ordinance was too short in terms of investment security. The switch to HEL saves NOx emissions in particular in the Graz air clean-up area.

Heavy fuel oil

Heating oil
other names

HOS, Heavy Fuel Oil, heavy oil

Brief description Fuel for commercial use; Complex combination of hydrocarbons,

Sulfur compounds and metal-containing organic compounds obtained as residue from refinery fractionation cracking processes.



CAS number


Physical state liquid

<50 mm 2 / s (100 ° C)


approx. 0.990 kg / l (15 ° C)

calorific value

39.1 MJ / l = 39.5 MJ / kg (at 0.990 kg / l) corresponds to 10.9 kWh / l = 11.0 kWh / kg

Calorific value

41.1 MJ / l = 41.5 MJ / kg (at 0.990 kg / l) corresponds to 11.4 kWh / l = 11.5 kWh / kg

Flash point

> 80 ° C

safety instructions
GHS labeling of hazardous substances
07 - Warning 08 - Dangerous to health 09 - Dangerous for the environment


H and P phrases H: 332-350-361-373-410
P: 201-260-281-312-391-501
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

The liquid hydrocarbon mixture most commonly used in power plants is heavy fuel oil (abbreviated: HOS-xx, with xx the sulfur content is specified in% wt (mass percent)). It belongs to the group of heavy oils , which also includes the so-called (residual) marine fuel oils. DIN 51603-3 and 51603-5 specify HOS.

There are currently several varieties on offer, which primarily differ only in the sulfur and metal content.


HOS consists largely of residues. A diluent such as heavy gas oil or light cycle oil is added to this to adjust the viscosity (for more see heavy oil ).

In 2007, around 12.0 million tons of HOS were produced in Germany.


In freshly blended HOS there are still small traces of H 2 S - depending on the manufacturing process . These outgas from the product - also because of the increased storage temperatures - and thus represent a safety risk, since the atmosphere above the product is enriched with this poisonous gas, especially during ship transport. To prevent this, so-called H 2 S scavengers (“hydrogen sulfide scavengers”) are added, which bind the hydrogen sulfide .


The main components of the HOS are predominantly alkanes , cycloalkanes and aromatic hydrocarbons with about 20 to 70 carbon atoms per molecule and a boiling range between 300 ° C and ~ 700 ° C (the end of boiling is a calculated quantity). In addition, heterocyclic nitrogen and sulfur compounds occur (nitrogen content up to 0.5%). All metallic impurities in petroleum such as nickel , vanadium , sodium , calcium etc. are concentrated in residual oils .


Section 10 (2) of the 10th BImSchV limits the sulfur content for heavy heating oil to a maximum of 1%. In addition, varieties with a lower sulfur content (0.5%) are offered. Firing systems with flue gas desulfurization can also burn higher sulfur fuel oils (DIN 51603-3).

Heavy fuel oil has a pasty consistency at room temperature. In order for it to be pumpable at all, heavy fuel oil is first heated from 60 ° C to 100 ° C (corresponds to the storage temperature).

A flash point of 80 ° C is required to ensure safe storage. This means that there is still a “safety margin” of 20 K to the storage temperature.

The viscosity at 100 ° C is 50 · 10 −6  m² / s.

In order to achieve the usual viscosity of ~ 12 · 10 −6  m² / s at the burner tip , the viscous oil must be heated to approx. 150 ° C before combustion.

The pour point of (below) 40 ° C guarantees - like the viscosity - the handling of this product.

The calorific value (H i ) is 39.5 MJ / kg. This value can also be approximately calculated from the chemical composition (see calorific value).


In 2007 around 6.1 million tons of HOS were used in Germany. The production surplus is exported.

Around 83% of consumption is attributable to industry (including non-energetic use and industrial power plants), 9% to electricity generation in public power plants and 7% to district heating generation. The remainder (1%) is attributable in particular to the area of ​​small commercial consumers (e.g. gardeners).


The prices for HOS are based on the Rotterdam market. Two types are noted: LSFO (Low Sulfur Fuel Oil, corresponds to HOS-1.0) and HSFO (High Sulfur Fuel Oil, corresponds to HOS-3.5). Both types are traded in US dollars per 1,000 kg (US $ / t).


In addition to all of these price contributions, there are also taxes and duties, such as the levy for contributions to the petroleum storage association of around € 3.70 / 1000 kg, the energy tax of € 130.00 / 1000 kg or € 25.00 / 1000 kg ( privileged use, see § 3 of the Energy Tax Act) and - on the sum of all listed price contributions - 19% sales tax .

See also

Web links

Wiktionary: Heizöl  - explanations of meanings, word origins, synonyms, translations

Individual evidence

  1. a b c d e f g Entry on heating oil EL in the GESTIS substance database of the IFA , accessed on December 16, 2019(JavaScript required) .
  2. a b c d e f g h i j k l General information on heating oil
  3. a b c d MWV .
  4. ^ Language of oil , brochure of the Mineralölwirtschaftsverband eV
  5. berufssicherheit.de: Annex 2 TRGS 614, Dyes for marking mineral oils - Library - berufssicherheit.de ( Memento of the original from November 12, 2016 in the Internet Archive ) Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. , accessed November 11, 2016. @1@ 2Template: Webachiv / IABot / www.arbeitssicherheit.de
  6. ^ The entire consumption tax law 2011 directives, laws, regulations; Text collection . Walhalla Fachverlag, 2011, ISBN 978-3-8029-1912-1 , p. 161 ( limited preview in Google Book search).
  7. German Statutory Accident Insurance BK Report Aromatic Amine - A working aid in occupational disease determination procedures - Report of the accident insurance institutions and the IFA - ( Memento of the original from November 12, 2016 in the Internet Archive ) Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. , accessed November 11, 2016. @1@ 2Template: Webachiv / IABot / publications.dguv.de
  8. ANNUAL REPORT 2011 Rhineland-Palatinate State Office for Metrology and Calibration , page 30
  9. Information on calibration , page 14, dbb.de
  10. https://www.thermondo.de/blog/heizoel- Delivery /
  11. https://www.easyheizung.de/informationen/details/schummelei-beim-heizoelkauf-die-tricks-der- Liefer-0066 /
  12. https://www.stuttgarter-nachrichten.de/inhalt.tricks-der-betrueger-der-grosse-heizoel-reibach.99f1ab68-4409-4ef7-9d19-0c8a85b1b15f.html
  13. https://www.baumarkt.de/ratgeber/a/augen-auf-beim-heizoelkauf/
  14. https://www.welt.de/regionales/stuttgart/article106217435/Alles-im-Lot-Unterwegs-mit-einem-Eichbeamten.html
  15. Trade Union of Metrology and Calibration: Information on calibration . Edition 2/2011
  16. https://www.thermondo.de/info/rat/oel/heizolkauf-worauf-achten/
  17. https://www.baumarkt.de/ratgeber/a/augen-auf-beim-heizoelkauf/
  18. https://www.easyheizung.de/ratgeber/energiekosten/schummelei-beim-heizoelkauf-die-tricks-der- Lieferanten /
  19. Report on t-online
  20. ^ Report of the Stuttgarter Nachrichten
  21. a b "Taxes" .
  22. a b "Energy Taxes" .
  23. Opinion - Styrian Plant Emissions Regulation 2012 , Styrian Chamber of Commerce (to the state government), August 6, 2012.
  24. ^ Karl Strauss: Power plant technology for the use of fossil, nuclear and regenerative energy sources . Springer-Verlag, 2016, ISBN 978-3-662-53030-6 , pp. 47 ( limited preview in Google Book search).
  25. a b c d e f g h i j k OMV: Fuel oil specifications .
  26. a b gkg-oel.de heavy fuel oil according to DIN 51603 part 3 + 5 , June 6, 2016, accessed on December 16, 2019
  27. H 2 S scavengers .