What is made from fuel oil? Types of fuel oil (boiler fuel)

1. Area of ​​application of fuel oil

Fuel oil (possibly from the Arabic mazhulat - waste), a dark brown liquid product, the residue after the separation of gasoline, kerosene and gas oil fractions from oil or its secondary processing products, boiling to 350-360 ° C. Fuel oil is a mixture of hydrocarbons (with a molecular weight of 400 to 1000 g/mol), petroleum hydrocarbons (with a molecular weight of 500-3000 or more g/mol), asphaltenes, carbenes, carboids and organic compounds containing metals (V, Ni, Fe, Mg, Na, Ca).

Fuel oils are used as fuel for steam boilers, boiler plants and industrial furnaces. The yield of fuel oil is about 50% by weight based on the original oil. Due to the need to deepen its further processing, fuel oil is subjected to further processing on an increasingly large scale, distilling distillates under vacuum, boiling in the range of 350-420, 350-460, 350-500 and 420-500°C. Vacuum distillates are used as raw materials for the production of motor fuels and distillate lubricating oils. The residue from the vacuum distillation of fuel oil is used for processing in thermal cracking and coking plants, in the production of residual lubricating oils and tar, which is then processed into bitumen.

The main consumers of fuel oil are industry and housing and communal services. In 2005, 45.8 million tons of fuel oil worth $10.2 billion were exported from Russia. Fuel oil ranks fourth after oil, gas and diesel fuel in the structure of Russian exports (in monetary terms).

From fuel oil, lubricating oils are obtained through additional distillation for lubrication of various mechanisms. Distillation is carried out under reduced pressure in order to lower the boiling point of hydrocarbons and avoid their decomposition when heated. After distillation of fuel oil, a non-volatile dark mass remains - tar, which is used for asphalting streets.

Super-light fuel oil is used as a process fuel at industrial enterprises, heat supply enterprises, as well as on sea and river vessels.

2. Physico-chemical properties of fuel oil

Super-light fuel oil contains 25-50% stabilized gas condensate containing the C1-C4 fraction in an amount of no more than 0.3-1.0% and the rest is fuel oil grade M100 and/or M40.

The physicochemical properties of fuel oil depend on the chemical composition of the source oil and the degree of distillate fraction distillation and are characterized by the following data: viscosity 8-80 mm 2 /s (at 100 ° C), density 0.89-1 g / cm 3 (at 20 ° C), pour point 10-40°C, sulfur content 0.5-3.5%, ash up to 0.3%, lower calorific value 39.4-40.7 MJ/mol. The typical distribution of resinous-asphaltene substances in fuel oil is presented in table. 2.

Table 2.

The main characteristics of fuel oil are: density, viscosity, and pour point, which are described in more detail in table. 3.

Table 3.

Index	Standard by brand
	Navy		Furnace
Viscosity: at 50 0 C, no more than conditional, 0 VU kinematic, cSt at 80 0 C, not more than conditional, 0 VU kinematic, cSt
Temperature, 0 C: hardening, no higher	-7/-5	-8	10	25
Density at 20 0 C, kg/m 3, not less	910/955	930/960	965/1015	1015

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Magazine "Heat Supply News", No. 6 (10) June 2001, pp. 15 – 18, www.ntsn.ru

Ya.M. Shchelokov

Fuel oil has a number of undoubted qualities as a fuel:

1. High calorific value -9500 kcal/kg.

3. Possibility of obtaining a luminous flame, providing high radiation heat transfer in the combustion space.

4. Possibility of organizing, under certain conditions, its combustion in small-sized furnaces.

But fuel oil as a fuel has a number of serious disadvantages:

1. The unstable composition of each batch of fuel oil - from close to oil to predominantly in the form of high-viscosity cracking residues. In the latter case, the injectors quickly become coked and the combustion process is delayed.

2. Increased safety requirements. For example, the flash point is not higher than 100-120°C.

3. High sulfur content, about 3.5%>

4. High pour point +(25-30 °C).

5. High price, especially recently.

But, in our opinion, the most significant disadvantages of fuel oil are the following: inconvenience in operation caused by the multi-stage preparation of fuel oil for use: heating, draining, organizing storage without separation into fuel oil and water, heating and mixing in tanks, transportation through pipelines, additional heating before nozzles, spraying, combustion, prevention of corrosion processes in boilers and environmental consequences in terms of the composition of emissions into the atmosphere and drainage of oil-contaminated water, ensuring safety requirements. And at each stage of preparation and use, high quality performance must be ensured. There are no exceptions to this requirement.

High-cost mechanism for using fuel oil:

Only the standard for heat losses for own needs is more than 10% (for natural gas - 3%);

Electricity costs for pumping;

Additional personnel for draining fuel oil, organizing its storage, etc.;

Increased temperatures for flue gases behind the boiler, to reduce their corrosiveness, etc.

That is, fuel oil requires a responsible, qualified and sober attitude at all stages of its use.

Preparing fuel oil for combustion

Preparing fuel oil for use begins with one of the most important operations - heating it in tanks and draining it for storage. In this case, heating is carried out by supplying fresh steam to the layer of fuel oil using rods or flexible metal hoses. In this case, large steam leaks and watering of fuel oil occur. Moreover, the main part of the moisture enters the fuel oil during the period of tank cleaning. During this time, fuel oil is watered by 2-4.5%. The main performance indicators of the devices when heating M-100 fuel oil with fresh steam with parameters of 12 ati and 280 °C (tank volume 50 m 3, air temperature -10 °C):

Ensuring the optimal temperature for draining is not lower than 60 °C with a total steam consumption per tank of about 2.7 tons with a draining duration of 5.5 hours.

If steam with lower parameters is used, its consumption increases by 15-20%.

In this case, it is recommended to drain most of the fuel into the main fuel oil tanks before cleaning the tank. And when cleaning the tank, drain the watered fuel oil into a special intermediate tank. In this case, the amount of condensate supplied with fuel to the main fuel oil tanks can be reduced by 2-5 times, i.e. reduce water cut to 0.5-1.0%. This division of fuel by moisture will allow differentiation to approach the issue of organizing its combustion. Water in fuel oil affects the efficiency of its use. If poorly mixed, watered fuel oil is supplied to the nozzles, combustion pulsations are observed, which lead to flame failure. There is also excessive fuel consumption due to underburning.

At the same time, when burning fuel oil with water well dispersed in it, with its content of 5-10% or even more, the atomization efficiency increases, combustion stability increases, and the content of harmful emissions (nitrogen oxides, carbon, etc.) decreases. Therefore, when preparing fuel oil for combustion, the following should be ensured:

Low (up to 3%) water content in fuel oil;

Deep mixing of water with fuel oil;

Required heating oil temperatures.

The reduction in water content was mentioned above. With a low degree of watering, the necessary mixing of fuel oil can be ensured by implementing its circulation heating. In this case, fuel from the tank is supplied by a pump to a special external heater and then returned heated to the tank. If there are heaters inside the tank, it is usually sufficient to recirculate the fuel oil in the tank before supplying it to the nozzles.

Additional heating of fuel oil in front of the nozzles is desirable, especially with mechanical atomization. But at the same time, care should be taken to ensure that the heat exchanger pipes provide the necessary vapor density to avoid additional watering of the fuel oil.

Temperature parameters when heating fuel oil are given in Table 1.

At all stages of fuel oil preparation, it must be possible to measure and control its temperature.

Fuel oil pipelines

To avoid clogging of oil lines and especially nozzles, it is necessary to install coarse and fine filters. A 100% reserve of their capacity must be ensured.

The dimensions of the fuel oil supply lines depend on fuel consumption (see Table 2).

When calculating the supply steam and air pipelines, it is recommended to take the following speeds of the medium (m/s): for saturated steam 20-30, superheated steam 30-60, fan and compressor air - 10-15 and 15-20, respectively.

Fuel oil pipelines are laid with satellite steam pipelines in the same insulation. It is imperative to provide for the possibility of purging fuel oil pipelines with steam.

Burning fuel oil

The temperature parameters of fuel oil before its combustion are indicated in Table 1. Boilers use steam (steam-mechanical) or mechanical nozzles to spray fuel oil. What are the requirements for their selection?

Currently, boilers most often require the installation of mechanical nozzles. The minimum permissible fuel oil pressure in front of them is 18 atm. Table 3 shows the required dimensions of the nozzle nozzle depending on the fuel oil consumption (fuel oil pressure 18 atm).

The diameter of the outlet section of the fuel oil nozzle should be taken to avoid clogging and coking of at least 3 mm, even if a smaller value is obtained by calculation. That is, all nozzles with a flow rate of less than 500-550 kg/h must have a nozzle of at least 3 mm in diameter, and therefore must be steam-mechanical or steam in design with a steam flow rate of up to 10% of the fuel oil flow rate. The speed of fuel oil from the nozzle should be about 60-80 m/s. When using steam-mechanical nozzles on water heating boilers, steam flow should be limited as much as possible to avoid sulfur corrosion of screen pipes.

From the table 3 also shows that when the nozzle diameter changes by 0.5 mm, the fuel oil consumption increases from 500 to 680 kg/h, that is, by almost 40%. Therefore, it is necessary to calibrate the nozzles on the stand when supplying water, which allows:

Select nozzles with the same flow rate;

Ensure visual spray quality;

Determine the torch opening angle;

Ensure that the fuel consumption through the nozzle corresponds to that required by the parameters of the burner (boiler).

The air speed in the burner should be about 40 m/s. In this case, chemical underburning can be avoided. In this case, it is advisable to ensure a high degree of turbulence of the air flow from the burner (use of blade devices). In this case, the absence of mechanical underburning is ensured. It is also advisable to heat the air to a temperature of 15-200°C.

For burners with fuel oil consumption of 450 - 550 kg/h, the length of the torch in the firebox should not exceed 2.5 m. If the length of the torch is longer, you should look for the cause (poor atomization, untared nozzle, etc.). It is allowed to increase the visual length of the torch by approximately 1 m for every 200 kg/h increase in fuel consumption through the burner. The fuel oil torch should not hit the lining, much less the heating surface. It is unacceptable.

On fuel oil boilers, it is imperative to ensure scale-free operation of the boilers by softening the water or treating it with anti-scale agent SK-110. This alone makes it possible to reduce fuel consumption by 20-25% and reduce the amount of repair work.

If a fuel oil boiler has convective heating surfaces or an air heater, then the temperature of the flue gases should not be lower than 155-160 °C in order to avoid sulfuric acid corrosion. Local “hypercooling” of pipes, metal lining, etc. is unacceptable. due to the intake of cold air into the flue, etc. Corrosion damage is inevitable in these areas.

Conclusion

In Soviet times, fuel oil was legally prescribed (in SNiP, OST, GOST) as the main, reserve, emergency, and process fuel. As a result, a large number of facilities appeared where fuel oil was the only and irreplaceable fuel. Which is what many are still trying to preserve. But the situation has changed radically:

The price of fuel oil is 3-5 times higher than the average for fuels;

Fuel oil is not distributed, but purchased for the so-called. market;

Its use becomes costly (large own needs, high sulfur content, etc.).

Therefore, fuel oil in almost all its parameters does not meet the requirements that must be provided simultaneously by the main and reserve fuel. This implies:

The operation of heat sources using fuel oil and primary and reserve fuel cannot be reliable from the point of view of eliminating emergency situations;

Fuel oil now itself requires the availability of backup fuel, and in some cases, its complete replacement with local types of fuel.

In table For comparison, Table 4 shows approximate performance indicators of a hot water boiler house with boilers with a rated power of 6.5-10 Gcal/hour, depending on the type of fuel combustion. The economic indicators of local types of fuels are higher than those of coal fuel and fuel oil, and according to the economic indicators of local fuels, the potential harmfulness (hazard) of combustion products is almost at the level of the danger of natural gas combustion products.

Fuel oil is a special material obtained from oil refining products or is a residue from its distillation. The composition of this type of fuel includes mainly resins with a molecular weight of 500-3000 g/mol, as well as hydrocarbons with a mass of 400 to 100 g/mol. These can be carbene, asphaltene, carboide, as well as various kinds of organic compounds.

Types of heating oil

Currently, the industry uses mainly the following types of material:

cracking;

straight-run;

naval;

furnace.

The last variety is very popular. As the name suggests, it is mainly used for heating rooms.

Types of heating oil and its scope of application

This variety itself is divided into two large groups:

Actually heating oil.

Diesel fuel.

Fuel oils of the first group are by their nature a heavy form of oil. Most often, such material is used in old boiler houses of various types of agricultural enterprises. Sometimes it is also used by commercial enterprises for heating offices or departments. usually purchased for heating private or even multi-storey buildings in various (mostly remote) regions of Russia, for example, in the Northern Urals, in the Arctic, etc. It differs from purely heating oil (red diesel) in its greater degree of purification and ease.

The use of this material is usually justified in cases where there is no gas pipeline in the area where a residential building or production workshop is located. Fuel oil is very inexpensive, but burning it greatly pollutes the environment. In addition, this type of fuel, due to its flammability, is quite difficult to store, and this is often expensive.

Main characteristics

When choosing a material such as heating oil for a boiler room, you usually pay attention to indicators such as:

material viscosity;

its level of density;

flash point;

percentage of sulfur;

pour point.

Viscosity of heating oil

Based on this indicator, two main types of material are distinguished. Fuel oil 40 and 40V is considered medium-viscosity, 100 and 100V is considered heavy. Light materials are not used for heating various types of premises. They are mainly used only in the navy as diesel fuel and are labeled as F5 and F12.

The viscosity of fuel oil is most often expressed in degrees (°VU). This parameter is determined by the Engler viscometer. In this case, the time of passage of fuel oil through a calibrated hole at a certain temperature is taken into account. For fuel oil 40, the last parameter is 80 degrees, for material grade M100 - 100 degrees. The change in the viscosity of fuel oil at different temperatures is explained primarily by the presence of a series in it.

Density

This parameter characterizes such an important property of the material as the ability to settle from water. The latter can get into the heating oil when it is heated using dry steam or when it is transported on old ships.

To extract water from the material, special installations are used to increase its density. What should this indicator be for this or that brand of material such as heating oil? GOST provides standard standards for each of them (at a temperature of 20 o C). You can find out the specific indicator for each brand from the table below.

The density of heating oil is therefore one of the most important parameters that you should definitely pay attention to when purchasing this material. Otherwise, you may end up with a low-quality product.

Flash point

This property of fuel oil is determined in an open crucible placed in an iron cup with sand. The flash point is measured with a special thermometer during the ignition of its vapors mixed with the surrounding air when an open flame is brought to them. This parameter can fluctuate for different types of fuel oil within the range of 90-170 o C. For fuel material M100, according to the standard, it should be 110 o C. For M40 - 90 o C. That is, the latter can be considered safer during storage. When performing such an operation as heating fuel oil, according to the standards, it is necessary to maintain a temperature that is 10 degrees below the flash point.

Ash content of fuel oil

This parameter is also an important characteristic of the fuel. An increase in the ash content of fuel oil leads to a decrease in its heat transfer during combustion. As a result:

the consumption of fuel required for combustion increases;

the degree of environmental pollution increases.

Pour point

This indicator directly depends on viscosity. The pour point of fuel oil is determined simply. The material is poured into a test tube and tilted 45 degrees. Next, they look at what minimum temperature its level will remain stable for one minute.

What should be the solidification temperature of a material such as heating oil? GOST prescribes the following:

For M40 grade material this indicator should be 10 o C.

For other brands of fuel oil, the temperature can rise to 36 o C.

This indicator is determined mainly by the degree of paraffin content in the material. The higher the pour point of fuel oil, the more difficult it is to transport it through pipelines.

Based on this indicator, several types of fuel oil are also distinguished. The sulfur content of a material depends primarily on what kind of oil was used to make it. The range of content of the mentioned substance in fuel oil is 0.5-3.5%. Most of the sulfur is included in the composition of the M100 grade material. This impurity is considered harmful because it increases the metal parts of boilers. In addition, the use of fuel oil with a high sulfur content contributes to very strong air pollution. The percentage of this substance in the fuel can be reduced by hydrogenating it or passing it through sorbents. Sometimes fuel oil is simply diluted with another, cleaner one.

Price

Currently, fuel oil is considered one of the most economical types of fuel. In this regard, it is significantly superior to even cheap natural gas. The brand is what primarily determines the cost of such a material as heating oil. The price for M40 material usually does not exceed 9-13 thousand rubles per ton. The cost of the most popular heating oil M100 is usually 6-10 thousand rubles per ton (depending on the supplier). When purchasing this type of fuel, among other things, you should pay attention to whether VAT is included in its price.

So, we examined the characteristics of heating oil in detail. Thus, when purchasing this inexpensive material, you should first pay attention to indicators such as viscosity, density and flash point. You should also find out how much sulfur is contained in the fuel oil and what is the degree of its ash content.

1. Area of ​​application of fuel oil

2. Physico-chemical properties of fuel oil

3. Methods for obtaining fuel oil and features of the chosen method

4. Description of the production scheme

Section 1. Information about heating oil.

Fuel oil is a dark brown liquid product, the residue after separation of gasoline, kerosene and gas oil fractions from oil or its secondary processing products.

Fuel oil is a mixture of hydrocarbons, petroleum resins, asphaltenes, carbons, carboids and organic compounds containing metals (V, Ni, Fe, Mg, Na, Ca). The properties of fuel oil depend on the chemical composition of the original oil and the degree of distillation of distillate fractions. The main consumers of fuel oil are industry and housing and communal services.

Heating oil is a type of petroleum fuel obtained from heavy residues from the refining of oil, coal and oil shale.

Information about heating oil

Used as boiler fuel in energy, shipping and industry.

Heating oils differ according to the following indicators:

Viscosity index (pumpability, spraying in the firebox)

Pour point

Ash content (ash deposits on boiler units)

Density

Flash point (fire hazard).

1. Low-sulfur heating oil

To reduce the viscosity, fuel oils are heated before combustion and additionally turbolized with live steam in the furnace.

Russian oil refining produces the following grades of heating oil (GOST 10585-99):

The most common grade is M-100; from it you can get M-40 fuel oil by adding diesel fuel. M-200 is very viscous, so its use causes a number of difficulties.

Heating oil is used for stationary boiler houses and technological installations. It is produced on the basis of atmospheric and vacuum distillation residues with the addition of heavy gas oil fractions.

Fuel oil, including its M100 grade, is used as boiler fuel. This type of fuel is widely used as fuel for some ship engines and for heating systems for various purposes. There are two types of fuel oil for heating systems: grade M-40 and grade M-100. The main differences between these varieties are their viscosity and composition. M-100 grade fuel oil is in greatest demand.

In the production of many products such as motor oils, coke, bitumen, lubricating oils, etc., fuel oil is used. In addition, fuel oil is also used as boiler fuel.

Fuel oil is a petroleum product, but it can also be produced from coal and oil shale, however, such versions of fuel oil are intended for consumption at the point of production and are therefore not produced in large quantities.

Fuel oil is a mixture of a large number of different components, among which there are some organic compounds, petroleum resins, carbenes, hydrocarbons with a molecular weight of 400-1000 g/mol. The consistency of the fuel oil is liquid and the color is dark brown.

Currently, the following types of fuel oil are known: furnace fuel, straight-run fuel oil, cracked fuel oil, naval fuel oil, and household heating oil.

Fuel oil is a residue from the primary distillation of oil and can be used as boiler fuel - light fuel oil (above 330? C), as well as as a raw material, subsequently processed into oil fractions to tar, which is used in the production of oils - heavy fuel oil (above 360 ?WITH).

In addition, if previously fuel oil was used as a raw material for thermal cracking units, today it is also used as a raw material for hydrocracking and catalytic cracking units.

Using different compositions and physicochemical properties of the starting material, it is possible to obtain fuel oil with different properties. Depending on the density, viscosity and sulfur content of fuel oil, its quality is assessed. The density of fuel oil is determined at a temperature of 20? C, and it should be 0.89 - 1 gram per cubic centimeter.

An equally important parameter for assessing quality is the pour point, which varies from 10 to 50? C, but the exception is naval fuel oil, for which this temperature ranges from minus 5 to minus 10? C. The viscosity of fuel oil should be in the range of 8-80 mm2/s and is measured at a temperature of 100? C.

2. Mazut M100

Today, large quantities of fuel oil are processed into distillate lubricants and motor fuels. Despite the fact that fuel oil is used in many industries, its main consumers are industrial enterprises, as well as housing and communal services.

Fuel oil is used in the engines of marine vessels and diesel locomotives, but is most widely used as a fuel for steam boilers, industrial furnaces and boiler plants.

The peak consumption of fuel oil falls in the winter season, however, this does not mean that there is no demand for it during the rest of the year.

Basic requirements for physical and chemical properties.

Let us consider the basic physicochemical properties of boiler fuels. Viscosity is the main indicator included in the designation of brands. Viscosity is determined by:

· fuel atomization (i.e. completeness of its combustion);

· conditions for draining and filling during fuel transportation;

· diagram of the consumer's fuel systems (heating, pumping, hydraulic resistance when transporting fuel through pipelines, efficiency of injectors).

The rate of sedimentation of mechanical impurities during storage, as well as the ability of the fuel to settle from water, largely depend on viscosity.

In the USA, the Saybolt universal viscometer (for low-viscosity fuel oils) and the Saybolt-Furol viscometer (for high-viscosity fuel oils) are used to determine viscosity, and in England, the Redwood viscometer is used. There is a relationship between viscosity values ​​defined in different units. A number of specifications indicate viscosity found experimentally and converted to kinematic.

In practice, viscosity-temperature curves are often used. With increasing temperature, the difference in fuel viscosity decreases significantly.

For fuel oil, as for all dark petroleum products, the dependence of viscosity on temperature is approximately described by the Walther equation:

lglg(v*10-6 + 0.8) = A – B*lgT,

where v is kinematic viscosity, mm2/s; A and B are coefficients; T - absolute temperature, K.

Viscosity is not an additive property and when mixing different boiler fuels it should be determined experimentally.

Viscosity standards at 50 °C range from 5 to 12 °VU (36 and 89 mm2/s), and at 80 °C for M-40 and M-100 - 8 and 16 °VU (59 and 118 mm2/s) . Export fuels have a lower viscosity and a VU80 viscosity of no more than 2-5 °VU is allowed for them.

Boiler and heavy motor fuels are structured systems, therefore, during draining and loading operations, in order to characterize them, in addition to Newtonian viscosity, it is necessary to take into account rheological properties (shear stress and dynamic viscosity, determined on a Reotest viscometer). All residual fuels are characterized by a viscosity anomaly: after heat treatment or mechanical action, the re-determined viscosity at the same temperature turns out to be lower than the initial one.

Fuel oil is a type of petroleum fuel used as boiler fuel in the energy, shipping and industrial sectors. Fuel oil is used as boiler fuel for various heat generators, as the main source of thermal energy in heating systems and boiler houses. Boiler fuels include heating oils of grades 40 and 100. Technical conditions for heating oil are standardized by GOST 10585-99.

3. Test report, heating oil

Household heating fuel is intended for combustion in low-power heating installations located directly in residential premises, as well as in medium-power heat generators used in agriculture for preparing feed, drying grain, fruit, canning and other purposes.

The requirements for the quality of boiler fuels, heavy motor and marine fuels, establishing the conditions for their use, are determined by such quality indicators as viscosity, sulfur content, calorific value, pour point and flash point, water content, mechanical impurities and ash content.

The standard for boiler fuel - GOST 10585-99 - provides for the production of four grades: naval fuel oil F-5 and F-12, which are classified by viscosity as light fuels, heating oil grade 40 - as medium and grade 100 - heavy fuel. The numbers indicate the approximate viscosity of the corresponding brands of fuel oil at 50 °C.

Heating oils of grades 40 and 100 are produced from oil refining residues. To reduce the pour point to 10 °C, 8-15% of middle distillate fractions are added to fuel oil of grade 40; diesel fractions are not added to fuel oil of grade 100. Navy fuel oils of grades F-5 and F-12 are intended for combustion in ship power plants. Compared to heating oils of grades 40 and 100, they have better characteristics: lower viscosity, content of mechanical impurities and water, ash content and lower pour point.

Navy fuel oil grade F-5 is produced by mixing straight-run petroleum products: in most cases, 60-70% straight-run fuel oil and 30-40% diesel fuel with the addition of a depressant. It is allowed to use up to 22% of kerosene-gas oil fractions from secondary processes, including light gas oil from catalytic and thermal cracking. F-12 naval fuel oil is produced in small quantities in direct oil distillation plants. The main differences between fuel oil F-12 and F-5 are more stringent requirements for sulfur content (0.6% versus 2.0%) and less stringent requirements for viscosity at 50 °C (12 °VU versus 5 °VU).

Area of ​​application of fuel oil

Fuel oil (possibly from the Arabic mazhulat - waste), a dark brown liquid product, the residue after the separation of gasoline, kerosene and gas oil fractions from oil or its secondary processing products, boiling to 350-360 ° C. Fuel oil is a mixture of hydrocarbons (with a molecular weight of 400 to 1000 g/mol), petroleum hydrocarbons (with a molecular weight of 500-3000 or more g/mol), asphaltenes, carbenes, carboids and organic compounds containing metals (V, Ni, Fe, Mg, Na, Ca).

Fuel oils are used as fuel for steam boilers, boiler plants and industrial furnaces. The yield of fuel oil is about 50% by weight based on the original oil. Due to the need to deepen its further processing, fuel oil is subjected to further processing on an increasingly large scale, distilling distillates under vacuum, boiling in the range of 350-420, 350-460, 350-500 and 420-500°C. Vacuum distillates are used as raw materials for the production of motor fuels and distillate lubricating oils. The residue from the vacuum distillation of fuel oil is used for processing in thermal cracking and coking plants, in the production of residual lubricating oils and tar, which is then processed into bitumen.

The main consumers of fuel oil are industry and housing and communal services. In 2005, 45.8 million tons of fuel oil worth $10.2 billion were exported from Russia. Fuel oil ranks fourth after oil, gas and diesel fuel in the structure of Russian exports (in monetary terms).

From fuel oil, lubricating oils are obtained through additional distillation for lubrication of various mechanisms. Distillation is carried out under reduced pressure in order to lower the boiling point of hydrocarbons and avoid their decomposition when heated. After distillation of fuel oil, a non-volatile dark mass remains - tar, which is used for asphalting streets.

Super-light fuel oil is used as a process fuel at industrial enterprises, heat supply enterprises, as well as on sea and river vessels.

Physico-chemical properties of fuel oil

Fuel oil belongs to the group of residual hydrocarbon fractions obtained during oil refining. The properties of fuel oil depend on the initial properties of crude oil and the depth of its processing at oil refineries. In fuel oil, as the final product of oil refining, ballast is concentrated - a non-flammable part consisting of mineral mass and water. In oil cracking processes, light hydrocarbon fractions, gasoline, kerosene, and diesel fuel are saturated with the hydrogen contained in oil to a greater extent; therefore, the hydrogen content in fuel oil decreases compared to crude oil, which leads to a decrease in its calorific value.

The decrease in the calorific value of fuel oil is caused by the increased content of sulfur, nitrogen, oxygen, resins, asphaltenes, ash, and mechanical impurities in its composition.

The mineral mass of fuel oil contains a significant amount of various metals, including vanadium. Vanadium is concentrated in petroleum resins and asphaltenes, which are also the main sulfur-containing components. Vanadium oxides cause both low-temperature and high-temperature, at 600-700°C, corrosion of metals, leading to destruction of heating surfaces, sealing surfaces of exhaust valves and gas turbine blades.

According to international quality standards, the mineral mass contained in fuel oil should not exceed 0.1-0.3%, but, despite its low content, the ash formed during the combustion of fuel oil, deposited on the heating surfaces of boiler units, significantly reduces the transfer of heat from combustion products . Ash deposits on the surfaces of diesel piston parts cause accelerated wear of rubbing surfaces and make it difficult to remove heat to the cooling media.

During transportation and storage in containers, the quality of fuel oil changes. As a result of constant oxidation, polymerization, and chemical reactions, fuel oil hydrocarbons are converted into solid products that precipitate.

In cold weather, when railway tanks are heated with live steam, the water content in fuel oil can reach 10-15%. During further storage, fuel oil is additionally watered with atmospheric moisture. Analyzes of the quality of fuel oil stored in tanks at one of the oil depots showed that the water content in samples taken at a level of 4-5 m from the bottom reaches 5%, and in the bottom layers -12%.

Bunker companies heat fuel oil in containers to a temperature at which pumping and mixing of fuel oil is ensured. If heating is insufficient, settling of water in high-viscosity fuel oil with high density becomes practically impossible and it is highly likely that excessively watered fuel oil is supplied to consumers. The quality of fuel oil may also deteriorate when it is mixed in oil depot tanks with fuel oil, in which, due to long-term storage, the quality characteristics do not meet standard requirements. Bunkering companies purchase batches of fuel from various suppliers and mix them, maintaining only quality standards for viscosity, and almost no other indicators are taken into account. In doing so, they are based on international quality standards that do not include testing for contamination levels, fuel stability, or the calculated carbon aromatic index (CCAI), which has a significant impact on the fuel's ignitability. When the CCAI index is more than 850-890, the ignition ability of the fuel sharply deteriorates.

This leads to emergency contamination by combustion products of the cylinder-piston group, exhaust valves, and gas turbochargers. Unburned fuel can accumulate in the exhaust tract, which leads to an increase in combustion pressure, knocking in the cylinders, explosions, and a fire in the exhaust tract. An increased content of aromatic fractions is most possible in fuels with reduced viscosity from 180 cSt to 220 cSt, obtained by mixing distillate fuels with high-viscosity fuel oil. Mixing hydrocarbons of different natural origins with incompatible molecular structures can lead to a rapid loss of fuel stability. The use of unstable fuel in power plants causes rapid deposition of oil sludge in pipelines, obstruction of filters, and leads to emergency contamination by combustion products of parts of the cylinder-piston group and components of the gas exhaust tract of diesel engines.

Bunkering companies take measures to prevent the supply of low-quality fuel, but their ability to improve the quality of stored fuel oil is limited, and they are forced to supply it to the consumer in an “as is” condition. Therefore, each fuel mixing operation carries uncertainty regarding the quality of the final product.

Taking into account all risk factors, the ship's crew must use the ship's express laboratory at its disposal to check the quality, involve third-party thermal laboratories and take other necessary measures to prevent the acceptance of low-quality fuel. The final responsibility for the consequences of using low-quality fuel always rests with the ship administration. To prevent negative consequences, the ship's fuel treatment system must be equipped with effective technical means that allow improving its quality characteristics before burning fuel oil in power plants.

Improving the physicochemical properties of fuel oil on ships is achieved through the use of various homogenizing devices. For example, our hydrodynamic equipment has been successfully used in fuel systems of ship power plants for fuel homogenization and preparation of highly dispersed water-fuel emulsion since 1985.

Super-light fuel oil contains 25-50% stabilized gas condensate containing the C1-C4 fraction in an amount of no more than 0.3-1.0% and the rest is fuel oil grade M100 and/or M40.

The physicochemical properties of fuel oil depend on the chemical composition of the source oil and the degree of distillate fraction distillation and are characterized by the following data: viscosity 8-80 mm2/s (at 100 °C), density 0.89-1 g/cm3 (at 20 °C) , pour point 10-40°C, sulfur content 0.5-3.5%, ash up to 0.3%, lower calorific value 39.4-40.7 MJ/mol.

The main characteristics of fuel oil are: density, viscosity, and pour point

Methods for obtaining fuel oil and features of the chosen method

Oil prepared using ELOU is supplied to primary distillation units for separation into distillate fractions and fuel oil or tar. The resulting fractions and residue, as a rule, do not meet the requirements of GOST for commercial petroleum products. Therefore, for their upgrading, as well as deepening oil refining, products obtained in atmospheric and atmospheric-vacuum distillation plants are used as raw materials for secondary (destructive) processes in accordance with the oil refining option.

The technology of primary oil distillation has a number of fundamental features determined by the nature of the raw materials and the requirements for the resulting products. Oil as a raw material for distillation has the following properties: it has a continuous boiling character, low thermal stability of heavy fractions and residues containing a significant amount of complex low-volatile and practically non-volatile resinous-asphaltenic and sulfur-, nitrogen- and organometallic compounds, which sharply worsen the operational properties of petroleum products and complicate their subsequent processing.

Since the temperature of thermal stability of heavy fractions approximately corresponds to the temperature boundary of oil division between diesel fuel and fuel oil along the ITC curve, the primary distillation of oil to fuel oil is usually carried out at atmospheric pressure, and the distillation of fuel oil in a vacuum. The choice of temperature limit for oil division at atmospheric pressure between diesel fuel and fuel oil is determined not only by the thermal stability of heavy oil fractions, but also by the technical and economic indicators of the separation process as a whole.

In some cases, the temperature limit of oil division is determined by the requirements for the quality of the residue. Thus, when distilling oil to produce boiler fuel, the temperature division boundary is about 300 0C, i.e. approximately half of the diesel fuel fraction is taken with fuel oil to obtain low-viscosity boiler fuel.

However, this option is not currently the main one. In recent years, to expand the resources of diesel fuel, as well as catalytic cracking raw materials—the most important and developed process that deepens oil refining—in atmospheric and atmospheric-vacuum distillation (AT and AVT) installations, an increasingly deeper selection of the diesel fraction and vacuum gas oil has been carried out, respectively. To obtain boiler fuel of a given viscosity, the process of visbreaking of heavy vacuum distillation residue is used.

Thus, the question of justification and choice of temperature limit for oil division depends on the options for technological schemes for the distillation of oil and fuel oil and options for oil refining in general.

Typically, the distillation of oil and fuel oil is carried out respectively at atmospheric pressure and in vacuum at the maximum (without cracking) heating temperature of the raw material with stripping of light fractions with water steam. The complex composition of distillation residues also requires the organization of a clear separation of distillate fractions from them, including highly efficient phase separation during a single evaporation of the raw material. For this purpose, fender elements are installed, which helps to avoid the entrainment of droplets by the steam flow.

Description of the production scheme

At the end of the 40s, AVT installations had a productivity of 500-600 thousand tons/year. Soon these capacities turned out to be insufficient to meet the growing demand for bulk petroleum products. Since 1950, they began to build AVT plants at an accelerated pace, operating according to a double evaporation scheme, with a capacity of 1, 1.5 and 2 million tons/year.

The temperature and pressure in the installation apparatus are given below:

Temperature 0C:

heating oil in heat exchangers 200–230

heating of stripped oil in coils of a tube furnace 330–360

vapors leaving the topping column 120–140

at the bottom of the topping column 240–260

vapors leaving the main column 120–130

at the bottom of the main column Pressure, MPa:

in the topping column 0.4–0.5

in the main column 0.15–0.20

Different pressures are created in the columns. As is known, the pressure in the column is determined by the fractional composition of the overhead and, ultimately, by the residual pressure of saturated liquid vapor after condensation of the overhead vapor and their separation in a container (gas separator).

In K-1, the light (head) gasoline fraction of n.c. is selected in the vapor phase. – 62 0С or n.c. – 85 0C, and in K-2 there is a heavy gasoline fraction that boils above 62 0C or 85 0C, therefore the pressure in K-1 is higher than in K-2 (0.4-0.5 MPa compared to 0.15 -0.20 MPa). This is caused by the need to preserve fractions in the liquid phase after condensation of vapors at a final cooling temperature of 30-35 0C. However, for the lighter fraction, complete condensation is difficult. More complete condensation is achieved by using additional water cooling (after air cooling). At the same time, it is possible to condense light gasoline fractions more completely (this is especially important in the summer and in hot climates).

Sources

Wikipedia – The Free Encyclopedia, WikiPedia

altexp.ru – Altex plus

eurobitum.ru – Eurobitum

aex.com.ua – Auto Expedition

Glagoleva, O.F. Oil refining technology. Part one. Primary oil refining / O.F. Glagoleva; Ed. V.M.Kapustina, E.A.Chernysheva. – M.: Khimiya, KolosS, 2005.–400 p.

Rudin, M.G. Pocket reference book of an oil refiner [Text]/ M.G. Rudin; – L.: Chemistry, 1989.–464 p.

diseltoplivo.ru Diesel fuel

revolution.allbest.ru Abstract

ko4egar.ru Fireman

blackgold.com.ua Black gold

ru.wikipedia.org Wikipedia – the free encyclopedia

Most often used for heating and energy.

Fuel oil is also obtained as a by-product from the recycling of petroleum compounds (such as gasoline, kerosene and gas oil compounds) and heated to a certain temperature, or it is separated from oil. The hazard class of fuel oil is fourth (low-hazard).

If we turn to chemistry, we will see that fuel oil is a compound of hydrocarbons, petroleum resins, substances containing metals (ferrum, nickel, sodium. Also magnesium, calcium, vanadium), carbenes, asphaltenes and carboids. The properties of this substance depend on the raw materials used in production, physical and technical characteristics and quality.

What is fuel oil produced for: areas of use

Fuel oil is primarily associated as a widely used fuel. This petroleum product is suitable for various industrial furnaces, complex heating systems, maintenance of various levels of production, and is even widely used in domestic situations and agriculture.

Depending on the feedstock, certain types of fuel oil can be used as marine fuel.

In addition to its main purpose - fuel for heating and propulsion energy, fuel oil is used as basis for many materials and substances (fuel distillation products).

If we consider fuel oil in the field of use, the following types are distinguished:

• boiler fuel;

• fuel for domestic use;

• heavy motor fuel;

• fuel for ships.

The requirements that allow the use of fuel oil in specific types of activities are determined by the properties determined during the examination:

• viscosity;

• water level in the composition;

• level of mechanical substances in the composition;

• ash rate;

• combustion, pour and flash temperatures.

Viscosity according to GOST is indicated at the moment when the fuel oil is at a temperature of fifty degrees Celsius (navy grade).

Fuel for domestic heating can be found in

at home used for heating a residential building. It is intended for use in small heating systems of low and medium power, in small industries. Also in farming, in particular for the production of animal feed. Also storing hay for the winter, fruits, vegetables and many other purposes.

Heavy motor fuel is created for use on ships and, according to regulatory documents, this includes naval fuel oil F-5, which, however, is defined by standards as light boiler fuel.

These fuel oils are intended to create energy in combined heat and power plants, furnaces in large industries, including for real estate industrial heating devices.

According to GOST 10585-2013, this type includes grades 40 and 100. The first is classified by viscosity as medium fuel, and the second, accordingly, as heavy fuel. The difference between grades 40 and 100 is that grade 100 fuel oil does not contain diesel fuel.

Note that naval fuel oils are considered to be of higher quality than heating oils: they have a low viscosity level, low content of harmful substances, water, sulfur level (0.6%), and they are also characterized by a lower pour point.

F-5 grade fuel oil has a different composition from fuel oils and usually includes approximately sixty percent straight-run fuel oil and forty percent diesel fuel. The composition may contain some impurities and is not the same. F-5 fuel oil is a by-product of oil distillation; the output is a limited amount.

Types of fuel oils

Types of fuel oil differ in composition and characteristics:

• water and impurities (diesel fuel, depression additives and others);

• viscosity;

• combustion temperature and ash content.

The composition of fuel oil is regulated by GOST and is divided into grades, which, in turn, are divided into types (indicated by Roman numerals from one to seven).

The number indicating the brand is the number of the calculated viscosity of the fuel oil.

The calculated viscosity for each type is determined at different temperatures:

• For fuel oil F-5 - temperature fifty degrees;

• For fuel oils M40 and M100 – temperature eighty degrees;

• Fuel oil M100 – temperature 100 degrees (optional).

More about heating oil: how it is used, main properties and parameters

As already mentioned, heating oil has two main grades - M100 and M40. The brand is influenced by many parameters, but the key ones are the viscosity level and the pour point.

Another important difference is that grade 40 contains diesel fuel, which is a substance that allows you to reduce the pour point of fuel oil.

Heavy motor fuel suitable for boiler houses, as the main fuel in large industries, generators, etc. Grade 100 fuel oil is often used, but grade 40 is also suitable for some systems.

Transportation of heating oil is carried out by rail in specialized tank trains, as well as by machines for transporting bitumen.

During transportation and sale, heating oil has a special technical passport, which must indicate the main characteristics. Performance information is pre-established in laboratory conditions.

Among these characteristics:

The characteristics of fuel oil are directly affected by its shelf life. The longer fuel oil is stored, the worse its characteristics and the higher the water level, the level of various impurities and the ignition temperature will be far from GOST standards.

Similar to its brother - bitumen - the level of sales of fuel oil depends on the time of year. While bitumen sells well in the warm season (due to the road construction season), heating oil is needed in the cold seasons.

How to replace fuel oil and is it realistic?

Despite the fact that fuel oil remains the most popular boiler fuel, it can be replaced with other liquids, the parameters of which, however, will not meet the standards.

These substances include:

• “Stale” fuel oil with a long shelf life;

• Fuel oil with a large number of impurities;

• Fuel oil with a large proportion of water;

• Coke fuel oil;

• A mixture of petroleum products;

• Gas condensate.

Although the listed liquids will work as fuel, please note that the use of low-quality fuel oil and its cheap substitutes cannot be a full replacement for good raw materials, and in some cases will lead to dire consequences in the form of malfunctions in the system, bringing a minimum of heat and benefit.