Category Archives: Fuel blending

Production of Multicomponent Mixed Fuels

Fuel blending,

GlobeCore’s line USB units produce high-quality mixed fuels as well as ensuring their homogenization.  All the fuel components are supplied to a common collector through a blending process that is realized in a hydrodynamic mixer.

The following is the list of the components used in fuel blending:

  • low-octane gasoline;
  • distilled gasoline;
  • stable gas gasoline;
  • biological components of motor oils; and
  • additives that increase gasoline’s octane rating.

The main benefits of GlobeCore USB units are as follows:

(1)    precise components for metering and control;

(2)    reduced blending cycle times; and

(3)    no mixing tanks for final product homogenization;

If the resuling mixture is properly homogenized, it will not separate into its component parts even if it is stored for a long period of time.

Fuel Requirements

Fuel blending

All fuel requirements can be roughly divided into four groups such as (1) those related to engine operation, (2) transportation and handling, (3) mass production, and (4) the environment.

Evaporation is considered to be the most important performance characteristic of fuel. It is characterized by (1) fractional composition of fuel, (2) pressure of the saturated vapor, and (3) antiknock rating.  The environmental requirements impose restrictions on the non-saturated aromatic hydrocarbons, sulphur compounds, and antiknock agents.

The Fuel Analysis

The typical fuel found at gas stations is a mixture is the result of various technological processes.

The GlobeCore USB type blending units, for production of multicomponent fuels, has gained a wide popularity recently.  Operating properties of fuel depend on the content and the interaction of the hydrocarbons.

The quality of the product, or its components, is assessed at the oil refineries by laboratory methods that provide information about physical and chemical characteristics of the product. Then, the results are compared with the characteristics specified in special regulations.

Special attention is paid to such fuel characteristics as the octane number (determined on the basis of motor and research methods), density, fraction composition, the content of lead and oxygen, aromatic compounds, and other performance characteristics.

The quality of the blending components and the characteristics of the final product should be under strict control in the course of the compounding process.  Product quality analysis is realized by the online analyzer (analyzer in the infrared region).  It allows the operators to obtain results quickly as well as to take a wide range of the additional readings (apart from the basic ones) from one sample.  The monitoring of the blending processes is realized due to the automation process.

The analysis of the blending process quality allow the operators to fulfil such  tasks as:

(1) to improve the output quality;

(2) to reduce the costs for laboratory tests; and

(3) to receive information on the process parameters in the real-time.

The octane number may be received no earlier than in 1 hour due to the standard laboratory-based methods.  But, in fact, this process typicall takes 2 or 3 hours.

It is however, the octane number that may be determined by the rapid test methods that have gained widespread acceptance.  These methods are based on the spectral analysis, including the analysis of the IR (infrared) region.

Fuel is characterized by the IR spectrum, which allows the operators to define such characteristics of fuel as its fractional composition and the octane number.

How to Increase the Cetane Number of Diesel Fuel?

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Such additives as nitro compounds or synthins are added to diesel fuel to increase its cetane number.  In practical terms, the special equipment in the USB line is used to inject additives and obtain homogenized fuels.  They are considered to be an integral part of the production process when increasing the cetane number by a described method.

The combustion of diesel fuels is affected by the design of the equipment and its operational principles.  The combustion chamber should be designed in such a way that it will benefit the vortex formation (when the air is compressed) that allows for the reduction of fuel heating.   It is desirable to use cast iron pistons, as they have a lower thermal conductivity that reduces the combustion distance (the air and fuel are heated actively).

The fractional composition of fuel is needed while assessing the quality of diesel. This composition may be defined by the flash temperature or in the same way as fuel composition.

How to Define the Cetane Number?

Fuel blending,

A test engine is used to measure the cetane number of diesel fuel.  When using other mehods of measurig the cetane number, the result will depend on the diesel fuel composition.  The motor method provides the exact results for the fuels with any fractional composition.  The various express analyzers require the recalibration when changing from one type of oil product to another, which is very difficult and time consuming.

In general, three approaches are used to identify an accurate value of the cetane number: (1) flare coincidence; (2) ignition lag; and (3) the critical rate of compression.  The ‘method of flare coincidence has gained a widespread acceptance.  It is realized by such types of equipment as IT9-3, It9-3M, or ITD-69 which have single-cycle four stroke engines.  When testing, the shaft speed should be maintained at the level of 900±10 revolutions per minute (rpm).

The cetane number of diesel fuel is largely determined by the hydrocarbon composition.  The cetane number of the benzene hydrocarbons is the  lowest while that of the paraffin hydrocarbons is the highest.

The Cetane Number

Fuel blending

The cetane number is one of the most important performance characteristics of diesel fuels which indicates the ignition lag of blended diesel fuel.  The higher the cetane number is, the faster the fuel will ignite and the more completely it will burn.

Standard diesel engines operate on diesel fuels with a cetane number ranging from 40 to 55 units.  The reduction of the cetane number usually results in ignition lag.   As a result, the pressure in the combustion chamber is growing faster, and the wear rate of engine will be increased.  The cetane number of the standard types of fuel is between 40-45 units.  While that of high-quality fuel is between 45-50 units. High-quality diesel fuel (premium) is light and contains more flammable factions.  It is therefore, desirable to use such fule to start cold engines.  Additionally, the premium fuel emits less smoke while combusted.  It is due to the increased ratio of hydrogen to carbon in light factions.

The increased cetane number (more than 60 units) results in a range of negative factors such as: (1) the combustion efficiency is reduced; and (2) fuel consumption and smokiness are increased.
In part, the cetane number is defined by the amount of such components as paraffins, naphthenes, and olefins.  The paraffins are considered to be a desirable component of oil product due to such performance characteristic as self-ignition in cold weather.

Fuel and oil additives

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Additives, especially cleaning additives and ones of unknown makes, are not to be overdone in winter. A cleaning additives can dislodge all sediment from the tanks and fuel line and cause fuel pump contamination. The filter might not be able to protect the pump. The result is usually costly repairs of the pump and/or the engine. A good thing to have in winter is anti-gel. Add it to fuel as instructed in the manual and all the way to fuel cloud point, after which the additive loses its efficiency, although good diesel fuel should not form too much gel at moderate low temperatures (about -10… -15°С). It is best not to fill the tank full with fuel of known or doubtful fuel, the optimum being 10 – 15 liters, which is enough for 200 – 400 km, so as to expend the low quality fuel faster.

A recommended additive is REDEX molybdenum additive. First, the molybdenum compounds in this additive create a thin molecular protective layer on friction parts in the motor, reducing wear and friction. Second, these compounds heal micro cracks and tiny surface dents. It lasts long, i.e. the protective layer is not washed away when oil is changed. In practice this additive manifests itself by significant noise reduction of the motor and better fuel economy.

It is also advisable to occasionally add some of the so called conditioners, i.e. additives improving fuel performance. Producers usually claim their product has magical qualities, such as water binding, cetane number increase, fuel consumption reduction etc.

Try to get all additives and fuel from one company. Although generally compatible, mixing additives from different manufacturers is not a good idea. Neither are experiments with additives to increase compression when ring change is in order. It is impossible to really help the engine, while damaging it is quite so.

Ethanol Blending

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Interest to alcohols is caused by a ratio between their prime cost and their useful properties as gasoline components,  be more specific their ability to increase octane number. As the component to fuels ethanol represents better interest, than methanol as it is better dissolved in hydrocarbons and is less hygroscopic. It was set that the additive of 5% of ethanol to gasoline doesn’t lead to deterioration of operation characteristics of the engine and doesn’t require regulation. Essential lowering of bursts essential lowering of CO and hydrocarbons. Optimization of gasoline composition looks not such complex challenge. It is really possible by using of “USB” (Ethanol blending system) which are manufactared by the GlobeCore company. Ethanol alcohol concentration of 92-96% blends with gasoline using GlobeCore company Ethanol Blending system. Time of phase stability of a compound makes not less than 6 months.

By the GlobeCore company it was developed and delivered on a mass production a number of Ethanol Blending Systems “USB”  which are applied to ethanol blending and to mixing of different liquids. Blending systems are as stationary and mobile execution. Manufacture of Ethanol Blending Systems “USB” is coordinated with the customer and generally made under personal requirements of the customer depending on required compoundings and receiving the final product.

Ethanol blending is used in a hydrodynamic blender “USB”. This process allows to present all components at the same time in coordination to a formula.The benefit of this technology is in the following: each element dosing accurate control, substantial reduction of batching process duration, no need in batching vessels for finished product homogenization. In the ethanol blending process at stream mixer the consumption of each element are controlled for the purpose of providing completed product outlet with parameters wich corresponds to the formulas.

Chemical Blending

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Chemical blending is one of frequent kind of chemical process that is commonly used in chemical application. The procedure of blending chemical can potentially save chemical manufacturers time, labor, inventory, and transportation costs. Organic and inorganic chemicals can be blended. Chemicals could be blended in liquid form to a variety of pH levels and viscosities.Blending chemical services consist of multi-component blending chemical, homogenization, liquid blending, high Intensity and liquid powder blending.

For manufactaring of blending chemical system “USB” the most important the choice of materials and compatibility of components. Not for the last part is assigned to the principle of blending chemical system operations and stability of materials. Blending chemicalsystem “USB” are used in case of cultivation of substances, and also during the mixing and preparation of different chemicals, for example in case of cleaners production and detergents. At the request of the customer we make diagrams for specific distribution of products. Productivity and automation level of blending chemicalsystem is defined depending on its components. Blending chemical systems “USB” supplies blending chemicalequipment for the worldwide chemical industry. Globecore has designed and manufactured industrialblending chemical systems “USB” for over 12 years. The blending chemical systems “USB”is equipped with the high-tolerance additives batching electronic system with digital display, allowing to set the additives dosing extremely accurate.

USB_system

Blending chemical process is used in hydraulic blender. This process allows supplying of all components simultaneously according to the set formula to batching collector. Through the collector finished product is delivered to storage vessel. The advantage of such technology is in the following: each component dosing accurate control, substantial reduction of batching process duration, no need in batching vessels for finished product homogenization. In the course of blending chemical process at stream mixer the consumption of each component are permanently controlled for the purpose of providing finished product outlet with steady quality parameters, set with the formulas.  Finished product, received from stream mixer, has homogenizing structure and component content in accurate compliance to set formulas.

USB_blending

The role of oil and gas in modern world

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Energy is a key resource in today’s economy. National production development is largely defined by the consumption of energy. The importance of energy resources is emphasized by the fact that over 70% of mineral resources are sources of energy.

The main energy sources today are coal, oil, natural gas, hydropower and nuclear power.

Oil and gas have become the leaders in world energy since the 1960s. In Germany and the UK, for instance, oil and gas account for 55-60% of total energy consumption, while the the US and Japan the number is even higher: 75 – 80%.

Some of the advantages of oil and gas as energy sources are relatively low production cost, waste-free processing with production of various types of fuel and chemicals. However, world deposits of oil and gas are not limitless. They are significantly lower than coal, shale and asphaltic sand. At the same time, the production of oil and gas by far exceeds that of other combustible minerals.

The high level of oil consumption causes the concern that the world supply of oil may be exhausted in the relatively near future. It is commonly accepted that oil is due to run out by the end of the 21st century.

As oil became the main energy source, its political and economic significance has increased. Availability of own oil, the ability to organize export of oil and oil products has allowed some countries many achievements in their economic and social development. At the same time, the fluctuations of the world’s oil prices and the market condition lead to significant changes in the policy of both oil producing countries and those countries with economy based on imported oil.

The world oil prices have been fluctuating in recent  years.  In the first years after World War II, the price of oil was dictated by the International oil cartel, dominated by the US. The cartel purchased oil from exporters, developing nations, at low price (22 USD per 1 cubic meter in 1970), while selling oil products to importers at relatively high prices.  To protect their economic interests, the developing nations created OPEC in 1960. OPEC includes Iraq, Kuwait, Saudi Arabia, Qatar, Venezuela, Indonesia, Libya, Nigeria, Algeria and Ecuador.

Considering a sharp increase of demand in the world market, OPEC increased their pressure on the oil monopolies in 1972-1973 and increased the price four times. The increase lead to unstable oil supply in several industrialized countries and oil shortages.

The West implemented measures to decrease their dependence on foreign oil by increasing their production of own oil and coal,  reducing consumption and the use of other energy sources (solar, nuclear and geothermal). These measures caused the world oil price to drop.

The chemistry of catalytic reforming

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The chemistry of catalytic reforming

Catalytic reforming is a complicated process which involves various transformations of hydrocarbons. Straight run gasoline fractions, which are the raw material of the catalytic reforming, contain parafins, naphthenes and aromatics.

The reactions in the catalytic reformers deeply transform the hydrocarbons. Aromatization of hydrocarbons is the main and most important direction of the process. Before looking at various reactions, it should be noted that reforming catalysts feature two types of catalytically active centers: dehydrating centers on platinum and isomerizing centers on the carrier.

One of the main reactions of the process is dehydration (dehydrogenation) of naphthenic hydrocarbons. Dehydration of pentatomic hydrocarbon rings of naphthenic hydrocarbons occurs through formation of cycloolefine hydrocarbons with rearrangement of the ring.

The second type of reaction is dehydrocyclization of paraffinic hydrocarbons; the mechanism of this reaction is not entirely clear yet. Aromatization of paraffinic hydrocarbons may occur either by formation of naphthenic or olefinic and cycloolefinic hydrocarbons.

Other main reactions of the process include isomerization of paraffinic hydrocarbons, which occurs via an intermediate stage of carbonium ion formation; in reforming conditions isomerization leads to formation of unbranched isomers.

Hydrocracking reactions run in parallel on reforming catalysts.

Hydrocracking affects paraffinic hydrocarbons, and, to a lesser extent, naphthenic hydrocarbons. Hydrocracking of paraffins occurs in several stages through formation and disintegration of carbonium ions. Propane and high-molecular compounds prevail in the products of this reaction. Hydrocracking occurs on acidic centers of the catalyst, but the first and final stages of the process, I.e. formation of olefins and hydration of other breakdown products, occur on the metal parts of the catalyst, which feature the hydration-dehydration function.

Hydrocracking of paraffinic hydrocarbons leads to formation of two or more hydrocarbons with lower molecular mass.

In some cases of reforming, hydrogenolysis becomes significantly developed on the metal parts of the catalyst. Unlike hydrocracking, hydrogenolysis leads to more prominent formation of gaseous hydrocarbons, especially methane. In the process of hydrogenolysis, the destruction of carbon-carbon bonds of methyl cyclopentane leads to formation of paraffinic hydrocarbons.

Besides, reforming favors reactions which significantly influence catalyst activity and stability; including formation of coke on the catalyst, as well as hydrodecay of sulfuric, nitric and chlorine substances.

Formation of coke is related to the reactions of compaction on the surface of the catalyst. This causes not only reduction of catalyst activity, but also degrades process selectiveness. Coke formation is promoted by decreased partial pressure of hydrogen and molar hydrogen/raw material ratio, poisoning of the catalyst by contact poisons, disruption of balance between hydrating and acidic functions of the catalyst, processing of raw material with increase content of light (C5 – C6) and heavy (C10 and above) hydrocarbons.

The fastest of the main reforming reactions is the reaction of dehydrogenating of alkyl cyclohexanes into the corresponding aromatic hydrocarbons, the slowest reactions are de dehydrocyclization of paraffinic hydrocarbons. The rate of naphthenic and paraffinic C6 – C10 hydrocarbons increase on homologous sequences with the increase of molecular mass.

Reforming reactions leading to formation of aromatic hydrocarbons from naphthenic and paraffinic substances absorb heat; hydrocracking and hydrogenolysis reactions emit heat, isomerization reactions of paraffinic and naphthenic hydrocarbons have little thermal effect. For C5 – C10 hydrocarbons, molar thermal effects are almost independent of molecular mass and change little in the temperature range of 470 – 500oC.