A refinery is an industrial plant made up of several equipment required in transforming petroleum (crude oil) into several usable petroleum by-products. Before this process can be carried out, petroleum/natural gasses in its crude state need to be drilled out of the earth crust using highly sophisticated machinery.
Oil and gas refining processes can be divided into chemical methods and physical chemistry methods. The available equipment, quality of crude oil, and the application of the refined oil will determine which of the processes is suitable. Some of the by-products that are extracted from Crude oil include gasoline (petrol), asphalt base, diesel fuel, heating oil, liquified petroleum gas (LPG), petrochemical feedstocks and many more.
This article contains the history of oil refining, the impact of oil refinery machines, and all major processes required in refining crude oil.
History of Oil Refinery
Ever since the invention of proper oil refinery equipment, crude oil discovery has been a global phenomenon. According to one of the famous works of Chinese geographer, politician, and writer Li Daoyuan, the history of oil refining can be traced back to the Northern Wei Dynasty, in the first century, around 512 – 518 AD.
Along the years, there have been a lot of notable periods where crude oil was processed to form usable products. One of which was recorded in the year 865 – 925 AD, where some Arab handbooks were said to have contained descriptions of how crude oil was often distilled by Arab chemists to make tar used on its streets.
The modern history of crude oil is said to have begun in the year 1846 when the Canadian Abraham Gessner devised a means to produce kerosene using coal. A few years later, Igy Łukasiewicz adopted the process and commenced the production of kerosene from hand dug oil wells. Meanwhile, Romania was able to house the world’s first industrial petroleum refinery due to the abundance of crude oil on its soil.
Initially, kerosene was the first by-product derived from crude oil refining. And this discovery paved the way in the oil producing sector as kerosene was in high demand to fuel oil lamps. Gradually, with the advent of the internal combustion engine and its relevance in the automobile industry, a huge market was created for gasoline.
Ever since then, several private and public refineries have sprouted out of different locations around the world. As time went by, the big players began to inject huge amounts into manufacturing sophisticated oil drilling and processing equipment to foster maximum yield.
As of 2017, the oil refining market was valued to be over $6 trillion and consumption is estimated to increase abundantly due to the rapid rise in population and technological adoption. This makes it one of the biggest and growing sectors in world economics today.
Why Performance Oil Refinery Machines are Necessary
The sole purpose of all technological development is either to solve a problem or to enhance performance. Setting up the right equipment and machines will not only enhance a refinery’s performance but will help tackle all issues that may arise from the use of obsolete machines.
Below are some of the reasons why performance oil refinery machines are necessary.
- For Proper Storage of Oil Produce
A refinery must be equipped with proper tank facilities. The tanks are used to store raw materials and already refined products. When there are enough tanks in the refinery, there will be a continuous flow of operation as crude oil will be easily collected from the oil well and transferred into the necessary tank required for processing simultaneously.
More tanks need to be provided for intermediate processing and finished products compared to crude oil itself. This is because they tend to be more volatile and contain a lot of pressure. Furthermore, extra tanks must be provided for processed and finished products to avoid disruption in the supply chain during times of maintenance.
Most tanks are capable of storing crude oil / products with about 50 days processing cycle. Non-volatile products such as fuel oil and diesel are stored in cylindrical tanks with a low-pitched conical roof. While volatile products need floating roof tanks to reduce evaporation. Types of refinery tanks include horizontal tanks, pressure tanks, variable vapor space tanks, internal/external floating roof tanks, fixed roof tanks e.t.c.
- To Expel Toxic Hydrocarbon
Expelling hydrocarbons is an important process in oil refineries and this process is carried out using Flares. A Flare is built in the form of a tall stack with flames burning at the top. This equipment is very important for the plant safety as volatile hydrocarbons can be explosive when exposed to air.
In the event of machine failure or shut down, all toxic elements must be flushed out of all equipment before they can be serviced. Flare consists of a closed piping system that helps to deliver all toxic hydrocarbons down to the flare site where they are burned out under close supervision.
- To Facilitate Bulk Transportation
To ensure bulk materials are easily transported, ocean going tankers and a network of pipelines have been constructed. The ocean going tankers made it possible for refineries to be located closer to market areas, rather than oil fields. Deepwater ports have since then been constructed in some cities to connect major refineries through pipelines.
Pipelines are now found all over the world because it remains the most efficient means of transporting bulk petroleum products through refineries and maritime loading ports. With the use of sophisticated refining machines such as centrifugal pumps and booster stations built along pipeline routes, the transported material will get enough pumping power to reach its destination.
- To Conduct Thermal Energy Between Two Media
In every refinery, most especially the cracking unit where oil and water are separated, thermal energy is an essential need for product processing. Although, it can pose great damage to control systems and sensitive machinery when it is not properly regulated. This is why the heat exchanger machine is required.
The heat exchanger is a thermo-regulation equipment primarily used to disperse excessive heat and regulate temperature during processing. The first media is the liquid or gas being processed, while the other media is the heat absorbing collant made up of chilled gas or liquid.
The Working Process of Full-Continuous Oil Refinery
When crude oil has already been drilled from an oil well, the transformation process requires four different stages before they can be moved to the market. They are Separation, Conversion, Treatment, and Blending.
Catch up on these processes in the next paragraphs.
This process is carried out mainly to separate petroleum contents (also known as fraction) through distillation. Separation is done by piping crude oil through a hot furnace to form liquid and vapor components. These components are then transferred into an atmospheric distillation unit or a vacuum distillation unit.
The distillation units ensure liquid and vapor contents are separated into fractions. After attaining a certain boiling point, heavy fractions stay at the bottom part, while light fractions stay above. Petroleum and gasoline which are the lightest form of fraction rises to the top of the distillation unit to be condensed back to liquid.
Medium weight fractions like distillants and kerosene stay in the middle of the distillation unit, while the heaviest fractions like heavy fuels and residual fuel oils stay at the bottom. In terms of number, separators are the most processing machine present in any refinery. This machine can also be called Scrubbers, Centrifuge, Slug catcher, and many other names.
This is the second stage of processing where the fractions are transformed in terms of size and structure through several processes, like hydro, thermal, and catalytic cracking or cooking. This process ensures heavy, lower value fractions are further processed into lighter, higher value fractions, such as gasoline.
Cracking is the most common form of conversion because it is powered by catalyst, pressure, heat, and maybe hydrogen. In this process, heavy hydrocarbon molecules are cracked into lighter ones. The cracking unit is made up of thick walled reactors; heat exchangers, chain of furnaces, and many other types of vessel.
Contaminants such as heavy metals, sulphur, and nitrogen are often present in crude oil. These contaminants are undesirable in gasoline powered engines therefore, it needs to be properly treated before distribution.
The major treatment process is hydrotreating and it involves removal of chemicals by binding them with hydrogen, adding acid to remove them, or absorbing them in a different column. Some finishing touches are carried out in this stage by combining several streams with the processing unit.
Blending is the final stage of the refining process. This involves mixing various fractions into usable petroleum products. There are different grades of gasoline fuel, and these grades actually depend on the fractions they are blended with i.e. alkylate, reformate, cracked gasoline, e.t.c.
Refineries tend to produce from about 8-15 fractions of hydrocarbons that must be mixed with engine fuels. Additives such as octane enhancer, anti-oxidant, rust inhibitors, metal deactivator, and others are used for proper blend. Gasoline blends are determined by the ratings of vapor pressure, octane level, and some other unique considerations.
Operation Process of Oil Refinery
Refining is a downstream phase in the oil production and processing sector, and it is made up of seven basic operations. These processing operations can either be done physically or chemically depending on the choice of the operators. But in recent times, the chemical process seems to be prevalent.
The operation process can be categorized into seven stages and each stage consists of a different processing means. The processes and required means are listed below.
|Solvent refining. Distillation.
|Hydrogen addition. Carbon removal.
|Catalytic reforming. hydrocarbon reforming.
|Catalytic polymerization Alkylation.
|Treating, Finishing, and Blending
|Gasoline, Kerosene, and diesel. lubes and waxes. asphalt.
|Protecting the environment
|Wastewater treatment. Disposal of solids. Sulphur recovery.
Chemical Processes in Oil Refinery
Chemical processing in oil refining is carried out for the breaking of large hydrocarbons into smaller pieces (cracking), combining smaller pieces to form larger ones (unification) or by rearranging various pieces to produce desired hydrocarbons (alteration). This chemical process can be divided into Thermal and Catalytic forms which will be explained below.
In this process, petroleum fractions from the distillation tower are heated to a level of 900⁰F/482⁰C . It is then cooled down using gas oil and hurriedly flashed in the distillation tower. This process is required in order to reduce the viscosity of oils with heavy weight.
- Delayed Coking
During the delayed cooking process, fractions from the distillation tower are heated till they are above 900⁰ F/482⁰ C until they begin to crack into gasoline, nepeta, and heavy oil. After the whole process is finalized, residues in the form of heavy, pure carbon (coke) are left behind in the cokers.
This form of thermal cracking process is associated with the gasification of coke using steam and air. Flexicoking helps to transform a large amount of carbon coke into carbon monoxide before getting mixed with light hydrocarbons to get a low quality petroleum gas. Part of the coke is burned just to provide the required heat during the process of converting vacuum residue into distillate, gasses, coke, and liquid.
This process is used in converting heavy gas oil to petrol and it is mostly applied on oil, kerosene, naphtha, and gas. These materials are heated at high temperature with hydrogen in the presence of a catalyst till they attain 300-400⁰ Centigrade. Also, Hydrocracking assists in eliminating impure materials such as nitrogen, sulphur and trace metals.
- Catalytic Cracking
This process is suitable for transforming residual oil or gas oil into petrol or diesel. Both residual and gas oil undergo intense heat and pressure to be broken down in the presence of a catalyst. When hydrocarbons come in contact with the catalyst, they begin to break down into smaller hydrocarbons. At times, products with such little hydrogen contents i.e bitumen may be added to the process as hydrocarbons.
The polymerization process ensures light olefin gasses i.e. ethylene, butylene, and propylene are converted into hydrocarbons with higher molecular weight, and higher octane number enough to serve as a gasoline blending stock. This process is often carried out in the presence of an acidic catalyst. The processing temperature is about 300-450⁰ F and can be controlled by injecting cold feedstock and cooling water into the reactor.
- Catalytic Dewaxing
Catalytic dewaxing ensures that oil produced such as diesel maintains a liquid state at the exact temperature range in which they are to be utilized. To make these products meet commercial needs, the temperature range must be inline with the cold flow requirements. Actually, catalytic dewaxing is literally a low-severity conversion process that involves a form of selective catalyst cracking of n-paraffins.
Alkylation is a chemical process which involves the combination of light, gaseous hydrocarbons to produce high-octane components of petrol. These hydrocarbons contain olefins like butylene, and isoparaffins like isobutane. All of these components are transferred into the reactor to form a mixture of heavy hydrocarbons with the process carried out in the presence of hydrochloric-acid catalyst.
What Needs to be Consider When Using Oil Refinery Equipment
Below are the factors you need to consider when using oil refinery equipment:
- Highly Prone to Corrosion
Corrosion is one of the biggest challenges most refineries face. This is because most of the refinery equipment are made from steel and metal. Corrosion is a form of material deterioration that arises as a result of its interaction with its surroundings. Corrosion won’t only affect the chemical properties of a material but also cause a negative change in their physical structure.
There are certain anaerobic microorganisms present in crude oil that cause corrosion. It can also occur when water is allowed to settle at the bottom of a storage tank. Desalting can help remove inorganics from crude oil to reduce corrosion. cathodic protection, metal coating, and material selection can also help in controlling corrosion.
- Require Frequent Maintenance
Equipment in a refinery can only operate effectively when kept clean as possible and constant check-up is done. A lot of these equipment are mounted in open areas, leaving them exposed to bad weather and salty air. Apart from this, damage can be caused as a result of wear and tear; human/machine error. For these reasons proper maintenance needs to be done.
Maintenance techniques include; cleaning, lubrication, replacing, testing, repairing e.t.c. The maintenance engineer’s job is to ensure preventive and predictive form of maintenance is carried out frequently or on relevant intervals. Cost spent on pipeline valve maintenance can be reduced when contracted to a professional like a butterfly valve manufacturer.
- Equipment Must be Handled by Qualified Personnel
Most equipment in a refinery requires adequate technical know-how. Unqualified or untrained people must not be allowed to use machinery to avoid damages. In a case where the equipment is fully automated, reprogramming must only be done by a skilled personnel assigned for the job. Also, control switches need to be boldly marked in case of emergency. It is essential to use fixed guards to enclose crucial and dangerous equipment.
- Lubricants Should be Decontaminated
All rolling pieces of material in a refinery need to be lubricated. Contamination of lubricant can lead to bearing failure of some refinery equipment. Therefore, flushing, varnish removal, and fluid replacement must be done regularly. So it is best for refineries to partner with firms specialized in lubrication maintenance to get the best result.
In order for petroleum products to be easily controlled and travel faster within the piping system, they need a high amount of pressure and use of oil field valves. Petroleum products can range from light to heavy. In order for easy flow of heavier substances through a long piping system, a stronger type of pump is required. The various types of pumps include; Centrifugal pump, Reciprocating plunger pump, Cavity pump, Progressive cavity pump, Gear pump e.t.c.
Frequently Asked Questions
- What is Barrel of Oil
Barrel of oil refers to the unit of volume for oil measurement and one barrel is approximately equal to 42 US gallons.
- What is an Offshore Rig
An offshore rig is a facility that is specifically built on water, to be furnished with facilities drilling, extraction, and processing of crude oil and natural gasses present beneath seabeds. The facility is large enough to house workers and also store products till a vessel is available to transport.
- What Type of Crude Oil is Stored in the Reserve
Reserves have been in existence for quite a long time. Crude oil is categorized as “sweet” or “sour”. Sweet contains a sulfur content not more than 0.5 percent, while sour contains sulphur content higher than 0.5 percent but below 2.0 percent. Most reserves only accept crude oil that meets their laid down specifications.
- What are the Uses of Crude Oil
The uses of crude oil include transportation, residential, electric power, industrial, and commercial purposes.
- What is the Difference Between Upstream and Downstream Oil Processing
The Upstream stage comprises the exploration, drilling, and extraction phase, while the downstream stage includes the refining and distribution phases.
- What is a Casing Head
Casing head is an upstream equipment. It is used in connecting pipe casings with wellheads. The casing head is furnished with a string and bore bowl with a 45 C landing shoulder to prevent damages caused by excess pressure.
- Uses of an Industrial Ball Valve
An industrial ball valveis used in controlling the oil/gas flow and pressure rate within pipelines by rotating the ball embedded in the valve.
The sole purpose of all petroleum refineries is to transform crude oil into petroleum products that can serve as fuel for heating, transportation, chemical feedstock, paving roads, and more. This transformation process falls under the downstream production stage, as well as crude oil transportation.
To ensure crude oil is fully utilized, investors must set aside enough resources to procure and assemble equipment that will ensure all processing needs are met. There are numerous equipment needed in a refinery, but when it comes to valves, Dombor stands out as one of the best industrial valve manufacturers and supplier. Our valves are built to properly manage fractional flow and withstand intense temperatures.