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Introduction to Refining Processes
on the lower-boiling products increased, particularly when the market for aviation fuel developed.
Thereafter, refining methods had to be constantly adapted and improved to meet the quality requirements and needs of car and aircraft engines.
Since then, the general trend throughout refining has been to produce more products from each
barrel of petroleum and to process those products in different ways to meet the product specifications for use in modern engines. Overall, the demand for gasoline has rapidly expanded and demand
has also developed for gas oils and fuels for domestic central heating, and fuel oil for power generation, as well as for light distillates and other inputs, derived from crude oil, for the petrochemical
industries.
As the need for the lower-boiling products developed, petroleum yielding the desired quantities of the lower-boiling products became less available and refineries had to introduce conversion
processes to produce greater quantities of lighter products from the higher-boiling fractions. The
means by which a refinery operates in terms of producing the relevant products depends not only
on the nature of the petroleum feedstock but also on its configuration (i.e., the number of types of
the processes that are employed to produce the desired product slate), and the refinery configuration is, therefore, influenced by the specific demands of a market. Therefore, refineries need to be
constantly adapted and upgraded to remain viable and responsive to ever-changing patterns of crude
supply and product market demands. As a result, refineries have been introducing increasingly complex and expensive processes to gain higher yields of lower-boiling products from the higher-boiling
fractions and residua.
To convert crude oil into desired products in an economically feasible and environmentally
acceptable manner, refinery processes for crude oil are generally divided into three categories:
(1) separation processes, of which distillation is the prime example, (2) conversion processes, of
which coking and catalytic cracking are prime examples, and (3) finishing processes, of which
hydrotreating to remove sulfur is a prime example.
The simplest refinery configuration is the topping refinery, which is designed to prepare
feedstocks for petrochemical manufacture or for the production of industrial fuels in remote oilproduction areas. The topping refinery consists of tankage, a distillation unit, recovery facilities for
gases and light hydrocarbons, and the necessary utility systems (steam, power, and water-treatment
plants). Topping refineries produce large quantities of unfinished oils and are highly dependent
on local markets, but the addition of hydrotreating and reforming units to this basic configuration
results in a more flexible hydroskimming refinery, which can also produce desulfurized distillate
fuels and high-octane gasoline. These refineries may produce up to half of their output as residual
fuel oil, and they face increasing market loss as the demand for low-sulfur (even no-sulfur) fuel oil
increases.
The most versatile refinery configuration today is known as the conversion refinery. A conversion refinery incorporates all the basic units found in both the topping and hydroskimming refineries, but it also features gas oil conversion plants such as catalytic cracking and hydrocracking
units, olefin conversion plants such as alkylation or polymerization units, and, frequently, coking
units for sharply reducing or eliminating the production of residual fuels. Modern conversion
refineries may produce two-thirds of their output as unleaded gasoline, with the balance distributed between liquefied petroleum gas, jet fuel, diesel fuel, and a small quantity of coke. Many
such refineries also incorporate solvent extraction processes for manufacturing lubricants and
petrochemical units with which to recover propylene, benzene, toluene, and xylenes for further
processing into polymers.
Finally, the yields and quality of refined petroleum products produced by any given oil refinery
depends on the mixture of crude oil used as feedstock and the configuration of the refinery facilities.
Light/sweet crude oil is generally more expensive and has inherent great yields of higher value lowboiling products such naphtha, gasoline, jet fuel, kerosene, and diesel fuel. Heavy sour crude oil
is generally less expensive and produces greater yields of lower value higher-boiling products that
must be converted into lower-boiling products.
Introduction to Refining Processes
on the lower-boiling products increased, particularly when the market for aviation fuel developed.
Thereafter, refining methods had to be constantly adapted and improved to meet the quality requirements and needs of car and aircraft engines.
Since then, the general trend throughout refining has been to produce more products from each
barrel of petroleum and to process those products in different ways to meet the product specifications for use in modern engines. Overall, the demand for gasoline has rapidly expanded and demand
has also developed for gas oils and fuels for domestic central heating, and fuel oil for power generation, as well as for light distillates and other inputs, derived from crude oil, for the petrochemical
industries.
As the need for the lower-boiling products developed, petroleum yielding the desired quantities of the lower-boiling products became less available and refineries had to introduce conversion
processes to produce greater quantities of lighter products from the higher-boiling fractions. The
means by which a refinery operates in terms of producing the relevant products depends not only
on the nature of the petroleum feedstock but also on its configuration (i.e., the number of types of
the processes that are employed to produce the desired product slate), and the refinery configuration is, therefore, influenced by the specific demands of a market. Therefore, refineries need to be
constantly adapted and upgraded to remain viable and responsive to ever-changing patterns of crude
supply and product market demands. As a result, refineries have been introducing increasingly complex and expensive processes to gain higher yields of lower-boiling products from the higher-boiling
fractions and residua.
To convert crude oil into desired products in an economically feasible and environmentally
acceptable manner, refinery processes for crude oil are generally divided into three categories:
(1) separation processes, of which distillation is the prime example, (2) conversion processes, of
which coking and catalytic cracking are prime examples, and (3) finishing processes, of which
hydrotreating to remove sulfur is a prime example.
The simplest refinery configuration is the topping refinery, which is designed to prepare
feedstocks for petrochemical manufacture or for the production of industrial fuels in remote oilproduction areas. The topping refinery consists of tankage, a distillation unit, recovery facilities for
gases and light hydrocarbons, and the necessary utility systems (steam, power, and water-treatment
plants). Topping refineries produce large quantities of unfinished oils and are highly dependent
on local markets, but the addition of hydrotreating and reforming units to this basic configuration
results in a more flexible hydroskimming refinery, which can also produce desulfurized distillate
fuels and high-octane gasoline. These refineries may produce up to half of their output as residual
fuel oil, and they face increasing market loss as the demand for low-sulfur (even no-sulfur) fuel oil
increases.
The most versatile refinery configuration today is known as the conversion refinery. A conversion refinery incorporates all the basic units found in both the topping and hydroskimming refineries, but it also features gas oil conversion plants such as catalytic cracking and hydrocracking
units, olefin conversion plants such as alkylation or polymerization units, and, frequently, coking
units for sharply reducing or eliminating the production of residual fuels. Modern conversion
refineries may produce two-thirds of their output as unleaded gasoline, with the balance distributed between liquefied petroleum gas, jet fuel, diesel fuel, and a small quantity of coke. Many
such refineries also incorporate solvent extraction processes for manufacturing lubricants and
petrochemical units with which to recover propylene, benzene, toluene, and xylenes for further
processing into polymers.
Finally, the yields and quality of refined petroleum products produced by any given oil refinery
depends on the mixture of crude oil used as feedstock and the configuration of the refinery facilities.
Light/sweet crude oil is generally more expensive and has inherent great yields of higher value lowboiling products such naphtha, gasoline, jet fuel, kerosene, and diesel fuel. Heavy sour crude oil
is generally less expensive and produces greater yields of lower value higher-boiling products that
must be converted into lower-boiling products.