428
The Chemistry and Technology of Petroleum
increasingly complex and expensive processes to gain higher yields of lower-boiling products from
the higher-boiling fractions and residua.
The configuration of refineries will, more than likely, vary from refinery to refinery. Some refineries may be more oriented toward the production of gasoline (large reforming and/or catalytic
cracking), whereas the configuration of other refineries may be more oriented toward the production
of middle distillates such as jet fuel and gas oil.
In addition to feedstock such as heavy oil and tar sand bitumen, there is also the need for a refinery to be able to accommodate more opportunity crude oils and/or high acid crude oils (Chapter 1).
Opportunity crude oils are often dirty and need cleaning before refining by removal of undesirable constituents such as high-sulfur, high-nitrogen, and high-aromatics (such as polynuclear
aromatic) components. A controlled visbreaking treatment would clean up such crude oils by
removing these undesirable constituents (which, if not removed, would cause problems further
down the refinery sequence) as coke or sediment.
On the other hand, high-acid crude oils cause corrosion in the atmospheric and vacuum distillation units. In addition, overhead corrosion is caused by the mineral salts, magnesium, calcium, and
sodium chloride which are hydrolyzed to produce volatile hydrochloric acid, causing a highly corrosive condition in the overhead exchangers. Therefore, these salts present a significant contamination
in opportunity crude oils. Other contaminants in opportunity crude oils that are shown to accelerate
the hydrolysis reactions are inorganic clays and organic acids.
Basic refining process for heavy oil (and residua) to lower-boiling salable products and the conversion of distillation residues consist of cracking the feedstock constituents to increase the hydrogen
content and to decrease the carbon content of the derived products (Chapter 23). While such processes
will continue (at least) for the next 50 years and even throughout the remainder of the twenty-first
century (Speight, 2011b), many refiners are investigating the potential large-scale utilization of biomass as partial feedstocks. For practical reasons, small capacity refineries might be the first to attempt
such uses of biomass in a bio-petroleum refinery complex. The biomass might be used in the form of
prepared pellets (obtained from agriculture residues such as forestry residues, corn stock, and straw)
as a feedstock blend with heavy oil. The approach could produce benefits such as (1) improvement in
the quality of the final market products and of the economics of the entire activity, (2) positive impact
on rural development (new jobs and new income for farmers), and (3) decrease in carbon dioxide emissions by substitution of renewable biomass to hydrocarbons (Grassi, 2004).
The concept of using other feedstocks to blend with petroleum feedstocks bring to the fore the
concept of a gasification refinery, which would use gasification technology as is the case of the
Sasol refinery in South Africa (Chadeesingh, 2011). The refinery would produce synthesis gas (from
the carbonaceous feedstock) from which liquid fuels would be manufactured using the Fischer–
Tropsch synthesis technology (Speight, 2008). Synthesis gas is used as a source of hydrogen or as
an intermediate in producing hydrocarbons via the Fischer–Tropsch synthesis.
As petroleum supplies decrease, the desirability of producing gas from other carbonaceous
feedstocks will increase, especially in those areas where natural gas is in short supply. It is also
anticipated that costs of natural gas will increase, allowing coal gasification to compete as an economically viable process. Research in progress on a laboratory and pilot-plant scale should lead to
the invention of new process technology by the end of the century, thus accelerating the industrial
use of coal gasification.
15.16.2 reFInery ConFIgurAtIon
The main technological progress will be directed to heavy oil upgrading, cleaner transportation
fuel production, and the integration of refining and petrochemical businesses. Even the tried-andtrue processes will see changes as they evolve (Speight, 2011b). The distillation units (Chapter 17)
will continue to be the mainstay of petroleum refining and the main short-term developments are
in improved integration through the use of heat recovery technology and integration of different
The Chemistry and Technology of Petroleum
increasingly complex and expensive processes to gain higher yields of lower-boiling products from
the higher-boiling fractions and residua.
The configuration of refineries will, more than likely, vary from refinery to refinery. Some refineries may be more oriented toward the production of gasoline (large reforming and/or catalytic
cracking), whereas the configuration of other refineries may be more oriented toward the production
of middle distillates such as jet fuel and gas oil.
In addition to feedstock such as heavy oil and tar sand bitumen, there is also the need for a refinery to be able to accommodate more opportunity crude oils and/or high acid crude oils (Chapter 1).
Opportunity crude oils are often dirty and need cleaning before refining by removal of undesirable constituents such as high-sulfur, high-nitrogen, and high-aromatics (such as polynuclear
aromatic) components. A controlled visbreaking treatment would clean up such crude oils by
removing these undesirable constituents (which, if not removed, would cause problems further
down the refinery sequence) as coke or sediment.
On the other hand, high-acid crude oils cause corrosion in the atmospheric and vacuum distillation units. In addition, overhead corrosion is caused by the mineral salts, magnesium, calcium, and
sodium chloride which are hydrolyzed to produce volatile hydrochloric acid, causing a highly corrosive condition in the overhead exchangers. Therefore, these salts present a significant contamination
in opportunity crude oils. Other contaminants in opportunity crude oils that are shown to accelerate
the hydrolysis reactions are inorganic clays and organic acids.
Basic refining process for heavy oil (and residua) to lower-boiling salable products and the conversion of distillation residues consist of cracking the feedstock constituents to increase the hydrogen
content and to decrease the carbon content of the derived products (Chapter 23). While such processes
will continue (at least) for the next 50 years and even throughout the remainder of the twenty-first
century (Speight, 2011b), many refiners are investigating the potential large-scale utilization of biomass as partial feedstocks. For practical reasons, small capacity refineries might be the first to attempt
such uses of biomass in a bio-petroleum refinery complex. The biomass might be used in the form of
prepared pellets (obtained from agriculture residues such as forestry residues, corn stock, and straw)
as a feedstock blend with heavy oil. The approach could produce benefits such as (1) improvement in
the quality of the final market products and of the economics of the entire activity, (2) positive impact
on rural development (new jobs and new income for farmers), and (3) decrease in carbon dioxide emissions by substitution of renewable biomass to hydrocarbons (Grassi, 2004).
The concept of using other feedstocks to blend with petroleum feedstocks bring to the fore the
concept of a gasification refinery, which would use gasification technology as is the case of the
Sasol refinery in South Africa (Chadeesingh, 2011). The refinery would produce synthesis gas (from
the carbonaceous feedstock) from which liquid fuels would be manufactured using the Fischer–
Tropsch synthesis technology (Speight, 2008). Synthesis gas is used as a source of hydrogen or as
an intermediate in producing hydrocarbons via the Fischer–Tropsch synthesis.
As petroleum supplies decrease, the desirability of producing gas from other carbonaceous
feedstocks will increase, especially in those areas where natural gas is in short supply. It is also
anticipated that costs of natural gas will increase, allowing coal gasification to compete as an economically viable process. Research in progress on a laboratory and pilot-plant scale should lead to
the invention of new process technology by the end of the century, thus accelerating the industrial
use of coal gasification.
15.16.2 reFInery ConFIgurAtIon
The main technological progress will be directed to heavy oil upgrading, cleaner transportation
fuel production, and the integration of refining and petrochemical businesses. Even the tried-andtrue processes will see changes as they evolve (Speight, 2011b). The distillation units (Chapter 17)
will continue to be the mainstay of petroleum refining and the main short-term developments are
in improved integration through the use of heat recovery technology and integration of different