OIL PRICES
179
differentiated by their density (measured as API gravity), as well
as their sulfur content. Crude oil with a low API gravity is considered a heavy crude oil, and typically has higher sulfur content
and a larger yield of lower-valued products. Therefore, the lower
the API of a crude oil, the lower the value it has to a refiner as it
will either require more processing or yield a higher percentage of
lower-valued by-products, such as heavy fuel oil, which usually
sells for less than crude oil.
6.6.1 Refinery Types and Crude Slate
A refinery is an installation that manufactures finished petroleum
products from crude oil, unfinished oils, natural gas liquids, and
other hydrocarbons using heat, pressure, catalyst, and chemicals.
Early refineries were simple, batch distillation units that processed hundreds of barrels of crude oil per day from one or a
small collection of fields. Current refineries are complex, highly
integrated facilities that contain a dozen or more process units
capable of handling numerous crude oils from around the world
with capacities generally varying from 100,000 to 500,000 barrels
per day.
Every crude oil produced in the world has a unique chemical
composition that will determine the optimal manner in which to
process the crude and the final product slate. Crude oil contains
distillates of different molecular composition and shape, burning
qualities, and impurities, such as metals, asphaltene constituents,
nitrogen, and sulfur (Speight, 2007). The types, size, number, and
flow sequences for each refinery vary, depending on crude oil input
quality, output product slate and quality, and environmental, safety,
and economic conditions.
Refineries evolve with changes in market demand, feedstock,
product specification, and environmental regulation; and will
typically possess both very old and modern process units. In most
refineries, operating variables, such as temperature, pressure, residence time, feed quality, cut points, recycle-gas ratio, space velocity, and catalyst allow refineries to balance feedstock, product, and
quality. The limits of these variables are unique to the plant design
and nature of the input and output requirements. For a specific
feedstock and catalyst package, the degree of processing and conversion increases with the severity of the operation. The type of
179
differentiated by their density (measured as API gravity), as well
as their sulfur content. Crude oil with a low API gravity is considered a heavy crude oil, and typically has higher sulfur content
and a larger yield of lower-valued products. Therefore, the lower
the API of a crude oil, the lower the value it has to a refiner as it
will either require more processing or yield a higher percentage of
lower-valued by-products, such as heavy fuel oil, which usually
sells for less than crude oil.
6.6.1 Refinery Types and Crude Slate
A refinery is an installation that manufactures finished petroleum
products from crude oil, unfinished oils, natural gas liquids, and
other hydrocarbons using heat, pressure, catalyst, and chemicals.
Early refineries were simple, batch distillation units that processed hundreds of barrels of crude oil per day from one or a
small collection of fields. Current refineries are complex, highly
integrated facilities that contain a dozen or more process units
capable of handling numerous crude oils from around the world
with capacities generally varying from 100,000 to 500,000 barrels
per day.
Every crude oil produced in the world has a unique chemical
composition that will determine the optimal manner in which to
process the crude and the final product slate. Crude oil contains
distillates of different molecular composition and shape, burning
qualities, and impurities, such as metals, asphaltene constituents,
nitrogen, and sulfur (Speight, 2007). The types, size, number, and
flow sequences for each refinery vary, depending on crude oil input
quality, output product slate and quality, and environmental, safety,
and economic conditions.
Refineries evolve with changes in market demand, feedstock,
product specification, and environmental regulation; and will
typically possess both very old and modern process units. In most
refineries, operating variables, such as temperature, pressure, residence time, feed quality, cut points, recycle-gas ratio, space velocity, and catalyst allow refineries to balance feedstock, product, and
quality. The limits of these variables are unique to the plant design
and nature of the input and output requirements. For a specific
feedstock and catalyst package, the degree of processing and conversion increases with the severity of the operation. The type of