Asphalts
The production of the asphalt grades and their specification have been described
and discussed under “non-energy refineries.” A good source of information is the
Asphalt Paving Design Guide available from the Asphalt Paving Association of
Iowa (undated).
Petroleum Coke
Petroleum coke is not found in crude oil, but is the carbon compound formed from
the thermal conversion of petroleum containing resins and asphaltenes. Coke is
formed in the processes to convert the residuum fuels to the more desirable distillate
products of naphtha and lighter, through to the middle distillates. There are two
routes by which this coking process proceeds. The first and the most common is the
delayed coking route. The second is the fluid coking method, and this has been
made more attractive to many refiners with the development of ExxonMobil’s
proprietary process of FLEXICOKING. This proprietary process eliminates the
coke completely by converting it to low-Btu fuel gas. By far the largest production
of coke is the sponge coke from the delayed coking process. Uncalcined sponge
coke has a heating value of about 14,000 Btu/lb and is used primarily as a fuel.
High-sulfur sponge coke however is popular for use in cement plants since the
sulfur reacts to form sulfates. Sponge coke is calcined to produce a coke grade
suitable for anodes in the aluminum industry. Details of the specifications for green
(uncalcined) coke and calcined coke are given in Table 11.
Sulfur
Sulfur is a by-product of modern-day refineries. By the processes that make up the
modern hydrogen skimming refinery, a significant portion of the sulfur contained in
the crude is removed as elemental sulfur for marketing as a product. It is true to say
that as the environmental requirements for the reduced sulfur levels in products and
Table 11 Specification
for sponge coke
Parameter
Green coke
Calcined coke
Fixed carbon %
86–92
99.5
Moisture %
6–14
0.1
Volatile matter %
8–14
0.5
Sulfur %
>2.5
>2.5
Ash %
0.25
0.4
Silicon %
0.02
0.02
Nickel %
0.02
0.03
Vanadium %
0.02
0.03
Iron %
0.01
0.02
Quality Control of Products in Petroleum Refining
661
The production of the asphalt grades and their specification have been described
and discussed under “non-energy refineries.” A good source of information is the
Asphalt Paving Design Guide available from the Asphalt Paving Association of
Iowa (undated).
Petroleum Coke
Petroleum coke is not found in crude oil, but is the carbon compound formed from
the thermal conversion of petroleum containing resins and asphaltenes. Coke is
formed in the processes to convert the residuum fuels to the more desirable distillate
products of naphtha and lighter, through to the middle distillates. There are two
routes by which this coking process proceeds. The first and the most common is the
delayed coking route. The second is the fluid coking method, and this has been
made more attractive to many refiners with the development of ExxonMobil’s
proprietary process of FLEXICOKING. This proprietary process eliminates the
coke completely by converting it to low-Btu fuel gas. By far the largest production
of coke is the sponge coke from the delayed coking process. Uncalcined sponge
coke has a heating value of about 14,000 Btu/lb and is used primarily as a fuel.
High-sulfur sponge coke however is popular for use in cement plants since the
sulfur reacts to form sulfates. Sponge coke is calcined to produce a coke grade
suitable for anodes in the aluminum industry. Details of the specifications for green
(uncalcined) coke and calcined coke are given in Table 11.
Sulfur
Sulfur is a by-product of modern-day refineries. By the processes that make up the
modern hydrogen skimming refinery, a significant portion of the sulfur contained in
the crude is removed as elemental sulfur for marketing as a product. It is true to say
that as the environmental requirements for the reduced sulfur levels in products and
Table 11 Specification
for sponge coke
Parameter
Green coke
Calcined coke
Fixed carbon %
86–92
99.5
Moisture %
6–14
0.1
Volatile matter %
8–14
0.5
Sulfur %
>2.5
>2.5
Ash %
0.25
0.4
Silicon %
0.02
0.02
Nickel %
0.02
0.03
Vanadium %
0.02
0.03
Iron %
0.01
0.02
Quality Control of Products in Petroleum Refining
661