(d)
Alkylation unit uses a process which converts the separated gases from
a vapor recovery unit (particularly propane, butane, and sometimes pentane) into
high octane gasoline.
These gases are compressed into a liquid and then passed
through sulfuric acid (the catalyst) causing the separate gases to bond (Figure 2-
35).
The octane gasoline produced by an alkylation unit is piped to a treating
unit for final processing. Major recognition features of alkylation unit include:
Three to six tall, thin fractionators arranged in a line
One tower may be taller than the others
Spherical gas storage tanks(s) present.
Figure 2-35.
Alkylation Unit.
(e)
Polymerization.
This process is very similar to alkylation.
It uses
heat, pressure, and an acid catalyst to combine propane and propane gas, supplied
by a vapor recovery unit, into high octane gasoline inside a reactor.
The high
octane gasoline produced by the polymerization unit is stable and routed to the
treating unit (Figure 2-29).
Major recognition features of polmerization unit
(Figure 2-36) include:
Five to 10 tall, thin fractionators
One or two pipe furnace(s)
Reactor columns, possibly enclosed in tall, rectangular steel structures or
in buildings; or may be short, thick columns located among the fractionators
Compressor house may be present.
IT 0673
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