Brochure

6 | Fisher
®
Olefin Production Solutions
Feed gas into the pyrolysis furnace can be a number of
feedstocks, including ethane, propane, butane, gas oil, or
naphtha. Regardless of feedstock, the feed rate must be
balanced with dilution steam to lower hydrocarbon partial
pressure and increase olen yield. An improper ratio reduces
efciency of the furnace and will impact ethylene conversion.
Valves in the furnace section play a critical role in maximizing
ethylene production and throughput.
Hydrocarbon Feed
Control Valve
In this particular application, a number of valves in parallel are
commonly used to control the ow of the feedstock into the
furnace. Reliability is the foremost requirement of inlet feed
valves. Unexpected maintenance or surprise failures can stop
production. In addition, these valves must be able to provide
precise, stable control through a wide range of ow rates from
startup and commissioning through full rated output of the
plant. These valves must operate with minimal variability to
help ensure stable and predictable performance of all process
units downstream. Depending on the operating pressure of
the pipeline, these valves can also experience a signicant
pressure drop. If not addressed properly, damaging noise and
vibration may occur.
Dilution Steam Ratio
Control Valve
An improper feed-to-steam ratio reduces efciency of the
cracker and can result in the need for additional decoking
cycles, therefore reducing furnace uptime. The quantity of
steam used varies with feedstock, cracking severity, and
design of cracking coils. With the feed-to-steam ratio directly
impacting olen yields, it is important to maintain precise
control of that ratio. In addition, steam assists to reduce
coking deposits by reacting with coke to form carbon dioxide
(CO
2
), carbon monoxide (CO), and hydrogen (H
2
).