The Model 8800C Handles both Gas and
Liquid Flow in the same Process Line at a Naphtha Cracker
Measuring Steam to Distillate Ratios
A naphtha cracker heats Light Distillate Feedstock (LDF), such as naphtha
or ethane, with steam to very high temperatures (approximate 1427 °F or 800 °C) to crack the LDF into basic feedstocks for downstream processes. A typical
installation consists of ten furnaces with 8 LDF and 8 steam feedlines going to each
furnace. Each feedline requires an accurate flow measurement to control the ratio of
steam-to-LDF flow.
Every 60 days, coke deposits must be removed from the furnace tubes.
During the cleaning, the flowmeters normally used to measure the LDF flow must accurately
measure the air flow into the furnace tubes. The flowmeter must also handle transitional
flow between air and LDF and vice versa.
Flowmeters for the cracking furnace process must be able to handle both
gas and liquid flows, generate very accurate measurements, and operate effectively over a
wide range of process temperatures.
Vortex Flowmeters: A Logical Choice
Vortex flow measurement technology is the preferred method compared with
other measurement techniques because of the high accuracy, rangeability, and ability to
accurately measure gas and liquid flows.
The feedstock substance clogs easily with other flow measurement
methods, such as DP/Orifice plate impulse lines. Clogging results in lost or inaccurate
measurement and high maintenance costs.
Rosemount Vortex Flowmeters: The Best Choice
One customer with cracking furnaces found that the Rosemount competitors'
vortex flowmeters clogged around the sensing mechanisms, causing loss of measurement. The
customer was forced to remove and clean these vortex flowmeters after each cleaning cycle
(also referred to as the "burn-out" cycle).
The Rosemount Model 8800C Vortex Flowmeter's crevice-and port-free
design eliminates clogging problems caused by sensor coating. The flowmeters have operated
maintenance-free since the customer installed them in July 1994.
The customer was impress with the Model 8800C's advanced digital signal
processing, which effectively filtered out noise while measuring the air and liquid flows,
no reconfiguration at fluid changeover was required.
Finally, the Model 8800C isolated pulse output had the flexibility to
meet the 3-wire pulse output requirements of the customer.
For more information, link to the
Model 8800C product
page or call Customer Central at 1-800-999-9307 or 612-906-8888 and learn how the
Rosemount Model 8800C can be used for your applications.
|
|
|
|
|
Emerson Process Management,
Rosemount Division, 8200 Market Blvd.
Chanhassen, MN USA 55317
North America: 1-800-999-9307 International:
952-906-8888 Fax: 952-949-7001
|
|
