Chemical Engineering May 2021 - 49

Gulf Coast 2021 Special Advertising Section
Sampling for Sulfuric Acid Alkylation Unit
A
sulfuric acid alkylation unit (SAAU) in a refinery is the process
by which isobutane is combined with light olefins over a sulfuric
acid catalyst of 87-92.5% strength to produce high octane
gasoline. The alkylation process results in reduced sulfuric acid
strength, which must be monitored closely to prevent acid runaway.
To prevent this, fresh concentrated sulfuric acid is added to the
process. For a unit to operate as efficiently as possible, Operations
must make sure that acid levels are maintained above the required
strength for the process while also minimizing acid consumption, as
sulfuric acid is one of the major costs of the refinery. Such a balancing
act, between safety and efficiency, can be difficult to manage in
real world situations where conditions can change quite rapidly. An
inline system that is engineered to address the most common issues
found with traditional sampling methods is the key to higher
productivity and efficiency, improved safety, and a plant's bottom
line.
Safety: As sulfuric acid is toxic and extremely corrosive, the
sample system should be designed to ensure exposure is kept to an
absolute minimum. Sulfuric acid will react with moisture in the atmosphere
and produce a highly visible acid mist which can lead to
severe irritation of the eyes and respiratory tract in high concentrations.
While collecting the sample, the operator must be protected
from acid fumes at all times.
Ease of use: The sampling process should be made as simple as
possible so that the room for error is greatly reduced or eliminated
entirely. This means that there should be as few procedural steps as
possible to grab a sample. Sampling systems which feature numerous
connections and tubing are not very robust, and also present
potential leak points.
Representative samples:
Accurate samples
are a critical factor in determining
acid strength. If
the sample is influenced
by product left in the process
line, a representative
sample is difficult to
achieve, particularly if the
line has to be flushed or
purged before a sample is
taken. This process also
produces waste which
must be neutralized, and
represents a significant
cost to the refinery.
The most effective way
to mitigate the risks associated
with sulfuric acid
is to isolate people from the hazard using engineering controls.
An inline solution offers the safest, most robust, reliable and cost
effective solution for grab sampling sulfuric acid to monitor acid
strength in a sulfuric alkylation unit.
Contact BIAR Sampling Systems to discuss your Sulfuric Acid
Alkylation Sampling requirements and download our whitepaper on
Sampling Sulfuric Acid
www.biar.us/saau.
Keeping Turnarounds on Track
with a Reliable Plugging Solution
Pop-A-Plug® Tube Plugs from Curtiss-Wright EST Group
M
Pop-A-Plug Tube
Plugs maintain
a leak-tight seal
without causing
damage to tubes
or tube sheets
any turnarounds may be scheduled months in advance, yet
plants still struggle to meet start-up and completion dates. By
some industry estimates, up to 90% of turnaround projects extend
beyond their scheduled time. Delays of even a few days can add millions
of dollars to the cost of a turnaround when factoring in reduced
productivity of the facility and additional on-site contractor labor.
For over 50 years, Curtiss-Wright's EST Group have been designing
and manufacturing products and systems to simplify maintenance
to shorten turnaround times for operation-critical equipment,
from shell-and-tube and air-cooled heat exchangers to pipelines, piping
systems, and pressure vessels.
A Permanent & Cost-Effective Solution for Tube Plugging
Shell-and-tube heat exchangers represent one of the most common
and critical pieces of process equipment in plants. In most environments,
heat exchanger tubes eventually degrade or leak as a
result of prolonged runs, impurity-induced fouling, and corrosive
fluids that run through the system.
One traditional process of sealing tubes involves installing tapered
plugs, often welded into the tubes with pre-heat and postweld
heat treatments. This process is both time-consuming and
unreliable. Tubes and tube sheets may suffer from circumferential
cracking after units are brought back into service from pressure
and temperature cycles that are common during normal operation.
Curtiss-Wright EST Group's heat exchanger plugging system greatly
minimizes delays in equipment maintenance during turnarounds by
eliminating welding
altogether.
The system includes G-160 Tube Testing Tools for leak detection
in shell-and-tube heat exchanger, boiler, and condenser tubes. These
tube testers can rapidly pinpoint tube leaks while providing a safer environment
for plant personnel with their patented gripper technology.
Once leaks are identified, Pop-A-Plug Tube Plugs deliver a permanent
and cost-effective plugging solution. Plugs install hydraulically
using a unique breakaway, eliminating the labor and time associated
with welding tapered plugs into place. Installed properly, Pop-A-Plug
Tube Plugs maintain a helium leak-tight seal without causing damage
to tubes or tube sheets. They can withstand extreme thermal and
pressure cycling at working pressures up to 7,000 PsiG (483 BarG),
and meet ASME PCC-2 (Article 3.12) recommendations for the inspection
and repair of shell and tube heat exchangers.
Pop-A-Plug Tube Plugs are available in wide range of materials,
including corrosion-resistant alloys, matched to the metallurgy of
the unit in which they are to be installed. Matching plug and tube
material mitigates thermal expansion/contraction issues, and undesirable
galvanic corrosion, ensuring the leak tight seal.
Curtiss-Wright EST Group serves a global customer base with an
extensive inventory ready to ship, and 24/7 emergency manufacturing
available. For more information, visit
www.cw-estgroup.com
CHEMICAL ENGINEERING WWW.CHEMENGONLINE.COM MAY 2021
49
http://www.biar.us/saau http://www.cw-estgroup.com http://WWW.CHEMENGONLINE.COM
Chemical Engineering May 2021

Table of Contents for the Digital Edition of Chemical Engineering May 2021
