Chemical Engineering June 2018 - 80

ments of the process system using the
current condensate system, incurring
relatively minor capital costs but saving
millions of dollars per year over the
long run.
Steam balance Example 2. In the
second example, a steam balance
determined that a few minor steampiping
changes allowed low steam
pressures to be consumed by end
users, thus reducing the flash steam
losses. The changes improved condensate
drainage and further reduced
the flash steam venting. The
result was increased steam-system
thermal-cycle efficiency with a reduction
in energy and emissions and increased
overall reliability.
Steam balance Example 3. Figure
2 shows different methods to recover
the condensate under pressure,
which can help save energy and reduce
emissions for the plant operation.
Switching from a low-pressure
deaerator to a high-pressure deaerator,
with some changes to the
condensate line, allowed the return
of condensate from non-modulating
processes to the high-pressure deaerator,
resulting in higher steamsystem
cycle efficiency.
Steps for a steam balance
A steam-balance flow document
(such as that shown in Figure 3)
provides all the required steam and
condensate information, capturing
relevant information about the steam
flows, pressures, end users, pressure-reduction
stations, turbines,
boilers, condensate tanks and more.
The more detail added into a steambalance
flow diagram, the more important
and valuable the document
becomes to the plant operation.
Shown below are some of the essential
items that should be properly
documented during the process:
1. All boilers or steam generators
a. Steam output
b. Operating steam pressures
c. Safety valve set pressures
2. Deaerator system details
a. Operating pressures
b. Steam flows
3. Makeup water system for the
deaerator
a. Flowrates
b. Average temperatures
4. Steam turbines
a. Supply pressures
b. Extraction pressures
c. Electrical or drive output
5. Steam headers by operating
pressure
6. Steam pressure-letdown stations
a. Inlet and outlet pressures
b. Maximum and minimum flowrates
7.
End users or consumers
a. Energy requirements (Maximum
and minimum)
8. Condensate headers
a. Operating pressures
b. Flowrates
9. Flash tanks
a. Integration into the system
b. ASME stamping
10. Condensate tanks
a. Venting or not venting
b. Pressure ratings
11. Other site-specific details that
can help support the project
The list will grow as the steam balance
process continues.
Closing thoughts
Every plant, regardless of size, from
a small food processing plant to a
large petroleum refinery, needs to
prepare a steam balance in a format
that works to support the plant's operation.
Conducting a steam balance
does not necessarily require a complex
software system in order to be
beneficial to the steam system manager;
rather, it can be accomplished
using
a
simple
graphic
software
package. Whatever method is selected,
carrying out a steam balance
is the first step in increasing overall
steam system thermal-cycle efficiency,
which will reduce energy use
and emissions and increase overall
system efficiency.
n
Edited by Suzanne Shelley
Author
Kelly Paffel currently serves as
technical manager at steam engineering
firm Inveno Engineering,
LLC (7320 East Fletcher Ave,
Tampa, FL
289-3667; Email:
invenoeng.com).
33637; Phone: 239kelly.paffel@
Paffel
has
41
years
of experience in steam and
power operations and is an experienced
lecturer who has published
many technical papers on the topics of steam system
design and operation. He is known for writing " Steam
System Best Practices, " which are used by plants and
engineers globally to ensure proper operation of steam
and condensate systems.
CHEMICAL ENGINEERING WWW.CHEMENGONLINE.COM
JUNE 2018
Your fast lane to
advanced mixing technology:
Phone: +1 201 825 4684
Ext.: 205
usa@ekato.com
www.ekato.com
2018.06 ChemEng_ProcessPlants INTERPHEX JAPAN.indd 128.03.2018 07:36:31
For details visit adlinks.chemengonline.com/70307-25
71
Hydrogenation
Solids blending / drying
Pharma, food, cosmetics
Finechemicals
Visit us in Tokyo, June 27-29, 2018
Booth E8-20
PROCESS
PLANTS FOR
http://www.invenoeng.com http://www.ekato.com http://adlinks.chemengonline.com/70307-25 http://WWW.CHEMENGONLINE.COM
Chemical Engineering June 2018

Table of Contents for the Digital Edition of Chemical Engineering June 2018
