weyer special | fired heater simulation
weyer group
allround. smart.
FIRED HEATER
SIMULATION
www.weyer-group.com
weyer special | fired heater simulation
Fired heater simulation
Direct fired heaters are generally used in processes where the process temperature required is greater than 300 °C. A distinction is made here between process heaters and refinery heaters. The most widely used refinery heaters are those which
are used for heating or evaporating hydrocarbons. There can be 20 different heaters in a typical refinery. For this common
type of furnace, a range of different validated simulation tools are available on the market. The weyer group uses Xfh developed by HTRI, the tool widely used in the refinery industry for the modeling of furnaces. The following describes the scope
of a simulation such as this, as well as the use of the simulation results.
Our services:
Furnace recalculations
 Recalculations in the
event of a product
change
 Burner optimisation
 Design of new pipe-
work
 Furnace documen tation

weyer special | fired heater simulation | page 2
1 What is simulated?
The weyer group has extensive experience in the rigorous thermodynamic simulation of these types of process
heaters.
First, sophisticated software is used to
map out the complete geometry of the
furnace. The arrangement of the pipework and headers, of both the convection and radiation zones, are faithfully
reproduced from customer documentation.
The geometry of the firebox and the arrangement of the burners, including the
type of burner, can be modeled in exacting detail using our system. And of
course air preheaters and natural
draught furnaces can also be modeled.
Properly characterizing the actual function of the furnace is essential to achieving a result that is useful and accurate.
weyer group employees have in-depth
knowledge of the refinery and petrochemical industries, which allows us to
create a simulation based on the proper
design and operating conditions. We
can import chemical property data from
process simulators (Pro/II and Aspen
Hysis) used by the weyer group or data
supplied by the customer. The use of
boiling point analyses according to
ASTM D86 or true boiling point is also
possible.
2 How are the results used?
The applications for this type of furnace
simulation are wide and varied:
weyer group
allround. smart.
 Life Cycle Analysis
Information on the lifespan of the tubes
can be produced from the simulation
results according to
API 530. The
Maximum Tube Metal Temperature
(MTMT) can be predicted from the operating point of the furnace, and is used as
the basis of strength calculations. The operation of the fired heater can also be evaluated retrospectively on the basis of TRD
508 and information can be provided
about the current state of the furnace.
The operation of a furnace is more reliable
with furnace simulations: Potential tube
failures which could lead to the release of
hydrocarbons into the combustion
chamber, can be identified at an early
stage. Repair measures can be planned
into normal maintenance turnarounds,
avoiding an unplanned outage.
conditions thanks to rigorous heater simulation. The following results from the simulation can then be used to define the
best “operating window” for the case at
hand:
•
•
•
•
•
•
Tube wall temperatures
Burner flame lengths
Film temperatures
Pressure profile in the pipe
Fired heater internal pressure profile
Flow regimes in the pipes
(one- / two-phase flows)
The operating window forms the basis for
fired heater automation, the safety
concept and a corresponding operating
manual. It can allow you to avoid operating conditions which could result in
damage to the furnace.
synthesis gas. These furnaces are often
specially designed for their particular application. There is, for example, a significant difference between cracking furnaces for the production of ethylene, which
use naphtha and those which use LPG.
Semi-empirical simulation tools are used to
model furnaces such as these, which have
been designed specifically for the application. The weyer group employees, who
are experienced in process simulation, are
familiar with a number of these tools, such
as Spyro manufactured by KTI for ethylene
plants. So, weyer offers the capability not
only to simulate general service refinery
heater applications, but also process fired
heaters as well.
 Fired heater optimisation
A rigorous fired heater simulation provides
valuable information regarding expected
throughputs, energy consumption and efficiency. You can also examine the effects
of modifications or retrofits of existing furnaces before they are put into service. This
can significantly reduce re-commissioning
times.
It is possible, for example, to examine the
effects of
•
•
•
•
 Identifying the ”operating window”
Process furnaces very rarely only have one
specific use. It is far more likely in practice
that the uses, throughputs and also
product temperatures to be achieved
change frequently. Optimum operating
windows for a process fired heater can be
identified for many different operating
new pipe geometries
fin tubes versus smooth-bore pipes
alternative burner arrangements
or the
refitting of fans
As mentioned at the outset, so-called
process fired heaters are used in the basic
chemical industry, much like they are in
refinery operations. However, chemical reactions take place in these furnaces during
the flow of reactants through the heated
zones. These furnaces are used, for
example, for the production of ethylene or
Your benefit:
 Enhanced process reliability with "life cycle analysis"
 Optimised fired heater operating point
 Pre-planning of
• Revamps
• Recoiling
• Product changes
 Standardised documentation indepen-
dent of the fired heater manufacturer
weyer special | fired heater simulation | page 3
weyer group
allround. smart.
Your Contact
www.weyer-group.com
The weyer group is an independent association of engineering and consulting companies based in Germany, Austria and Switzerland.
Starting with the expectations and wishes of its customers, the weyer group has developed a wide range of skills and expertise since it was founded over 30 years ago.
www.weyer-group.com