Hydrocarbon Processing - November 2022 - 54

Heat Transfer
TABLE 1. Partial experience list with high-vol% H2
fi red heaters
Heater type
EDC cracker
Petrochemical heater
Petrochemical heater
CO boiler
Delayed coker
CCR platformer
Delayed coker
Region
Asia
Middle East
Middle East
North America
Asia
North America
Middle East
Fired duty,
MMBtu/hr
97
594
148
195
174
377
160
fuel
Max. vol% H2
in fuel
100%
91%
86%
80%
78%
64%
65%
system to reduce the water content in the flue gas. This could
be accomplished by diluting or reheating the gas before it exits
the heater. Alternatively, methods to condense and collect the
water may be considered.
FIG. 6. Mass and volumetric fuel gas flowrate with increasing vol% H2
This assumes a 100-MMBtu/hr (fired duty) heater, the balance of fuel
is CH4
leading to the heater should be carefully reviewed to ensure proper
pipe sizing for acceptable hydraulics.
Making fired heaters H2
.
, with 15% excess air. As such, the fuel gas skid and burner piping
fuel firing. However, the potential to reduce CO2
-ready.Clearly, many unique chalemislenges
are associated with designing and converting fired heaters
to H2
sions in a fired heater is unlimited if 100% H2
fuel is utilized.
fuel
Furthermore, the challenges are not new to the authors' company,
which has been designing fired heaters with high H2
content for decades. A partial list of recent relevant experience
is provided in TABLE 1.
Making the switch to H2
fuel is an exciting, yet challenging
endeavor. Teaming up with experienced fired heater experts is
a vital step in the development of safe, effective solutions to the
many challenges involved.
LITERATURE CITED
1 Silberberg, M., Principles of General Chemistry, 1st Ed., McGraw Hill, New York, 2007.
2
3
FIG. 7. Chart A shows vol% flue gas composition with 100% CH4
fuel and 15% excess air.
fuel
and 15% excess air, and Chart B shows vol% flue gas composition
with 100% H2
Burner piping and fuel gas skid sizing. For a given heat
release, 100% H2
than CH4
fuel requires significantly less mass flowrate
. However, the volumetric flowrate required is more
than three times as high, as displayed in FIG. 6.
9
Stack plume. The key variable contributing to the visibility
of flue gas exiting a stack is its water content.10
After exiting the
fired heater, hot flue gas cools and the water in the flue gas condenses,
often creating a visible white fog. Although not necessarily
harmful, this visible water plume may become a nuisance
to neighboring communities and act as a transport medium for
other pollutants in the gas. This poses a potential challenge as
combusting higher quantities of H2
water in the flue gas. As demonstrated in FIGS. 7A and 7B, with
100% H2
proximately one third of the flue gas volumetrically.
The water content may be reduced by burning less H2
the fuel. If this is not an option, the end user may consider a
54 NOVEMBER 2022 | HydrocarbonProcessing.com
10
Reed, R. J., North American combustion handbook: A basic reference on the air and science
of industrial process heating with gaseous and liquid fuels, Vol. 1, 3rd Ed., Fives North
American Combustion Inc., 2001.
4
5
6
7
8
Glassman, I. and R. A. Yetter, Combustion, 4th Ed., Academic Press, Cambridge
Massachusetts, 2008.
Guarco, J., B. Langstine and M. Turner, " Practical considerations for firing hydrogen
versus natural gas, " Zeeco.
Sherman, R., " Radiation from luminous and non-luminous natural gas flames, " PhD
thesis, Transactions of the America Society of Mechanical Engineers, 1934.
Mekler and Fairall, " Evaluation of radiant heat absorption rates in tubular heaters, "
Petroleum Refiner, 1952.
American Petroleum Institute (API), Damage Mechanisms Affecting Fixed Equipment
in the Refining Industry, 2nd Ed., API 571, April 2011.
Rivkin, C., R. Burgess and W. Buttner, " Hydrogen technologies safety guide, "
National Renewable Energy Laboratory (NREL), 2015.
Herssens, Y. and S. Safariyeganeh, " Supressing the steam plume, " Digital Refining,
2021.
LUKE GLASHAN has 10 yr of experience in the thermal and
hydraulic design of fired heaters and proposal development.
He holds a BS degree in mechanical engineering from Rutgers
University, and is a Professional Engineer in the state of
New Jersey, U.S.
yields higher quantities of
fuel, the water content in the flue gas increases to apin
KARTHIKEYAN
THIRUNAVUKKARASU has more than 18 yr of
experience in the thermal and hydraulic design of fired heaters
on a concept to completion basis covering thermal and process
design to commissioning. He holds an MS degree in energy
engineering from National Institute of Technology, Trichy, India.
Baukal, C. E., The John Zink Combustion Handbook, CRC Press, Boca Raton Florida,
2001.
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