Leading fertilizer technologies – Ammonia

In order to secure global food supplies, our engineers at

ThyssenKrupp Industrial Solutions have been developing large-
scale plants for the fertilizer industry for over 80 years now. As
a leading general contractor we offer our customers throughout
the world a wide range of cutting-edge Uhde technologies.

4,400 t/day of ammonia

In Arzew, Algeria, we built the Sorfert complex comprising
2 x 2,200 t/day ammonia plants and a 3,450 t/day urea plant
based on our proven Uhde ammonia process, UFT urea
granulation technology and the Stamicarbon urea melt process.

ThyssenKrupp
Industrial Solutions
2

Contents

04 ThyssenKrupp Industrial
Solutions’ ammonia experience
07 The Uhde ammonia process
08 - Steam reforming
10 - CO2 removal
11 - Ammonia synthesis
12 - Steam system
13 - Concept variants
14 - The Uhde Dual-Pressure Process
16 Proprietary Uhde equipment designs
17 - The Uhde primary reformer with
a cold outlet manifold system
20 - The Uhde secondary reformer
21 - Process gas cooling train downstream
of the Uhde secondary reformer
22 - Uhde ammonia converter and
waste heat recovery
25 - Production and consumption figures
26 Services for our customers
27 Recent references
 3

Engineering Excellence3 –
Think globally, act locally

Having erected several thousand plants, ThyssenKrupp Industrial Solutions is one of the
world's leading engineering companies. Our Business Unit Process Technologies supplies
chemical plants, refineries and coking plants on the basis of tried-and-tested technologies
made by Uhde, while the portfolio of the Business Unit Resource Technologies comprises
complete cement plants and grinding systems of the Polysius brand, as well as machines,
plants and systems for mining, extraction, preparation, processing or transshipment of
commodities.

With many years of experience in the EPC business, we offer our customers concepts,
market studies, plant layouts, design engineering, supplies, manufacturing services,
erection and commissioning – all from a single source. Our employees on all continents
use their knowledge and engineering competence to create innovative solutions and to
look for ways to conserve natural resources.

Over 40 locations in 25 countries – divided into six regions – form a close-meshed

network that allows us to align our services to local conditions consistently. Thanks
to this on-site expertise and global networking, we are able to set standards that offer
our customers a true competitive edge.

Our comprehensive service concepts take the entire life cycle of a plant into account.
We offer OEM spare parts service and complete maintenance management, as well
as servicing, modernisation projects and conversions.
4

ThyssenKrupp Industrial Solutions’

ammonia experience

The first ammonia plant to use an Uhde proprietary have had to be focused on reducing power consump-
process went on-stream at the site of the Mont-Cenis tion, improving process heat recovery, minimising stack
coal mine at Herne-Sodingen, Germany, as far back losses and cutting energy consumption for CO2 removal.
as 1928. The plant had an output of 100 t/day of
ammonia and comprised four reactors with a capacity The company's objective of making a substantial
of 25 t/day each, the loop operating at a pressure of improvement in energy efficiency has relied heavily on
100 bar. experience and involved a broad spectrum of technical
expertise including a technical review of process design,
The fact that the first Uhde-engineered ammonia reac- engineering design, research and development and the
tors were equipped with an internal heat exchanger and evaluation of operating data. Equally important has
a synthesis loop with an integrated two-stage refrigera- been the enhancement of plant operability and reliability.
tion unit deserves a special mention. Unfortunately, this Hence, much attention has been paid to past successful
efficient system was soon considered outdated, and it experience and proven energy-saving features.
was not until the seventies that these design principles
were taken up again. In 1998, Uhde joined forces with Synetix, now Johnson
Matthey Catalysts (JMCatalysts), to further improve the
Rising energy prices have posed an increasing challenge Uhde ammonia process. This partnership builds on the
for ammonia plant designers since this period. As early traditional strengths of the two companies and takes
as 1968, Uhde took up the challenge and engineered a advantage of JM Catalysts' know-how in catalysis, am-
plant with an energy consumption of only 7.8 Gcal per monia plant operation and support services together
tonne of ammonia. with the experience in design, engineering and project
execution that ThyssenKrupp Industrial Solutions can
This natural gas-based plant with a capacity of 880 t/day offer. The partnership allows strong collaboration
incorporated the following essential elements for reduc- between JM Catalysts and ThyssenKrupp Industrial
ing energy consumption: Solutions' engineers so that the Uhde ammonia process
can be further optimised to take best advantage of the
• Maximum heat recovery from the primary reformer latest high-performance catalysts from JM Catalysts,
flue gas by cooling it to 135°C at the stack inlet. thus improving efficiency and lowering cost.

• Preheating of the combustion air for the primary The most recent successful implementations of the
reformer. Uhde ammonia process include a plant in Turkmenistan
with a capacity of 600 t/day, a 2,000 t/day plant for
• Generation of 125 bar steam from process waste Qatar Fertiliser Co. (QAFCO) in Mesaieed, Qatar, seven
heat downstream of the secondary reformer and in 1,200 t/day plants in Egypt, a 2,000 t/day plant in the
the ammonia synthesis unit. UAE (FERTIL 2) and a 2,200 t/day plant in Iowa, US,
which is under construction.
• High-pressure steam superheating with waste
process heat downstream of the secondary reformer. A new milestone in ammonia technology was achieved
with the plant built for Saudi Arabian Fertilizer Company
• Three-bed ammonia reactor with heat exchangers (SAFCO) in Al Jubail, Saudi Arabia. It was the first plant
between catalyst beds. to be based on the "Uhde Dual-Pressure Process" and,
with a single-train capacity of 3,300 t/day, it was and
All subsequent ammonia plants designed by still is one of the world's largest ammonia plant. Built in
ThyssenKrupp Industrial Solutions have incorporated 2006, it has since been marginally topped by an Uhde
most of these low-energy features. Dual-Pressure plant built in Saudi Arabia (MAADEN I).
Two other plants of this type and capacity are currently
In recent years, ammonia plant technology has under- under construction, one in Saudi Arabia (MAADEN II)
gone radical developments in terms of both design and and the other in Louisiana, US.
equipment. In order to improve plant efficiency, efforts
 5

Process flow sheet of Uhde’s first ammonia plant

in Herne, Germany, completed in 1928

Ammonia plant in fertiliser complex

in Tecen, Turkmenistan
Capacities: 600 t/day of ammonia
1,050 t/day of urea synthesis
1,050 t/day granulation unit
6

1,500 t/day ammonia

plant and fertiliser complex,
Saskferco, Canada
 7

The Uhde ammonia process

The block diagram of an Uhde ammonia The following process areas have under-
plant found below shows the conventional gone major modifications in order to achieve
sequence of process steps that form the these figures:
basis of most present-day ammonia pro-
cesses. However, ammonia processes • Steam reforming section including
cannot be judged solely on the basis of a its waste heat recovery system.
block diagram. A more detailed scrutiny • Steam system.
of the facts and figures shows that what
• Optional gas turbine drive for
appears to be a conventional set-up is in
the process air compressor.
fact a state-of-the-art ammonia plant
concept. • CO2 removal unit.
• Ammonia synthesis unit.
The total consumption figure (feed + fuel +
electric power) per metric ton of ammonia Assuming the reader to be familiar with the
produced is in the range of 6.4 to 7.2 Gcal basics of ammonia technology, attention in
(26.8 - 30.1 GJ), depending on local con- the following sections has been restricted
ditions (e.g. cooling water temperature) and to those aspects specific to the Uhde low-
project-specific requirements (such as the energy concept.
natural gas price, etc.).

Natural gas feed

Desulphurisation
Fuel Process steam

Combustion
Primary reformer
air

Process air
Secondary reformer

HP steam
superheated

BFW
CO shift

CO2
CO2 removal

Methanation
Syngas compressor

HP steam to
superheater

Product
Refrigeration NH3 synthesis
NH3

H2 to syngas compressor Fuel

H2 recovery

Block diagram
of an Uhde ammonia plant
8

The Uhde ammonia process

Steam reforming

Primary and secondary The following modifications to conventional plant • Increase in the feed / steam mixture preheat tem-
reformer of the AFC designs have contributed to improvements in overall perature. This reduces the firing requirements in the
ammonia plant in Egypt.
efficiency: primary reformer by shifting the heat transfer duty
from the radiant section to the convection section.
• Shift of part of the reforming reaction from the
primary to the secondary reformer as a result of the • Decrease in the steam-to-carbon ratio to 3.0. This
following measure: includes an adequate safety margin against the
formation of carbon deposits on the primary refor-
Installation of a purge gas recovery unit, by means mer catalyst. Reducing the admixture of steam to
of which hydrogen is recycled to the suction side of the feed results in less heat being absorbed in the
the syngas compressor, thereby allowing operation primary reformer radiant section and therefore lower
of the secondary reformer with excess air while the fuel consumption. Nevertheless, the steam-to-gas
hydrogen-to-nitrogen ratio of the make-up gas is ratio is high enough to minimise by-product forma-
kept close to 3:1. tion in the HT shift through the use of commercially
proven catalysts.
• Preheating of the process air for the secondary
reformer to a higher temperature of up to 600°C. The process data of the reforming section are
Shifting part of the reaction to the secondary summarised below:
reformer leads to lower operating temperatures in
the primary reformer and therefore to fuel savings. Steam / carbon ratio 3.0
Feed / steam, primary reformer inlet °C 530 - 580
• Optimum use of the reduced primary reformer load
is achieved by increasing the reformer pressure to Pressure, primary reformer exit bar 39 - 43
about 44 bar whilst maintaining the estimated life- Methane, primary reformer exit vol.% 10 - 13
time of the reformer tubes at 100,000 hours. This
Methane, secondary reformer exit vol.% 0.3 - 0.6
step entails a reduction in overall energy consump-
tion as the aggregate power required for the syn- Process air temperature °C 520 - 600
thesis gas compressor is reduced. Combustion air temperature °C 250 - 440
125 bar steam, superheated °C 530 - 540
Stack temperature °C 120 - 180
 9

Special mention should be made of an essential item A superheater of this type was installed by what was
of equipment in the steam reforming section: the steam then Uhde for the first time in the Gewerkschaft Victor
superheater, located in the process train downstream of plant, which went on stream in 1970. This same design
the secondary reformer. configuration was also used for the CIL plant in Canada
(on-stream since 1985) and is now the superheater of
In a low-energy plant, the objective is to recover as choice in all of the ammonia plants recently built by
much heat as possible from the convection section for ThyssenKrupp Industrial Solutions. Firstly this arrange-
direct process use, thereby reducing the fuel require- ment provides the necessary flexibility to adapt the plant
ment. This reduces the heat available in the convection to any given set of process requirements, and secondly,
section for superheating HP steam. The balance of the it enables the steam system to operate safely under any
energy required for this purpose is therefore recovered normal, or abnormal, operating conditions.
in the superheater downstream of the secondary re-
former. The duty of this superheater is in the range An internal bypass in the evaporation section permits
of 15 to 40% of the heat available between the second- the shifting of heat transfer duty between the evapora-
ary reformer exit and HT shift inlet, depending on the tor and the steam superheater. In normal operation, the
process parameters selected. internal bypass remains partially open. By closing it, the
gas temperature at the superheater inlet can be re-
The lower the fuel consumption figure, the more process duced, thus increasing steam generation. This is impor-
gas heat is utilised to superheat the HP steam, whereas tant in overcoming partial plant failures, e.g. in the case
the total HP steam generated is reduced. In other words: of a loss of steam production in the ammonia synthesis
fuel savings also reduce the net energy export. section.

Steam reforming
Fuel HP steam and CO shift

Secondary
reformer

Steam drum
Reformer HP steam
Desulphurisation superheater
➀➁ ➂ ➃ ➄

Process
gas cooler
HP steam
Feed
MP steam
LT shift HT shift
Process air
Combustion air

Convection bank coils BFW

➀ HP steam superheater
Process gas
➁ Feed/steam preheater
➂ Process air preheater BFW
➃ Feed preheater
➄ Combustion air preheater
10

The Uhde ammonia process

CO2 removal

Various chemical and physical absorption systems are The design selected incorporates a two-stage absorber.
available for the removal of CO2, e.g. aMDEA®, Benfield, Most of the CO2 is removed in the lower part using a
Amine Guard and Selexol. ThyssenKrupp Industrial semi-lean solution that has been regenerated in a two-
Solutions has used all these processes in the past and stage flash loop without any need for stripping energy.
has the experience of many years of commercial opera- Final purification to the ppm range then takes place in
tion. The lowest energy consumption is achieved using the upper part of the absorber with a relatively small por-
the OASE WHITE® process licensed by BASF. The key to tion of the total circulating solvent. It is only this portion
these energy savings is that the solution is primarily re- that has to be thermally regenerated by a stripping pro-
generated by flashing rather than steam stripping. cess in a reboiling column. This process scheme permits
a reduction in the specific energy consumption of the
The activated OASE WHITE® process uses a solution of CO2 recovery system to 1,340 kJ / Nm3 of CO2 (13,000
N-methyldiethanolamine and water with a special activ- BTU / lb mole of CO2).

CO2 (high purity)

Fuel Absorber

Flash
vessel

Stripper

C.W. C.W. Pure

gas
LP steam

aMDEA® CO2
removal system
Process gas

ator as the solvent. As the activated MDEA solution In addition, the process offers the following advantages:
isotherms for CO2 are between those of a typical
chemical solvent and a physical solvent, this process • High CO2 recovery rate (> 96%) and CO2 purity
combines the benefits of both chemical and physical (> 99% by volume).
CO2 removal processes.
• No need for corrosion inhibitors as the solution is
not corrosive to carbon steel.

• 
Minimisation of solution losses because activated
MDEA has a low vapour pressure and does not
degrade during operation. No reclaiming of the
solution is required.

• No toxic solvents.

• No crystallisation problems.
 11

The Uhde ammonia process

Ammonia synthesis

The most fundamental improvements to earlier designs therefore uses only well-proven magnetite-based cata-
have been effected in the ammonia synthesis unit. lysts in all three beds. The first of the three beds will
typically be filled with prereduced catalyst to accelerate
The main feature of this unit is its high conversion rate the initial start-up.
which is achieved by a large catalyst volume. In order to
minimise reactor size and cost while keeping the pres- Depending on the site-specific and project-specific con-
sure drop low, the large catalyst volume requires: ditions, the three catalyst beds are arranged in either
one or two ammonia reactors.
• Use of small grain-size catalyst.
Designs with one ammonia reactor and one waste heat
• Application of the radial-flow concept in the boiler cannot optimally exploit the reaction heat for the
ammonia reactor. generation of high-pressure steam. However, optimum
heat recovery can be achieved if an additional waste heat
HP steam boiler is introduced between the second and third bed.

This arrangement improves the gas-side temperature of

the boilers and provides an additional advantage in that

Purge
Ammonia
converter
C.W.

NH3
BFW (liquid)
Make-up gas Syngas compressor

Ammonia synthesis

Uhde has always advocated three-bed reactors with high it permits a higher boiler feed water temperature at the
ammonia conversion rates per pass. Therefore, the Uhde boiler inlet, which means that the preheating of the boiler
ammonia synthesis unit is based on a three-bed reactor feed water can be enhanced by using the low-level heat
system, each bed with a radial flow. A high-conversion available in other plant sections, for example downstream
synthesis loop offers considerable advantages since the of the LT shift.
recycle gas quantity is considerably reduced and, conse-
quently, power requirements for the circulator are lower The effect of a two-boiler system on high-pressure steam
and heat exchanger surfaces smaller. Refrigeration re- generation is significant: it is increased from 1.1 to 1.5
quirements also decrease overproportionately because t / t of ammonia. The process parameters of the
most of the ammonia produced is condensed upstream synthesis loop design are shown below:
of the loop chiller.
H2 / N2 ratio, methanation exit 2.95
Studies on innovative high-activity precious metal-based Synthesis loop pressure bar 140 - 210
catalysts have revealed that no economic advantage can
be gained through their use in view of the uncertainty of NH3 reactor inlet vol.% 3 - 5
future prices for the precious metals required. Further- NH3 reactor outlet vol.% 20 - 25
more, due to the different physical properties operational
HP steam generation t / t NH3 1.1 - 1.5
problems can be expected. For maximum reliability and
cost-effectiveness ThyssenKrupp Industrial Solutions Number of reactors 1 or 2
12

The Uhde ammonia process

Steam system

Process gas Flue gas Steam system

HP steam header
112 bar, 530 °C
Turbine syngas compressor
Steam drum
125 bar
Process gas

NH3
Process gas synthesis Process gas

Process steam MP steam header

415 °C, 49 bar
Turbine process air
compressor and alternator

LP steam consumers BFW pump

LP steam header

C.W. Surface condenser

BFW
Condensate Condensate
treatment Condensate pump

The diagram shows the heat management system un- The superheated steam is expanded in the high-pres-
derlying the Uhde low-energy ammonia plant concept, sure part of the syngas compressor turbine and fed to
the essence of which is the optimum utilisation of the medium-pressure system.
process waste heat for the generation of superheated
high-pressure steam. Medium-pressure steam at 49 bar, 415°C, is used as
process steam or for the following equipment:
High-pressure boiler feed water is heated in a first step
downstream of the LT shift; the stream is then split into • Condensing turbine that drives the syngas
two, one part-stream going to the ammonia synthesis compressor.
unit and the other to the HT shift for further preheating.
• Condensing turbine that drives the process air
compressor / alternator.
High-pressure steam is only generated from process
waste heat at two locations: • Back-pressure turbine driving the boiler feed
water pump.
• Downstream of the secondary reformer.
Depending on the plant requirements, the process air
• In the ammonia synthesis unit.
compressor turbine or the refrigeration compressor
turbine can be fed with HP steam. All other machines
Superheating of high-pressure steam takes place
are driven by electric motors.
downstream of the secondary reformer and in the
primary reformer convection bank.
Further reduction of the overall energy consumption is
achieved by application of a gas turbine drive combined
with a heat recovery system.
 13

The Uhde ammonia process

Concept variants

The plant concept presented here constitutes the basis

of the Uhde low-energy ammonia technology. The design
can easily be adapted to suit the specific conditions of
any project. Variations may range from minor process
modifications (e.g. in the steam system) to the replace-
ment of entire units (e.g. substitution of the aMDEA®
CO2 removal system for an Amine Guard, Benfield or
Selexol unit).
14

The Uhde ammonia process

The Uhde Dual-Pressure Process

Chemical plant capacities have for a long time been lower temperature than in the conventional ammmo-
taking on ever greater dimensions. The reason for this nia process. The high synthesis loop pressure is
is the reduction of the specific production costs through achieved through a combination of the chilled second
economies of scale. More than ever before, the plant casing of the syngas compressor and a slightly
construction sector is facing the challenge of exploiting elevated front-end pressure. In this conventional am-
this advantage while at the same time continuing to monia synthesis loop the remaining two thirds of the
employ proven technologies and equipment. total ammonia is produced.

ThyssenKrupp Industrial Solutions and Johnson Technology highlights

Matthey Catalysts have risen to this challenge and
developed a process based on existing technology • Well-proven magnetite-based catalysts can be used
which now enables ammonia plants to produce very in all stages of the new process.
large capacities. This new process (see flowsheet)
delivers a capacity of 3,300 t/day using well-tried • Energy efficiency is improved by 4% compared to the
and tested equipment. It also provides the basis for conventional Uhde process.
even larger plants (e.g. 4,000 - 5,000 t/day).
• A high conversion rate in the high-pressure synthesis
The first plant to apply this process was the SAFCO IV loop combined with the reduced production require-
ammonia plant in Al-Jubail, Saudi Arabia. With a ca- ment results in reduced piping sizes in the high-pres-
pacity of 3,300 t/day it was by far the largest ammonia sure loop. Standard piping can be used for capacities
plant worldwide. The plant has been in operation since of 4,000 t/day and more.
2006. A second plant based on the Dual-Pressure Pro-
cess came on stream with a similar capacity in 2011 • The syngas compressor of a 3,300 t/day dual-
and the next two plants are under construction. pressure plant is the same size as that in current
2,000 t/day ammonia plants; several reference
The key innovation of the Uhde Dual-Pressure Ammo- compressors are in operation.
nia Process is an additional medium-pressure once-
through ammonia synthesis connected in series with • Only 2/3 of the hydrogen recovered from the purge
the conventional high-pressure ammonia synthesis loop gas has to be recompressed to the loop; 1/3 is con-
as follows: verted to ammonia in the once-through synthesis.

1. The once-through ammonia synthesis involves • The process design is extremely flexible with a large
compression of the make-up gas in a two-stage number of process parameters available to optimise
intercooled compressor. This is the low-pressure the use of catalyst and machinery.
(LP) casing of the syngas compressor. The pressure
at the discharge of the compressor is about 110 bar. • It is now possible to achieve a synthesis capacity of
At this pressure the three-bed, intercooled, once- about 3,300 t/day of ammonia using conventional
through converter produces approximately one third equipment and catalysts that have proved to be reliable
of the total ammonia output. The syngas-ammonia and efficient in existing plants.
mixture leaving this converter is cooled and 85% of
the ammonia produced is separated from the gas as • There are no major deviations from proven process
liquid. conditions.

2. The remaining syngas is then compressed in the • 

The front-end of the plant is very similar to the con-
high-pressure (HP) casing of the syngas compressor ventional Uhde design except that it operates at a
to the operating pressure of the ammonia synthesis pressure of about 3 bar higher, a process condition
loop (up to 210 bar). Since the syngas has been which is well within our proven long-term design and
cooled down the HP casing can operate at a much operating experience.
 15

The Uhde Dual-Pressure Ammonia Process

Off-gas
Second
ammonia
converter PGR unit

HP HP ~ 210 bar Purge gas recovery

steam steam
CW
First
ammonia
converter
NH3 chiller NH3
~ 110 bar

LP HP Once-through Ammonia
casing casing ammonia converters from
Note: Molecular HP loop
sieves (dryers) CW
not shown
NH3 NH3 chiller
chiller
HP
steam
H 2O

CW

Make-up gas from front-end NH3 chiller Ammonia from once-through conversion NH3

Low pressure section

High pressure section
16

Proprietary Uhde equipment designs

A good process alone is not sufficient. • Primary reformer with a cold outlet manifold system.

It is at least as important to have proven and reliable • Secondary reformer.

designs for critical items of equipment. Only the two
combined will make a good plant. • Process gas cooling train downstream of the
secondary reformer for
ThyssenKrupp Industrial Solutions has pioneered - generating high-pressure steam
the development of essential items of equipment for - superheating high-pressure steam.
ammonia plants and is one of the leading contractors
in this field. These developments include: • High-efficiency ammonia converter system with three
beds, indirect heat exchange and radial flow.

• Ammonia synthesis waste heat boiler.

ThyssenKrupp Industrial Solutions holds, or has

pending, a number of patents for such equipment and
has granted numerous manufacturing and marketing
licences to equipment manufacturers and chemical
engineering contractors.

Primary reformer Cold outlet manifold system

Inlet manifold

Secondary reformer

Burners
Process air

Reformer Water jacket

tubes
Refractory

Catalyst bed

Gas outlet

Cold outlet Reformer radiant section, outlet

manifold system manifold system and secondary reformer
 17

Proprietary Uhde equipment designs

The Uhde primary reformer with a
cold outlet manifold system

The Uhde primary reformer is a furnace in which • Small number of burners (in comparison with a
a multiplicity of tubes filled with catalyst are heated by side-fired reformer).
burning fuel. The process gas temperature required
at the outlet of the catalyst-filled tubes is about 800°C • Internally insulated cold outlet manifold system made
at a pressure of approximately 45 bar. Inevitably, the from carbon steel and located externally under the
service life of components such as the reformer tubes reformer bottom.
is limited. Material deterioration occurs through the
combined effects of creep, alternating thermal and • Internally insulated reformer tube-to-manifold con-
mechanical stresses, external and internal oxidation nection which operates at moderate temperatures.
and carburisation.
• Each tube row is connected to a separate outlet
Consequently, the furnace designer is faced manifold.
with two main tasks:
Advantages of the Uhde reformer:
• 
Firstly, to minimise the number of components
subject to wear and tear due to the combined effects • No high-alloy outlet pigtails and / or outlet manifolds
of high temperatures and pressures. or risers which work at creep conditions.
Feed/steam
• Secondly, to allow as smooth and safe an operation • Minimum number of components exposed to the
as possible. severe process conditions.

Furnace arch The following main features show our approach to • Uniform temperature profile over the entire length
fulfilling the above requirements: of the reformer tube with the lowest possible peak
Reformer tube temperature, resulting in optimum utilisation of the
Fire box
• Top-firing for an optimum uniformity of the tube skin reformer tube material.
temperature profile.
• No thermal expansion problems with the outlet mani-
fold system. The slight remaining thermal expansions
do not have to be compensated by materials exposed
to the severe process conditions. The design of very
large single-box reformers is possible.
Furnace bottom
• The process gas outlet temperature is monitored for
Catalyst grid each tube row and is adjustable during operation for
Skin temperature optimum reformer performance and temperature
profile
Bellow uniformity.

• Almost unlimited service life of the Uhde outlet mani-

Gas conducting tube
fold system with no maintenance required other than
painting.
Shop weld

Field weld • Considerable operational allowance of the outlet

Carbon steel manifold system with regard to process gas tem-
Refractory
perature and pressure.

More than 60 reformers of this type have so far been

300 600 900
Skin temperature [°C] designed and constructed since 1966. All have per-
Outlet manifold
formed excellently. The two largest units are equipped
with 630 and 960 tubes, respectively.

Reformer tube-to-manifold connection

with skin temperature profile
18
 19

Fertiliser complex no. 4 (SAFCO IV) for Saudi

Arabian Fertilizer Company in Al Jubail, Saudi Arabia
Capacities: 3,300 t/day of ammonia
3,250 t/day of urea
3,600 t/day granulation unit
20

Proprietary Uhde equipment designs

The Uhde secondary reformer

Particularly challenging areas in secondary reformer

design include:

• The transfer line from the primary reformer outlet

to the secondary reformer.
Secondary reformer
Process air • The refractory lining including the ceramic
arch which bears the catalyst weight.

• The burners.

Combustion ThyssenKrupp Industrial Solutions’ answer to a safe

zone and reliable secondary reformer comprises the following
features:

Water jacket • 
A refractory-lined transfer line between the primary
and secondary reformer, which is only short as it is
connected to the process gas inlet nozzle of the
secondary reformer. Once in the secondary reformer,
Catalyst the gas passes through an central internal riser into
the combustion chamber. This design facilitates
Refractory ducting and eliminates thermal stress between the
transfer line and the secondary reformer.

• A multi-layer refractory lining with high-alumina

Arch
bricks in the hot zones.

Process gas • A ring-shaped arch made of high-alumina bricks that

provides a highly stable support for the catalyst. Due
to the internal riser, the arch spans only half of the
vessel diameter, resulting in improved stability com-
pared to other designs.

• A multiple nozzle burner system comprised of nozzles

equally distributed round the circumference of the
Process gas combustion chamber at two levels.

• Discharge of the process gas from the central internal

riser into the dome by reversing the flow direction. Air
CFD optimisation is added via a specific number of nozzles installed in
the vessel wall at a defined angle, thus creating a
vortex flow in the combustion chamber. The vortex
The process gas leaving the primary reformer enters the flow ensures optimised mixing of air and process gas.
secondary reformer at the bottom. The gas is routed The flames do not come into contact with the vessel
through the central internal riser pipe into the combustion refractory or the central riser pipe.
chamber at the top of the secondary reformer. Process
air is introduced into this combustion chamber via noz- • A proprietary burner design, first applied in 1992,
zles, arranged at equal intervals round the circumference which avoids any metallic parts coming into contact
of the combustion chamber in two rows. The partially with the hot reacting process gas.
oxidised gas passes through the catalyst bed from top
to bottom, the catalyst bed being supported by a ceramic Since its introduction in 1968, the Uhde secondary
arch. Finally, the gas leaves the secondary reformer reformer has proved to be a reliable item of equipment
through the outlet nozzle at the bottom. with a long service life.
 21

Proprietary Uhde equipment designs

Process gas cooling train downstream
of the Uhde secondary reformer

The process gas from the secondary reformer has to be

cooled from 1,000°C to a controlled temperature suitable
for the downstream CO shift. The sensible heat can best
be utilised in the generation and superheating of high-
pressure steam.

The challenge in designing suitable cooling train equip-

ment is to arrive at a concept which provides safe tem-
perature limitation for all parts according to their particular
load sensitivity and materials of construction. In addition,
the equipment should be available at competitive prices.

Since 1966, ThyssenKrupp Industrial Solutions has

both used and promoted use of the horizontal fire-
tube boiler for this purpose. In 1969, the process gas
cooling train was first modified to include a high-pres-
sure steam superheater. Uhde secondary reformer and process gas cooling train

Features of the Uhde process gas cooling train Advantages of the horizontal fire-tube boiler:

Horizontal fire-tube boiler with: • Simple, fixed-tubesheet design.

• Thin flexible tube-sheet design. • No crevice corrosion.

• Full-penetration tube to tube-sheets welds. • Reliable natural water circulation.

• Tube inlets protected by ferrules to limit the head flux • No heated dead ends on water side where debris
at the tube inlet. can settle.

• Double layer refractory lining for the inlet and, if • Low metal temperatures at and near tubesheets due
necessary for the outlet chamber with high-duty bricks to efficient insulation and ferrules.
on the hot surface.
• Simple and reliable process gas temperature control.
• Internal gas bypass for temperature control with
steam-cooled damper blades. • Easy access for inspection and maintenance.

• Steam drum mounted on top of the boiler and • Low erection costs due to shop assembly of boiler
supported by downcomers and risers. and drum.

High-pressure steam superheater with: Advantages of the high-pressure steam superheater:

• Process gas inlet and outlet at the bottom. • Coil designed for high mechanical flexibility.

• Preferably vertical arrangement of the super- • Thermal expansions compensated for within the coil.
heating coil.
• Safe metal temperatures maintained by efficient
• Pressure shell in contact with the cooled process bypass control.
gas only.
• Temperature of the pressure-bearing shell governed
• Internal bypass for temperature control. by cooled outlet gas.

• Simple steam and process gas temperature control.

22

Proprietary Uhde equipment designs

Uhde ammonia converter and
waste heat recovery

Fertiliser complex of The demand for energy-efficient Features of the Uhde Features of the Uhde
EFC in Ain Shukna ammonia production dictates the single-converter design: two-converter design:
(near Suez), Egypt.
following criteria for the design
Capacities: of the ammonia synthesis unit: • Heat exchanger between • Location of the first two
1,200 t/day of ammonia catalyst beds for indirect catalyst beds in the first
1,925 t/day of urea • High conversion rates and cooling of synthesis gas; converter vessel and of the
2,000 t/day granulation unit therefore large catalyst consequently, highly efficient third bed in the second
volume. temperature control. converter vessel.

• Maximum utilisation of • Radial flow from outside to • Radial flow from outside to
reaction heat for the genera- inside through all catalyst inside through all catalyst
tion of high-pressure steam. beds. beds.

• Low pressure drop in the • Design adaptable to full-bore • Simple U-tube heat ex-
loop. or drawn-in top closure of changer between first and
converter, depending on pro- second catalyst beds for
Such criteria, in turn, ject constraints. indirect cooling of the
call for the: synthesis gas.
• Heat exchangers extractable
• Use of fine-particle without removal of cartridge. • Design adaptable to full-bore
catalyst. or drawn-in top closure of
• An externally arranged BFW converter, depending on
• Application of the radial-flow preheater / HP steam boiler project constraints.
principle. downstream of the third bed.

• High-pressure steam gen- Gas inlet

eration wherever feasible. Start-up gas Bypass

Start-up gas Gas inlet
control

The Uhde ammonia synthesis

design therefore incorporates
three radial-type catalyst beds
arranged in either one or two
First bed First bed
ammonia converters.

Second bed

Second bed

Third bed
Left:
Three-bed ammonia
converter, radial flow

Right:
Ammonia converter I, radial flow,
catalyst beds 1 and 2

Gas outlet Gas outlet

 23

Features of the Uhde Advantages of Uhde

HP steam boilers: HP steam boilers:

• Easy withdrawal of internal • Tubesheet cooling to prevent • All components fabricated

heat exchanger without nitriding. from hydrogen-resistant,
removing catalyst. easy-to-handle, low-alloy
• Channels in contact solely materials.
• Smaller dimensions and with the cooled synthesis
lower weight of vessels to gas leaving the boiler. • Elimination of stress
reduce transport and corrosion cracking and
handling problems. • Freely movable U-tube crevice corrosion.
design of the bundle.
• An external HP steam boiler • Low thermal stress.
downstream of the second • Internal bore welding, the
catalyst bed. heat exchanger tubes being • Integrated boiler feed water
joined to the tubesheet by preheating.
• An externally arranged BFW means of full-penetration
preheater / HP steam boiler welds. • Tube-to-tubesheet
downstream of the third bed. welds all subjected to
• Steam / boiler water separ- non-destructive tests.
ation in the upper part of the
waste heat boiler.
Vane Steam outlet
separator
The design of HP synthesis
loop boilers is a long-standing
tradition at ThyssenKrupp
Industrial Solutions, dating
back to 1969 when equipment Cont.
of this type was pioneered. BFW
blow down

bypass
Temp.
blow down

Third bed

BFW inlet

Ammonia converter II ,
radial flow, catalyst bed 3 Gas Gas outlet HP Steam boiler
inlet

Gas inlet Gas outlet

24

SAFCO IV fertiliser complex.

Capacities: 3,300 t/day of ammonia
3,250 t/day of urea
3,600 t/day granulation unit
 25

Proprietary Uhde equipment designs

Production and consumption figures

Overall view of the QAFCO 4

ammonia / urea complex
successfully commissioned
by Uhde back in 2004.

Capacities:
2,000 t/day of ammonia
3,200 t/day of urea
3,500 t/day granulation unit

Feed and Energy Consumption

Natural gas as feed and fuel ....................Gcal(1) .............. 6.8 ....to...... 7.4
Electric power ........................................kWh............... 15 .......to.... 90
Overall feed and energy(2) ........................Gcal(1) .............. 6.4 ....to...... 7.4

Utilities
Cooling water ( T = 10 K) .......................mt ............... 120 .......to.. 260
Demineralised water (net cons.) ...............mt ................... 0.65 ..to...... 0.75

Effluents
Treated process condensate(3) ..................mt ................... 0.85 ..to ..... 1.15

Product Quality
Ammonia content ...................................% by wt. ........ 99.8 ....to...100.0
Water content .......................................% by wt. ........ 0.0 ....to...... 0.2
Oil content.............................................ppm by wt. ...............max. ... 5
(1)
expressed as lower heating value of natural gas per metric ton of ammonia
(2)
electric power and steam export converted into fuel equivalents
(3)
routed back to the demineralisation unit for re-use

All consumption figures are per metric ton of liquid ammonia and serve as general information only.
Local climatic conditions and gas composition may have a considerable influence on the performance figures.
26

Services for our customers

ThyssenKrupp Industrial Solutions is dedicated to pro- We like to cultivate our business relationships and learn
viding its customers with a wide range of services and more about the future goals of our customers. Our after-
to supporting them in their efforts to succeed in their sales services include regular consultancy visits which
line of business. keep the owner informed about the latest developments
or revamping options.
With our worldwide network of local organisations and
experienced local representatives, as well as first-class Our policy is to ensure utmost quality in the implemen-
backing from our head office, we have the ideal qualifi- tation of our projects. We work worldwide to the same
cations to achieve this goal. quality standard, certified according to:

We at ThyssenKrupp Industrial Solutions place particu- DIN / ISO 9001 / EN29001.

lar importance on interacting with our customers at an
early stage to combine their ambition and expertise with We remain in contact with our customers even after
our experience. project completion. Partnering is our byword.

Whenever we can, we give potential customers the op- By organising and supporting technical symposia, we
portunity to visit operating plants and to personally eval- promote active communication between customers,
uate such matters as process operability, maintenance licensors, partners, operators and our specialists. This
and on-stream time. We aim to build our future busi- enables our customers to benefit from the development
ness on the confidence our customers place in us. of new technologies and the exchange of experience
as well as troubleshooting information.
We provide the entire spectrum of services associated
with an EPC contractor, from the initial feasibility study, ThyssenKrupp Industrial Solutions stands for tailor-
through financing concepts and project management made concepts and international competence.
right up to the commissioning of units and grassroots
plants. For more information contact one of the ThyssenKrupp
Industrial Solutions offices near you or visit our website:
Our impressive portfolio of services includes:
www.thyssenkrupp-industrial-solutions.com
• Feasibility studies / technology selection.
• Project management.
• Arrangement of financing schemes.
• Financial guidance based on an intimate
knowledge of local laws, regulations and
tax procedures.
• Environmental studies.
• Licensing incl. basic / detail engineering.
• Utilities / offsites / infrastructure.
• Procurement / inspection / transportation services.
• Civil works and erection.
• Commissioning.
• Training of operating personnel using operator
training simulator.
• Plant operation support / plant maintenance.
• Remote Performance Management (Teleservice).
 27

Recent references

E Engineering
P Procurement
C Construction

Completion Customer Plant Site Plant Capacity Contract Project Notes

2016 Daelim for Saudi Arabian Ras Al Khair, Ammonia 3,300 t/day E, P
Mining Company, Ma'aden Saudi Arabia
2016 CF Industries Port Neal, USA Ammonia 2,200 t/day E, P
2015 CF Industries Donaldsonville, USA Ammonia 3,300 t/day E, P
2013 Samsung for Ruwais Ruwais, Ammonia 2,000 t/day E, P
Fertilizer Industries Abu Dhabi, UAE
2014 Egyptian Agrium Nitrogen Damietta, Ammonia 2 x 1,200 t/day Turnkey
Products Co. SAE Egypt
(EAgrium)
2013 Orascom Construction Arzew, Ammonia 2 x 2,200 t/day E, P
Industries for Sonatrach Algeria
Orascom Fertiliser
Company (Sorfert)
2011 Samsung for Saudi Ras Al Khair, Ammonia 3,300 t/day E, P
Arabian Mining Company, Saudi Arabia
Ma'aden
2008 Misr Oil Processing Co. Damietta, Ammonia 1,200 t/day Turnkey
Egypt
2008 Kuibyshev Azot Togliatti, Ammonia 1,800 t/day E Expansion
Russia
2007 Duslo a.s. Sala, Ammonia 1,300 t/day E Expansion
Slovakia Expansion by 300 t/day
2007 Helwan Helwan, Ammonia 1,200 t/day Turnkey
Fertilizer Co. Egypt
2006 Egyptian Fertilizer Ain Sukhna / Suez, Ammonia 1,200 t/day Turnkey
Co. (EFC II) Egypt
2006 Alexandria Fertilizers Co. Alexandria, Ammonia 1,200 t/day Turnkey
(AlexFert) Egypt
2006 Saudi Arabian Fertilizer Al Jubail, Ammonia 3,300 t/day Turnkey
Company (SAFCO IV) Saudi Arabia
2004 Turkmendokunhimiya Tecen, Ammonia 600 t/day E,P
via Gap Insaat Turkmenistan
2004 Qatar Fertiliser Mesaieed, Ammonia 2,000 t/day Turnkey
Company (QAFCO IV) Qatar
2003 ASEAN Bintulu Fertilizer Bintulu, Ammonia 1,350 t/day E 3rd Expansion
Sdn Bhd (ABF) Malaysia Expansion by 30 t/day
2000 Egyptian Fertilizer Co. Ain Sukhna / Suez, Ammonia 1,200 t/day Turnkey
(EFC) Egypt
1999 Istanbul Gübre Körfez, Ammonia 1,200 t/day E, P Expansion
Sanayii A.S. (IGSAS) Turkey Expansion by 50 t/day
1998 Abu Qir Fertilizers and Abu Qir, Ammonia 1,200 t/day Turnkey
Chemical Ind. (AFC) Egypt
(Abu Qir III)
1997 ASEAN Bintulu Fertilizer Bintulu, Ammonia 1,320 t/day E, P 2nd Expansion
Sdn Bhd (ABF) Malaysia Expansion by 120 t/day
1997 Saskferco Products Inc. Belle Plaine, Ammonia 1,800 t/day E Expansion
Canada Expansion by 300 t/day
1997 SASTECH (Pty) Ltd. Sasolburg, Ammonia 830 t/day E Expansion
South Africa Expansion by 100 t/day
1997 Qatar Fertiliser Mesaieed, Ammonia 1,500 t/day Turnkey
Company (QAFCO 3) Qatar
 PT 004/0/e/1000/201501/PM/Printed in Germany

ThyssenKrupp Industrial Solutions AG

Business Unit Process Technologies
Friedrich-Uhde-Str. 15 · 44141 Dortmund
Phone +49 231 5 47-0 · Fax +49 231 5 47-30 32
www.thyssenkrupp-industrial-solutions.com