Licensing urea technologyProviding integral innovative technologies for reliable, cost-effi cient urea plants

3Content

1 About us 4

2 Urea licensing 5

3 A winning product from a winning player 7

4 Innovation 9

5 Safurex stainless steel: resistant to corrosion 10

6 Stamicarbons urea processes 11

6.1 Synthesis 1: Avancore urea process 14

6.2 Synthesis 2: Urea 2000plus Pool Condenser Concept 16

6.3 Synthesis 3: Urea 2000plus Pool Reactor Concept 18

6.4 Low-pressure recirculation section 19

6.5 Evaporation section 20

6.6 Waste-water treatment section 21

6.7 Finishing technology 1: Fluid-bed granulation 22

6.8 Finishing technology 2: Prilling 24

6.9 Finishing technology 3: Pastillation 25

6.10 Urea in solution for NOx reduction 27

7 UAN Process 28

8 Mega Plant Concept 30

9 Full life cycle support 32

9.1 Plant operation 33

9.2 Plant maintenance 33

9.3 Plant improvement and debottlenecking services 35

9.4 Equipment supply 36

9.5 Process control & optimization solutions 37

9.6 Plant staff training 38

Information sheets 39

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About us1

Stamicarbon, the licensing and IP center of Maire Tecnimont, is the global market leader in the development and licensing of urea technology and the supply of services to its customers.

Stamicarbons solutions are the accumulation of generations of high-quality research and in-depth knowledge of our customers processes, requirements and operating practices. Around the world, over 250 urea plants have used or are currently using our technology. Our innovation is continuous: working in close cooperation with research institutes, suppliers to the urea business, and our licensees, we are constantly developing new technologies and upgrading our existing technologies. Stamicarbons head offi ce is in Sittard, The Netherlands. Our representative offi ces are in Beijing, China and Moscow, Russia. The offi ces addresses can be found on the attached sheet in the back cover.

Our expertiseWherever our customers are based in the world, they can all draw on Stamicarbons more than 60 years of experience in the urea industry. We also work with a number of reputable

engineering, procurement and construction (EPC) contractors, suppliers of specifi c products and critical equipment and technology suppliers. Together, this network offers the expertise that enables us to create the best solution for your business. An overview of our contractors and suppliers can be found on the attached sheet in the back cover.

What we do

Our Full Life Cycle Services include: Licensing and process design of grass root urea plants Revamping existing urea plants Plant commissioning support Equipment procurement services Equipment supply Engineering services Trouble-shooting, both mechanical and operational Equipment and plant inspections Plant Staff Training Process control & optimization solutions Feasibility studies

Our market-leading urea licensing expertise includes the following elements:

Providing technology licenses for new urea plants

Traditionally, many urea plants are built under LSTK (Lump Sum Turn Key) conditions. In these cases, Stamicarbon provides its urea license, process design and related services through licensed contractors, who have been carefully selected to ensure that they have the capability and experience to implement large-scale ammonia/urea projects. Their names can be found in the supplement at the back of this brochure. Nowadays alternative contract models become increasingly relevant in mitigating project costs and risks. As a result, Stamicarbon has diversifi ed its urea licensing options, tailoring our services to the needs of specifi c projects.

Process design package Contractors or customers who obtain a license to apply the Stamicarbon urea process are supplied with a comprehensive process design package.

This generally includes: Process description Material balance, steam balance and cooling water balance for different operating modes - all with accompanying process fl ow diagrams Piping and instrumentation diagrams (PIDs) Equipment data sheets Instrument index, setting list and data sheets

Data sheets for safety valves Logic diagrams and functional control diagrams General design and material speci cations Operating manual Process Performance Guarantees. Our comprehensive process design package enables an experienced engineering contractor (who is ultimately appointed by the customer) to:- Carry out the basic & detailed engineering (E)- Procure equipment and materials (P)- Construct the plant (C).

Thanks to the expertise and capabilities of our licensed contractors, customers projects will be executed both professionally and competitively.

Project execution servicesStamicarbon can provide the following services at any point during project implementation - either directly to the customer or indirectly through a contractor: (Critical) equipment supply Equipment inspection services Basic Engineering Design Package (BEDP) Front-end Engineering Design (FEED) Contractor guidance and control HAZOP assistance Plant Operators Training, using state-of-the-art Operator Training Simulator (OTS) (Pre-)Commissioning and Start-up support Plant simulation and optimization (Pre-)Commissioning and Start-up support

Urea licensing2

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With a market share of over 50%, Stamicarbon is the worlds leading player in the fi eld of urea licensing. This position is the result of our:

Extensive experienceStamicarbon has over 60 years experience in licensing its urea technology. In fact, we have licensed over 250 new urea plants and have completed over 90 revamp projects in all kind of urea plants. A complete list of references is available in our Reference List brochure.

Leading innovationsStamicarbon has been at the forefront of urea research and innovation for over half a century. As a result, we have been able to revolutionize the urea production process several times.

Low costsOur latest urea plants were designed by our task force of

experienced engineers, contractors and material and equipment suppliers. In creating a new plant design, the task force used the Urea 2000plus technology, Safurex material, Avancore technology, fl uid-bed granulation technology, as well as their extensive experience, gained from completing many successful plant revamps. As a result of such work, plant investment costs were cut massively in the past and will continue to be cut in the future.

Our competitive advantages include: Low plant height Low investment, operating and maintenance costs: minimum cost of ownership Competitive energy consumption gures* Stochiometric raw-material consumption gures* Low emissions and ef uents* The typical consumption fi gures can be found in the supplement at the back of this brochure.

Technology exchangeIn some cases, customers may require information additional to that supplied in the process design package. To meet this need, we provide customers with any additional information or expertise they require, through training, know-how exchanges and symposia, or other methods agreed with our customers. In cases where our customers need something completely new, we will work jointly with them to develop the required adjustment.

Revamping existing urea plantsIn a dynamic business environment, customers needs will shift due to changing market conditions and governmental regulations. Stamicarbon has developed several safe, cost-effective and environmentally friendly revamp schemes to enable urea producers to cope with these changes. Depending on customer requirements, Stamicarbon can develop a tailor-made solution based on proven technology and the best engineering practices. We offer detailed plant-performance studies to our customers to determine revamp needs, plus a variety of revamp technologies, including capacity expansion technologies, and services to ensure that those needs are met.

Replacement of high-pressure urea equipmentWhen the high-pressure equipment comes to the end of its life, there is a real opportunity to improve the effi ciency and capacity of a plant. Stamicarbon can provide solutions that not only improve your high-pressure equipment, but also require only minimum changes and minimum downtime in your plant.

Experience us for yourselfStamicarbon is the global market leader in the development and licensing of urea products and technology. We invite potential licensees to visit one of our plants so they can see for themselves how we boost operational fl exibility, reduce maintenance requirements and increase on-stream times. After the visit, we will work closely with you to assess your needs and develop a customized proposal for your urea plant.

A winning product from a winning player 3

8 State-of-the-art urea production technologiesStamicarbon technologies offer customers a variety of ben-efi ts, including:

Excellent performance Unparalleled synthesis ef ciency with high conversion of ammonia and carbon dioxide Low temperatures and pressures in the urea production process Easiest operations High on-stream time and utilization rate Meeting all product quality standards Long turnaround intervals (3-4 years) Compliant with the most stringent environmental requirements

Simplicity and reliability Minimum number of high-pressure equipment items and piping The only urea process that requires only one single recirculation stage Superior corrosion resistance of duplex stainless steels used in plants Stable and easy to operate process Unbeaten lifetime of critical equipment

Flexibility Single-train capacity allowing for up to 6000 mtpd Various synthesis choices: Avancore or Urea 2000plus Process both featuring a pool condenser or a pool reactor Multiple nishing choices: Fluid-bed Granulation, Prilling and Pastillation Urea Ammonium Nitrate (UAN) and Ad-Blue/SCR/ automotive grade urea solution technologies available as an integrated, cost-effi cient design

Sustainable technologyFor Stamicarbon, sustainability is a precondition of innovation, while Safety, Health, and Environment (SHE) awareness is a key condition for sustainable licensing. This focus ensures our technology is effi cient, environmentally friendly, reliable and above all, safe.

CollaborationIn order to create and improve innovative urea plants, Stamicarbon collaborates with a number of suppliers of critical equipment to ensure product quality. Stamicarbon is also collaborating with all leading ammonia technology suppliers. Further we co-develop new technologies with strategic partners. The names of these companies can be found in the supplement at the back of this brochure.

Global reachWith the experience of licensing in more than 80 countries, we have the tools to meet your requirements - wherever in the world you need us.

Innovation4

At Stamicarbon, we recognize the power of innovation. Thats why the professionals in our Technology Department are always on the look-out for innovative ways to renew, improve and add to the portfolio of products that we offer our customers. We spend about 10% of our turnover on developing breakthrough innovations. Working together with R&D groups, universities, customers and suppliers, our Technology Department creates technologies that optimize the urea production process. This has resulted in a number of developments that have improved the urea production process.

These developments include: Passivation of urea synthesis by air CO2 stripping process Application of 25-22-2 steel N/C measurement system Non-destructive testing techniques Online Leak Detection System Waste-water treatment section UAN Process Urea 2000plus Pool Condenser Concept Safurex duplex stainless steel material (together with Sandvik Material Technology) Urea granulation technology ( uidized bed type) Siphon jet pumps Urea 2000plus Pool Reactor Concept Integrally geared CO2 compressors Mega Plant Concept (e.g. 6000 mtpd) Pastillation technology processing urea or UAS (together with Sandvik Process Systems) Zero-emission technologies (featuring acid wash and/or fl are systems) RADAR level measurement in the high pressure reactor and high pressure stripper (together with Vega) Avancore urea process

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Safurex duplex stainless steel: resistant to corrosion

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Stamicarbon has a long and distinguished track record in developing superior, cutting-edge urea plant materials.

X2CrNiMoN 25-22-2With the introduction of the high-pressure stripper in the Stamicarbon urea process, a new stainless steel was needed. Together with Sandvik, a Swedish stainless-steel supplier, we developed the X2CrNiMoN 25-22-2 material in the mid seventies. This in urea plants widely used austenitic stainless steel, has superb corrosion resistant properties in carbamate solutions; however still needs oxygen for passivation.

Safurex

Despite the success of the 25-22-2 material, Stamicarbon continued the search for ways of developing even better materials. The ultimate breakthrough came in 1996 with the creation of a special duplex steel grade called Safurex, developed together with Sandvik Materials Technology. This innovative material is highly resistant to corrosion. It has already been demonstrated that Safurex allows for drastically reduced oxygen intake (upto now 0.1% in CO2 supply).

Safurex offers numerous signifi cant benefi ts, including: Lower emissions Lower corrosion rates, leading to longer lifetimes No risk for active corrosion No stress corrosion cracking No risk for condensation corrosion No risk for crevice corrosion Better mechanical properties, allowing for smaller wall thickness and piping Improved fatigue properties Improved weld ability

Whats more, Safurex requires a lower investment than traditional materials and offers you a nearly maintenance-free urea plant with a signifi cant longer lifetime than any other commercially available urea process.

Stamicarbons urea processes6

At Stamicarbon, we are committed to the continuous innovation and development of our technologies so we can provide our customers with the best urea production technology available.

One acknowledged breakthrough was our Urea 2000plus technology - a major improvement on our well-known CO2 stripping process. Urea 2000plus is an innovative process that reduces the plant height considerably and simplifi es its

overall design, piping and construction. The Urea 2000plus synthesis section incorporates either a high-pressure pool reactor, or a high-pressure pool condenser combined with a vertical reactor.

The following chart shows the development of the Stamicarbon urea process over the last decades and the consequences for the plant height.

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The Avancore Urea process

Our latest development is the Avancore urea process, which further enhances our proven Urea 2000plus technology. In the plant height chart the Avancore technology is shown in a confi guration for large capacities plants with a pool reactor and vertical high-pressure reactor.It reduces the required plant height to just 25m.

This obviously has brought down investment costs considerably. However the Avancore process is also available with only a pool reactor for urea plants up-to medium capacities. Customers can now choose among basic synthesis concepts that use either Avancore or the Urea 2000plus technology.

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The Avancore urea process is a new urea synthesis concept that incorporates all the benefi ts of Stamicarbons earlier proven innovations. The Avancore urea process combines the advantages of Urea 2000plus technology, Safurex and experiences gained from revamp projects.

Urea 2000plus The Urea 2000plus technology already provided the technological advantage of improving heat transfer in the condensing part of the urea synthesis, achieved by the application of pool condensation, and increasing the available temperature difference over the condenser by combining carbamate condensation and urea reaction in one vessel.

Safurex

Safurex material has demonstrated best corrosion resistance (no active corrosion, no stress corrosion cracking, no condensation corrosion and no crevice corrosion). The ammonia emissions are also kept to an absolute minimum.

Revamp experiencesExperiences gained in revamp projects have also led to the incorporation of the following innovations into the Avancore urea process:

Low elevation lay-out of the synthesis sectionWhile the urea synthesis loop still relies on gravity fl ow, thus offering maximum reliability, the equipment elevation has been reduced, allowing for lower investment.

Reduced-pressure inert washing systemThe vapor leaving the urea synthesis section is treated in a scrubber operating at a reduced pressure, with the carbamate solution coming from the downstream low-pressure recirculation section as absorbent. As a result, no additional water needs to be recycled to the synthesis section, meaning that the urea reaction is therefore not affected.

Synthesis 1: Avancore Urea Process6.1

Features Avancore

No high-pressure scrubber

Pool condensation

All gravity ow

Low elevation

Best corrosion resistance

Minimum ammonia emissions

Low maintenance synthesis

Lower investment

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The Avancore urea process works as follows:Ammonia and carbon dioxide are introduced to the high-pressure synthesis using a high-pressure ammonia pump and a carbon-dioxide compressor. The ammonia, as well as the carbamate solution from the downstream recirculation section, enters the pool reactor. The major part of the carbon dioxide enters the synthesis through the high-pressure stripper counter-current to the urea/carbamate solution leaving the reactor. On the shell side, the high-pressure stripper is heated with steam. The off-gas of the high-pressure stripper, containing the carbon dioxide, together with the ammonia and carbon dioxide resulting from dissociated carbamate, is fed into the pool reactor. The minor part of the carbon dioxide entering the synthesis as a feed enters the vertical reactor at the bottom in order to produce suffi cient heat for the endothermic urea reaction. In the pool reactor, ammonia and carbon dioxide are condensed to form carbamate and a substantial part of the conversion to urea is already established here. The heat released by condensation and subsequent formation of carbamate is used to produce re-usable low-pressure steam. Downstream from the pool reactor, the urea-carbamate liquid enters the vertical reactor located at ground level. Here, the nal part of the urea conversion takes place. The urea solution then leaves the top of the reactor, all by gravity fl ow (via an overfl ow funnel) before being introduced into the high-pressure stripper.

Gases leaving the vertical reactor are combined with the gases leaving the pool reactor and are fed into the scrubber operating at a reduced pressure. Here, the gases are washed with the carbamate solution from the low-pressure recirculation stage. The enriched carbamate solution is then fed into the pool reactor. This enriched carbamate fl ow contains no more water than in earlier generations of Stamicarbon CO2 -stripping plants, meaning that the conversions in the synthesis section are as high as ever. Inert gases leaving the scrubber at reduced pressure containing some ammonia and carbon dioxide are then released into the atmosphere after treatment in a low pressure absorber.Optional is a fl ash at a reduced pressure of the liquid leaving the high-pressure stripper, after which the resulting vapor is mixed with the vapor leaving the urea synthesis and the carbamate solution coming from the downstream low-pressure recirculation section. Additional carbamate condensation in this mixture is done at the shell side of the fi rst stage evaporator. This option allows for a decreased high-pressure steam consumption in the high-pressure stripper, while low-pressure steam consumption is decreased due to the carbamate condensation supplying heat to the fi rst stage evaporator.

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Synthesis 2: Urea 2000plus Pool Condenser Concept6.2

The Urea 2000plus Pool Condenser process works as follows:Ammonia and carbon dioxide are introduced to the high-pressure synthesis using a high-pressure ammonia pump and a carbon dioxide compressor. The ammonia then drives an ejector, which conveys a carbamate solution into the pool condenser. In the high-pressure stripper, the carbon dioxide, entering the synthesis as a feed, fl ows counter-current to the urea solution leaving the reactor.

On the shell side, the high-pressure stripper is heated with steam. The off-gas of the high-pressure stripper, containing the carbon dioxide, together with the dissociated carbamate, is then fed into the pool condenser. In the pool condenser, ammonia and carbon dioxide are condensed to form carbamate, and a substantial part of the conversion to urea is already established here. The heat released by condensation and subsequent formation of carbamate is used to produce re-usable low-pressure steam.

After the pool condenser, the remaining gases and a urea-carbamate liquid enter the vertical reactor. Here, the nal part of the urea conversion takes place. The urea solution then leaves the top of the reactor (via an overfl ow funnel) before being introduced into the high-pressure stripper.Ammonia and carbon dioxide conversions in the synthesis section of a Stamicarbon carbon dioxide stripping plant are high, reducing the need for a medium pressure stage to recycle any unconverted ammonia and carbon dioxide. As a result, the Stamicarbon CO2 stripping process is the only commercial available process that does not require a medium-pressure recirculation stage downstream from the high-pressure stripper. Gases leaving the reactor are fed into the high-pressure scrubber. Here, the gases are washed with the carbamate solution from the low-pressure recirculation stage. The enriched carbamate solution is then fed into the high-pressure ejector and, subsequently, to the pool condenser. Inert gases, containing some ammonia and carbon dioxide, are then released into the 4-bar absorber.

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Synthesis 3: Urea 2000plus Pool Reactor Concept6.3 Low-pressure recirculation section6.4

The Urea 2000plus Pool Reactor process works as follows:Unlike the Pool Condenser concept, the Pool Reactor concept combines the condenser and reactor within a single pool reactor. This is achieved by enlarging the horizontal condenser so as to incorporate additional reactor volume. As a result, it becomes possible to achieve suffi ciently high residence times, eliminating the need for a separate vertical reactor, while creating the conditions that will allow the reaction to reach its optimum condition. The high-pressure

scrubbing operation can also be simplifi ed in the Pool Reactor concept by placing the scrubber sphere above the pool reactor and adding the ammonia to the synthesis via this scrubber. This ensures that no separate heat-exchanging section in this scrubbing operation is required. In the Pool Reactor concept, carbamate from the low-pressure recirculation section fl ows together with the absorbed gases and the ammonia via a sparger into the pool reactor. As the static liquid height ensures gravity fl ow, no high-pressure ejector is needed.

This stage recovers the ammonia and carbon dioxide still present in the urea solution coming from the high-pressure stripper. Thanks to the low ammonia and carbon dioxide concentrations in the stripped urea solutions, the Stamicarbon CO2 stripping process is the only process that requires just one single low-pressure recirculation stage.Coming out of the stripper, the urea solution is fed into the dissociation heater, where most of the ammonia and carbon dioxide are removed. The heat required for this heater is derived from the condensation of the low-pressure steam produced in the urea synthesis. The ammonia and carbon dioxide are then fed into the low-pressure carbamate condenser, where they are condensed. Because the ratio between ammonia and carbon dioxide in the recovered gases is optimal, the quantity of water needed to dilute the resultant ammonium carbamate solution can be kept to a minimum, maximizing conversion fi gures for the urea plant. The resultant carbamate solution is fed, via a high-pressure carbamate pump, back to the synthesis as a scrubbing agent in the high-pressure scrubber.

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Before entering the urea solution tank, part of the water present in the urea solution is evaporated by further pre-fl ashing in two steps (atmospheric and sub-atmospheric). The vent gas from the recirculation stage is practically free from ammonia because it is scrubbed in an atmospheric absorber.

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Evaporation section Waste-water treatment section6.5 6.6

Before the entire urea production process is complete, the urea solution present in the urea solution tank must be concentrated. The urea solution is therefore sent to an evaporation section. The topology of this evaporation section depends on the applied fi nishing section (prilling, granulation or pastillation). Depending on the requirements of the fi nishing section, the evaporation section may, for example, consist of two consecutive evaporators, where the water in the urea solution is evaporated under vacuum conditions. The remaining urea melt has a urea concentration varying from 96 to 99.7wt%, depending on the requirements of the downstream fi nishing section.

The process condensate coming from the evaporation section, together with other process effl uents such as sealing water from stuffi ng boxes, contains ammonia and urea. All of the process condensate is collected in the ammonia water tank. From this tank, the water is fed to the top part of the desorber. In the top part of the desorber, the bulk of ammonia and carbon dioxide are stripped off from the water phase by using the off-gas from the bottom part of the desorber as a stripping agent. The descending effl uent still contains urea and some ammonia. To remove this urea, this effl uent is then fed to the hydrolyzer. The hydrolyzer is a liquid-fi lled column. In the hydrolyzer, the urea, at elevated pressure and temperature, is dissociated into ammonia and

carbon dioxide by the application of heat (steam) and retention time. The process condensate feed is kept in counter-current contact with the steam in order to obtain extremely low urea content in the hydrolyzer effl uent. The remaining ammonia and carbon dioxide in the effl uent of the hydrolyzer are stripped off with steam at a reduced pressure in the bottom part of the desorber. The off-gases leaving the top part of the desorber are recycled to the synthesis section after being condensed in the refl ux condenser. The purity of the remaining water satisfi es requirements for boiler feed water make-up or cooling water make-up - which means that Stamicarbon urea plants do not produce a waste-water stream.

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Finishing technology 1: Fluid-bed Granulation6.7

Stamicarbons fl uid-bed granulation technology offers: Large reductions in formaldehyde content compared to other fl uid-bed granulation technologies Unprecedented uninterrupted run times, which can exceed 100 days before washing of the granulator is required Excellent product quality (spherical, with a smooth surface) More stable operation conditions in a wide operating window Low urea dust formation, resulting in a lower wet recycle Low opacity at outlet granulation vent stack Substantial savings on operational costs when compared to other fl uid-bed granulation technologies Excellent surface properties for downstream coating (for specialty fertilizers)

Film spraying:The key of the success of the Stamicarbon urea granulation technology is the fi lm spraying characteristic of the nozzles. This way of spraying not only requires a minimum amount of formaldehyde, but also reduces the amount of dust formed compared to other fl uid-bed granulation technologies.

Principles of Stamicarbons fl uid-bed granulation process:A urea melt stream with a urea concentration of 98.5wt% is introduced into the fl uid-bed granulator through the injection headers, which are connected to the urea melt line and the secondary air system. Each injection header comprises vertically placed risers fi tted with spray nozzles that create a liquid fi lm that subsequently is distributed onto the seed particles in the fl uidized bed. The secondary air, required to transport the granules through the urea melt fi lm, is provided by a secondary air fan. Urea formaldehyde is added to the urea melt as a granulation additive and anti-caking agent. It also improves the granule crushing strength. The granulator is divided into a granulation section and a cooling section. In both sections, fl uidization air is evenly distributed to fl uidize and cool the granules. Seed (recycled) material is introduced into the fi rst chamber of the granulation section.

The urea melt is then distributed over this seed material. As the granules move through the granulation section, their size steadily increases by layering until they reach the required granule diameter. Fluidization air and secondary air are exhausted from the top of the granulator by means of an off-gas fan downstream the granulator scrubber. In the scrubber, the air is washed with diluted urea solution, and the cleaned air is exhausted into the atmosphere. Part of the scrubbing solution is recycled to the scrubber. A purge stream is also pumped to the urea-dissolving vessel and recycled to the urea melt plant. The product from the granulator passes a safety screen to separate the lumps. The lumps are conveyed to the dissolving tank. A bucket elevator lifts the urea granules onto screens, where they are classifi ed. Fine product is recycled to the granulator. Coarse product is cooled and then crushed to a smaller size and added to the fi ne recycle fl ow. On-size product is transported to the product cooler, where it is cooled in a solid fl ow heat exchanger. The solid fl ow cooler is cooled with cooling water.

Today, the most commonly used fi nishing technology is fl uid-bed granulation, which was commercialized by Stamicarbon in response to changing market needs. In less than 10 years after its introduction, Stamicarbons fl uid-bed granulation technology has been licensed over 15 times for commercial scale plants, including capacities exceeding 3500 mtpd. The plants using this technology are operating at or above their original design capacity, producing superior products complying with all required product quality standards. Nowadays the Stamicarbon market share reaches over 30%.

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Stamicarbon continuously endeavors to improve the urea process and has introduced the Rotoformer pastillation process designed by Sandvik Process Systems as a very useful alternative or addition to the traditional fi nishing techniques of prilling and granulation. Applications for the pastillation process are found in the production of special urea compositions or for small revamp capacities. The pastillation process has been successfully employed in the petrochemical, chemical, food and fertilizer industries since the early 1980s and there are currently more than 1500 pastillation units in operation worldwide.

The pastillation principleThe pastillation principle brings together the specially designed drop-former with the outstanding features of the steel belt cooler. This technology is ideal for removing bottlenecks, for upgrading the prill tower or granulation section, or for the production of specialty urea products (UAS S-urea, multi nutrients). Premium-quality pastilles can be produced at low investment costs, low operating costs and with minimum emissions.

The pastillation process offers the following advantages: Very low dust emissions Simple solution to realize very low ammonia emissions Very low power consumption More uniform product Good crushing strength even without adding formaldehyde Flexible production by switching on/off pastillation lines Lower investment costs Possibility of producing controlled-release urea and mixed fertilizer

Finishing technology 2: Prilling Finishing technology 3: Urea pastillation6.8 6.9

The prilling process operates as follows:The urea solution is concentrated to 99.7% urea in two subsequent evaporators under vacuum. The resultant urea melt is prilled with the aid of a rotating prilling bucket, designed by Stamicarbon. Using an optional technique, called seeding, prills with a better impact-resistance are obtained. These prills are very resistant to degradation during product handling. The urea melt droplets fall down in a tower, while crystallizing to become prills. Typical diameter is about 2.0 mm.

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Urea in solution used for NOx reduction 6.10

Ad Blue or DEF are some of the brand names for a 32.5 % urea solution used in diesel engines to reduce the NOx emissions of such engines. Due to the increase in environmental consciousness more and more countries enforce stringent regulations on NOx emissions for diesel engines, which result in an increasing part of urea being used for this application.

As a licensor of urea technology, Stamicarbon is in an ideal position to develop a state-of-the-art solution not only taking into account the current regulations but also anticipating future developments and requirements.

Although it seems easy to make such a solution without an in depth knowledge of the application it is used for, crucial and costly mistakes are easily made. Realizing this, Stamicarbon has thoroughly investigated all the requirements, evaluated the options and designed a cost effective solution for our customers ensuring, guaranteed, the highest quality product for now and for the future.

Such a solution used for NOx reduction cannot be made by simply diluting or dissolving urea as it was thought originally. It has to be virtually free from everything but urea, which proves to be a challenge as most urea contains a certain concentration of free ammonia, biuret and formaldehyde. This is often out of the required specifi cation, and as such, prone to either damage or foul the expensive catalyst, used for NOx reduction. This is however not the only issue. Also the water added for dilution or the water formed while producing urea, contains an unwanted byproduct (corrosion or polymerization products) which is not acceptable for the market. Not every plant is directly suited to produce such a urea solution and as result of this, investments may well be much higher than originally anticipated.Stamicarbon designs will supply a reliable and high quality solution for the long term with lifetime support.

The urea pastillation processMechanically, a single pastillation unit for urea pastillation consists of a drop-former feeding device at the beginning of a moving steel belt and a scraper at the discharge end. The feed to the pastillation unit is urea melt concentrated in two subsequent evaporators under vacuum. The urea is introduced in molten form to the droplet former. The droplet former consists of a rotating drum which shell contains rows of small holes. The heat released during crystallization and cooling is transferred through the stainless-steel belt to the cooling water. Under no circumstances can the cooling

water come into contact with the urea product. After solidifi cation, the pastilles are smoothly released from the steel belt via an oscillating scraper. The product then falls directly onto a conveyor belt for transfer to storage. The section above the moving steel belt is enclosed with a hood and vented to an existing vent system. There is no visible urea dust emission, only some ammonia vapors which can be easily removed from the very small air fl ow by means of a normal atmospheric absorber. Several pastillation units can be installed in parallel in order to achieve higher capacities.

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Ammonia and nitric acid react exothermically to form ammonium nitrate according to the following reaction equation:

HNO3 + NH3 NH4NO3Nitric Acid + Ammonia Ammonium Nitrate

The presence of liquid in the circulation tube and of the gas-liquid mixture in the mixing tube causes the fl uid to circulate. The heat from the reaction is used for the evaporation of water and to increase the temperature to about 135C. The pH of the solution is controlled by the addition of nitric acid. The gas and liquid phases are separated in the separator, the liquid being sent to the (optional) ammonium nitrate storage tank.

In the mixing pipe, the following substances can be mixed: Urea solution, still containing some ammonia (temperature 110C) Ammonium nitrate solution, containing some 0.4% HNO3 (temperature 135C) Ammonia Nitric acid Acidic condensate from off-gas puri cation

Here again, the heat from the reaction is utilized to increase the temperature and to evaporate water. The ammonium- nitrate-to-urea ratio is controlled at about 4:3. The pH is controlled at 5-6 pH by means of the nitric acid feed. The resultant UAN solution is either stored or pumped to battery limits. The off-gases from the neutralizer are treated in the off-gas purifi cation section. Nitric acid is supplied to this section to neutralize any ammonia that is contained in the off-gases from the neutralizers. Part of the liquid effl uent from the purifi er fl ows down to the mixing pipe; the remainder can be sent to battery limits and is generally used in a nearby nitric acid plant.

UAN Process7

The Stamicarbon partial-recycle CO2-stripping process is eminently suitable for the manufacture of Urea Ammonium Nitrate (UAN) solutions. The ratio of unconverted ammonia to urea is such that the required ratio between urea and ammonium nitrate for the production of UAN solutions can be achieved directly. Ammonia still present in the stripped urea solution, together with the ammonia in the reactors off-gases, is converted into ammonium nitrate in a neutralization reactor using nitric acid. UAN solution product is obtained by mixing the urea and ammonium nitrate solutions. The Avancore and Urea 2000plus process can both be applied for the Stamicarbon UAN process.

The UAN process works as follows: In the high-pressure synthesis section, carbon dioxide and ammonia are converted into urea in very much the same way as in the previously described processes. The urea formation is an equilibrium reaction, so the urea solution formed contains unconverted ammonia and carbon dioxide. Stripping with carbon dioxide causes the greater part of these components to evaporate from the solution.

Evaporated ammonia and carbon dioxide, together with fresh ammonia and carbon dioxide, are condensed in the pool reactor, the heat from this condensation being used to produce low-pressure steam. The condensed ammonia and carbon dioxide are partly converted into urea and water. In the low-pressure dissociation section, the stripped urea solution is almost entirely freed from ammonia and carbon dioxide. The overhead vapors of the reactor, mixed with off-gases from the dissociation section and the ammonia present in the urea solution from the urea solution tank, are all sent to the neutralization section. The neutralization section comprises a neutralizer, an (optional) ammonium nitrate storage tank, a mixing pipe, a UAN storage tank and off-gas purifi cation equipment. The neutralizer consists of a U-type combination of a circulation tube and a mixing tube with a separator. It operates just above atmospheric pressure. The ammonia-containing gases from the urea plant are fed into the bottom of the mixing tube; the nitric acid is introduced somewhat lower in the circulation tube.

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carbamate is dissociated into ammonia and carbon dioxide. Our Mega Plant Concept does not need the ammonia recycle section or the ammonia hold-up steps that are commonly seen in competitors total recycle urea plants. This is because the low ammonia-to-carbon dioxide molar ratio in the separated gases allows for easy condensation as carbamate only. The operating pressure in this medium-pressure recirculation stage is about 20 bars. After the urea solution leaves the medium-pressure dissociation

30

Mega Plant Concept8

Large urea plants require large high-pressure equipment that are more costly to manufacture and transport. While straightforward scaling up remains certainly feasible for 6000 mtpd (for which we checked the deliverability of all equipment), Stamicarbon has developed a lower cost single line Mega Plant concept that allows for the same capacity. In the Stamicarbon Mega Plant concept, a proportion of the liquid effl uent from the reactor is diverted to a medium-pressure recycling section, thereby reducing the size of the high-pressure vessels needed. In fact, thanks to the Mega Plant concept, the size of the required high-pressure equipment and lines will not exceed the size of equipment needed for a 4000 mtpd pool condenser type CO2-stripping urea plant! A Mega Plant can be built with Avancore or Urea 2000plus technology.

The Mega Plant process works as follows:About 70% of the urea solution leaving the urea reactor fl ows to the high-pressure CO2 stripper, while the remainder is fed into a medium-pressure recirculation section. This reduced liquid feed to the stripper in turn reduces not only the size of the stripper needed, but also the heat exchange area of the pool condenser. The degree of stripping effi ciency is adjusted to ensure that as much low-pressure steam is produced by the carbamate reaction in the pool condenser as is needed in the downstream sections of the urea plant. About 30% of the urea solution that leaves the reactor is expanded and enters a gas/liquid separator in a recirculation stage operating at a reduced pressure. After expansion, the urea solution is heated by medium-pressure steam. By heating the urea solution, the unconverted

separator, it fl ows into an adiabatic CO2 stripper, which uses carbon dioxide to strip the solution. As a result of this process, the ammonia-to-carbon dioxide molar ratio in the liquid leaving the medium-pressure recirculation section is reduced, facilitating the condensation of carbamate gases in the next step. The vapors leaving the medium-pressure dissociation separator, together with the gases leaving the adiabatic CO2 stripper, are condensed on the shell side of the evaporator. The carbamate formed in the low-pressure recirculation stage is also added to the shell side of this evaporator. The heat released by condensation is used to concentrate the urea solution. Further concentration of the urea solution is achieved using low-pressure steam produced in the pool condenser. The remaining uncondensed ammonia and carbon dioxide leaving the shell side of the evaporator are sent to a medium-pressure carbamate condenser. The heat released by condensation in this condenser is dissipated into a tempered cooling water system. This process forms medium-pressure carbamate that contains only 20-22wt% water. The carbamate is transferred via a high-pressure carbamate pump to the high-pressure scrubber in the urea synthesis section. The urea solution leaving the adiabatic CO2 stripper and the high-pressure stripper are expanded together in the low-pressure recirculation section.

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Plant operation9.1 Plant maintenance9.2

How do you ensure your urea plant not only operates in a sustainable manner, but also produces its products at maximum capacity and maximum on-stream times? The solution is to optimize equipment and processes. To help customers ensure their urea plant operates with maximum effi ciency, we have developed a range of plant operation services to improve plant performance, production and energy consumption. These services are usually carried out within the framework of a Plant Performance Assessment. Throughout this assessment, we pay special attention to: Minimizing ammonia consumption Minimizing energy consumption Minimizing ef uents Maximizing plant on-stream time Maximizing plant capacity

Stamicarbon offers a range of services to ensure that your urea plant is well maintained. These include:

Corrosion inspectionsWe offer corrosion inspections to assess the general condition of urea plants and to determine the remaining lifetime of tubes, lining and equipment. In addition, recommendations for inspection intervals are provided.

Equipment criticality assessmentIt is vital that producers know the criticality of their equipment (i.e., the probability that it will fail and the probable effects of any such failure). Equipment failure may not only have economic effects, such as costly plant shutdown and repairs, but also serious health, safety and environmental implications.

Full life cycle support9

Successful urea plants comply with all applicable rules and regulations and produce products effi ciently and effectively with maximum on-stream times. However, as plants get older, it may become increasingly diffi cult to maintain effi cient production and full compliance. Many urea plants have been designed for a service life not greatly exceeding twenty years. However, such plants can remain competitive due to the depreciated initial capital investment. Well maintained and upgraded with state-of-the-art technology, these plants succeed in producing at competitive cost prices. To ensure that our customers urea plants remain competitive, we offer a range of activities and services covering the complete life cycle of a plant: Plant operation Plant maintenance Plant improvement and debottlenecking services Equipment supply Advanced Process Control and optimization solutions Plant staff training

Examples of Stamicarbons full life cycle support are: Corrosion inspection of the critical urea equipment Process analyses and plant optimization Debottlenecking ideas and life study Simpli cation of the urea process steps for ease of operation Supply of critical equipment items Schemes for sustained maximum output Operator training programs

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Plant improvement and debottlenecking services9. 3

Stamicarbon has carried out more than 90 revamp projects at all kinds of urea plants, including both Stamicarbon and non-Stamicarbon plants. Thanks to a combination of state-of-the-art technologies and expert know-how, our revamp services can dramatically improve plant performance.

Rigorous onsite revamp studyThe desire to increase the profi tability of the plant, or the replacement of critical equipment, is often the initiation for a revamp study.At the start of the process, Stamicarbon performs a rigorous onsite revamp study to determine the present performance of the plant and to design the optimum revamp solution.

A revamp may lead to: Increasing plant capacity Reducing ammonia consumption and emissions Optimizing energy consumption Increasing product quality Increasing plant reliability

DebottleneckingOne of the revamp services offered by Stamicarbon is debottlenecking.

Debottlenecking will enable your urea plant to: Take full advantage of the plants design margins Boost urea production with the same number of people and basic infrastructure Reduce total xed and operating costs, lowering the price of the urea produced Improve the plants competitive advantage

Debottlenecking conceptsDebottlenecking your urea plant effectively will depend on the availability of feed, utilities and particular plant limitations. And because the availability of feed stocks and utilities varies from site to site, we have developed several debottlenecking concepts that enable us to meet your exact requirements. Depending on your needs, even a combination of debottlenecking concepts can be implemented. This table details some of the concepts available and the expected capacity increases:

Concept type Expected capacity increase More In, More Out 10 - 30 %Double Stripper 30 - 40 %MP add-on 30 50 %Pool condenser / reactor 50 -100 %The reference for the given capacity increase is the nameplate capacity. It should be noted that the actual achievable plant capacity increase depends on the original design margins of the large capital equipment.

Re-lining of high-pressure urea equipmentOver time, the alloy protection lining in high-pressure urea equipment may become so thin that the equipment needs to be replaced. But in fact, replacement of the equipment as a whole is often unnecessary! We are experts in replacing the alloy protection lining in high-pressure urea equipment - extending the lifetime of the equipment by many years. All our re-lining services follow a carefully planned preparation to ensure minimum down-time and optimum results.

Replacement of high-pressure equipmentChoosing the right replacement for your high-pressure equipment can be diffi cult. Thats why Stamicarbon cooperates with customers to make customized high pressure equipment that not only incorporates the most advanced process and mechanical design features, but that is also designed and manufactured in the shortest lead-time to ensure minimum down-time and maximum production yield/output.

The Stamicarbon services can include:In addition to the supply of high pressure equipment, Stamicarbon can also supply other critical items such as:

High pressure piping and its components RADAR-based level measurements N/C meter (measuring the NH3 /CO2 ratio, which is an important steering parameter in urea synthesis) Leak Detection Systems for high pressure equipment Prilling buckets

Next to this Stamicarbon is very experienced with providing the following services: Customized equipment speci cations in consultation with the customer Preparation of the Invitation to Bid (Technical) Evaluation of the bids and manufacturer selection together with the customer Inspections during equipment manufacturing to check compliance in accordance with the Stamicarbon specifi cations (from process and mechanical/corrosion point of view) Expediting during fabrication Assistance during installation and start up of equipment Stamicarbon provides you a single point of contact for your critical urea equipment with high equipment quality and shortest lead times, resulting in optimum utilization of your plant.

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Equipment supply9. 4 Process control and optimization solutions9. 5

The design and fabrication of the high pressure synthesis is the most critical part of the development and construction of a new urea plant. Replacements of equipment units are even more critical, given their design constraints and the very time sensitive nature of such projects.

Design and engineering of high pressure equipment and piping systems for urea plants is an expertise in which Stamicarbon has more experience than any other party. We offer our clients access to our knowledge and expertise through our Equipment Supply services.The combination of our design and engineering competences with our in-depth knowledge of the fabrication process, results in a very effi cient delivery of high quality reactors, heat exchangers, piping and valves.

Flawless project execution is guaranteed through our own specialized project management and the close co-operation with our carefully selected equipment fabrication partners.The availability of high quality Safurex materials for our equipment supply projects is warranted through our unique

strategic partnership with Sandvik, the leading stainless steel manufacturer and co-developer of Safurex.

Stamicarbon, together with its partners provide one point of responsibility of critical high pressure equipment and piping systems. We have extensive experience in both delivering total high pressure synthesis systems and critical equipment replacements.

We provide all the necessary services to ensure that our customers get unmatched quality in equipment and support. Customers turn to us in particular when faced with time critical or complex challenges such as the need for on-site assembly of equipment because of transportation limits.

Nowadays a majority of our customers choose Stamicarbon as the supplier of equipment and piping systems based on our proven and reliable track record.

Stamicarbon is committed to give Full Life Cycle support to customers and wants to be best in class also in the fi eld of advanced process control.Sirius@Max (STAMICARBON IPCOS REAL TIME UREA SOLUTIONS) is the result of the combination of Stamicarbons leading urea process knowledge and IPCOS state-of-the-art Advanced Process Control (APC) technology called INCA, specifi cally designed for Stamicarbon Urea plants.The Sirius@Max solution is implemented using a phased methodology. The fi rst phase focuses on the optimization of the base layer controls, whilst the second phase focuses on the implementation of the APC solution.

Layered approachOptimized base layer control provides more stable operation throughout the entire urea plant, and helps reduce the impact of disturbances on the plant with minimal operator intervention. The Sirius@Max Urea APC solution will optimize the operation of the unit minute to minute, every hour of the day, ensuring maximum effi ciency and stability.

The Sirius@Max Urea APC solution helps you achieve optimal operation of your urea plant, by pushing it closer towards the active constraints like: Limitation on condensation capacity in synthesis/low- pressure section Exceeding ammonia emission limits Available CO2-compression capacity (max. RPM compressor) Stripper ooding

The benefi ts are obvious Increase overall plant stability: Due to the typical complexity (high degree of interactions and recycles) of a urea plant, the INCA APC controller is the perfect tool to reach the optimal, stable operating point in a straightforward way.

Maximize throughput: Once the desired stability is reached, the INCA APC controller will be used to smoothly maximize the urea production by increasing e.g. CO2 fl ow without violating any of the operating constraints.

A typical constraint can be the maximum pressure of the reactor or a too low cooling water temperature at the inlet of the low pressure carbamate condenser.

Increase yield: By increasing the yield in the high pressure reaction section, less carbamate will be recycled which will result in minimization of the energy consumption of some 0.5 %.

In addition, reduced emissions, increased uptime, minimal alarms (operators can focus on essential operations), and improved equipment reliability can be achieved due to consistent, best-practice operation.

SIRIUS@MAX at workSirius@Max contains a Yield Optimization Module, which is based on a detailed rigorous model of your urea plant. This module computes the optimal yield point online. The optimal yield point changes with the active constraints and process conditions. This means that it has to be calculated in real time.It can be proven that the optimal yield point coincides with the point of minimal specifi c steam consumption. Sirius@Max can therefore guarantee maximal throughput under the optimal energy conditions. These ideal operating conditions are enforced on the plant via the Advanced Process Controller.The APC controller is also responsible for stabilizing the plant by reducing the process variations. In addition, the APC system will drive the plant towards the most economical constraints (e.g. not exceeding pressure in the recirculation section).Revamping the plant up and down in a very effi cient and almost hands free way is one of the possibilities of the Sirius@Max system. This is very useful before and after granulator cleaning actions.Via an Open Process Control (OPC) server these optimal control signals are communicated with the DCS. With the use of an OPC interface any common and modern DCS is able to integrate with the Sirius@Max system.

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Plant staff training9. 6

To help customers ensure that their urea plant operates with maximum effi ciency, we developed tailor made training programs on process as well as process control, mechanical and inspection subjects to improve skills of plant staff (e.g. Head of Section, chief supervisors, shift engineers, maintenance and inspection engineers).

A typical training program consists of the following subjects: Unit operations involved as well as the philosophy of the chosen process lay-out Fundamental theory behind the process design Control strategy Trip schedules Operations, discussion covering the control of key parameters in the plant Special operating cases, trouble shooting in a urea plant. Maintenance Experience Failure mechanisms Non Destructive Inspection Methods Corrosion phenomena in traditional steel materials of construction and Safurex.

All technical and other information contained herein is based on general Stamicarbon experience and within this limit is accurate to the best of our knowledge. However, no liability is accepted therefore and no warranty or guarantee is to be inferred. Copyright Stamicarbon BV. All rights reserved. No part of this publication may be reproduced in any form or any means without the permission of Stamicarbon BV. You will acces its contents solely for your own private use and will comply with all applicable laws and regulatory requirements relating to your use of this information.

Contact us

For more information on what Stamicarbon

can do for your organization, please contact us at:

Phone.: +31 (0)46 423 7070

Fax: +31 (0)46 423 7001

Email: info@stamicarbon.com

www.stamicarbon.com

Visiting address:

Stamicarbon B.V.

Mercator 2

6135 KW Sittard

The Netherlands

Mailing address:

Stamicarbon B.V.

PO Box 53

6160 AB Geleen

The Netherlands

Stamicarbon is the licensing and IP Center of

Maire Tecnimont. Stamicarbon has offi ces in

Sittard (The Netherlands), Beijing (China) and

Moscow (Russia). For further information:

www.stamicarbon.com

Maire Tecnimont S.p.A. is the parent company of

an Engineering & Construction International

industrial group which operates in three

sectors: Oil, Gas & Petrochemicals, Power,

Infrastructure & Civil Engineering. The Group,

quoted on the Milan Bourse, is present in over

30 Countries, controls over 50 operating

companies and can rely on a workforce of about

5,200 employees, of which more than half are

located internationally. Its main offi ces are in

Rome and Milan, Italy. For further information:

www.mairetecnimont.it