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As the world's leading UREA authority we are committed to the long-term success of this industry - and that means sharing our insight and knowledge.

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Granulation The Stacx Project

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The Agrium Fort Saskatchewan Urea plant has been operating with a Stamicarbon CO2 stripping synthesis section and an NSM (now HFT) fluidized bed granulation section since the original start-up in 1983

. The Urea Synthesis section had a nameplate capacity of 908 tonnes per day, while the urea granulation section consists of two trains (North and South), each with a nameplate capacity of 544 tonnes per day. These two trains are independent of each other. Over the last 20 years, the Fort urea plant has been operated at rates up to 1250 tonnes per day while producing good quality granular product. Well over 6 million tonnes of urea have been produced. It was decided to convert the Fort Saskatchewan granulation trains to Stamicarbon technology. The conversion project was completed in three months1 and the granulation plant was restarted on September 30, 2003. This paper presents a summary of the project, the changes completed, the operating results, potential savings in operating costs, and the product characteristics associated with the conversion.

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Urea storage and handling, let's keep caking in the kitchen

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Reviewing the history of urea technology and Urea technology development, we may conclude that from the beginning of commercial Urea Technology development and Urea Production until now much attention

has been given to developing and optimizing the synthesis- and recycling-section in the urea plant, that in the last decade increased attention has been given to developments and optimizations regarding Urea shaping technology (granulation and prilling), whereas over the entire Urea history, also much attention has been given to storage and handling, indicating the importance of product quality, storage and handling. The most important problems occurring in Storage and Handling are directly or indirectly related to (results of) caking, like lump-formation and dusting. Therefore the mechanism of caking of Urea has been made the subject of a paper because we realize that large efforts and considerable amounts of money can be involved with the consequences of caking. In this paper the mechanism of caking via water sorption and desorption is discussed. Especially the caking, spreading through a heap of Urea, observed even in Urea of good quality will be highlighted. This is often caused by moisture migration. The mechanisms of caking are then explained by discussing some examples from practice.

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A specialty SAFUREX™ for HP stripper tubes

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This paper presents a historical overview of the corrosion behavior of the Safurex® HEx tubes in HP strippers and gives an account of the development of the new specialty grade. 

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Report of the steps description

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Stamicarbon Critical Proprietary Equipment

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Quality & Safurex • Proprietary Equipment • PEQ procurement

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Stamicarbon Stripper Performance in Non-Stamicarbon Plants

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This paper describes the successful experience of a Stamicarbon designed Safurex® HP Stripper in a world scale Snamprogetti urea plant commissioned in early 2001. The Stamicarbon designed Safurex® HP

Stripper replaced a bi-metallic designed Snamprogetti stripper in 2003 which suffered extreme corrosion issues within a short period after startup in the bottom channel section of the vessel that caused persistent operational outages and huge financial losses. The problems encountered with the original HP bi-metallic stripper and results of the decision to replace the bi-metallic tube stripper with a HP Safurex® stripper are addressed. The subject Safurex® stripper was in service for 850 operational days from March 2003 up until November 2006, after which the subject stripper was returned to Canada and installed in another Snamprogetti urea plant in 2007. The subject stripper has been in operation in Canada since 3Q 2007 and has had no issues in its new location as of this writing.

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Advance Monitor Leak Detection Monitoring System

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Stamicarbon’s ADVANCE MONITOR™ Leak Detection Monitoring System for both new and existing High Pressure equipment. Existing Leak Detection Monitoring System can be inspected to ensure proper operation

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Leak Detection Safeguarding Stamicarbon's High Pressure Urea Vessels

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Urea solutions are not very corrosive, but ammonium carbamate, an intermediate in urea synthesis is highly corrosive. To protect the carbon steel high pressure synthesis equipment from corrosion, stai

nless steel loose liners are commonly applied. With a loose liner a hazardous situation may arise if a leak occurs and carbamate containing fluids enters the space between liner and carbon steel. For this reason Stamicarbon designed a system which continuously monitors for leaks to allow safe operation of said equipment.

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Blockage of leak detection system

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A leak detection system is installed at the High Pressure equipment items of a Urea Plant in order to detect any leakage in these HP Equipment. Normally vacuum is maintained in this system, blockage i

n the system is checked by opening atmospheric valves and breaking the vacuum on a defined frequency of one month. We could not check the blockage on this defined frequency, we performed a blockage test after a period of 10 months; blockage was found in valves V-16 & V-17 in the leak detection system of the HP Stripper. After further investigation it revealed that the blockage in the leak detection system was inside the stripper top dome. We tried to de-block the system with instrument air having a pressure of 7 bar and with low pressure steam but this failed. Then on the running plant we tried to de-block using an argon cylinder having a pressure of 100 bar and de-blocked the lines at 30 bar. The root cause of the blockage was corrosion inside the leak detection tube due to moisture ingress through the atmospheric valves. The equipment condition was found healthy on inspection during a turnaround.

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New Overpressure Protection System for the Urea Synthesis

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The motivation for the development of the New Overpressure Protection System for the Urea Synthesis results from the following safety-related and process-related facts: Urea plants in Germany be

long to the so-called accident plants. For these plants it is required that the security is improved constantly. The management wants to constantly improve the environmental-protection and upgrading the technological conditions to increase the production and to save energy.

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Reliable radar level measurement in Urea synthesis equipment

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As we all know measuring level in high pressure urea synthesis equipment is not an easy job. Extreme process conditions especially with respect to the corrosiveness of the process media and the w

ay the equipment is constructed  eliminates most of the measuring principles available. Radio-active level measurements are common practice in urea synthesis equipment, but there is a tendency in the market to eliminate radio-active level measurements in Urea plants, due to several reasons (maintainability, public aversion against radio-activity, legislation, etc). During the symposium of 2008 the radar level measurement was introduced as an alternative for radio-active level measurements in the Urea synthesis equipment, based on experience of a few radar measurements in operation at that moment. Currently, 4 years ahead, radar technology became Stamicarbon’s standard for level measurement applications in the urea synthesis. This document gives an update on our latest developments, experiences and requirements, which results in a reliable radar level measurement in Urea synthesis equipment.

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Round table Operations, topic RADAR

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Sustainable plant operation without stripper level indication

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Stripper level indication is critical in CO2 Stripping plant as loss of level can cause CO2 Slippage towards the LP Section whilst too high level causes unequal distribution of CO2 resulting in poor s

tripper performance.  The stripper level indication (Radioactive type) LT-1043 got erratic at our plant and we sustained plant operation without this indication by: 1. Keep the plant load constant and avoid any changes in plant load.  2. Observe the stripper outlet temperature as this temperature will change with increase or decrease of the stripper bottom level.  3. Observe the steam consumption of the stripper as the steam flow will change with a change in the liquid level. 4. Observe the N/C Ratio and keep it constant. 5. Observe the downstream section pressure at constant plant load.

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THE VALUE OF A RELIABLE LEAK DETECTION MONITORING SYSTEM IN HP SYNTHESIS SECTION

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• A urea plant contains large amount of toxic ammoniaat elevated temperature and pressure. • For instance:the synthesis section of a1000MTD urea plant contains > 35ton of NH3 • Keeping this ammon

ia inside the process equipment is essential from a safety,environmental andeconomica lpoint of view

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Urea Synthesis gas lines suffering from leakages

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In the 2014 turnaround all original AISI316L-UG high-pressure gas lines were replaced in the urea synthesis section, in accordance with advice from Stamicarbon. The material utilized for the replaced

gas lines was again AISI316L-UG, because there were still some such tubes in stock, dating from the time the plant was constructed.The affected areas showed evidence of stress corrosion cracking (SCC), but reduction in the wall thickness was also observed. This was attributable to condensation corrosion, which is normally observed in the gas lines. It was most severe in the heat-affected zones (HAZ) near the welds. The affected elbows were subjected to metallographic examination in Brazil as well as in Stamicarbon laboratory. This paper presents the investigations carried out on the elbows and piping removed from the urea synthesis gas lines in order to find the root cause of the leakages. 

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Shiphon Jet Pumps

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While revamping a Stamicarbon Urea plant, in most of the cases, the specific reaction volume is decreased with the revamp. As a result the residence time of the urea solution in the reactor will decre

ase and thus the efficiency of the reactor will go down. However, by changing the internals of the reactor (using a different type of trays) the efficiency in the reactor can be improved. In the past two types of trays were used in Stamicarbon Urea plants: the conventional trays and the high efficiency trays. Now a new type of trays is introduced, which improves the efficiency of the reactor and thus results in savings of the high-pressure steam consumption. These trays are called the Siphon Jet Pumps. The first trays have successfully been installed in SKW Piesteritz. In this paper the Siphon Jet Pumps are introduced and several aspects around these trays are discussed.

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CONSEQUENCES OF LOSS OF PASSIVATION AIR

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• Initial Shut-down June 2nd, 2013 for a planned maintenance outage. • The inspection of the R-101 Reactor produced a number of routine findings and small repairs. • All internal surfaces (liner and

weld overlays) are in passive state

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Corrosion aspects in urea plants

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Special stainless steel grades developed Design requirements Fabrication requirements

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Design improvements by sharing incidents

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Effective incident investigation, reporting and follow-up are necessary to achieve a safe operational environment. Incident investigations provide the opportunity to learn from reported incidents and

to use this information to take corrective action and prevent recurrences. Stamicarbon has been recording major process safety incidents in urea facilities for 48 years, but because they are on the whole so few and far between it is questionable whether they provide sufficient input to identify common causes and inadequate protective measures for them to be corrected before a serious incident actually takes place. Near misses and lower-consequence incidents are increasingly thought of as the most important indicators of major accidents; therefore, we have expanded our database of major process safety accidents to include them in the interests of improving understanding of process safety.  Besides our major incident database we also consult internet news channels and fertilizer industry associations to find more incidents within urea manufacturing facilities. But it has to be acknowledged that we will only hear about major events from these sources; lower-consequence incidents are unlikely to see the light of day. So we are left with lagging indicators instead of the leading indicators that are so badly needed!  Also, incident databases at customers’ individual sites contain insufficient data points to uncover common causes. This is why urea manufacturers need to work together and build an incident database from which all can benefit. To enable the urea community to learn more from near misses and low-consequence accidents, Stamicarbon is launching a process incident sharing portal service for its customers. The service will contain the following:  • Stamicarbon will host the HSE platform and subscribing members can access the posted HSE information at any time, free of charge.   • Subscribing members will periodically receive a report by e-mail to learn about relevant accidents and near misses and possible improvements in terms of process design and operational practices.   • Customers who report an incident or near miss to Stamicarbon can receive tailored HSE support under an applicable service agreement. • The incident report and other relevant HSE information that Stamicarbon considers appropriate to share with its customers can also be downloaded from the HSE portal. The procedure for reporting incidents is as follows.  • To obtain access to the HSE portal the customer will first need to register on the Stamicarbon HSE portal http://hse.stamicarbon.com . • Customers will initially provide a rough description of their process safety event by filling out a simple incident notification form, which is designed to minimize their administrative effort.  • Stamicarbon’s HSE engineer will contact the issuer of the notification to find out in detail exactly what happened. Further administration will be handled by Stamicarbon.

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Disposal of emergency relief discharges

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Ammonia is a toxic substance. In a Urea plant, relative large amounts of ammonia are present under elevated temperature and pressure. Engineering guidelines, such as the well known ‘API recommended pr

actices’ give guidelines about the necessity and sizing of emergency relief systems, aiming at protection of the plant under emergency conditions. Traditionally, disposal of the ammonia containing gases from such emergency relief systems (safety valves or rupture discs) from urea plants has been done as direct discharge into the atmosphere. Recently a study was conducted by Stamicarbon to see whether this practice is acceptable from a safety point of view, taking into account progressing insight gained in the subject of emergency relief in recent years.

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Result of recent she studies for urea plants

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Safety and Product Stewardship in the Fertilizer Industry

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I believe the fertilizer industry has a prosperous future. By 2050 it is estimated that 70% more food will have to be produced compared to today. This will demand a continuous growth in fertilizer pro

duction. At the same time, we must expect that society will focus even more on safety and environmental issues associated with fertilizers, such as Health and safety risks from working in fertilizer plants Major accident risks, to avoid disasters like the explosion in Toulouse Terrorist acts, using fertilizers for bomb-making Pollution risks from the manufacturing processes and from the use of fertilizers Climate change and the role of fertilizers and agriculture Use of limited energy and mineral resources, such as phosphates The public perception of Good Citizenship has changed over the years. Today, many people look upon the chemical industry as a burden to future sustainability. This perception will deepen if the industry has a poor safety and environmental performance. It is vital to perform well and to eliminate bad practices. Otherwise we must expect that much stricter regulations will be enforced upon the industry. In this paper I will focus on the 3 first bullet points above, those that are related to safety and product stewardship, with some practical advice on actions the industry should take in order to be in command and avoiding over regulation. 

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SAFETY ASPECTS WITH THE DESIGN AND OPERATION OF UREA PLANTS

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Urea production takes place at high pressures (> 140 bar), it applies large volumes, it utilizes a feedstock containing a toxic component (NH3) and explosive components (e.g. H2) and the reaction p

roducts are highly corrosive. Risks discussed in this presentation: •Explosion •Loss of mechanical integrity

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SIL Classification in Urea Plants

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The concept of Safety Integrity Levels (SIL) was introduced during the development of IEC 61508/61511 as measure of the quality or dependability of an instrumented system that has a safety function (S

IS). To comply with internationally recognized standards, Stamicarbon introduced the concept of SIL in its standard design urea plants. This paper focuses on the risk graph method, which is a means of quickly assessing and screening a large number of scenarios resulting in loss of containment (LOC). A limitation of the risk graph method however is that it leaves some subjective elements in assessing the consequences (severity) of LOC scenario, whereas these consequences are increasingly important in the ever increasing capacities of urea plants and equipment. To overcome this limitation Stamicarbon developed a quick reference chart covering all sections of the urea plant that allows quick and objective assessment of the severity and SIL parameters. Further, the paper highlights SIL-equivalents for safety relief valves in crystallizing media and risk reduction by means of Safety Instrumented Systems (SIS).  

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