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100 years young

Summary

Haldor Topsøe, the Danish founder of the chemical engineering company that bears his name, will celebrate his 100th birthday on May 24th this year. Haldor Topsøe A/S, the company he founded in Copenhagen in 1940, will mark the occasion with a year of celebrations all over the world.

Abstract

Celebrating a 100th birthday is a remarkable enough achievement, but doing it while still being in charge of the company that you founded over 70 years earlier is one that almost defies belief. Yet that is exactly what Haldor Topsøe is about to do. Born on May 24th, 1913, Haldor Topsøe was the eldest son of Captain Flemming Topsøe and Hedvig Sofie, and grew up in Copenhagen. While Denmark escaped the ravages of the First World War, the 1920s and 30s were a time of economic dislocation and social unrest, and his father’s involvement in voluntary social work, covering vital services during general strikes, made a lasting, life-long impression on him. To this day he recognises the importance of overcoming the boundaries between social strata to enable people to work together. Keywords: Snamprogetti, Denmark, Catalyst

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Gas developments in the eastern Mediterranean

Summary

While Europe has steadily become a larger importer of natural gas from outside the region, recent large scale discoveries of natural gas in the eastern Mediterranean could change things dramatically over the coming decade. There is already LNG capacity planned, but could ammonia or methanol capacity follow? Or will the region's political divides slow or even prevent development?

Abstract

European gas production has been in steep decline for several years, and is expected to contract 30% to 2035, according to the European Union, while demand is expected to continue to rise, and imports will rise accordingly. However, recent discoveries in the eastern Mediterranean could see the EU developing a new gas hub in Cyprus. The new gas finds are in the Levant Basin Province Assessment Area (see Figure 1). According to US Geological Survey estimates, there could be 122 tcf of natural gas and 1.7 billion bbl of oil in that area, with claims split between Cyprus, Lebanon and Israel. This includes the two largest deep water gas finds in the past decade, Leviathan and Tamar, with 33 tcf of discoveries since 2009. Cyprus has 7 tcf of those reserves, in the Aphrodite field, but experts say that the final figure could be closer to 60 tcf, and it has been suggested that Cyprus could be supplying 50bcm of gas to Europe by 2030, or around 10% of the EU’s annual consumption. keywords: Cyprus, Israel, Lebanon, Egypt, Turkey, LNG

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Engro keeping up with the times

Summary

In 1992, Engro relocated a 1966 vintage urea plant from ICI Billingham in the UK to Daharki, Pakistan. In this article, M.Idrees and M. S. Muddasar of Engro Fertilizers Ltd report on Engro's 20 years of experience with operations, re-engineering, modernisation and revamps of this unit that have led to reduced environmental impact, increase of capacity by 100% and energy savings of 20%; thus, bringing it on a par with most modern urea technologies.

Abstract

Engro Fertilizers Ltd is the second largest urea manufacturer in Pakistan. In 1992, Engro relocated a 1,000 t/d urea plant, from ICI Billingham, UK, to its manufacturing site in Daharki, Pakistan. The ammonia for the production of prilled urea is supplied from a relocated ammonia plant from Pascagoula, USA. The Toyo Total Recycle C urea plant from ICI was commissioned in 1993. Ever since its commissioning, the urea plant has undergone various debottlenecks and capacity enhancement programmes, energy index improvement schemes and various environmental control measures. Urea process description The relocated urea plant now employs Toyo’s ACES process to manufacture prilled urea. In this CO2 stripping process, NH3 is recovered within the HHP loop (ACES loop), and sent back to the reactor along with CO2 (Fig. 1). The Urea-2 plant synthesis loop is designed to operate at isobar equivalent to 174 kg/cm2, and liquid mass flows inside the HHP loop under gravitation effect (liquid head). The plant is operated at N/C = 3.79, H/C =0.79 and 66% CO2 conversion is attained at the reactor outlet. Raw materials (CO2 and NH3) are imported from the ammonia plant and reacted to produce 46.6% nitrogenous fertilizer. Carbon dioxide from the ammonia plant, at a pressure of 0.50 kg/cm2 and temperature of 43.3°C, containing 2,500 ppm oxygen, is compressed by reciprocating compressors operting in parallel. Ammonia at 25.5°C is stored in the ammonia receiver, which receives fresh ammonia from the ammonia plant and recovered ammonia from the ammonia condenser and ammonia absorbers. Ammonia is fed to the reactor after passing through the pre-heat stages, where steam and LPD off gases heat is utilised to maintain the ammonia temperature at 80°C. Carbamate from the high pressure absorber cooler (HPAC) is pumped to the HHP scrubber and carbamate condenser-2, where reactor off-gases and gases from stripper are absorbed to recover reactive mass. The urea concentration at the stripper outlet is 42%, rising to 61% at the high pressure decomposer (HPD or MPD in modern plants) outlet. The HPD is operated at 16.8 kg/cm2 pressure, using 12.3 kg/cm2 steam as thermal medium in the thermo syphon reboiler to decompose unreacted mass and recover it in the HPA. The concentration is further enriched to 68% urea at the LPD which is operated at 2.1 kg/cm2 pressure and 4.92 kg/cm2 saturated steam is used in the reboiler for breakdown of unconverted mass. The low low pressure and vacuum loop operate at slight positive atmospheric pressure and 178mm Hg (0.24 kg/cm2 abs) pressure respectively. Concentrated urea (76%) at pre-concentrator outlet is pumped to the atmospheric falling film evaporators to produce 98.6% urea. Evaporator off gases, mainly air, are directly routed to atmospheric scrubbers to recover ammonia and urea and prevent the release of these gases to the atmosphere. Urea (98.6%) is sent to a wide umbrella Vibro priller through melt urea pumps to the natural draft prill tower to convert the urea melt into prilled urea, which is transported to the bulk storage and bagging facility. Keywords: relocated urea plant; ACES process; chloride stress cracking; off gas heat recovery; revamp; start-up optimisation; stripper inspection

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Improving energy efficiency in an ammonia plant

Summary

D. Velázquez, F. Rossi and J. Rodríguez of DVA Global Energy Services and F.Galindo of Fertiberia present the results of an energy study carried out in an ammonia plant in Spain. A comprehensive energy audit of the main equipment (furnaces, syngas, air and ammonia compressors, steam turbines, cooling towers and refrigeration systems), pinch analysis and steam modelling resulted in the proposal of 34 projects, some of which have cost savings of more than one million euros per year with payback times of less than one year.

Abstract

The directives 2003/87/EC and 2009/29/EC1,2 set strict CO2 emission limits for some chemical industries and can have a significant impact on companies’ profits. Because of this, as well as the increase in the price of natural gas in recent years, many European ammonia producers have been forced to carry out important energy efficiency improvements, in order to maintain their competitiveness within the international market. During recent years, the average specific consumption of ammonia production has been globally quantified as 36.6 GJ/t NH3 (LHV base). Performance indicators of ammonia plants located in Canada and western Europe show the best values3. Keywords: CO2 emissions reduction; pinch analysis; equipment audit

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Improved safety system in a nitric acid plant

Summary

The existing alarm and safety system in a nitric acid plant in Croatia was replaced by a new microprocessor-based system in order to increase the safety requirements and to modernise the production process. The main task of such a system is to continuously monitor all important process parameters and quickly inform operators about potential dangers that could lead to disastrous consequences and associated hazards.

Abstract

The nitric acid production process is a very demanding process from a safety standpoint. Special attention must be taken regarding power recovery by the turbo set and the reactor section. The turbo set is the mechanical equipment that drives the air and nitrous oxide compressors. In the reactor section, there are special preconditions relating to the exothermal reactions involving the oxidation of a gaseous mixture of ammonia and air. In order to prevent disastrous consequences and hazards, the nitric acid production process must be continuously monitored using control and safety systems. A control system is considered to be safety related if it provides functions that significantly reduce the risk of a hazard, and in combination with other risk reduction measures, reduces the overall risk to a tolerable level, or if it is required to function, maintains or achieves a safe state for the equipment under control. Keywords: emergency shutdown; safety integrity level; process control

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High performance catalysts for sour gas shift reactions

Summary

Clariant's latest generation sour gas shift catalyst, ShiftMax® 820, significantly increases the operating temperature window and provides proven operational activity at the low temperatures that favour reaction equilibrium. Y. Cai, J. Wang, C. Zeng and P. Morse of Clariant discuss the superior performance and benefits of using ShiftMax 820 and report on recent commercial operating experiences.

Abstract

Feedstock diversity is an increasingly important challenge in the global chemicals and energy industries. In some regions, price volatility in petroleum markets in recent years has pushed many chemical producers to use alternative feedstocks, such as coal, natural gas, and biomass. In other areas, local resources encourage use of these alternatives as a means to build energy self-sufficiency and provide business opportunity to local communities. As the optimum use of these feedstocks shift, producers need the flexibility to integrate new options into their operations. Most chemicals processes that use alternative feedstocks begin with synthesis gas, which is a blend of hydrogen and carbon monoxide. This mixture, typically referred to as syngas, can also contain several impurities that can create unique challenges in downstream processes. Sulphur is a particular concern, as it is a poison to catalysts used for many chemical and fuel conversion processes. Such streams are typically referred as “sour” indicating sulphur levels above several parts per million (ppm). Keywords: water-gas shift; sour gas shift catalysts; pre-sulphided catalyst

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Plant Manager+ Problem No. 17 Loose liner or overlay welding?

Summary

In urea plants, high pressure equipment typically has a carbon steel pressure-bearing wall, which is protected against carbamate corrosion by means of a protective layer, typically made from 316L UG or 25-22-2 stainless steel. Typically a loose liner or overlay welding is selected to provide this protective layer. But what is the best choice, what are the advantages and disadvantages of loose liners and overlay welding and what are the actual experiences in the field? An important difference between the two options is that an overlay welding leads to a leak before break scenario, while a loose liner leads to a break before leak scenario. Loose liners therefore require a proper leak detection system.

Abstract

Mr Mark Brouwer of UreaKnowHow.com in the Netherlands starts up the following discussion: What is more reliable/safe/easy to maintain as a protective layer for the carbon steel pressure-bearing walls of high pressure equipment items in urea plants: a loose liner or overlay welding? What are your experiences? Mr Muhammad Adnan Hanif of Fauji Fertilizer Corporation in Pakistan replies: In my opinion, a loose liner is the more attractive option compared to overlay welding owing to: l ease of installation especially when the area to be covered is large e.g. a high pressure reactor; l maintenance is easier and less time consuming as normally a new liner is installed on the old liner without cutting/removing the old one; l thickness monitoring of a loose liner is easy and preventative maintenance planning is easy as the lining area is normally divided into a number of sections. Keywords: preventative maintenance; leak detection system; carbon steel wall

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