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Summary
Fundamental and practical aspects of Claus converter catalysisAbstract
Over the last few years, research work in our laboratories has unravelled some, perhaps much of the fundamental surface chemistry of the Claus reaction on alumina. This knowledge, besides being of intrinsic interest, is useful in understanding the day-to-day operation of converter units and is helpful in deciding which catalyst to use and when to replace it. The aim of this article is to explain the chemistry of Claus catalysis and show how this information can be used in the commercial sphere.
Summary
In an interview with Sulphur magazine, Matthias Kleinhans, Managing Director of Sandvik Process Systems, Fellbach, Germany, gives an account of the new state-of-the-art sulphur handling facilities at Bapco in Bahrain.Abstract
The Bahrain Petroleum Company (Bapco), wholly owned by the Government of Bahrain, is engaged in the exploration and prospecting for oil, drilling, production, refining, distribution of petroleum products and natural gas, sales and exports of crude oil and refined products.
The company owns a 250,000 barrels/day refinery, storage facilities for more than 14 million barrels, a marketing terminal, and a marine terminal for its petroleum products. Bapco is an exporter of crude oil and refined products (95% of refined products are exported) to customers based in the Middle East, India, the Far East, South East Asia and Africa.
Summary
Alberta's tar sands already represent one third of Canada's oil output. However, a slew of new projects are now underway which could see output leap over the next few years. Exploitation is also increasingly turning from large open-cast surface mining to steam-driven in-situ methods.Abstract
As the world’s resources of conventional oil are gradually being exhausted, so producers are increasingly turning to so-called unconventional reserves; insufficiently liquid to be extracted or transported in a conventional manner. One major source of unconventional oil is in the heavy oil belt of Venezuela, as discussed elsewhere in this issue. However, with the exploitation of Venezuela’s reserves subject to political uncertainty due to the stance of the Chavez government, attention is focusing on the oil/tar sands of northern Alberta.
Both Canada and Venezuela claim to have the largest accumulation of hydrocarbon reserves in the world, but Canada’s claim seems the stronger, with between an estimated 1.7 and 2.5 trillion barrels of oil trapped in a complex mixture of sand, water and clay. This oil sand deposit is primarily located in and around Fort McMurray, Alberta (see Figure 1). Much of the oil is effectively a heavy, bituminous coating around individual wet sand grains, giving the formation its name of oil sands or tar sands. The percentage of bitumen in oil sand can range from 1-20%.
Summary
Reliance Petroleum is currently expanding the capacity of the Jamnagar Refinery. B&V is responsible for delivery of the sulphur processing facility. Angela Slavens of Black & Veatch discusses the project objectives and the different process configuration options considered. The refinery will be the first to combine CBA and amine-based H2S absorption TGTU technologies in a single sulphur recovery complex.Abstract
Reliance Petroleum built the world’s largest grassroots refinery in 1999, and is currently in the process of expanding to double the capacity, making the Jamnagar Refinery Complex in Gujarat, India, the largest in the world. In addition to its impressive size, Reliance’s Jamnagar Refinery can process a wide variety of crude oils ranging from sweet to heavy, with sulphur content up to 4.5 wt-%. Reliance’s existing refinery and petrochemical complex (referred to as DTA – Domestic Tariff Area) processes 660,000 bbl/d of heavy, sour crude and is currently exporting a large proportion of its products. The high sour crude processing capability is centred on the 3 x 675 t/d Cold Bed Adsorption (CBA) sub-dewpoint sulphur trains, which Black & Veatch (B&V) licensed, engineered and procured for the grassroots refinery development from 1996 to 1999. At present, B&V are carrying out EPCM scope of work for the sulphur processing facilities associated with the new Jamnagar Expansion Refinery Project (JERP), which is planned for mechanical completion in 2008. When completed, the expanded Jamnagar Refining Complex will have a total sulphur processing capacity of nominal 4,050 t/d (6 x 675 t/d).
Summary
The Shell-Paques® process has been demonstrated to be a reliable and cost effective treatment for the recovery of small to medium quantities of sulphur from gas streams. Michael O'Brien of Natco Group, Inc. describes the experience of the first commercial Shell-Paques® Biodesulphurisation units for the removal of H2S from high pressure natural gas.Abstract
The recovery of small to medium quantities of sulphur from gas streams has typically been problematic for industry, especially at high pressure. Historically, available processes have been unreliable, costly to operate, required the use of expensive proprietary chemicals and/or generated undesirable waste products. In 1993 Paques commercialised Thiopaq®, an environmentally friendly process for treating biogas using naturally occurring bacteria to oxidise hydrogen sulphide to elemental sulphur in a simple, reliable and cost effective process. Shell Global Solutions (SGSI) invested in the technology to extend its use to natural gas, amine acid gas, Claus tail gas and syngas.
In these applications the technology is branded as Shell-Paques®. Through license agreements with both SGSI and Paques, Natco Group, Inc. designs, builds and services Thiopaq® patented technology in the United States, Mexico and Latin America.
Summary
Mark C. Anderson of ThioSolv, LLC presents a solution to the problem of increasing loads on sulphur recovery systems. The versatility of the chemistry in the SWAATS process is illustrated by the variety of applications described.Abstract
Several trends in the refining industry contribute to increasing load on sulphur recovery systems. Ongoing creep in refinery capacity, the economic incentive to use crudes discounted because of their sulphur and nitrogen contents, and increasing severity of hydrotreating, both of diesel pool components and gasoils, all add incrementally to the load. As the market for high sulphur offroad diesel fades away, refiners will have to hydrotreat even the most refractory diesel-range streams to fit them into the ultra low sulphur pool, continuing the upward creep through 2010. The increase in sulphur production that results from these developments is a readily calculable consequence of the change, but the effective increase in load on the sulphur recovery system is often unappreciated until later.
Claus unit capacity is commonly expressed in terms of sulphur recovery rate, but corresponding equipment in two units having the same nameplate capacity may be of quite different sizes. The reason is that the equipment in the gas path, from blower to tail gas vent, is sized not according to the sulphur rate but according to the flow of the combustion gas produced, which depends not only upon the sulphur rate, but also upon the other components of the feed. It is useful, therefore, to express the capacity demand of a feed stream to SRU in terms of “H2S-equivalent sulphur capacity”, defined as the rate of sulphur fed as pure H2S that would produce the same pressure drop in a Claus as the given feed. Table 1 lists the relative contribution to pressure drop of some components of amine acid gas (AAG) and sour water stripper gas (SWSG). These figures of course depend upon sulphur recovery rate and mode of operation, but are valid for estimating purposes.
Summary
Titanium clad steel has become the corrosion resistant alloy of choice for nickel pressure acid leaching (PAL) processes. It is a reliable, cost effective alternative to pure titanium, providing reliable equipment with high corrosion performance at much lower cost. John G. Banker of Dynamic Materials Corp. discusses the manufacture, application and benefits of titanium clad in the nickel industry.Abstract
Historically, pyrometallurgical processes have been the dominant method for recovering many metals from their ores. These processes have tended to be both energy and pollution intensive. For many metals newly developed hydrometallurgical processes provide a lower cost, cleaner alternative. These processes involve leaching the ores with aqueous solutions of common acids, frequently sulphuric acid. Acid leaching processes have been proven commercially viable for extraction of copper, gold, nickel, uranium, molybdenum, zinc and other metals.1 These hydrometallurgical processes can range from relatively low-tech heap operations to more sophisticated high pressure acid leaching (PAL) processes.
Summary
President Hugo Chavez's attempts to bring oil development in Venezuela back under state control have attracted a great deal of international attention. However, with the country potentially sitting on greater oil reserves than Saudi Arabia in the form of heavy crude, do the rewards outweigh the risks?Abstract
In 2006, Venezuela was the world’s eighth largest oil producer at 2.8 million bbl/day, and the third largest oil exporter in the world. It also has the largest proved reserves outside the Middle East, at some 80 billion barrels recoverable at current prices and technology. However, the country hopes to quadruple this estimate to 315bn barrels or more by counting its Orinoco heavy oil reserves by the end of 2008. President Hugo Chavez has said that “Venezuela has the largest oil reserves in the world”, and he was referring to the estimated 270bn barrels of oil which may be recoverable from the Orinoco belt. By comparison, Saudi Arabia’s oil reserves are put at 260bn barrels of proven reserves, or roughly 25% of the world’s ‘conventional’ oil, according to the US Department of Energy.
But ‘unconventional’ reserves such as Venezuela’s Orinoco and Canada’s tar sands are attracting increased interest. The Massachusetts-based Cambridge Energy Research Associates estimates that unconventional oils will account for nearly a third of world supplies by 2010, up from 22 % in 2005. As well as the US and Canada, other sources include US shale rock, natural gas liquids and potential deposits in very deep waters off Angola and in the Gulf of Mexico.
Summary
Jens K. Laursen and Frands E. Jensen of Haldor Topsøe A/S give an overview of the process principles of the WSA process for sulphur recovery, providing industry examples from a variety of applications.Abstract
The WSA process is a process for the conversion of sulphurous streams into sulphuric acid developed by Haldor Topsøe A/S, Denmark. Since its introduction in the 1980s, the WSA process has been recognised as an efficient process for recovering sulphur from various sources in the form of commercial quality sulphuric acid. The WSA process has found widespread application in the refineries, oil and coal based industries, the metallurgical industry, the steel industry (coking), the power industry, and the cellulose industry. More than 60 plants have now been licensed worldwide for treatment of process gases in a wide range of process industries.
Summary
The Alberta Energy and Utilities Board (EUB) has issued its latest statistics on sulphur recovery and sulphur emissions at Alberta sour gas plants, summarising results for sour gas plants across Alberta for 2000-2006.Abstract
In Interim Directive (ID) 2001-3, the Alberta Energy and Utilities Board set sulphur recovery requirements for new plants. It also committed to monitoring the sulphur recovery of older, so-called ‘grandfathered’ sour gas plants, which do not (yet) meet the sulphur recovery requirements for new plants. These grandfathered plants include some sulphur recovery plants and larger (> 1t/day) acid gas flaring plants. The Directive set out expectations on when older grandfathered plants are required to meet the same requirements as new plants, via a phased approach to the more stringent requirements, and encouraged operators of sulphur recovery plants to take early action to improve performance.