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Fertilizers boost demand

Summary

Rising fertilizer needs will help to boost China's sulphur demand to 7.2 million t/y by 2000, resulting in a predicted shortage of 100-150, 000 t/y of sulphur. Lin Le and Fan Kezheng* review China's sulphur balance and the country's plans to meet the deficit.

Abstract

Chinese sulphulr supply and demand is currently close to balance, with a small surplus. In 1993, consumption was close to 5million tonnes (4.6 million tonnes ofwhich was for sulphuric acid), while total production was slightly higher at 6 million tonnes, although 0.5-0.7 million tonnes of this remained at mines due to a shortage oftransport capacity. Butl by 2000, sulphur demand will rise to about 7.2 million t/y, of which 6.6 million t/y will be used for sulphuric acid production. Demand for sulphuric acid is expected to rise from 14 million t/y of acid in 1992 to 20 million t/y by the end of decade, mainly due to greater fertilizer requirements. Fertilizer production will use 70% of the acid.

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Selling sulphur safely

Summary

Environmental safety has become increasingly important in the sales system for elemental sulphur. Responsible Care, ISO 9000 standards and the MSDS all play an important role. Jim Hyne* reports.

Abstract

Sulphur has been sold "safely" for centuries and still is. At the March 1994 TSI Sulphur Markets Symposium, W. R. Atwood of Texasgulf Inc. noted that transportation of liquid sulphur by rail in the US has one of the lowest rates of "non-accident incidents" - only 0.01 %. Yet his European counterpart speaker on the same occasion opined that accidents still do occur in the process of selling elemental sulphur and legislation relating to the Transportation of Dangerous Goods (TDG) are constantly under review. Indeed, most recent changes in these regulations have recognized the inherently safe nature of commercially formed elemental sulphur (prills, pellets, pastilles, granules) by removing these forms from the previous Class 4.1 (flammable solid). Such forms of solid sulphur (see Sulphur May-Jun 1990 pp. 35-47) are now unclassified and are not regulated materials under the requirements of TDG. The classification of liquid sulphur has been changed to Class 9 (miscellaneous) largely on the grounds of that form being an elevated temperature product.

It is this changing nature of society's expectations regarding "safety" that makes the "safely" part of the title of this article such a moving target. What was considered "safe" 20 years ago is no longer acceptable operating practice. Not only have human safety standards been raised but environmental safety is now a major factor in designing the overall sales system for elemental sulphur. Considering that the annual elemental sulphur market is in excess of 35 million tonnes worldwide, the industry faces a considerable challenge in maintaining its good safety record.

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A dream come true

Summary

In this article Jack Babbitt* recounts Devco's role in sulphur pelletizing over the past 18 years with specific reference to its experiences in Saudi Arabia.

Abstract

How long should a bu iness chase a dream? Devco Overseas Company, headed by John F. Gack) Babbitt pursued one in the deserts of Saudi Arabia for five years until it became a reality. The chase to secure a contract with Petromin to process and market all or part of the sulphur to be produced in the Eastern Province of Saudi Arabia began in 1977 and the first shipment of pelletized sulphur was made from the King Fahd Industrial Port of Jubail in April 1982.

The Master Gas Plan adopted by Petromin and put into effect by Aramco called for the collection and treatment of all of the associated gas being produced in the .Eastern Province of Saudi Arabia. This would lead to the production of large quantities of natural gas liquids, dry gas and sulphur. While domestic markets were available for the gas and a burgeoning domestic petrochemical industry, plus exports, would dispose of all of the natural gas liquids, it was proposed to vat the sulphur at the three major production sites, Berri, Shedgum and Uthmaniyah.

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Another approach to S forming

Summary

Fluid drum granulation offers an alternative forming process for sulphur and sulphurcontaining products. Michel Besson* reports on a selection of its applications and product specifications.

Abstract

M odern trends in environmental protection have led to the current scenario where sulphur is produced in great abundance in the chemical and energy industries but has become increasingly deficient in our soils. In the chemical and energy industries, environmental laws obliging refineries and power stations to reduce hydrogen sulphide and sulphur dioxide emissions have resulted in the generation of large quantities of sulphur and sulphur-containing compounds. In addition, large quantities of crystalline ammonium sulphate are produced as a by-product from caprolactam plants. Ammonium sulphate is also found in waste streams from chemical plants.

The sulphur deficiency in soils is largely due to the shift from ammonium sulphate as a nitrogen fertilizer to MAP and DAP, which do not contain sulphur, and due to the reduction in acid rain brought about by more stringent environmental regulations.

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Smarter acid equipment

Summary

Proper design of acid distributors and tower packing is critical for optimum tower performance in sulphuric acid plants. This article reviews existing technology on acid distribution and reports on experiences with an improved distributor design which is gaining wide acceptance in the industry.

Abstract

In modern sulphurjc acid plants, good drying, absorption and SOz stripping from product acid require efficient contact of the gas streams with sulphuric acid. For these services, most plants use bricklined towers with ceramic packing. For good tower performance, it is necessary to distribute the acid uniformly over the tower packing, whose function is to provide the maximum effective area for acid-gas contact with minimum resistance to acid and gas flow through the tower. The design must also avoid the generation- and entrainment of acid mist as it can corrode and foul downstream equipment or cause an environmental nuisance.

Over the last several decades, plant capacities have increased and towers now operate at higher throughput. In modern sulphuric acid plants with capacities up to 4,000 tid the towers can be as large as 30 ft (9.14 m) in diameter with acid flow as high as 10,000 US gall min (2,264 m3/h) and gas flow as high as 150,000 std ft3/min (255,000 m3/h). The risks of poor tower performance and acid entrainment causing catalyst fouling and corrosion of expensive downstream equipment have therefore significantly increased. Maintenance and downtime costs have also escalated, increasing the need for a better distributor.

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