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Mosaic's bigger picture

Summary

The cost of raw materials, sulphur included, has taken much of the blame for the downturn in fortunes of the phosphate fertilizer business in the US. Is the closure of two plants by the industry's biggest producer a backlash that will disturb the balance of the sulphur market?

Abstract

When news arrives that around 4.5 million t/y of sulphuric acid-producing capacity is about to shut down, first thoughts are likely to be that the bottom of the sulphur market is taking on a distinctly thin appearance. That’s 1.5 million tonnes out of the demand side, isn’t it? And when the context is North America where there is little prospect of refineries letting up on their output of sulphur, the future for the balance of the market seems unpromising.

But is this so? First reactions to the impending shut-down, by the sulphur industry’s single biggest customer, of two phosphate fertilizer plants, each producing sulphuric acid to digest rock into phosphoric acid, may have taken this line of argument. However, lost capacity and lost demand are far from identical commodities. In the case of Mosaic’s doomed plants in Florida, they are some way from being the same thing.

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A collision of interests

Summary

Initially suspended because it was proving to be too expensive, the Goro laterite nickel ore processing project in New Caledonia encountered another shutdown when local rights activists attacked its construction site.

Abstract

Foreign mine owners rarely make the most popular of neighbours when they operate among developing economies. New wealth for export and lasting disruption to the landscape are always likely to be sources of opposition if local mining and processing skills can make only a limited contribution. When the argument extends to the possibility of some threat to indigenous culture and the environment, then the level of objection may reach ignition point. Canada’s Inco was confronting the full force of such problems as the second quarter of 2006 unfolded.

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Hazards of sulphur storage, forming and handling - part two

Summary

The concluding part of an article by Johnny E. Johnson of Washington Group International and Peter D. Clark of ASRL reflecting a design engineer's application of the results of the most recent pertinent research, actual project design, results of HAZOP reviews, and start-up and operating experience gained from several types of SRU, degassing, forming, storing, transfer and loading facilities.

Abstract

In Part One of this article (Sulphur No. 303, pp. 41-53) the focus was on the hazards of storing, forming and handling molten sulphur. In part two the discussion moves on to solid sulphur forming and handling systems.

A process flow diagram for a typical sulphur recovery, forming and handling system reflecting a composite industry-wide perspective was presented in Fig. 1 (Part One). Most modern facilities that form sulphur into solid product for marketing have recognised the safety and product quality benefits associated with degassing of the molten sulphur from the SRU. Therefore, included in the represented system is a material balance based on further processing of sulphur degassed to <10 ppmw total H2S plus H2SX. A nominal 100 long t/d production of sulphur has been assumed.

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Sulphation of alumina catalysts

Summary

In laboratory testing a new alumina Claus catalyst from Russia has shown greater resistance to sulphation whilst maintaining a catalyst activity similar to current industrial aluminas. Lisa Connock reports on recent investigations of alumina catalysts and their resistance to sulphation.

Abstract

It is generally acknowledged that conventional activated alumina Claus catalysts have a high activity for converting H2S and SO2 to sulphur under most normal conditions. However, alumina has two serious drawbacks:

  • A limited ability to convert COS and CS2
  • The overall activity of alumina deteriorates under severe sulphating conditions, even for the basic H2S/SO2 reaction.

These problems are overcome by employing more costly titania catalysts, which enable high conversions of all sulphur species to elemental sulphur, even under the sulphation conditions that deactivate alumina. Using titania also allows the conversion of COS and CS2 to proceed at low temperature; this is essential if benzene, toluene or xylenes (BTX) are introduced in the feed.

Titania-alumina hybrids that demonstrate a much higher capacity for conversion of COS and CS2 than activated alumina alone are also available on the market.

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Combustion solutions for SRUs

Summary

Pillard combustion technology is constantly developing to meet the most stringent operator requirements for optimal sulphur recovery, reliability and flexibility. The tangential double impulse burner technology achieves high performances even when treating very lean acid gases. Louis Ricci and Robert Klein of Pillard and Jean Nougayrède, of NGD Consult report on the evolution of Pillard combustion systems.

Abstract

Pillard has been developing combustion solutions since 1920. The first acid gas burners for sulphur recovery units were installed in the sixties. Since then the supply of hundreds of burners, under the trademark of Pillard or Foyers-Turbine (bought by Pillard in 1983), for reaction furnaces, auxiliary burners and tail gas incinerators, have proven their capability to meet operator requirements for efficiency, reliability and durability.

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