BC Insight - Nitrogen+Syngas, Sulphur, Fertilizer International
Login
BCInsight Ltd
China Works
Black Prince Road
London, SE1 7SJ
United Kingdom
Tel: +44 (0)20 7793 2567
Fax: +44 (0)20 7793 2577

Publication > Issue > Articles

A global snapshot

Summary

After many years of inactivity in the world liquid sulphur tanker fleet, new vessels are coming into service. During 1994 and 1995, a total of eight new ships were delivered and a further five are being planned. Lynda Davies reviews the recent developments

Abstract

For many years the world liquid sulphur tanker fleet saw little change and by the late 1980s, a large proportion of the fleet was over 15 years old and a number of ships were 25 or more years old. There seemed to be little incentive to build: the volume of liquid sulphur traded looked set to decline further and newbuilding costs of these highly specialised vessels was prohibitively high.

During the past four years several ships have been scrapped, notably in the Japanese fleet, but the 28year old1 Louisiana Brimstone and the notorious Carlos J have also been sent to the scrapyard. Meanwhile, several ships have entered service: seven have been built by Japanese owners against long-term charters to Japanese traders, and the US Gulf has seen two new deliveries. For the future, Polish shipowner Polsteam Tankers has a vessel on order for the Japanese export trade and is also planning to build two more to replace some of its own fleet. A further two ships are on order for the Japanese export trade for delivery next year.

Add to basket


Environmental excellence at UK SAC plant

Summary

Lambson's new sulphuric acid reconcentration plant in west Yorkshire can accept a range of organic-contaminated "spent" sulphuric acids and provides its customers with an environment-friendly alternative to the increasingly restricted and unpopular practice of neutralizing and dumping. Sulphur went to take a look.

Abstract

In the majority of its industrial uses sulphuric acid does not form any part of the end product, being used simply as a processing aid. There are many sources of spent sulphuric acid, in varying degrees of dilution and contaminated with a variety of inorganic or organic impurities, depending on the purpose for which the acid has been used. The most extreme cases are the waste acid from the production of titanium dioxide from ilmenite, which contains a high concentration of iron and other inorganic salts, and the intractable organic-contaminated sludges from certain acid-catalysed petroleum refining processes, especially the alkylation process used to produce high-octane gasoline blending components. These wastes require drastic processing in dedicated facilities; in the latter case the acid itself is decomposed and reconstituted as "new" sulphuric acid.

Add to basket


Oxygen environment enhances plant performance

Summary

Oxygen enrichment in Claus sulphur plants has gained worldwide acceptance. Retrofitting existing air-based SRUs with oxygen enrichment technology provides an economical route for significant capacity increases. The use of oxygen enrichment for redundancy purposes is also increasing.

Abstract

Over the past ten years, oxygen t chnology has become an established method of overcoming capacity bottlenecks in existing Claus plants and of providing new plants with the necessary flexibility to meet specific operating requirements. The increasing interest in oxygen enrichment technology has been brought about by the drive towards clean air and clean fuels which has resulted in additional hydrodesulphurization and sulphur recovery capacities in refineries and gas plants worldwide. For many operators, the most economical route to incremental sulphur recovery unit (SRU) capacities is to apply oxygen enrichment. The investment cost associated with an oxygen enrichment revamp is typically only 10-15% of a new air-based SRU.

Two trends have emerged in oxygen enhanced SRU operations:

  • Step-wise oxygen enrichment for gradual capacity increases as needed;
  • High-level oxygen enrichment to give air-based SRU trains the ability to handle double their normal capacity for redundancy purposes.

Three levels of oxygen enrichment, representing three incremental steps of equipment modification and investment cost are available: low-level enrichment, medium-level enrichment and high-level oxygen enrichment. (see Fig. 1).

Add to basket


Where does the H2S come from?

Summary

Sulphur recovery plants feed on hydrogen sulphide in both natural gas processing plants and oil refineries. But in an oil refinery it doesn't start out that way. This article sketches out where the sulphur in refinery gas comes from.

Abstract

Sulphur is a very common constituent of b th natural gas and petroleum. Although it is by no means always to be found in either to any significant extent, more often than not it is present in sufficient quantities to be a nuisance. In these environmentally conscious days the nuisance threshold sulphur level in petroleum or refined products is being reduced by the actions of the regulatory authorities. But, although virtually all of the sulphur content of natural gas is abstracted from the gas and is converted into elemental sulphur at very high efficiency, the proportion of the total sulphur content of oil that is recovered as elemental sulphur is still quite low. A recent survey by Concawe (Brussels) estimated that only about 27% of the sulphur passing through European refineries was being recovered: the remainder was distributed between atmospheric emissions (8%), distillates (14%) fuel oils (37%) and other products such as bitumen, feedstocks and lubricants (13.5%).1 In the past few years the proportion recovered has risen to its present level mainly as a result of mandatory improvements in the efficiency of the sulphur recovery procedure itself. It is likely to continue to increase in the next two or three years as new standards for diesel fuels take effect. Current European regulations restrict the sulphur content of gas oils and diesel fuels to 0.2% and, from October next year, the diesel fuel sulphur limit will fall to 0.05%.2 A similar diesel fuel standard is on the slate for some Far Eastern countries from 2000 onwards.

Add to basket