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Auto/Oil Programme deals some cruel blows


The overall European Union reduction in the sulphur content of fuels encompassed in the air ­ quality targets and acidification ozone strategies could eventually result in 550,000 tonnes of sulphur being recovered by the year 2010. In particular, the new sulphur specifications for gasoline and diesel decided upon in Auto/Oil 1 (AOP1) will contribute 70,000 tonnes to this total amount. Jason Stevens examines AOP1 and its implications for the European refining industry.


The Auto/Oil Programme grew embryonically out of a European Commission proposal in the early 1990s to improve air quality by developing a strategy that jointly limited vehicle emissions and the sulphur content in fuels (See Fig 1). The oil and automobile industries agreed to participate as long as the process progressed along rational, scientific and cost-effective lines.

Three years of studies followed, built on careful and methodical research by bodies such as Concawe (The Oil industries’ European Organi­zation for Environmental, Health and Safety), The European Petroleum Industry Association (Europia), and The European Car Industry Associa­tion (ACEA).

Deficiencies between air quality targets and predicted air quality in the year 2010 were the drivers to decide on the necessary, cost-effective combination of measures to improve vehicle emissions, along with the required fuel quality changes.

The Commission presented its findings in June 1996. The Commis­sion proposal included a reduction in sulphur content after 1 January 2000 to 200 ppm and 350 ppm for gasoline and diesel respectively.

The automobile industry reacted with immediate fury to the decision and lobbied for tighter fuel specifications so that they would have to shoulder less of the costs.

Car manufacturers argued that sulphur was especially poisonous to their new generation of catalysts and should be removed by the refiners, while the oil companies countered that a new generation of sulphur-­tolerant technology was being researched and developed for use in cars.

However, the volatile exchanges between the two groups did not stop the directives being submitted to the European Parliament and Council of Ministers in early 1997.

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BTEX regulation in the USA


In the USA all hazardous air pollutants, such as benzene, toluene, ethylbenzene and xylene (BTEX) emissions from oil and gas production facilities, are subject to strict ­environmental regulations. Lisa Connock reports on new and emerging technologies for the control and measurement of BTEX from acid gas removal units.


The control of benzene, toluene, ethylbenzene and xylene (BTEX) emissions from amine acid gas removal units, glycol dehydration units and other gas processing facilities has become an important environmental and economic issue in the USA. Glycol units have been under close examination with regard to BTEX emissions for some time but now amine sweetening units are receiving the same environmental scrutiny.

Under the 1990 Clean Air Act Amendments, aromatic compounds such as benzene, toluene, ethylbenzene and xylene, amongst others, were designated as hazardous air pollutants (HAPs). The Act limits the total emissions of all 189 listed HAPs to 25 tons per year with a maximum of 10 tons per year for any individual component.

Higher emissions are permitted, but the emitting plant is defined as a major source of HAPs. All major sources of HAPs are subject to regulations according to national emission standards for hazardous air pollutants (NESHAP).

In February 1998, the Environ­mental Protection Agency (EPA) proposed the NESHAP for oil and gas production facilities as well as for natural gas transmission and storage facilities. These emission standards reflect the maximum degree of emission reduction for major sources of hazardous air pollutants by applying the Maximum Achievable Control Technology (MACT). The proposed NESHAP for major sources limits emissions from oil and natural gas production facilities by requiring the owner, or operator, to apply air emission control equipment and pollution prevention measures. Besides BTEX, other HAPs relevant in natural gas production are n-hexane, carbonyl sulphide and carbon disulphide.The reduction of hazardous air pollutants from equipment leaks also have to be reduced by establishing a leak detection and repair programme.

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Delivering safety


The safe transportation of sulphuric acid, spent acid and oleum continues to be a key concern for the international sulphuric acid industries. While industry players have broadly embraced the Responsible CareŽ * initiative, a foundation of any sound safety strategy, there is the ever-present danger of becoming complacent. Jason Stevens highlights some of the key challenges and innovations attached to this important industry.


The harmful effects of sulphuric acid, oleums, sulphur trioxide and spent acid on human beings are well-known. On direct contact with the skin sulphuric acid eats away at tissues, may produce burns and be ­accompanied by shock and collapse. Contact with the eyes may result in severe damage or even loss of eyesight. Sulphuric acid vapours cause a host of respiratory problems and also effect eyes and teeth. These effects are primarily the result of its dehydrating and corrosive properties.

Consequently, international regulations exist for the safe handling and conduct of acid between the producer and the customer.

Although legislation differs slightly from country to country, the United Nations Complete Hazard Classifica­tion governing the transportation of hazardous goods usually features strongly in individual nation’s regulations (please see box on page 25 for expanded account of the UN Com­plete Hazard Classific­ation which designates various characteristics of sulphuric acid, oleums and sulphur ­trioxide and the necessary actions to take in the case of exposure).

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SUPERŽ process ­doubles Claus capacity


A new process to expand the capacity of sulphur recovery units with minimal capital investment is now being offered by Calabrian Corporation. In the SUPERŽ process pure SO2 or oxygen enhanced SO2 is injected into the H2S burner instead of air, eliminating nitrogen from the Claus system. The technology can be used as retrofit to an existing sulphur recovery unit to double sulphur plant capacity.


Since the COPE1 process was first installed at the Conoco, Lake Charles Refinery, in 1985, there has been considerable interest in the expansion of existing sulphur recovery units by using oxygen instead of air.

Sulphur plant expansions using oxygen can have very favourable economics. Moreover, oxygen-based Claus sulphur recovery plants are environmentally superior because most tail gas treating processes are more efficient with oxygen enhanced units.

Today, there are a number of Claus sulphur recovery plants using modest oxygen enrichment of air to increase capacity. While enriched air can be used with relatively minor modifications, rich acid gas feed typically found in refinery applications requires a method to limit the temperature in the reaction furnace for oxygen concentrations greater than approximately 30%.

The COPE process (Fig. 1) does this by recycling gas exiting the first sulphur condenser.2 The increased flow in the reaction furnace and increased duty in the waste heat boiler normally requires substantial modification and plant down time for tie-ins. Also at a temperature of 300°F (149°C) and equilibrium favouring sulphur formation, this is a difficult service for the recycle compressor.

Other quench schemes proposed include the introduction of water/steam,3 liquid sulphur, or sulphur dioxide (Fig. 2). Another approach is to limit combustion and add an extra stage of combustion with interstage cooling.4 Each has its merits, but all have their drawbacks too.

From a technical viewpoint, sulphur dioxide (SO2) is the most desirable. The use of sulphur dioxide as a quench is documented in the literature.5 However, the introduction of pure sulphur dioxide into a Claus plant has always been difficult from an economic standpoint – until now.

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