Sulfur

The by-products of natural gas processing are sometimes more marketable than the gas itself. One such by-product that has a strong association with Alberta is elemental sulfur. The challenge of much of Alberta’s natural gas is that it is “sour,” containing toxic hydrogen sulfide (H₂S). Removing the H₂S from the sour gas through processing is an essential step in making the energy resource safe for industrial and domestic use. Once removed from the gas, the H₂S is passed through a condenser-converter series that transforms it into liquid sulfur.

The smell of sour gas and its consequent dangers were ever-present in the early days of Turner Valley until processing technology caught up with the need to remove it. Sulfur extraction technology was further developed during the 1960s after Alberta established guidelines for regulating air quality and emissions. The province’s progressive approach continued with the creation in 1971 of an

environment ministry, the first in Canada, and increasingly stringent regulations for reducing emissions of sulfur compounds.

Sulfur recovery was the subject of scientific experimentation well before the sour gas reserves of Alberta were ever penetrated. Two different removal processes, the Frasch process and the Claus process, were patented during the 1880s. The Frasch process, developed by German immigrant Herman Frasch, revolutionized the industry, and until the late 1950s, Frasch sulfur dominated the world supply of elemental sulfur. The process that became the industry standard, however, was developed by Carl Friedrich Claus, a German chemist working in England. In a modified form, his has become the method used to make sour gas sweet by most processors throughout the world. It is estimated that the Modified Claus Process produces approximately 90% to 95% of recovered sulfur in the world today.

While it was environmental concerns that drove sulfur recovery in Alberta, elemental sulfur is an extremely useful material with a variety of secondary industrial applications; it is employed in the manufacture of almost everything we eat, wear, or use. Sulfur is recovered in liquid form and then pumped outside to solidify in blocks; it is then typically shipped in pellet, slab or liquid form. The largest percentage of reclaimed sulfur is converted into sulfuric acid which is then put to other uses, most often fertilizers. Some of the many industrial products that rely upon sulfur derivatives also include pulp and paper chemicals, batteries, detergents, fungicides, cosmetic and hygiene products,

pharmaceuticals, and water treatments.

It was the development of sulfur recovery technology that made the sour gas fields at Jumping Pound (1944) and Pincher Creek (1948) worth developing. Other large natural gas processing plants in Alberta that now produce elemental sulfur as a byproduct of the H₂S in sour gas are Nevis (1956), Rimbey (1960), Waterton (1962) and Strachan (1970). By the time Alberta’s first sulfur recovery facilities were operational, Canada was importing large amounts of elemental sulfur to meet the rapidly rising demands of industry, but currently Canada is among the world’s largest producers and exporters of elemental sulfur.