Page 190 - Synthetic Fuels Handbook

176 CHAPTER SIX

sulfur fuel oil cutter stock, while the raw naphtha will be hydrotreated to remove nitrogen
and sulfur to below 1 ppm. The hydrotreated naphtha may also provide a feedstock for the
manufacture of clean gasoline with low emissions characteristics.

6.3.2 Brazil

The oil shale resource base is one of the largest in the world and was first exploited in the
late nineteenth century in the State of Bahia.
Brazil started production a long time ago in 1881 and has the second rank after the
United States for resources (well distributed) and after Estonia for production. In 1935,
shale oil was produced at a small plant in Sìo Mateus do Sul in the State of Paran and in
1950, following government support, a plant capable of producing 10,000 bbl/day shale oil
was proposed for Trememb, Sìo Paulo.
Following the formation of Petrobras in 1953, the company developed the Petrosix
process for shale transformation. Concentrating its operations on the reservoir of Sìo
Mateus do Sul, the company brought a pilot plant (8 in internal diameter retort) into
operation in 1982. Its purpose is for oil shale characterization, retorting tests, and devel-
oping data for economic evaluation of new commercial plants. A 6-ft retort (internal
diameter) demonstration plant followed in 1984 and is used for the optimization of the
Petrosix technology.
A 2200 ton/day, 18 ft (internal diameter) semi-works retort (the Irati Profile Plant),
originally brought on line in 1972, began operating on a limited commercial scale in
1981 and a further commercial plant, the 36 ft (internal diameter) Industrial Module
retort was brought into service in December 1991. Together the two commercial plants
process some 7800 t of bituminous shale daily. The retort process (Petrosix), where the
shale undergoes pyrolysis, yields a nominal daily output of 3870 bbl shale oil, 120 t of
fuel gas, 45 t of liquefied shale gas and 75 t of sulfur. Output of shale oil in 1999 was
195.2 thousand metric tons.
Brazil developed the world’s largest surface oil shale pyrolysis reactor being the Petrosix
11-m vertical shaft gas combustion retort (GCR). However, it seems that the Brazilian suc-
cess in oil and in biomass to liquids has put oil shale in the shade, as no new plan is found
on the web. The production of shale oil dropped from 3900 bbl/day in 1999 to 3100 bbl/day
in 2002. Late figures are not known with any degree of certainty.

6.3.3 Canada
Oil shale occurs throughout the country, with the best known and most explored deposits
being those in the provinces of Nova Scotia and New Brunswick. Of the areas in Nova
Scotia known to contain oil shale, development has been attempted at two—Stellarton and
Antigonish. Mining took place at Stellarton from 1852 to 1859 and 1929 to 1930 and at
Antigonish around 1865. The Stellarton Basin is estimated to hold some 825 million metric
tons of oil shale, with an in situ oil content of 168 million barrels. The Antigonish Basin has
the second largest oil shale resource in Nova Scotia, with an estimated 738 million metric
tons of shale and 76 million barrels of oil in situ.
Investigations into retorting and direct combustion of Albert Mines shale (New
Brunswick) have been conducted, including some experimental processing in 1988 at the
Petrobras plant in Brazil. Interest has been shown in the New Brunswick deposits for the
potential they might offer to reduce sulfur emissions by cocombustion of carbonate-rich
shale residue with high-sulfur coal in power stations.