Brazzil

{mosimage}Peat is usually known as the fuel used for whisky distillation in Scotland, but it has much more usefulness. Large peat deposits occur in the cold countries of Northern Europe, but there are also deposits in warm countries like Brazil.

Peat is the accumulation of partially decomposed plant material, originated in low oxygen aqueous environment, usually in large marshy bogs.

Plant material accumulated at the bottom of these bogs gradually transforms into peat under appropriate conditions. If inorganic sedimentary deposits cover peat subsequently, the pressure from these overlying materials causes the expulsion of water and organic gases.

The percentage of carbon then increases and begins the transformation from peat to coal, in a very slow process. As peat contains around 60% carbon and 30% oxygen, is used as a low-grade fuel in some countries.

Other uses include oil and heavy metals absorption, agriculture, land reclaiming, gardening and medical applications.

In Brazil, some industries used peat as fuel in the 1930's. During the World War II, the locomotives of the railroad between São Paulo and Rio de Janeiro burned peat in their furnaces. After the conflict, the coal supply was re-established and the peat use stopped for 40 years in Brazil.

During the oil crisis in the 1970's, peat studies considered its energetic use. Now, peat is used in Brazil mainly for agricultural purposes, land reclaiming and energy generation. Some researchers are also starting to study its medical uses.

Peat in Brazil - The History

In 1891, peat like material found in Maraú, state of Bahia, led British entrepreneurs to produce candles and kerosene during a short time from that substance known as "marauito".

According to Fróes de Abreu (1973), that material was not a true peat, but a sapropelite, formed from alga deposition.

In 1930, the grass burning in a farm in Resende, state of Rio de Janeiro, ignited a dark material removed from drainage channels. It was peat.

Then, the locomotives of a sugar plant of Porto Real successfully used peat as fuel and wood was soon replaced by peat in all the plant.

A textile industry in Taubaté, state of São Paulo, also used peat in the 1930's. Although considered interesting by some researchers, the alternate fuel did not attract so much attention before the World War II.

In the period 1942-1945, there was a serious lack of imported coal due to the war and about 20,000 tons of peat were used in the locomotives of the EFCB - Estrada de Ferro Central do Brasil, linking the towns of São Paulo and Rio de Janeiro.

The fuel peat was extracted in some deposits along the Paraíba do Sul River, between the towns of Jacareí and Taubaté. The heat value of the peat varied from 3,200 to more than 5,000 Kcal/kg and about 76% of the total was between 3,500 and 4,500 Kcal/kg.

The peak of the consumption was in 1943, with 10,000 tons. After the war, the use of peat was abandoned and the only recorded studies in the period 1945-1975 are those of Knecht (1955/58) and Knecht (1982). He studied some peat deposits between 1955 and 1974 and wrote about their potential and economic applications.

Alternate Fuel Rush

In the oil crisis of the 1970's, many alternate fuel researches took place in Brazil due to the problem with foreign oil supply.

One of these initiatives was the peat project of the CESP - Companhia Energética de São Paulo, a state owned energetic company at that time.

In 1978, the Instituto de Pesquisas Tecnológicas do Estado de São Paulo S.A. - IPT, a state research institution, undertook the execution of the project. The target was the valley of the Paraíba do Sul River, in the Eastern region of the state, where peat was formerly extracted.

The most representative samples from 13 mapped peat deposits were submitted to physical and chemical analyses and a first pyrolysis test. Preliminary data of peat resources indicated about 40 million tons of dried peat in the region (Shimada & Carvalho 1980).

Peat deposits are mainly associated to flood plains in Brazil with some differences if compared, for example, to the deposits of northern Europe, mainly associated to large lakes of glacial origin.

Brazilian peat deposits are usually smaller in area and thicker, with a higher ash content due to the more pronounced mineral contribution during the sedimentation.

In 1979, the CPRM - Companhia de Pesquisa de Recursos Minerais, a federal mineral exploration company, started to explore for peat in several regions in the country.

A preliminary CPRM's geological evaluation indicated a potential of 25 billion tons of in situ peat in Brazil. This fact justified further works in more detailed scales.

The Irish peat authority Bord na Móna has also carried out preliminary surveys in Brazil in the early 1980's, but no production has been developed.

The CESP's peat project was the restart of the peat studies and the government of São Paulo decided to prospect for new peat deposits in all the state, being the task trusted again to IPT's geologists in 1980.

In this work, Shimada et al. (1981) identified new peat deposits in the valleys of the Mogi Guaçu, Jacaré-Pepira, Ribeira de Iguape and Itapetininga rivers. They also found peat in a meteoritic crater close to the town of São Paulo.

These studies have shown a potential of 488 million tons of in situ peat in the state, that represents about 146 million of oil barrels (Motta et al. 1982).

The IPT's staff had the help of a Finnish specialist from the Geological Survey of Finland, Eino Lappalainen, Ph.D., who brought his knowledge of many years in peat studies.

The Brazilian researchers then learnt more about the wide range of peat uses and also about the appropriate techniques and equipment for its exploration.

A selected peat deposit - Eugênio de Melo, in São José dos Campos - was detailedly evaluated and bulk sampled for IPT's further researches in energetic use, including combustion and gasification tests.

In the 32th Brazilian Geological Congress, in 1982, many papers presented the results of peat studies in São Paulo and in the Northeast of Brazil.

In 1985, the CESP started the peat harvesting in the Eugênio de Melo deposit for energetic purposes. However, despite the interest of industry and many researchers, the attenuation of the oil crisis in the following years caused the gradual vanishing of the research fundings and the peat almost fell in forgetfulness for some years.

The control of peat harvesting in Eugênio de Melo has then changed to Eucatex, a private company, and its use to agricultural purposes.

Modern Peat Studies in Brazil

In the early 1990's, peat studies restarted in Brazil and changed their focus to aspects other than the energetic use. Garcia (1994, 2004) made palynological studies of the peat deposits in the Paraíba do Sul valley, relating them to the climatic changes in the Holocene.

The same author also wrote in Garcia (1996) a synthesis of the available knowledge about the potential and application of peat. Franchi (2000) and Franchi et al. (2003) presented the results of studies about peat use in reclaiming of land degraded by sand mining.

Moraes (2001) presented the geological knowledge about peat deposits in the states of Alagoas, Paraíba e Rio Grande do Norte, as a result of the CPRM's studies. Oliveira (2001) wrote about detailed CPRM's studies of peat deposits in São José dos Campos.

Updated information about geology, reserves, production and uses of peat in Brazil were presented by Franchi et al. (2004) in the 12th International Peat Congress in Finland.

According to these authors, there are two main peat production units with an annual output of 145,000 tons and 80% is intended for agricultural purposes.

The remaining 20% are divided into replanting of land areas and energy generation. The measured reserves are of 208.83 million m³ of in situ peat and the indicated and the inferred ones give an additional of 881.69 million m³.

Presently, there are multinational companies selling peat for oil and heavy metal absorption in Brazil, but the most of this peat is still imported from Canada as it must be pre-treated by specific technologies and also because there is a lack of pure peat similar to the ones from the Northern Hemisphere deposits, which are well suited for such applications. But there is still a lack of researches in this field with the local peat.

In the present year, the Finnish peat researcher Harry Uosukainen, Ph.D., ministered in São Paulo a short course about medical uses of peat for a group of local researchers.

This type of use is well known and has a secular development in European countries like Finland and Germany and now begins to attract the attention of researchers in Brazil.

Conclusions

Considering the geological timescale, peat is a material formed only in a very recent "blink" in the earth's history and has long been treated with disregard by the most of the "hard rock" geoscientists and even its significant energetic use is limited to few countries with availability of large and pure deposits, with very low ash contents.

The increasing environmental worries have changed the scene and peat is now currently used for management of accidental oil spills and for restoration in areas contaminated by organic and inorganic toxins. Brazilian peat was not yet tested for this use and researches are demanded in this domain.

In agriculture, peat appears as an important mean of organic matter restitution of soils. The medical uses of peat are important in some countries and researches on this theme begins in Brazil, but it is important to remark that the local peat probably has different chemical and physical properties if compared to those used in Europe and much more researches are needed to make safe and possible similar uses.

Concerning the peat reserves in Brazil, many deposits were accidentally found during exploration for other materials like sand, gravel and clay and there is still a lack of specific exploration projects for peat.

These works could substantially increase the country's reserves. It's time to do the work and this task belongs to the "soft rock" geoscientists.

For More Information:

Franchi, J. G. Aplicação de turfa na recuperação de solos degradados pela mineração de areia. Dissertação de Mestrado, Escola Politécnica, Depto. de Engenharia de Minas, Universidade de São Paulo, 2000, 105 p.

Franchi, J. G.; Sigilo, J. B.; Lima, J. R. B. de. Turfa utilizada na recuperação de áreas mineradas: metodologia para avaliação laboratorial. Revista Brasileira de Geociências, 2003, São Paulo, 33(3): 255-262.

Franchi, J.G., Motta, J. F. M., Uosukainen, H., Sígolo, J. B. Peat in Brazil: geology, reserves, production and use. In: International Peat Congress, 12., 2004, Tampere. Proceedings... Saarijärvi, IPS, 2004. p. 627-632.

Fróes de Abreu, S. de. Combustíveis Fósseis. Recursos Minerais do Brasil, 2nd Ed., 1973, São Paulo, Edgard Blücher, 2:321-337.

Garcia, M. J. Palinologia de turfeiras do médio vale do Paraíba do Sul, Estado de São Paulo. Tese de Doutoramento, Instituto de Geociências - Universidade de São Paulo, 1994, 3 v.

Garcia, M. J. Potencialidade e aplicação de turfas. Revista da Universidade de Guarulhos, 1996, São Paulo, ano 1, 1:16-30.

Garcia, M. J.; de Oliveira, P. E.; Siqueira, E.; Fernandes, R. S. A Holocene vegetational and climatic record from the Atlantic Rainforest Belt of coastal state of São Paulo, SE Brazil. Review of Paleobotany and Palynology, 2004, v. 131: 181-199.

Knecht, T. Notícia sobre turfa no Estado de São Paulo e sua aplicação econômica. O IGG - Revista do Instituto Geográfico e Geológico, 1955/58, São Paulo, 13:61-64.

Knecht, T. Estudo preliminar sobre as ocorrências de turfa no vale do Ribeira de Iguape, SP. Revista do Instituto Geológico, 1982, São Paulo, 3(1):5-14.

Moraes, J. F. S. de. Turfa nos Estados de Alagoas, Paraíba e Rio Grande do Norte. Recife: CPRM, 2001 (Informe de Recursos Minerais, Série Oportunidades Minerais - Exame Atualizado de Projeto, 14).

Motta, J. F. M.; Nakano, S.; Shimada, H.; Nucci, O.; Milko, P. E.; Coelho, J.C. Turfa: a experiência do IPT nos campos geológico e tecnológico. In: Congresso Brasileiro de Geologia, 32, Salvador, Anais..., SBG, 1982, 5:2238-2251.

Oliveira, C. A. de. Turfa de São José dos Campos: Estado de São Paulo. São Paulo: CPRM, 2001 (Informe de Recursos Minerais, Série Oportunidades Minerais - Exame Atualizado de Projeto, 24).

Shimada, H. & Carvalho, W. S. de. Perspectivas de utilização da turfa para fins energéticos no Estado de São Paulo. In: Seminário: Contribuição da geologia na busca e aproveitamento de fontes energéticas convencionais ou não, São Paulo, Boletim 1 - Comunicações, SBG, 1980, p.33-64.

Shimada, H.; Motta, J. F. M.; Cabral Jr., M.; Nakano, S. Prospecção de turfa no Estado de São Paulo. In: Simpósio Regional de Geologia, 3, Curitiba, Atas..., SBG, 1981, 3:259-273.

Hélio Shimada, Ph.D., is geologist and researcher at the Instituto Geológico, in São Paulo. You can e-mail him at: hshimada@igeologico.sp.gov.br

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