RECYCLING OF A PETROLEUM WASTE IN CERAMIC BODIES. G. P. Souza, R.S. Santos and J. N. F. Holanda

Transcription

1 RECYCLING OF A PETROLEUM WASTE IN CERAMIC BODIES G. P. Souza, R.S. Santos and J. N. F. Holanda Universidade Estadual do Norte Fluminense, CCT-LAMAV, Av. Alberto Lamego 2000 Campos dos Goytacazes-RJ CEP , Brazil. holanda@uenf.br Keywords: Petroleum waste, recycling, structural ceramic Abstract. In this work the recycling of a waste from the petroleum extraction industry is studied with the objective of obtaining the specifications of structural clay products. Various bodies were prepared with a kaolinitic clay and waste additions up to 20 wt% (powder). Emphasis is given on the ceramic properties. The results revealed that the waste addition modifies the physical characteristics and the physical-mechanical properties of the waste-free bodies. According to the results the bodies containing waste have potential for application in the structural ceramic field. INTRODUCTION During recent years, special attention has been devoted to waste minimization, pollution prevention and sustainable development as applied to the materials field[1]. Nowadays, the development of environment-friendly fabrication process is imperative An efficient way for the environmental problem minimization of a fabrication process is to promote the waste material recycling. The development of new technologies of recycling that are consistent with the currents needs is of high economic and environmental interest. The petroleum industry produces a great quantity of waste materials in its four principal areas[2,3]: 1) extraction of crude oil from the ground; 2) transportation to refineries and product distribution centers; 3) refining into finished products; and 4) marketing or sale of the products to consumers. These waste are basically constituted by hydrocarbons in the form of oil, water and solids in different proportions according to each area. Thus, the use different waste minimization technologies for final disposal is necessary. Campos-RJ county has the large Brazilian oil basin, which is responsible for more than 77 % of the national oil production with about 1,000,000 barrels per day of crude oil[4]. An oily waste is generated in oil rigs during the liquid/solid impurities separation step. Thus, the final disposal of this waste is a matter of great importance for the county because of the potential problems to the environment. The aim of the present work is to examine the recycling of an oily waste from the Brazilian petroleum extraction industry. Emphasis is given on the waste recycling in ceramic bodies for civil building. This methodology is environmentally correct and can contribute to the sustainable development of Campos-RJ county. The oily waste generated in the petroleum industry can be recycled by the local ceramic industry. In addition, preliminary works reported in the literature[5,6] indicated that likely the use of this waste form does not degrade the environment. MATERIALS AND METHODS

2 The waste material used in this work is generated during the process of oil extraction from the Campos-RJ basin. Raw waste presents a dark colour and has a slurry consistency, whose composition and characteristics are given in Table1[7]. This waste is mixed with an encapsulation substance, organophillic bentonite. The new waste is named as encapsulated petroleum waste. After mixture and drying the encapsulated waste takes the form of a granular powder. The ceramic masses were prepared with kaolinitic clay and waste additions of 0, 5, 10, 15 and 20 wt%. The masses were sieved until the fraction passing in a 60 mesh screen. The granulometric analysis of these masses were determined according to the NBR The Atterberg limits were obtained according to the NBR and NBR X-ray diffraction analysis have shown that the masses consist mainly of kaolinite, quartz, gibbsite and barium sulfate[8]. Table 1 - Composition and characteristics of the oily waste. Hydrocarbons (oil), % 16.7 Water, % 21.9 Solids, % 62.0 Sulfur 1.5 Calorific Power, kca/kg 2,078 Aspect dark viscous liquid Production 50 tons. per month The samples were formed by uniaxial pressing in a rectangular steel die at 24 MPa. The resulting x 2.25 cm rectangular samples were dried at 110 ºC for 24 h and slowly fired at 950 ºC for two hours in a muffle type electrical furnace. Heating and cooling rates have been controlled. Linear shrinkage (NBR MB-305, ABNT), water absorption (C , ASTM), apparent density (C , ASTM), apparent porosity (C , ASTM) and flexure strength (three-point loading, C , ASTM) of the samples were determined. The sampling size used was of five specimens. RESULTS AND DISCUSSION Granulometric analysis of the masses containing petroleum waste is showed in Table 2. In this table the granulometric analysis of the pure clay powder sample is comparatively reported. The granulometric behavior reveals that the clayey masses are constituted of particles in the range (< 2, 600 µm). Clay fraction varies of %, followed by silt % and sand %. As can be noticed from Table 2, the addition of petroleum waste provoked significant modifications on the masses granulometric behavior. The clay fraction content is decreased, while the sand content is increased with waste addition. Moreover, the increase of the sand fraction is mainly due the inclusions of quartz and barium sulfate particles originated of the waste. Table 2 - Granulometric analysis of the prepared clayey masses containing waste. Samples Clay (%) (< 2 µm) Silt (%) (2 φ 60 µm) Sand (%) (60 φ 600 µm)

3 A A A A A Atterberg limits of the studied masses are shown in Table 3. It is observed that the plasticity indexes of the investigated samples decreased with waste addition. According to the waste composition, the non-plastic materials such as quartz and barium sulfate may contribute to this phenomenon. Moreover, these clayey masses containing petroleum waste may be classified as belonging to the group of high plasticity inorganic clays. In addition, the correlation between the granulometric data and plasticity index of the ceramic masses is well established. Table 3 - Atterberg s consistency limits of the prepared clayey masses containing waste. Samples Plastic Limit (%) Liquid Limit (%) Plasticity Index (%) A A A A A The ceramic properties of the obtained bodies after drying are shown in Table 4. The obtained results show low drying shrinkage ( %), as well as values of apparent density in the g/cm 3 range and flexure strength values around MPa. It is observed also modifications of the properties with waste addition, where in general the ceramic bodies are more compact and more resistant. After drying step, the ceramic bodies presented brown colour. Table 4 - Ceramic properties of the obtained bodies after drying at 110 C. properties Dried Ceramic Bodies A0 A5 A10 A15 A20 LS (%) 0.14 ± ± ± ± ± 0.04 σ (MPa) 2.2 ± ± ± ± ± 0.2 ρ (g/cm 3 ) 1.73 ± ± ± ± ± 0.02 LS linear shrinkage; σ flexure strength; ρ apparent specific mass The use of ceramic bodies containing petroleum waste is highly desirable. This probable use is evaluated by the comparison of the ceramic properties of clayey bodies containing waste and Brazilian industrial clays taken in reference[9]. Table 5 shows the results of the ceramic properties of bodies fired at 950 ºC. The values for Brazilian industrial clays are also showed. The reason to choose the firing temperature of 950 ºC to comparison effect, is due this be the usual temperature for fabrication of structural clay products. It

4 is observed that the waste addition influenced the ceramic properties of the fired bodies in all cases. The waste addition reduced the strength of the ceramic bodies, mainly as was added over 10 wt%. This is related the occurred modifications in the physical-chemical-mineralogical characteristics of the waste-free masses. Quartz and barium sulfate particles are likely to induce flaws in the sintered microstructure, acting like stress concentrators. The results show that the values of water absorption (open porosity) and apparent porosity suffered only a small variation with waste addition. Ceramic bodies showed low firing shrinkage. Moreover, the waste addition reduced the linear shrinkage parameter, which is influenced by the presence of non-plastic components as previously discussed. In contrast, the apparent density is increased with waste addition. Table 5 - Results of the ceramic properties of the obtained bodies after drying at 110 C and firing at 950 C compared with the Brazilian clays values. Properties Ceramic Bodies Brazilian A0 A5 A10 A15 A20 Clays σ (MPa), 2.2 ± ± ± ± ± C σ (MPa), 7.3 ± ± ± ± ± C WA (%) 23.7 ± ± ± ± ± AP (%) 39.9 ± ± ± ± ± LS (%) 3.2 ± ± ± ± ± ρ (g/cm 3 ) 1.68 ± ± ± ± ± σ flexure strength; WA water absorption; AP apparent porosity; ρ apparent density As can be noticed also from Table 5, the properties are according with the limit values of the Brazilian clays: flexure strength ( MPa), water absorption ( %) and apparent specific mass ( g/cm 3 ). The apparent porosity values are lightly over of the reference values. However, this problem can be solved. Moreover, the flexure strength values ( MPa) of the ceramic bodies after drying are according to the reference values. The firing colour is an important criterion to the classification of a clay-bearing material. In this work, all ceramic bodies fired at 950 ºC presented red colour (2.5 YR/6 in Munsell Colour Dictionarie), independently of the added waste content. Thus, we can affirm that likely ceramic bodies containing encapsulated petroleum waste have potential for use in structural clay products. The added waste maximal quantity is related to two principal aspects: 1) evaluation of the global environmental impact caused by the use of the waste; and 2) imposed limits by the government regulations and/or very strict environmental laws. As discussed in this work, from the ceramic properties point of view there is no problem for recycling the studied petroleum waste. CONCLUSIONS The purpose of this work has been to evaluate the use of oily waste recycling in ceramic bodies for the structural clay products. The primary findings of this work are:

5 The characteristics of the studied masses are modified in function of the addition of encapsulated petroleum waste. It was observed that the higher added waste content decreases clay fraction content and increases the sand content, as well as decreases the masses plasticity. The drying and firing ceramic properties are influenced by waste addition, due mainly the inclusions of quartz and barium sulfate particles into the masses. The obtained ceramic bodies are very adequate for use in structural clay products. ACKNOWLEDGEMENTS The authors would like to thank the FENORTE-UENF, CAPES and FAPERJ for financial support of this work. REFERENCES 1. J. Szekely and G. Trapaga, J. Mater. Research 10, 9 (1995), p L. M. Curran, J. of Hazardours Materials 29 (1992), p S. P. Amaral and G. H. Domingues, Proc. of the 4th Petroleum Brazilian Congress, Rio de Janeiro-RJ, Brazil (1990), p Ciência Hoje, Suplemento Tecnologia, Vol. 2, 169 (2001), p F. A. N. Silva, Master Thesis, UENF-LAMAV, (2000). 6. R. S. Santos, Master Thesis, UENF-LAMAV, (2001). 7. E. A. Carvalho, E. M. S. Oliveira, R. S. Santos and S. N. Monteiro, Proc. of the 53th ABM Congress, Belo Horizonte-MG, Brazil (1998), p G. P. Souza, Master Thesis, UENF-LAMAV, (2001). 9. P. S. Santos, Ciência e Tecnologia de Argilas, Vol. 1, 2th edition, São Paulo, Brazil, Edgard Blücher (1989), p