Integração dos processos de flotação e foto-fenton para redução de óleos e graxas de água produzida em campos de petróleo

During production of oil and gas, there is also the production of an aqueous effluent called produced water. This byproduct has in its composition salts, organic compounds, gases and heavy metals. This research aimed to evaluate the integration of processes Induced Air Flotation (IAF) and photo-Fenton for reducing the Total Oils and Greases (TOG) present in produced water. Experiments were performed with synthetic wastewater prepared from the dispersion of crude oil in saline solution. The system was stirred for 25 min at 33,000 rpm and then allowed to stand for 50 min to allow free oil separation. The initial oil concentration in synthetic wastewater was 300 ppm and 35 ppm for the flotation and the photo-Fenton steps, respectively. These values of initial oil concentration were established based on average values of primary processing units in Potiguar Basin. The processes were studied individually and then the integration was performed considering the best experimental conditions found in each individual step. The separation by flotation showed high removal rate of oil with first-order kinetic behavior. The flotation kinetics was dependent on both the concentration and the hydrophilic-lipophilic balance (HLB) of the surfactant. The best result was obtained for the concentration of 4.06.10-3 mM (k = 0.7719 min-1) of surfactant EO 2, which represents 86% of reduction in TOG after 4 min. For series of surfactants evaluated, the separation efficiency was found to be improved by the use of surfactants with low HLB. Regarding the TOG reduction step by photo-Fenton, the largest oil removal reached was 84% after 45 min of reaction, using 0.44 mM and 10 mM of ferrous ions and hydrogen peroxide, respectively. The best experimental conditions encountered in the integrated process was 10 min of flotation followed by 45 min of photo-Fenton with overall TOG reduction of 99%, which represents 5 ppm of TOG in the treated effluent. The integration of processes flotation and photo-Fenton proved to be highly effective in reducing TOG of produced water in oilfields

Propriedades críticas do modelo z(4) em sistemas bi e tridimensionais

A real space renormalization group method is used to investigate the criticality (phase diagrams, critical expoentes and universality classes) of Z(4) model in two and three dimensions. The values of the interaction parameters are chosen in such a way as to cover the complete phase diagrams of the model, which presents the following phases: (i) Paramagnetic (P); (ii) Ferromagnetic (F); (iii) Antiferromagnetic (AF); (iv) Intermediate Ferromagnetic (IF) and Intermediate Antiferromagnetic (IAF). In the hierarquical lattices, generated by renormalization the phase diagrams are exact. It is also possible to obtain approximated results for square and simple cubic lattices. In the bidimensional case a self-dual lattice is used and the resulting phase diagram reproduces all the exact results known for the square lattice. The Migdal-Kadanoff transformation is applied to the three dimensional case and the additional phases previously suggested by Ditzian et al, are not found

Água residuária da mandioca como fertilizante orgânico em pasto de Brachiaria brizantha cv. Marandu

Brazil is the world's second largest producer of cassava, which most of the production is used to make flour and starch, generating large amounts of waste, cassava. In general, this waste is disposed of directly into the soil and waterways, causing serious environmental impacts. In view of this, the aim of this work was to evaluate the use of cassava wastewater water (cassava) as organic fertilizer in Brachiaria brizantha pasture. Marandu. The experiment was conducted at the Campus Macaíba the Federal University of Rio Grande do Norte. The treatments were increasing rates of cassava, applied to the soil as organic fertilizer. The experimental design was a randomized block design with six treatments and four replications. The treatments consist of cassava doses (0, 15, 30, 60 and 120 m³ ha- 1 ) and a treatment with mineral fertilizer (AM) in the form of NPK (140: 30: 120 kg ha-1 ). Three cuts with an interval of 60 days were carried out. The variables evaluated were: plant height; accumulation of morphological components of fodder; Trapping Light (IL); Leaf Area Index (LAI); Total chlorophyll (CT); Feature Production Seca (PMS). The dry matter production at a dose of 120 m³ha-1 had a quantitative increase, with a total production in 2796 kg ha-1 DM in the second cut, providing an increase of 493% compared to control, and the residual effect observed in the third cut caused a 100% increase compared to 0 m³ ha-1 . Comparing the PMS obtained with the use of AM and other treatments it was observed that it was the second cut equivalent to a dose of 120 m³ ha-1 and the third equivalence has been cut at doses 60 and 120 m³ha-1. For the variables plant height, IL, IAF, CT and leaves Mass adding cassava in the soil promoted a positive linear increase for the three cuts. However, with the AM the IAF was superior to the other treatments. The thatched mass reached its highest production (838 kg ha-1 DM) in the second cut when using a dose of 120 m³ha-1 . In dead material mass in the second and third sections, there was increased linearly increased total of 322 and 452% respectively, compared to a dose of 0 m³ha-1 . The use of cassava showed herbicidal effect for the variable mass of the undesirable negative linear response resulting in decreasing the amount of residue with increasing doses. Manipueira can be used as organic fertilizer in Brachiaria brizantha cv. Marandu for improvements in the productive characteristics, as promoted significant increases in 8 most of the variables studied, especially at a dose of 120 m³ha-1 . This benefits the environment by being alternative for disposal of cassava.