Made available in DSpace on 2014-12-17T15:01:27Z (GMT). No. of bitstreams: 1 BrunoCB_DISSERT.pdf: 4196751 bytes, checksum: 815046ef78a951368bb3e92819e92b89 (MD5) Previous issue date: 2012-05-04 / The pegmatite rocks in Rio Grande do Norte are responsible for much of the production of industrial minerals like quartz and feldspar. Quartz and feldspar are minerals from pegmatite which may occur in pockets with metric to centimetric dimensions or as millimetric to sub millimetric intergrowths. The correct physical liberation of the mineral of interest, in case of intergrowths, requires an appropriate particle size, acquired by size reduction operations. The method for treating mineral which has a high efficiency fines particles recovery is flotation. The main purpose of the present study is to evaluate the recovery of quartz and potassium feldspar using cationic diamine and quaternary ammonium salt as collectors by means of dissolved air flotation DAF. The tests were performed based on a central composite design 24, by which the influence of process variables was statistically verified: concentration of the quaternary ammonium salt and diamine collectors, pH and conditioning time. The efficiency of flotation was calculated from the removal of turbidity of the solution. Results of maximum flotation efficiency (60%) were found in the level curves, plotted in conditions of low concentrations of collectors (1,0 x 10-5 mol.L-1). These high flotation efficiencies were obtained when operating at pH 4 to 8 with conditioning time ranging from 3 to 5 minutes. Thus, the results showed that the process variables have played important roles in the dissolved air flotation process concerning the flotability of the minerals. / No Rio Grande do Norte os pegmatitos respondem por grande parte da produ??o dos minerais industriais quartzo e feldspato. O quartzo e feldspato dos pegmatitos podem ocorrer em bols?es com dimens?es centim?tricas a m?tricas ou na forma de intercrescimentos milim?tricos a submilim?tricos. No caso dos intercrescimentos, a libera??o f?sica correta do mineral de interesse envolve a adequa??o granulom?trica atrav?s de opera??es de redu??o de tamanho. O m?todo no tratamento mineral que apresenta alta efici?ncia na recupera??o de finos ? a flota??o. O presente trabalho tem como objetivo principal avaliar a recupera??o de quartzo e feldspato pot?ssico utilizando os coletores cati?nicos diamina e sal quatern?rio de am?nio no processo de flota??o por ar dissolvido FAD. Os testes foram realizados baseados em um planejamento central composto 24, atrav?s do qual verificou-se estatisticamente a influ?ncia das vari?veis de processo: concentra??o dos coletores sal quatern?rio de am?nio e diamina, pH e tempo de condicionamento. A efici?ncia de flota??o foi calculada a partir do grau de remo??o de turbidez da solu??o. Resultados de m?xima efici?ncia de flota??o (60%) foram encontrados nas curvas de n?vel, plotadas nas condi??es de baixas concentra??es dos coletores (1,0x10-5 mol.L-1). Estas altas efici?ncias de flota??o foram obtidas operando-se na faixa de pH 4 8 com tempo de condicionamento variando de 3 a 5 minutos. Sendo assim, os resultados obtidos mostraram que as vari?veis de processo desempenharam pap?is importantes no processo de flota??o por ar dissolvido em rela??o ? flotabilidade dos minerais.

Produced water is the largest waste product by volume in the oil industry and its treatment in onshore or offshore fields poses bigger and different challenges than what water engineers are used to encounter. Process to achieve reuse quality of this water is very expensive with many technical hurdles to overcome making the optimization of the treatment steps necessary. Electrocoagulation (EC) generates coagulants in-situ responsible for destabilizing oil droplets, suspended particles, and common pollutant in produced water. Furthermore, EC is a very efficient technology compared with traditional primary treatments used in the oil & gas industry and has several advantages such as: no hazardous chemical handling (which diminishes the risk of accident and logistic costs), high efficiency potential concerning boron removal, potential small footprint and less sludge generation. In this research, the treatment of produced water using EC was investigated in a practical manner for the oilfield to aim for a cleaner effluent for further processing and help to achieve a reuse quality. For this, an EC cell was designed using different parameters normally used in the literature to fit this scenario. After preliminary tests, the treatment time was set to 3 seconds. Response surface method (RSM) was employed to optimize the operating conditions for TOC removal on a broad quality of synthetic produced water while varying: salinity, initial oil concentration and initial pH. TOC was chosen to be the main response because of its importance in legislation and sensibility on the method. Furthermore, turbidity removal, change of pH value after EC in water with lack of buffer capacity, aluminum concentration and preliminary tests involving boron removal and influence of hydrogen carbonate were also studied. Real produced water was treated with EC to assess the optimum conditions obtained by the RSM showing the results were closely related. Finally, an estimation of volume required and operating cost for EC in the different types of produced water was made to assess how realistic it is for onshore and offshore applications.:ERKLÄRUNG DES PROMOVENDEN I ACKNOLEDGEMENT III ABSTRACT V TABLE OF CONTENT VII LIST OF FIGURES IX LIST OF TABLES X LIST OF EQUATIONS XII ABBREVIATIONS XIV 1. INTRODUCTION 1 2. PRODUCED WATER 6 2.1 Characterization of Oilfield Produced Water 6 2.2 Produced Water Management 10 2.2.1 Discharge and Regulations 10 2.2.2 Efforts on Reuse 11 2.2.3 Cost 14 3. PRODUCED WATER TREATMENT 17 3.1 Most Common Primary Treatment 17 3.1.1 Hydrocyclones 17 3.1.2 Flotation unit 18 3.2 Further Water Treatment Technologies 19 3.2.1 Membrane Process 19 3.2.1.1 Microfiltration 19 3.2.1.2 Ultrafiltration 21 3.2.1.3 Nanofiltration 23 3.2.1.4 Reverse Osmosis 24 3.2.1.5 Forward osmosis 24 3.2.2 Electrodialysis 25 3.2.3 Biological treatment 28 3.2.3.1 Aerobic and anaerobic process 28 3.2.3.2 Combining membrane and bio-reactor 29 3.2.4 Oxidative process 30 3.2.4.1 Oxidation process 30 3.2.4.2 Anodic oxidation 32 3.2.5 Thermal technology 34 3.2.5.1 Evaporation 34 3.2.5.2 Eutectic freeze crystallization 35 3.2.6 Adsorption and ion-exchange 36 3.3 Electrocoagulation 39 3.3.1 Colloidal Stability Theory 39 3.3.2 Theory of Electrocoagulation 40 3.3.3 Mechanism of Abatement of Impurities 44 3.3.4 Operational parameters and efficiency 49 4. MATERIALS AND METHODS 51 4.1 Analytical Techniques and Synthetic Solutions 51 4.1.1 Analytical Techniques 51 4.1.2 Synthetic Produced Water 51 4.2 Design of Experiment and Models 54 4.3 Experimental Protocol for EC 56 4 .4 Development of the new Electrocoagulation cell 57 4.5 Real Produced water 58 5. RESULTS AND DISCUSSION 59 5.1 Designing EC Cell Process 59 5.1.1 Computational Fluid Dynamics for EC manufacturing 59 5.2 Preliminary Experiments 61 5.2.1 TOC Removal and Residence Time Determination 61 5.2.2 Aluminum Concentration 64 5.3 Models Quality and Range of Validity 66 5.3.1 TOC Removal 66 5.3.2 Turbidity Removal 69 5.3.3 Final pH value 71 5.3.4 Ionic Strength and Interpolation for Different Salinities 73 5.3.5 Partial Conclusions 76 5.4 Evolution of the Final pH Value 78 5.5 Operation Region for Effective Treatment of Produced Water with EC 80 5.5.1 Produced Water with Low Salinity 80 Organic Compounds Removal 80 Turbidity Removal 83 5.5.2 Produced Water with Medium Salinity 84 Organic Compounds Removal 84 Turbidity Removal 86 5.5.3 Produced Water with High Salinity 87 Organic Compounds Removal 87 5.6 Influence of Hydrogen Carbonate 90 5.7 Real Produced water 91 5.8 Boron Removal 93 5.9 Estimation of the Size for EC in Full scale 94 5.10 Produced Water with Very Low Salinity and EC 95 5.11 Estimation of Operation Cost 96 6. CONCLUSION AND RECOMMENDATIONS 98 6.1 Conclusion 98 6.2 Recommendations for Future Work 101 Scale up on EC for upstream 101 Further processing and reuse 101 Online optimization for EC 101 Recommendations for any research related to upstream produced water 101 BIBLIOGRAPHY 102 APPENDIX A 117 APPENDIX B 120