Pre–treatment of coal seam gas produced water

Manthey, Byron (2014) Pre–treatment of coal seam gas produced water. [USQ Project]

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Abstract

This research addresses pre-treatment of Coal Seam Gas produced formation water using coagulation as the primary means of pre-treatment. Produced formation water pre-treatment currently involves the use of filtration and natural settlement. After pre-treatment the water is treated to the required standard using reverse osmosis. Due to the high solids content of produced formation water, filter media is regularly damaged or impeded, reducing the efficiency of the filter. The need for pre-treatment is imperative, without effective pre-treatment an undesirable level of solids in the water will be allowed to pass directly to the reverse osmosis membranes, causing irreversible damage. Coagulation has been identified as the most suitable pre-treatment option. The coagulation process agglomerates suspended solids into large bodies, increasing the rate of natural settlement and enhancing the filtration efficiency of the water. The coagulants investigated in this research have been selected due to their proven effectiveness for pre-treatment processes of the desalination of seawater. The similarities between seawater and produced formation water identified the suitability of coagulants for selection and subsequent testing. Ferric Chloride and Ferric Sulphate have been identified as the most suitable coagulants for testing and analysis. Aluminium Sulphate has also been tested and analysed due to its wide spread use in water treatment. The produced formation water used for testing was collected from an initial coal seam gas well unload in the Surat basin, it provided a suitable representation of produced formation water quality. Jar testing was selected as the most effective method of testing and analysis and accounts for the primary means of testing in this research. The focus of initial testing was to first quantify the efficiency of the chosen coagulants, then to identify the range of dosage for optimisation. Initial testing proved all coagulants effectiveness, and identified the following ranges for optimisation, Aluminium sulphate 10 - 100 mg/L, Ferric Chloride 60 - 140 mg/L, and Ferric Sulphate 60 - 140 mg/L. Statistical analysis software Minitab was used to formulate the experimental designs, and the models required for optimisation analysis, based on two factors being dosage and pH. Surface response methodology was used to predict the optimum values of the parameters, with the minimum number experiments. The predicted results have been analysed and validated using analysis of variance. The analysis of optimisation was undertaken using overlain contour plots and provided a graphical representation of the optimal region. The results of optimisation indicated Aluminium Sulphate and Ferric chloride reduced turbidity at optimal conditions by 99%. Ferric chloride required 140 mg/L of coagulant, twice the dosage of Aluminium Sulphate. Although requiring twice the dosage, Ferric Chloride resulted in a third 0.273 mg/L of heavy metal residual, namely iron. This research has identified coagulation as being an effective means of pre-treatment of produced formation water.


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Item Type: USQ Project
Item Status: Live Archive
Additional Information: Bachelor of Engineering (Mechanical) project
Faculty / Department / School: Current - Faculty of Health, Engineering and Sciences - School of Mechanical and Electrical Engineering
Supervisors: Aravinthan, Vasantha
Date Deposited: 09 Sep 2015 05:01
Last Modified: 03 Mar 2016 04:16
Uncontrolled Keywords: produced formation water; coal seam gas produced water; coal seam gas; coagulation; water filtration; natural settlement; reverse osmosis; water treatment; ferric chloride; ferric sulphate; aluminium sulphate; Surat Basin; Minitab; overlain contour plots
Fields of Research : 09 Engineering > 0905 Civil Engineering > 090508 Water Quality Engineering
09 Engineering > 0914 Resources Engineering and Extractive Metallurgy > 091405 Mining Engineering
09 Engineering > 0905 Civil Engineering > 090509 Water Resources Engineering
URI: http://eprints.usq.edu.au/id/eprint/27295

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