| Bitumen from the oil sands can be contaminated with chloride salts like NaCl, CaCl2.2H2O and MgCl2.6H2O originating from emulsified brines and process water. Available solutions like desalting and naphtha-based froth treatment do not ensure their complete removal. As bitumen undergoes upgrading processes, these salts hydrolyze on reaction with steam to form HCl, and can further react to give NH4Cl, thereby giving corrosion of upgrading and refining equipment.;To investigate the role of bitumen impurities, hydrolysis of salts was investigated in diluted bitumen, a bitumen/diluent/synthetic crude oil blend and model oil. Different concentrations of emulsified salts were added and the samples were steamed from 150-350°C to drive the hydrolysis reaction. Ion chromatography analysis of condensate samples showed increase in the % chloride released on addition of salts to heavy oil blends. Experiments with pure salts in model oil and a heavy oil blend showed complete conversion of MgCl2.6H2O and low conversions of NaCl. Conversion of CaCl2.2H2O was much higher in heavy blend than the model oil, exhibiting catalyzing effect of naphthenic acids. Selected experiments were run with inhibitors to prevent the release of chloride from the crude oils. Addition of inhibitors reduced the release of chlorides by as much as 94% and gave an overall delay in acid release, thereby giving protection in flow processes. |
