Silane surface modified ceramic membranes for the treatment and recycling of SAGD produced water

摘要

The extraction of bitumen using oil extraction and recovery processes such as SAGD (steam assisted gravity drainage) produces oily process waters that must be treated and recycled when possible. Ceramic membranes are well suited for this task. However, ceramic membranes in aqueous media have a pH dependent surface charge. It was hypothesized that these surface charges are responsible for the high fouling of ceramic membranes in treating wastewaters containing bituminous fines. To maintain desirable hydrophilic properties without surface charges, a highly hydrophilic and neutral organosilane was used to modify the surface of ceramic membrane disks. Membranes having pore sizes of 150 kDa, 300 kDa and 0.14 mu m were modified using this organosilane. The ceramic membranes were then used in the filtration of SAGD produced water. Results indicate that the modification was successful in mitigating the irreversible fouling caused by bituminous ultrafines. The permeate flux of the 150 and 300 kDa membranes more than doubled after modification in a 20% silane solution. Furthermore, the filtered water obtained from the modified membranes was of superior quality, to that of the untreated membrane, as evidenced by total organic carbon analysis. All of the ceramic membranes tested were shown to reduce the particle sizes in the produced water from >200 nm in the feed to <40 nm in the permeate.