| Steam flooding is widely used to production of viscous crude oil.Consequently,a large amount of high-salinity wastewater is produced,which failed to meet the Comprehensive Sewage Discharge Standard of China?GB8978-1996?.To avoid direct emmisions and high processing cost,Fengcheng oilfield carried out the development and evaluation of desalting technology.In the research,the thermal wastewater from viscous crude oil production was treated to meet the water quality requirements of thermal recovery boilers.In this study,the side line test and performance evaluation for desalination was carried out using Ultrafiltration?UF?-Reverse Osmosis?RO?technology.By optimizing the operation conditions?the UF system operating pressure is 0.5 MPa,the RO system operating pressure is 1.7 MPa,the RO concentrate backflow rate is 25%?,the UF system can obtain relatively high-quality effluent?turbidity is less than 0.8 NTU,silt density index is 5 on average?,which can guarantee the long-term stable operation of the subsequent RO system.And the RO system can generate higher-quality effluent?the average recovery rate is 73.4%,the salt removal rate is88.8%,and the salt content is 432 mg/L?,which meets the water quality requirements of thermal recovery boilers.Economic analysis shows that the direct operating cost of UF-RO technology is about 5.93 RMB/m3.The UF-RO process generates RO concentrate with higher content of salt?12000 mg/L?and Si O32-?225 mg/L?.This study continues the pilot-scale test to treat the RO concentrate by using the“siliconremoval-coagulation-UF-RO”technology.The results show that under the condition of 70%recovery rate,the effluent has a salt content of less than 1000 mg/L and a Si O32-content of less than 9.67 mg/L,which can also meet the water quality requirements of thermal recovery boiler.The research results can provide data and experience support for engineering design and operation for reusing wastewater. |
PDF Full Text Request