Hydrophobic in-situ SiO₂-TiO₂ composite aerogel for heavy oil thermal recovery: Synthesis and high temperature performance

In view of the global energy crisis, energy saving in high-temperature thermal production is urgent. The traditional rock wool and composite silicate board cannot meet the requirements of high efficiency thermal insulation for heavy oil recovery pipe due to their poor insulation performance, and the emerging SiO₂ aerogel production has poor shielding ability to infrared thermal radiation, resulting in limited application at high temperature industry. In this study, a novel SiO₂-TiO₂ composite aerogel was synthesized by synchronous sol-gel technique instead of simply particle doping method, high temperature hydrophobic property was obtained by surface modification and pre-heat treatment. The structure characterization, thermal conductivity test, infrared radiation heat transfer calculation and energy saving simulation calculation of SiO₂-TiO₂ composite aerogel were carried out, and the thermal insulation performance evaluation of high temperature steam pipes application was obtained accordingly. Compared with glass fiber/SiO₂ aerogel, the thermal conductivity of glass fiber/SiO₂-TiO₂ composite aerogel has achieved a 13.1% and 23.9% reduction in thermal conductivity at 300 °C and 400 °C, respectively. Energy saving simulation results showed that glass fiber/SiO₂-TiO₂ composite aerogel can save 31.94 wt% and 55.44 wt% of oil consumption annually comparing to the commonly used rock wool and composite silicate. At the same time, large hydrophobic angle (143.7°) and good stability are the guarantees for its long-term service under the complicated environment. To sum up, glass fiber reinforced SiO₂-TiO₂ composite aerogel can serve as super insulation to replace traditional insulation layer and pure SiO₂ aerogel product in the field of ground steam pipes application.