Analyses of non-aqueous reactive polymer insulation layer in high geothermal tunnel

The scenario of geothermal tunnel is commonly observed around the world,and increases with the new constructions in the long and deep tunnels,for example in China.Tunnel insulation is generally divided into active and passive insulation.In passive insulation,it is an effective way to set low thermal con-ductivity materials as the thermal insulation layer as the choice of insulation material mainly depends on the thermal conductivity.Polymer is a kind of material with good geothermal performance,but there are relatively few studies.In this context,the transient plane source(TPS)method was used to measure the thermal conductivity of the developed polymer.Then,the temperature field of the high geothermal tunnel insulated by the non-aqueous reactive polymer layer was simulated.With the parametric analysis results,the suggestions for the tunnel layers were proposed accordingly.It revealed that the thermal conductivity of polymer first increases and then decreases with temperature.There are two rising sec-tions(?40e10?C and 20e90?C),one flat section(10e20?C)and one descending section(>90?C).It is observed the thermal conductivity of polymer increases with increase of the density of insulation layer and the density,and the thermal conductivity decreases when exposed to high temperatures.The temperature of the surrounding rocks increases with increase of the thermal conductivity and the thickness of polymer.Finally,a more economical thickness(5 cm)was proposed.Based on the parametric study,a thermal insulation layer with thermal conductivity less than 0.045 W/(m K),thickness of 5 cm and a density less than 0.12 g/cm 3 is suggested for practice.

Challenges in developing polymer flocculants to improve bitumen quality in non.aqueous extraction processes:an experimental study

Western Canada’s oil sands hold the third-largest hydrocarbon deposits in the world.Bitumen,a very heavy petroleum,is currently recovered by surface mining with warm water or in situ.Recovery processes that use organic solvents are being developed to reduce water usage and tailings production.While solvent-based methods can effectively extract bitumen,removal of residual fine solids from diluted bitumen product(DBP)to meet the pipeline transport requirement of<0.5 wt%solids and water in DBP remains a major challenge.We propose a novel area of application of polymer flocculants for fine solids removal from DBP.In principle,polymer flocculants can be applied to help remove these residual solids in conjunction with physical separation processes to increase process effectiveness and energy efficiency.Several polymers are selected and screened for flocculation behavior using kaolinite suspended in DBP and toluene,as a model system.Focused beam reflectance measurements and force tensiometer techniques are used to determine flocculation and sedimentation in DBP.The observed flocculation and sedimentation rate enhancements indicate that the polymers tested have only minor effects,providing opportunities for advanced polymer development.These findings exemplify the challenges in identifying polymers that may be effective as flocculants in heavy petroleum media.

两种制备疏松PVC树脂的新型聚合方法

介绍了制备疏松PVC树脂的两种新聚合方法—以正丁烷为反应介质分散聚合和悬浮态乳液聚合,并对树脂颗粒的特性进行了简述。结果表明:以正丁烷为反应介质的非均相VC分散聚合所得树脂的粒径和颗粒形态与聚合体系VC/But比例和转化率等有关,由于存在向But的链转移,PVC分子质量小于相同聚合温度下生产的悬浮PVC树脂,悬浮态乳液聚合所得树脂粒径分布和颗粒形态与水油比、转化率和添加剂品种有关。