直流输电线路工程冻土区基础施工质量控制

格尔木～拉萨±400 kV直流输电线路工程7标段位于唐古拉山脉,沿线海拔在4 600～5 300 m之间,地形、地质、气象条件复杂恶劣,全线主要不良地质为季节性冻土和多年冻土。由于冻土是一种特殊的土体,冻土区的活动层中每年都发生着季节性融化和冻结,并拌有融沉、冻胀和各种不良冻土地质现象,以致冻土基础施工完毕,基础容易产生沉降和漂移,基础根开尺寸及高差控制难度较大。7标段冻土基础施工严格按要求进行冻土开挖、切实做好混凝土防冻、采取热棒和玻璃钢模板辅助措施、严格按设计要求回填土,从而使冻土区基础施工质量得到保证。     

空冷系统防冻及优化运行方法的探讨

在对空冷系统相关特性试验调整的基础上,探讨了冬季空冷系统的运行方式的方法;分析了影响空冷系统安全经济运行的主要问题,结合机组及空冷系统的变工况特性,确定了机组及空冷系统的优化运行方式。     

高压晶闸管换流阀外水冷系统分析

高压晶闸管换流阀是高压直流输电的核心设备之一,外水冷系统是其重要的一环.结合工作实践,在分析换流阀冷却系统换热工作原理的基础上,依据环境、水质及处理条件,运用换热器计算软件HTRI对外水冷系统空气冷却器进行设计,并开展相应的冬季换流阀停运防冻措施研究,提出了添加防冻剂、设置加热器设备以及排空冷却介质等预防措施,以避免装置出现冻结现象,保证换流站高压晶闸管换流阀高效、安全运行.     

适应环境温度变化的直接空冷机组空冷系统控制策略研究

从汽轮机背压调节、风机电耗、防冻控制等方面分析了环境温度变化对直接空冷机组空冷系统控制的影响,提出了与环境温度相适应的直接空冷系统控制策略。风机转速判断方式适宜于夏季风机列的自动投入、退出控制,且风机调速主控宜采用可变参数,随温度升高加强调节作用,而冬季风机列的投入控制更宜选择汽轮机背压判断方式;顺流风机防冻保护控制随冬季气温由高至低变化可依次采用停运触发保护街区的顺流风机、停运与逆流管束单元相邻的风机列和提高汽轮机背压设定值的方式;在冬夏季节温差大时宜分开投运隔离和非隔离街区风机,反之以分步方式投运隔离和非隔离街区风机;在冬季环境温度低时宜采用分步方式投运逆流风机。     

Stretchable and Freeze-Tolerant Organohydrogel Thermocells with Enhanced Thermoelectric Performance Continually Working at Subzero Temperatures

Aqueous thermocells that are eco-friendly and capable of converting low-grade heat into electricity continuously are promising candidates to power flexible and wearable devices in various application scenarios. However, challenges remain in their limited working temperatures, mechanical fragility, and poor thermoelectric performance, mainly due to the reduced entropy of both polymer chains and thermogalvanic ions at low temperatures. In this work, the challenges are addressed by introducing a synergistic chaotropic effect to destruct strong hydrogen bonds, increase polymers’ entropic elasticity, and enlarge the entropy difference of thermogalvanic ions. An organohydrogel thermocell is designed with a chaotropic comonomer and a chaotropic cosolvent. The maximum normalized power density of the thermocell achieves 0.1 mW m⁻² K⁻², which is in the same order of magnitude as the highest record in current quasi-solid thermocells. Even at −30 °C, the thermocell maintains the elongation at a break of more than 100% and a relatively high power density of 0.012 mW m⁻² K⁻². Furthermore, the thermocell shows the potential to light up a light-emitting diode and stably works when compressed, bent, and stretched in a wide temperature range. This work provides insights on developing reliable power sources to drive flexible electronics continually in extremely cold environments.     

Multifunctional Ionic Skin with Sensing,UV-Filtering,Water-Retaining,and Anti-Freezing Capabilities

Conductive polymer hydrogels are receiving considerable attention in applications such as soft robots and human-machine interfaces. Herein, a transparent and highly ionically conductive hydrogel that integrates sensing, UV-filtering, water-retaining, and anti-freezing performances is achieved by the organic combination of tannic acid-coated hydroxyapatite nanowires (TA@HAP NWs), polyvinyl alcohol (PVA) chains, ethylene glycol (EG), and metal ions. The highly ionic conductivity of the hydrogel enables tensile strain, pressure, and temperature sensing capabilities. In particular, in terms of the hydrogel strain sensors based on ionic conduction, it has high sensitivity (GF = 2.84) within a wide strain range (350%), high linearity (R² = 0.99003), fast response (≈50 ms) and excellent cycle stability. In addition, the incorporated TA@HAP NWs act as a nano-reinforced filler to improve the mechanical properties and confer a UV-shielding ability upon the hydrogel due to its size effect and the characteristics of absorbing ultraviolet light waves, which can reflect and absorb short ultraviolet rays and transmit visible light. Meanwhile, owing to the water-locking effect between EG and water molecules, the hydrogel exhibits freezing resistance at low temperatures and moisture retention at high temperatures. This biocompatible and multifunctional conductive hydrogel provides new ideas for the design of novel ionic skin devices.     

大型黄金堆浸场浸出液循环系统防寒技术与应用

内蒙古太平矿业有限公司为典型的特大规模低品位黄金矿山,采用堆浸工艺生产.由于其地处高寒地区,在冬季浸出液易冻结,生产无法正常进行.通过采用防寒技术,包括防寒贵液池、滴淋系统、堆浸场底垫分区等,有效解决了冬季浸出液冻结无法正常生产的难题,为高寒地区黄金矿山资源的开发利用与稳定生产起到良好的示范作用.     

负温高强泵送混凝土冻结损伤律及细观特征研究

通过对负温高强泵送混凝土的抗冻临界强度的研究 ,得出其早期承受冻结的冻结损伤规律 ,并且对不同程度冻结损伤的混凝土的细观结构进行了研究 ,研究表明 ,表征细观层次气孔的各项参数可以有效地反映出混凝土的损伤状况     

300MW直接空冷供热机组冬季优化运行

为了保证300 MW直接空冷供热机组在冬季运行的安全防冻,提高空冷供热机组的运行经济性,分别在冬季相同电、热负荷,不同环境温度下和不同电、热负荷,相同环境温度下对某电厂2×300 MW直接空冷供热机组风机不同运行方式进行了优化试验。分析了各工况下风机群冬季运行频率、电流、耗功关系,电、热负荷与排汽背压、风机耗功关系,低背压下机组电、热负荷与排汽量、热耗的关系等。对不同负荷下机组运行的防冻回暖提出了控制机组进汽量和供热抽汽量范围、保持较多排风机投入和频率相同且低频运行、投入逆流风机回暖等建议。机组经冬季优化运行后,排汽背压下降了3 kPa,供电煤耗平均下降了3 g/kWh,年经济效益增加192.7万元。     

用于寒区心墙冬季施工的相变黏土热学性能研究

寒区土石坝心墙土料冬季施工经常会受到冻融问题的困扰,而常规保温措施会干扰施工过程,且施工有效时间较短.相变黏土(PCM-clay)可在不干扰正常施工的条件下防止心墙土料发生表层冻结,从而延长寒区土石坝冬季施工时间.在相变黏土的防渗、强度等性能符合心墙功能的前提下,本文对其热学性能进行研究,分析了相变材料(PCM)掺量对...