垃圾填埋场反渗透浓缩液回喷至附近垃圾焚烧厂焚烧研究

为解决垃圾渗滤液经两级碟管式反渗透装置(DTRO)的处理后形成的高浓度浓缩液难以处理的问题,实现垃圾渗滤液反渗透浓缩液的高效无害化处理,以山东省某垃圾填埋场经两级碟管式反渗透装置(DTRO)分离形成的浓缩液为例,拟将其回喷至隔路建设的垃圾焚烧厂焚烧炉中,结合已有的垃圾填埋场浓缩液的COD浓度以及附近垃圾焚烧厂中焚烧炉的性能参数,研究了浓缩液的最大回喷比,以及回喷燃烧废气对大气环境的影响。结果表明:将回喷比控制在3.96%以内,采用该工艺既不会影响垃圾焚烧工况,又能实现对垃圾浓缩液的高效处理;该工艺产生的烟气焚烧污染物均满足该行业的污染物排放标准。     

Exergy analysis of the transcritical N2O refrigeration cycle with a vortex tube

In this article, a comparative study is presented for the transcritical cycle with expansion valve (TCEV) and transcritical cycle with vortex tube (TCVT) mainly based on the second law of thermodynamics. Natural refrigerant nitrous oxide (N₂O) is used in both the cycles for analysis. The evaporator and gas cooler temperatures are varied from ?55°C to 5°C and 35°C to 60°C, respectively. The effects of various operating and design parameters on the optimum heat rejection pressure, coefficient of performance (COP), exergy loss (irreversibility), and the exergetic efficiency are studied. Exergy analysis of each component in TCEV and TCVT is performed to identify the amount and locations of irreversibility. It is observed that the use of the vortex tube in place of the expansion valve reduces the total exergy losses and increases the exergetic efficiency as well as COP. The exergetic efficiency and COP of the TCVT are on average 10–12% higher compared to TCEV for the considered operating conditions. The computed values of the exergetic efficiency for TCVT using refrigerant N₂O are the highest at an evaporator temperature of ?55°C, and the corresponding values of exergetic efficiency and exergy losses varies between 25.35% and 15.67% and between 74.65% and 84.33%, respectively. However, COP at the same evaporator temperature of ?55°C varies between 0.83 and 0.51. Furthermore, the optimum heat rejection pressure in TCVT is lower compared to that in TCEV. The results offer significant help for the optimum design and operating conditions of TCVT with refrigerant N₂O.     

旋风除尘器的压力损失及减阻措施

通过探讨引起旋风除尘器阻力损失的原因，提出了相应的减阻措施－安装导向板和内筒。     

Investigations on an evacuated tube solar water heater using hybrid-nano based organic phase change material

ABSTRACT

This work explores the opportunities to address the setback in thermal energy storage of solar-based water heaters by uniting it with a suitable hybrid-nano composite phase change material (HNCPCM) in a static mode of operation. The experiments were conducted on a natural circulation all-glass evacuated solar water heating system (AGSWH). The investigation was steered in five cases such that the first case without any phase change material (PCM), the second with pure paraffin as PCM, and remaining three cases with three different mass percentage of HNCPCMs (0.5%, 1.0%, and 2.0% mass fraction of hybrid nanoparticles within PCM) in real-time solar exposure. The system was analyzed based on the first and second law of thermodynamics to assess the performance in all the five cases. Erstwhile, the hybrid nanoparticles were prepared by blending equal mass of SiO₂ and CeO₂ nanoparticles and characterized to gauge its thermal storage properties. The achieved results substantiated that the thermal conductivity had boosted with the accumulation of hybrid nanoparticles within the paraffin matrix, and maximum enhancement of 65.56% was attained with 2.0% mass fraction. The first law and second law investigations revealed that the incorporation of hybrid-nano composites improved the energy and exergy content of the system, distinctly. Among the experimented cases, HNCPCM with 1.0 mass% of hybrid nanoparticles remarkably yielded a better result of 19.4% and 1.28% improvement in energy and exergy efficiencies, respectively. Besides, it evidenced the necessity of choosing the right quantity of nanoparticles for achieving better overall results.     

非均质炸药冲击起爆临界判据中起爆参数的研究

以引信传爆序列中传爆管——主装药界面间的爆轰传递为例,研究了非均值炸药的冲击起爆理论,推导了飞片起爆和透射冲击起爆过程中爆轰界面的关键参数ｐ 和τ的计算关系式,对临界起爆能量的计算以及传爆序列的安全设计具有一定的指导意义。     

200 MW燃气流风洞高压氧气系统安全操作分析

为保证200 MW燃气流风洞高压氧气系统安全运行,从初始能量出发,对高压氧气系统充气、供气、排气时管道内的激波管流动、绝热压缩等过程进行安全分析,并提出针对性安全措施。结果表明:对于充气管道内存在的激波管流动,当驱动气体压力为20 MPa、被驱动气体压力为0.1 MPa时,激波反射后末端气体温度远远高于200 ℃,通过减小阀门开启速度,对阀前管道进行充气以减小上下游压差,可避免因绝热压缩产生的高温;供气管道充填时,管道内最高温度为73 ℃,通过控制充填速度,可进一步降低管道内氧气温度;通过高压排气、低压排气2种模式,可满足国标中对氧气流速的要求。研究结果可为氧气管道远程安全操作提供参考。     

北京市废旧荧光灯管回收现状与综合利用对策

为响应国家节能减排的号召,北京市自2004年起投入使用了大量的节能灯,节能灯灯管含有的汞对水环境造成严重的污染隐患,国家出台了一些关于危险废物回收处理,一定程度上减轻了废旧节能灯管对环境造成的污染。本文通过调查问卷的方式,进行统计、分析总结了北京市废旧荧光灯管回收现状,并根据实际情况提出综合利用建议。     

玻璃纤维滤筒采集铅尘、铅烟预处理方法

探讨了一种快捷有效的降低玻璃纤维滤筒铅空白方法,即直接烘烤滤筒。该法操作简便,减少了试剂消耗量与操作时间。     

甲醛渗透管的研制

本文主要介绍了用ｗｈ聚四氟乙烯膜作为渗透材料制作甲醛渗透管的方法,并且针对所研制的渗透管的特性,影响渗透率的主要因素及渗透率的稳定性等方面进行了探讨。     

炸药驱动式爆炸管的载荷计算

目的 建立管道内冲击波参数工程预示方法,指导炸药驱动式爆炸管载荷设计和试验调试.方法 建立炸药爆炸的多介质流动数值模型,研究圆形管道内冲击波的传播规律,给出冲击波参数与炸药量、传播距离之间的变化关系,基于已有的坑道内冲击波超压预示公式,建立表征模型.结果 冲击波在管道中经过一定距离的传播后,会逐渐形成平面冲击波.随着传...