蓝宝石热处理的现状及前景

本文根据蓝宝石的致色机理 ,总结了蓝宝石热处理的模式及影响因素 ,给出了现行蓝宝石热处理的实例 ,结合国内经济发展状况对蓝宝石热处理的发展前景作了展望 ,并根据相关学科的发展提出了一些建议及设想。     

新型换热器的传热性能研究

提出一种适合污泥处理过程中的余热回收的新型隔板管壳换热器,并与同样规格的普通管壳换热器性能进行对比。建立了简化的壳程计算模型,应用FLUENT计算软件分别对普通管壳换热器和新型隔流板式换热器进行数值模拟,获得了2种热交换壳程内部的流动分布、温度分布和压力分布,并将模拟结果和试验数据进行对比。试验及模拟结果表明,新型隔板式换热器温度分布均匀、流动死区少、传热效率高,综合性能远高于普通管壳换热器。     

废烟气回收管网保温的计算分析

铜陵市铜冠电工漆包线生产厂房的催化装置中产生大量温度高达500℃的烟气,该工业余热一直以废气的形式直接排放到大气中,造成热污染和能源浪费。回收该工业废热,利用该烟气余热直接驱动溴化锂吸收式制冷,不仅介绍了该技术的工艺特点,而且从传热学和工程热力学基本理论入手研究烟气回收管道保温的计算分析,建立管道等厚度保温层的管网计算模型和基本理论,为工程实践提供可借鉴计算模板。     

热管在空调热回收中的应用

空调系统的排风中存在大量低位热能。热管传热系数高,结构简单,是空调系统低位热能回收的有效手段。介绍了热管的结构特点、种类和原理,对目前常见的空调热回收装置进行了对比,论述了国内外热管技术的研究现状及其在空调热回收方面的应用。证明热管在降低能耗、减少热污染和环境保护方面有明显的优势,具有良好的经济和社会效益。同时也简述了当前的热管技术中存在一些问题和未来的发展方向。     

The challenge of integrating non-continuous processes – milk powder plant case study

The integration of non-continuous processes such as a milk powder plant presents a challenge for existing process integration techniques. Current techniques are generally based on steady and continuous operation which for some industries is not the case. Milk production varies considerably during the year as dairy cows in New Zealand are grazed on pasture. In this paper the potential for indirect heat transfer between the several plants using a heat recovery loop and stratified tank at a typical New Zealand dairy factory is investigated. The maximum amount of heat recovery is calculated for a range of recirculation loop temperatures. The maximum amount of heat recovery can be increased considerably if the temperature of the hot fluid in the recirculation loop is varied depending on which condition the site is operating under.     

沼气发酵罐热负荷特性研究与排料余热回收装置设计

针对天津市某养殖场沼气工程,基于热平衡模型,模拟分析了沼气发酵罐热负荷特性,发现发酵罐罐体传热负荷和加热发酵料液负荷是沼气生产过程中主要负荷组成部分,而其中加热发酵料液负荷占到了沼气工程总热负荷的87.5%~90.8%,约为发酵罐罐体传热负荷的8倍。为减少发酵罐排料造成的热量损失,设计了1套沼气发酵罐排料余热回收装置,并对其余热回收效率进行模拟计算。结果表明:该装置在春季余热回收量为1 472.3~2 216.5 MJ,夏季为747.4~993.5 MJ,秋季为1 515.7~2 069.3 MJ,冬季为2 526.3~2 707.7 MJ。全年节能率波动范围在25.36%~48.46%,在冬季其节能率仍能达到30%以上,有效减少了排料的热量损失。     

热泵蒸发及其在浓缩垃圾渗滤液中应用的初探

在热泵蒸发过程中,二次蒸汽压缩比是个至关重要的参数,它直接关系到热泵蒸发的经济程度。对热泵蒸发中的传热过程及可利用的余热作了全面分析。最后对热泵蒸发在浓缩垃圾渗滤液中的应用进行了探讨。     

矿区火电厂蒸汽余热的资源化利用

利用电厂蒸汽余热进行供热取暖和水产养殖是传统的有效方法,而将其用于矿区矿井水淡化脱盐处理中,意义重大,不仅实现蒸汽余热资源化利用,提高了电厂经济效益,同时缓解了矿区淡水缺乏的矛盾,具有良好的应用前景。     

Numerical prediction of radiative heat transfer in reciprocating superadiabatic combustion in porous media

A numerical study of Reciprocating Superadiabatic Combustion of Premixed gases in porous media (hereafter, referred to as RSCP) is performed. In this system the transient combustion of methane-air mixture is stabilized in a porous media combustor by periodically switching flow directions. The mass, momentum, energy and species conservation equations are solved using a two-dimensional control volume method. Local thermal non-equilibrium between the gas and the solid phases is considered by solving separate energy equations for the two phases and coupling them through a convective heat transfer coefficient. The porous media is assumed to emit, absorb and isotropically scatter radiation. The influences of the dominating operating parameters, such as filtration velocity, equivalence ratio and half cycle on the temperature profile, heat release rate, radiant flux, radiant efficiency and combustion efficiency are discussed. The results show that coupling calculating of flow field, combustion reaction and volume radiation of the optically thick media is successively achieved and heat radiation plays an important role in the overall performance of the burner. The temperature profile inside the RSCP combustor has a typical trapezoidal shape and the profile of radiation flux is similar to sinusoidal shape. Compared with the conventional premixed combustion in porous medium, combustion behavior in RSCP combustor is superior, such as better thermal structure and higher radiation efficiency and combustion efficiency.     

机械蒸汽再压缩(MVR)热泵干燥的研究进展

干燥是物料中的水分吸收足够的显热和潜热而蒸发去除的过程。水分蒸发会消耗大量的热量,同时产生大量的二次蒸汽。根据MVR热泵的高效节能原理,若将采用机械蒸汽再压缩技术提高焓值的二次蒸汽作为干燥过程的热源,则可回收二次蒸汽的全部潜热,在系统内实现水分蒸发汽化潜热与凝结潜热的互换,节能效果显著。总结了MVR热泵干燥的应用概况,阐述了过热蒸汽作为MVR热泵干燥介质的优势,以及MVR热泵干燥器的设计和选用压缩机时应考虑的问题,指出了进出料环节应尽量减少不凝气体进入干燥系统,以避免不凝气体对干燥过程冷凝换热的影响。