旋转杯粒化高炉渣显热回收工艺综述

分析了利用旋转杯粒化高炉渣回收热量的工艺优势,此工艺不仅可以回收炉渣显热,而且粒化后的高炉渣还可以做水泥材料。同时介绍了相关不同工艺的技术路线,对比后得出旋转杯粒化高炉渣与化学反应回收熔渣余热工艺相结合的工艺由于能量形式转换次数少,回收率高,且在实际中更具可操作性,因此被认为是一种更具发展前景的工艺。     

余热回收系统性能评价

一、概述 工业炉已在机械、冶金、化工等工业领域得到了广泛的应用,但由于其排烟温度较高,使得排烟热损失较大,热效率较低,因此,回收排烟余热对于提高热效率、降低产品能耗具有重要意义。 工业炉余热的常用回收方式是利用排烟余热预热助燃空气,此时,在不同的条件下具有三种不同的效果:(1)若炉内有效吸热量不变,由于预热空气后,进入炉内的物理显热增加,炉子燃料消耗量将下降;(2)若炉子燃料消耗量不变,由于空气温度提高,炉内温度上升,炉内有效吸热量将增加;(3)若进入炉内的化学热和物理显热之和不变,则预热空气一方面会使炉子燃料     

熔融高炉渣显热回收和利用

分析了现行高炉渣处理方法的缺点,指出离心粒化法的优势.根据利用余热资源原则,着重分析了以热风炉助燃空气为回收方式,结合炼铁工序,说明熔融高炉渣显热回收和利用对炼铁节能、钢铁企业降耗的重大影响.     

国内外熔融高炉渣显热回收方法

分析了熔融高炉渣显热回收的必要性。因为熔渣的物理性质和高炉出渣不连续性,导致熔渣显热回收存在困难。介绍了滚筒法、搅拌法、风淬法、连铸法、离心粒化和反应热法显热回收工艺,并指出甲烷-二氧化碳重整法有很好的发展前途。     

加热炉烟气余热自回收的节能计算

加热炉烟气余热自回收的节能计算江西新余钢铁总厂罗晓青，杨三根加热炉炉膛排出的烟气温度比较高，烟气余热的利用，通常是先回收用于自身（如预热空气，国标ＧＢ３４８６（评价企业合理用热技术导则》中规定有工业炉烟气余热回收率的要求），然后进一步进行用于炉外回收...     

高效板式空气预热器在轧钢加热炉余热回收中的应用

某轧钢加热炉采用管式空气预热器预热空气时,存在空气预热温度低,煤气预热温度频繁超高温报警的情况.通过应用高效板式空气预热器,并对燃烧控制系统进行适应性优化后,排烟温度得到显著降低,余热回收效率高,节能效果好.     

加热炉空气预热器最佳设计

一、前言 加热炉是将燃料的化学能转化成热能的主要设备。由于其排烟温度一般较高,使得热损失偏大,直接影响加热炉的热效率。为了节约燃料消耗,提高加热炉的热效率,大多数厂家对烟气余热进行了回收。随着能源的紧张,烟气余热回收已显得日趋重要。 加热炉的余热最普遍的回收方式是利用烟气余热预热助燃空气。如图1所示的空气     

高炉熔渣显热的高效利用--新一步法矿棉技术获得成功

1高炉熔渣显热回收的必要性及其现状 矿棉是一种优良的节能保温材料,主要燃料和原料为块状焦炭和块状高炉渣,将上述原燃料按一定比例加入矿棉冲天炉内进行熔炼,再经过成纤、成型、固化和切割等工序制成矿棉制品.     

蓄热器在锻造工业中的应用

一、引言 锻造工业的能源浪费主要表现在: 1.锻造加热炉的排烟温度高,热利用率低。 加热炉是一种低效用能设备,物料吸收的有效能量只有10％左右,大量的热量损失在排烟之中,排烟温度在900℃左右。虽然用烟气的余热来预热空气不失为节能的一种有效办法,但因烟气的温度较高,因而对预热设备的材质要求较高,给余热回收带来一定的困难。对于需要使用蒸汽的企业而言,利用余热锅炉产生蒸汽、利用蒸汽蓄热器来     

风冷式冷渣器的实验研究

测试了一种用于煤粉炉炉渣冷却的风冷式冷渣器 ,结果表明 ,此设备仅用空气冷却炉渣 ,起到了节水的作用 ,同时利用炉渣的余热预热了进入炉膛的部分空气 ,有效地利用了炉渣的余热。此设备在较低负荷下冷却效果较好 ,高负荷下不能满足排渣温度要求 ,需要作进一步改进。     

膜加湿器热质交换过程的理论分析

膜加湿器是保证质子交换膜燃料电池(PEMFC)正常高效运行的重要组成部分.以燃料电池的板式膜加湿器为研究对象,根据热质交换原理对膜加湿器的传热传质过程进行了理论计算,分析了空气质量流量、膜内加湿侧进口温度和膜内加湿侧进口湿度对传热传质过程的影响.在传热方面:当空气质量流量不同时,随着膜内加湿侧进口温度的变化,膜内的热流量变化趋势不一致;当膜内加湿侧进口相对湿度为95%时,随着空气质量流量的变化,膜内热流量变化不大.在传质方面:当加湿侧进口相对湿度不变时,膜中水传输速率随着空气质量流量的增大而减小;当空气质量流量不变时,膜中水传输速率随着加湿侧进口相对湿度的增大而增大.     

Heat pipe heat exchanger for heat recovery in air conditioning

The heat pipe heat exchangers are used in heat recovery applications to cool the incoming fresh air in air conditioning applications. Two streams of fresh and return air have been connected with heat pipe heat exchanger to investigate the thermal performance and effectiveness of heat recovery system. Ratios of mass flow rate between return and fresh air of 1, 1.5 and 2.3 have been adapted to validate the heat transfer and the temperature change of fresh air. Fresh air inlet temperature of 32–40 °C has been controlled, while the inlet return air temperature is kept constant at about 26 °C. The results showed that the temperature changes of fresh and return air are increased with the increase of inlet temperature of fresh air. The effectiveness and heat transfer for both evaporator and condenser sections are also increased to about 48%, when the inlet fresh air temperature is increased to 40 °C. The effect of mass flow rate ratio on effectiveness is positive for evaporator side and negative for condenser side. The enthalpy ratio between the heat recovery and conventional air mixing is increased to about 85% with increasing fresh air inlet temperature. The optimum effectiveness of heat pipe heat exchanger is estimated and compared with the present experimental data. The results showed that the effectiveness is close to the optimum effectiveness at fresh air inlet temperature near the fluid operating temperature of heat pipes.     

汽车空调暖风系统平行流换热器换热性能研究

平行流换热器以其结构紧凑、换热效率高的特点已广泛应用于汽车空调中.简要介绍了汽车空调暖风系统平行流换热器结构,采用计算流体力学(CFD)数值模拟方法对平行流换热器的换热性能进行了分析,比较了空气侧风速和水流量对其换热量和流动阻力的影响.模拟结果表明:在增加相同百分比的情况下,增加空气侧风速比增加水流量对换热器换热量的影响大16%左右,但增加空气侧风速和水流量对换热器换热能力的影响均有限;随着风速的提高,换热量增加率逐渐减小,而空气侧阻力增加率越来越大;随着水流量增加,水侧压降增大非常明显;但两者增加对空气侧出口温度影响均不明显.     

Theoretical performance analysis of heat pump water heaters using carbon dioxide as refrigerant

The aim of this paper is to simulate the performance of an air source heat pump water heater using carbon dioxide (CO₂) as a working fluid. The heat pump water heating system consists of a compressor, a gas cooler, an expansion device and an evaporator. The computer simulation model has been developed by using the heat transfer data and the thermodynamic properties of CO₂. The effects on the heat pump performance by the operating parameters such as the compressor rotational speed, the inlet water temperature at the gas cooler, the inlet air temperature at the evaporator and the mass flow rate ratio of water to refrigerant were presented. For rated capacities of a 4 kW compressor with a 10 kW gas cooler and a 6 kW evaporator, the coefficient of performance is found to be between 2.0 and 3.0. The mass flow rate ratio of water and CO₂ between 1.2 and 2.2 is the most suitable value for generating hot water temperature above 60°C at 15–25°C ambient air temperature. Copyright © 2007 John Wiley & Sons, Ltd.     

Experimental results of a sensible heat storage system for residential and light commercial application

This paper presents the performance results for a sensible heat storage system. The system under study operates as an air source heat pump which stores the compressor heat of rejection as domestic hot water or hot water in a storage tank that can be used as a heat source for providing building heating. Although measurements were made to quantify space cooling, space heating, and domestic water heating, this paper emphasizes the space heating performance of the unit. The heat storage system was tested for different indoor and outdoor conditions to determine parameters such as heating charge rate, compressor power, and coefficient of performance (COP). The thermal storage tank was able to store a full charge of heat. The rate of increase of storage tank temperature increased with outdoor temperature. The heating rate during a charge test, best shown by the normalized rate plots, increased with evaporating temperature due to the increasing mass flow rate and refrigerant density. At higher indoor temperature during the discharge tests, the rate of decrease of storage tank temperature was slower. Also, the discharge heating rate decreased with time since the thermal storage tank temperature decreased as less thermal energy became available for use. Copyright © 1999 John Wiley & Sons, Ltd.     

Techno-economic analysis of a novel hybrid heat pump system to recover waste heat and condensate from the low-temperature boiler exhaust gas

This paper is based on the proposal of a new waste heat recovery (WHR) system, which can be utilized to heat the boiler return water, boiler supply air, and building heating air. The system is the combination of an indirect contact condensing unit (IDCCU), a mechanical compression heat pump, and two air preheaters. The system is modeled on the basis of mass and energy balance and then thermodynamically analyzed. Improved performance results were obtained in the form of an increase in the boiler's energy efficiency of about 10.47%, with 4.87% increase in exergy efficiency. The coefficient of performance (COP) of the heat pump was increased from 1.23 to 1.45 by the addition of an air heater in the conventional heat pump. The exergy destruction in each component is calculated. Sensitivity analysis was performed to check the influence of different operating parameters on the performance of the WHR system and boiler. It can be observed from the results that for a specific refrigerant temperature and a calculated amount of mass, flow rate can maximize the condensation efficiency of IDCCU by decreasing the flue gas temperature, while the use of the air heater can further reduce the flue gas temperature, and a stream of hot air can be utilized for space heating. A comparison is made with the other system on a performance basis. The results shows a clear difference in efficiencies and profit earned.     

A numerical study of solar chimney for natural ventilation of buildings with heat recovery

The performance of a glazed solar chimney for heat recovery in naturally-ventilated buildings was investigated using the CFD technique. The CFD program was validated against experimental data from the literature and good agreement between the prediction and measurement was achieved. The predicted ventilation rate increased with the chimney wall temperature. The effects of solar heat gain and glazing type were investigated. It was shown that in order to maximise the ventilation rate in a cold winter, double or even triple glazing should be used. Installing heat pipes in the chimney for heat recovery not only increased the flow resistance but also decreased the thermal buoyancy effect. To achieve the required air flow rates in naturally-ventilated buildings with heat recovery, use should be made of wind forces.     

逆流-叉流板式全热空气热交换器换热效率的实验研究

全热空气-空气热交换器是能量回收的有效装置。本文在双房间环境的试验平台上,对逆流-叉流板式全热交换器在冬季标准工况和非标准工况下进行了实验测试,结果表明,在冬季标准工况下,其全热效率可达70％。风量、温度差、湿度差均对换热效率有影响,换热效率随风量增加而降低,随温度差和湿度差的增大而增大。根据试验结果,整理得到了换热效率的经验计算公式。