推广低温辐射加热节电新技术

一、由远红外加热到低温辐射加热低温加热多用于烘烤、脱水和加热三大工艺。被烘烤物大多属于薄壁、大面积和有机化合物,采用传统的火焰、热风、蒸发和电阻加热等工艺,热效率很低,70年代初远红处加热节电技术传入我国曾得到大规模推广,但由于炉内温度不够均匀,而热效率又和传统的热风循环炉仿佛。使推广工作一度陷于停顿。锦州红外技术应用研究所从提高元件辐射效率、实现匹配吸收和控温调节、采用定向辐射和均匀辐射等技术,开发出炉内温差为士3℃～7℃,热效率>30％的新型低温辐射加热炉。它和原有的热风炉、远红外炉对照如表1。     

保护气体电磁振底式光亮淬火电阻炉

RZQ—14—10型保护气体振底炉,最高工作温度为1000℃。炉内通有分解氨的保护气体,适用于微型轴承、标准件等大批量小型另件的光壳淬火,其上料机构、炉内传动机构采用电磁振动方式,淬火油槽内配有输送带,工件经淬火后可自动输出。工件的上料、加热、淬火,出料均能自动连续完成。     

红外线辐射加热器在焊缝予热及去应力中的应用

红外线辐射组合式加热器(以下简称组合加热器)国内已经试制成功(详见“电炉”1977年第三期),它的主要特点是: 1.可以进行任意面积、任意形状的简易筑炉、使用拆装极其方便,只要面向被加热物体配置组合一定大小的加热器就可以了。 2.面状发热具体有较高的辐射密度,故可实现快速加热、热容量也小、升温及冷却速度均可任意选择。 3.与感应加热器相同,因采取电气控制,故对整个被加热物体(工件)的表面温度能进行均匀控制、程序控制。     

陶瓷管少氧化节能加热炉节能理论分析与对策

陶瓷管炉(简称CT炉)是一种新型少氧化节能加热炉。钢坯在陶瓷管内隔焰加热,采用陶瓷换热器和串联的金属辐射换热器回收高温烟气余热。本文通过建立CT炉热力学模型,运用热力学第一定律建立系统稳定流动能量平衡方程,分析得出CT炉的节能原理,进而得出CT炉的节能措施。所得结论完全适用于各种加热类炉窑。     

热源石墨对VHB-6612真空钎焊炉温度场的影响

热源石墨是整个VHB-6612真空钎焊炉的能源提供部件,热源石墨的工作温度在整个VHB-6612真空钎焊炉加热过程起着主导作用,所以研究热源石墨升温速率对加热工件各部分影响非常重要。利用传热学基本原理讨论了热源石墨棒以不同的初始升温速率工作时对加热工件最高温度、最低温度以及两者差值的影响;研究了隔热层内表面钼层黑度对热源石墨棒的最高工作温度和工件整体最大温差的影响。     

一种新的节能技术——低温辐射加热

<正> 50—650℃加热,干燥与脱水工艺所需的设备,国外大多数采用强制对流传热的电热热风循环加热炉(热风炉);国内自制设备大多数用远红外加热炉。热风炉已有近百年历史,技术精湛、性能可靠、炉内温度均匀性可达到较高的水平(±1—5℃),几乎适用于所有工件的加热与干燥。但能耗高、设备热效率低(按国标GB2588—8K20％)。远红外炉已有二十年历史。实践证明,设备性能不理想,节电节能效果不明显,     

环形炉内辐射传热的新的物理-数学模型

建立了加热圆钢坯或方钢坯的环形转底炉的物理一数学辐射传热数学模型。计算的复杂性在于各点气体和固体之间的相互辐射、温度的不均匀和角度系数的难以确定。列出辐射能量守恒方程，然后进行求解，并认为所采取的求解方法有一系列优点，精度高，速度快。举例进行实算，列出了计算结果。该模型可以用来对各种形状钢坯在环形加热炉中加热时，计算加热时间和加热质量（热流分布）。     

炉体旋转式锻造炉的开发

为解决炉底旋转式锻造炉电动机同步不良和谋求烧嘴均匀加热,日本东京瓦斯公司开发了炉体旋转式锻造炉。该炉的主要特点是运行中整个炉体旋转;烧嘴仅一台设在加热室顶部的中心部,火焰呈扁平状,可对工件实施均匀加热,燃烧排气可由炉侧壁各装出料口排出;装出料口即为燃烧排气口,故工件装入过     

环形炉内管坯加热温度均匀性计算与分析

在考虑炽热炉底的辐射加热和导热加热的基础上,建立了环形炉内管坯二维加热模型。计算结果表明,管坯表面热流密度沿周向分布的不均匀性造成了管坯温度沿周向分布不均。炽热炉管对管坯下部表面的导热及辐射加热对其加热至关重要。     

用电辐射管改造K型炉

<正> 一、前言辐射管作为一种合理的加热元件已在可控气氛炉等热处理设备上普遍使用。据报道,日本现在热处理主要设备都采用辐射管加热技术,尤以连续渗碳炉和万能炉为多。辐射管加热具有以下特点:①生产中可以更换而不影响生产;③功率分布更加合理;③有利于炉内气氛的流动;     

间歇式热处理炉传热计算与分析

建立了台车式热处理炉炉膛传热数学模型和辐射换热器工作模型,分析了换热器的传热特性（空气预热温度、壁温、传热系数）随炉况的变化。结果表明,辐射换热器的传热特性随炉子的升温及保温过程变化而波动很大,因而对炉子的热工性能产生了影响。     

Efficiency analysis of radiative slab heating in a walking-beam-type reheating furnace

The thermal efficiency of a reheating furnace was predicted by considering radiative heat transfer to the slabs and the furnace wall. The entire furnace was divided into fourteen sub-zones, and each sub-zone was assumed to be homogeneous in temperature distribution with one medium temperature and wall temperature, which were computed on the basis of the overall heat balance for all of the sub-zones. The thermal energy inflow, thermal energy outflow, heat generation by fuel combustion, heat loss by the skid system, and heat loss by radiation through the boundary of each sub-zone were considered to give the two temperatures of each sub-zone. The radiative heat transfer was solved by the FVM radiation method, and a blocked-off procedure was applied to the treatment of the slabs. The temperature field of a slab was calculated by solving the transient heat conduction equation with the boundary condition of impinging radiation heat flux from the hot combustion gas and furnace wall. Additionally, the slab heating characteristics and thermal behavior of the furnace were analyzed for various fuel feed conditions.     

Analysis on Heat Transfer Characteristics of Constant‐Temperature Heat Pipe in Waste Heat Utilization for Semi‐Coke

In the coal chemical industry, an internal heating retort furnace is applied to the processing of low‐temperature coal pyrolysis so as to produce semi‐coke. Because the cooling water is used to reduce the temperature of semi‐coke from 500 °C to 60 °C, the waste heat carried by the semi‐coke is released. Meanwhile, the waste water of higher temperature involved with the hazardous substances is discharged into rivers or lakes, causing serious environmental pollution. In the present work, a constant temperature heat pipe is used to recover the waste heat. An iterative method is adopted to numerically solve the thermal resistances and the overall heat transfer coefficients. Results show that the conductivity thermal resistance decreases as the tube diameter increases. In the heating section, the main factors affecting the heat transfer are the thermal resistances of both the radiation heat transfer and the convective heat transfer. As the pressure climbs, the thermal resistance of radiation heat transfer increases, while the thermal resistance of convective heat transfer decreases. In addition, the overall heat transfer coefficients increase with the pressure. The heat transfer efficiency of the heat pipe is about 30%, and a higher economic benefit can be obtained.     

洛阳石化延迟焦化装置节能分析

洛阳石化140×104t/a延迟焦化装置采用"一炉两塔"和"可灵活调节循环比"的工艺流程,2008年和2009年装置综合能耗分别为35.42kg标油/t和33.36kg标油/t,与设计值、中国石化平均水平(24.27kg标油/t)相比差距较大。综合分析,能耗较高的原因包括蜡油汽包产0.4MPa蒸汽未计入能耗、1.0MPa蒸汽放空、低温热回收系统未投用、蜡油热输出量小、装置加工负荷率低以及加热炉效率低等。为此,对装置采取用0.4MPa蒸汽替代1.0MPa蒸汽;回收分馏塔顶油气、接触冷却塔顶油气和冷焦水低温热量;增加稳定汽油热出料流程;增设节电变频设施,减少电耗;降低加热炉排烟温度和炉外壁温度;加热炉进料泵叶轮抽级或更换为小叶轮,降压节能;增上加热炉先进控制(APC)手段,保证加热炉最佳燃烧;加热炉出口管线保温及管托更新换型,增加空气预热器等措施,有效降低装置能耗。     

环形加热炉热工过程CFD数值模拟及其应用

借助CFD商业软件CFX，考虑流动、辐射、燃烧等，对宝钢环形加热炉的热工过程进行了数值模拟，得到了炉膛内的温度、速度矢量等热工参数的分布图。通过简化处理，对环形加热炉各控制段内的加热过程进行了模拟分析，并根据所得到的管坯表面辐射热流、热电偶温度及管坯表面温度研究了各个段总括热吸收率的分布情况，主要分析了总括热吸收率在管坯圆周方向、长度方向以及各个段之间的变化规律。     

A heat transfer model for the analysis of transient heating of the slab in a direct-fired walking beam type reheating furnace

A mathematical heat transfer model for the prediction of heat flux on the slab surface and temperature distribution in the slab has been developed by considering the thermal radiation in the furnace chamber and transient heat conduction governing equations in the slab, respectively. The furnace is modeled as radiating medium with spatially varying temperature and constant absorption coefficient. The steel slabs are moved on the next fixed beam by the walking beam after being heated up through the non-firing, charging, preheating, heating, and soaking zones in the furnace. Radiative heat flux calculated from the radiative heat exchange within the furnace modeled using the FVM by considering the effect of furnace wall, slab, and combustion gases is introduced as the boundary condition of the transient conduction equation of the slab. Heat transfer characteristics and temperature behavior of the slab is investigated by changing such parameters as absorption coefficient and emissivity of the slab. Comparison with the experimental work show that the present heat transfer model works well for the prediction of thermal behavior of the slab in the reheating furnace.     

低碳钢丝热处理明火炉供热系统分配研究

以现有钢丝热处理明火炉为热工模型,根据低碳钢丝热处理生产过程的工艺特点,分析了低碳钢丝在不同温度阶段沿炉长方向的受热过程,并计算了钢丝及炉体热量吸收、损失,根据所得结果合理布置明火炉供热系统。     

Transient radiative heating characteristics of slabs in a walking beam type reheating furnace

Transient radiative heating characteristics of slabs in a walking beam type reheating furnace is predicted by the finite-volume method (FVM) for radiation. The FVM can calculate the radiative intensity absorbed and emitted by hot gas as well as emitted by the wall with curvilinear geometry. The non-gray weighted sum of gray gas model (WSGGM) which is more realistic than the gray gas model is used for better accurate prediction of gas radiation. The block-off procedure is applied to the treatment of the slabs inside which intensity has no meaning. Entire domain is divided into eight sub-zones to specify temperature distribution, and each sub-zone has different temperatures and the same species composition. Temperature field of a slab is acquired by solving the transient 3D heat conduction equation. Incident radiation flux into a slab is used for the boundary condition of the heat conduction equation governing the slab temperature. The movement of the slabs is taken into account and calculation is performed during the residence time of a slab in the furnace. The slab heating characteristics is also investigated for the various slab residence times. Main interest of this study is the transient variation of the average temperature and temperature non-uniformity of the slabs.     

300MW循环流化床锅炉屏式受热面传热系数计算及其变化规律

根据300MW循环流化床（CFB）锅炉现场测试数据并结合以往CFB锅炉传热系数的研究成果,建立了屏式受热面烟气侧的传热模型,包括辐射传热模型和对流传热半经验公式．利用该模型对某300MWCFB锅炉在94％锅炉最大连续蒸发量（BMCR）工况下炉膛内屏式受热面的传热系数进行了计算,分析了屏式受热面管间节距、炉膛温度、工质温度、壁面黑度及烟气速度等因素对传热系数的影响．结果表明：烟气速度、炉膛温度和壁面黑度对传热系数的影响较大,所建立的传热模型能够合理地反映主要因素对CFB锅炉屏式受热面传热的影响．