大型压力容器现场热处理技术

以大连石化350万t/a催化裂化装置再生器为例,研究开发大型炼油化工设备现场新型热处理工艺。通过设置必要的热气流导向装置,采用微正压内燃工艺,配备新型大功率燃油喷嘴、用DCS集散控制系统调节油风比例和烟囱热量排放张合度,对超厚壁板适当增加电加热辅助热处理,解决了大容积、变截面、不等壁厚、超重设备施工现场热处理温度调整难度大、不均衡等技术问题。实践证明,应用该技术进行热处理,具有工期短、效果好、经济效益明显等特点。     

疏水缔合型聚丙烯酰胺的合成与性能评价

为了提高高相对分子质量的聚丙烯酰胺的抗温抗盐性能,利用自制的两亲表面活性单体与丙烯酰胺共聚合成了疏水缔合型聚丙烯酰胺并进行室内评价。结果表明,在高温、高盐、高钙条件下,合成的疏水缔合型聚丙烯酰胺具有良好的增粘性和较强的热稳定性;克服了疏水缔合型聚合物在盐水中溶解性差的问题,可用各种矿化度的盐水和油田产出污水配制;具有良好的无机盐增粘性能和抗温性能。     

Time‐dependent heat transfer coefficient of a wall

A time‐dependent coefficient of heat transfer is proposed for the computation of thermal power required, so that a room temperature reaches a desired value within a given time. A mathematical formulation of the room heating transient phenomenon is constructed in a dimensionless form. Using an integral approximate solution an analytical expression for this coefficient is provided and it is verified by diagrams adopted by DIN 4701. Copyright © 2003 John Wiley & Sons, Ltd.     

Optimum thermoeconomic and thermodynamic performance characteristics of an irreversible three-heat-source heat pump

The coefficient of performance and specific heating load of an irreversible three-heat-source heat pump are given by using a general cycle model affected by the finite-rate heat transfer, heat leak and internal irreversibility of the cyclic working fluid. The heat pumping load divided by the total cost per unit time is taken as a new objective function and used to investigate the performance of the heat pump. The thermoeconomic and thermodynamic performance characteristics of the heat pump are discussed in detail. Some important performance parameters such as the thermoeconomic objective function and coefficient of performance are optimized. The optimally operating regions of the heat pump and the bounds of several performance parameters are determined. Finally, it is pointed out that the Carnot heat pump may be taken as a special case of a three-heat-source heat pump and consequently its optimal performance can be directly derived from the results obtained here.     

A simplified method for modelling the effect of blinds on window thermal performance

An approximate method is presented for predicting the effect of a louvered blind on the centre‐glass thermal performance of a fenestration. The method combines a one‐dimensional heat transfer model with data from a numerical simulation of the window and blind. Sample results for a blind mounted on the indoor surface of a window show the effect of blind slat angle on heat transmission. Both summer and winter conditions are considered. The results show that a louvered blind can improve the U‐value of a standard double‐glazed window by up to 37%. Also, the radiation heat exchange with the room can be dramatically reduced (by up to 60%), which will improve the level of occupant comfort. However, there was found to be a trade‐off between U‐value and occupant comfort; placing the blind closer to the window improves the U‐value, but increases the radiation heat exchange with the room. The predictions from the present simplified method compare well with results from a full two‐dimensional computational fluid dynamics solution of the conjugate blind/window interaction. Copyright © 2005 John Wiley & Sons, Ltd.     

撬装式油井热洗装置研制及应用效果评价

油井热洗是油田最常用的一种清蜡方法。靖安长6油藏是采油三厂的主力油藏,截至2004年底建成油井1064口,由于长6层原油含蜡量高,油井结蜡严重,通常采用常规热洗方法进行油井清蜡。存在以下两方面问题：一是常规油井热洗方法操作比较复杂,运行动力设施多,热洗费用较高；二是常规洗井油源均来自联合站或接转站,为不同层所采的混合原油,进入地层后,会对地层造成一定程度的伤害。为此,我们认真分析了现有油井热洗工艺的不足,查找了油井热洗费用高的影响因素,结合靖安油田长6油藏丰富的伴生气资源,自主研发了撬装式油井热洗装置,经过现场应用取得了较好的效果。     

后热处理对新型马氏体耐热钢焊缝性能的影响

针对电力施工过程中对具有冷裂倾向的马氏体型耐热钢焊后后热处理时机选择与标准存在差异，即是否必要在冷却至100-120℃恒温一段时间后再进行后热处理的问题，安排了一系列的试验对后热处理的最佳时机予以讨论，对热处理后的焊缝组织进行力学性能试验和金相分析，对冲击后的试样进行了断口分析。试验证明，后热处理时机的不同对马氏体耐热钢焊缝冲击韧度有比较大的影响，马氏体耐热钢的后热处理应在马氏体转变完全后开始较为合适。     

冷却水污垢及其对冷却器换热的影响

分析了冷却器的结垢机理 ,提出了冷却器污垢层、污垢热阻随运行时间的规律 ,以及污垢热阻与换热系数、换热面积的关系式 ,并通过算例阐述了污垢热阻对冷却器的影响程度 ,进而定性地分析了污垢热阻对空分装置的影响。     

ESW激波吹灰器在余热锅炉的应用

介绍了ESW激波吹灰器的工作原理及其在茂名分公司Ⅲ套催化裂化装置余热锅炉的应用情况。应用结果表明，使用ESW激波吹灰器吹灰效果明显，吹灰后余热锅炉排烟温度可下降29℃，过热蒸汽产量增加7t/h，锅炉自产饱和蒸汽产量增加2t/h，有效提高了余热锅炉的传热效率和过热能力，节能效果显著。对应用中出现的一些问题提出了改进建议。     

Pulsating Jet Impingement Heat Transfer Enhancement

This article presents results from a numerical study of pulsating jet impingement heat transfer. The motivation is to seek conditions offering a significant enhancement compared to steady flow impingement drying. The CFD software package FLUENT was used for simulating slot-type pulsating jet impingement flows with confinement. The parameter study included velocity amplitude ratio, mean jet velocity, and pulsation frequency. The distance from nozzle exit to surface was three times the hydraulic diameter of the nozzle. The Reynolds number based on the nozzle hydraulic diameter and jet temperature was 2,460 with a mean jet velocity of 30 m/s, which is the base case of the numerical experiments. Results showed that time-averaged surface heat transfer increased with increasing velocity amplitude for the same mean jet velocity. Large velocity amplitudes helped enhance heat transfer by two mechanisms: high jet velocity during the positive cycle and strong recirculating flows during the negative cycle. For the cases with different mean jet velocities but the same maximum velocity, time-averaged surface heat flux decreased with decreasing mean jet velocity. As for the effects of pulsation frequency, with high-velocity amplitude ratio, time-averaged surface heat fluxes were at the same level regardless of frequency. However, at low-velocity amplitude ratio, high frequency caused stronger recirculating flows resulting in greater heat transfer compared to the cases with a lower frequency.