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冶金步进加热炉基本采用列管式换热器进行高温烟气余热回收,但列管式换热器换热效率低、积灰严重、回收温度低,烟气余热利用程度有限。板式换热器具有传热系数高、结构紧凑、占地面积小的优点。专门针对冶金加热炉开发了全焊接结构的新型高效板式换热器,根据不同现场条件,在设计阶段通过采用不同强化板型结构,调节板间距离、叠加厚度来达到最优的换热效果。梅山钢铁公司实施新型高效板式换热器代替列管式换热器改造,相对于改造前空气预热温度提高了平均100℃,一年最高为加热炉节约1907.1万标方煤气,产生经济效益801万元,在冶金加热炉节能减排领域起到了示范作用。 相似文献
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分析了某石化公司油页岩干馏系统加热炉、冷却塔等装置循环冷却水余热回收潜力,指出回收该部分余热具有较好的环境效益和经济效益。提出了该部分余热的回收利用方案,即采用BR型板式换热器对循环水进行换热回收。介绍了BR型板式换热器结构与特点。方案实施后,节约了采暖用蒸汽180t/d,减少软化水外排量约60t/d,节约费用约140万元。 相似文献
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锅炉排烟余热回收器的设计参数优化模型 总被引:3,自引:0,他引:3
在锅炉尾部烟道中加装余热回收器,可以降低排烟温度,进而降低煤耗率,该文以670t/h锅炉为例,通过对余热回收器10个受热面积方案的换热计算,系统热力计算和技术经济指标计算,并以资金净现值最大为优化目标,得出了余热回收器的最优受热面积与负煤比价,运行寿命,机组年发电量之间的函数关系式。 相似文献
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由江苏工学院与镇江市地质通用机械厂共同研制的烟气余热回收装置一一复合式相变换热器已通过了江苏省科委主持的技术鉴定,并申请了中国专刊.复合式相变换热器由空气预热和相变换热器两部分组成.它利用锅炉废气的余热预热空气,还可提供70-80℃的热水.与普通省煤器、热管换热器和真空变相换热器相比,复合式相变换热器由于采用独特的结构形式和传热机理,并运用优化设计,使该设备的重量、尺寸大幅度下降, 相似文献
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在炼油加工过程中,加热炉是能耗大户.对新建炼厂,在设计阶段提高加热炉热效率,对节能减排有重要意义.在设计过程中,采取燃料气脱硫等措施以降低排烟温度、降低空气过刹系数和漏风量等措施以降低过剩空气量、优化设计加热炉衬里以降低散热损失、优化余热回收系统方案和控制方案以提高烟气余热利用率和操作稳定性、利用装置废热预热助燃空气,... 相似文献
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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. 相似文献
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间歇式热处理炉传热计算与分析 总被引:1,自引:0,他引:1
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。 相似文献
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İsmail Teke Özden Ağra Ş. Özgür Atayılmaz Hakan Demir 《Applied Thermal Engineering》2010,30(6-7):577-583
It is a common problem to choose the most appropriate heat exchanger configuration for heat recovery. In this study, a new model has been developed for determining the area and type of the most appropriate waste heat recovery heat exchanger for maximum net gain. A non-dimensional E number has been defined based on known technical and economic parameters such as the life-time, unit area cost of the heat exchanger, lower heating value of the fuel, overall heat transfer coefficient of heat exchanger, boiler efficiency, operation time per year, heat exchanger effectiveness, ratio of heat capacities, annual variation of the temperature of fluids supplied to the heat exchanger and present worth factor. The non-dimensional E numbers has been demonstrated in graphical forms as a function of NTU and ratio of heat capacities and corresponding heat exchanger area giving maximum net gain can easily be obtained from these graphs. The best heat exchanger type and its area can be determined comparing net gains or effectiveness of heat exchangers at NTUmax. Application of the new method has been given with a case study as a sample calculation. 相似文献
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To improve the practicability of the waste heat recovery system for internal combustion engines, the compact potential of exhaust heat exchangers using metal foams is investigated. In the present study, the performance of compact exhaust heat exchangers is compared with that of a conventional shell and tube heat exchanger in a real test bench. Both heat transfer and pressure drop performance are considered when assessing the performance of heat exchangers because these two factors normally show a trade‐off relationship when designing exhaust heat exchangers. Compared with the conventional heat exchanger, the compact heat exchanger can achieve a similar pressure drop, and at the same time the heat transfer is increased by 30%, whereas the volume and the weight are each reduced by 2/3. The performance of compact heat exchangers with six types of Ni metal foams is also investigated under different mass flow rates and thicknesses of the porous layer. Results show that the optimum compact heat exchanger enhances the comprehensive performance 1.9 times compared with original one. This study shows that metal foams have great potential in realizing a compact exhaust heat exchanger for engine waste heat recovery. 相似文献
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《International Journal of Hydrogen Energy》2019,44(46):25221-25228
This paper reports the heating performances of steam generator for solid oxide fuel cell using waste heat from solid particles. The model of trapezoid-fin-tube heat exchanger was set up by using FLUENT 14.0. The model has been used to investigate the effects of fin tip width (2 mm–4 mm) and fin height (34 mm–46 mm). The fin surface temperature, the particle temperature, the fin total heat flux, the heat recovery efficiency and the heat transfer coefficient were studied. The heating performance of steam generator is improved when the trapezoid-fins are placed on heat transfer tubes, which is conducive to increase the power generation efficiency of solid oxide fuel cell. When the fin height increases from 34 mm to 46 mm, the average temperature of calcined petroleum coke decrease from 414 K to 376 K, the maximum temperature decrease from 498 K to 442 K, the average heat transfer coefficient of internal and external heat exchanger increase 12.4% and 12.7% respectively, the heat recovery efficiency increases 4.3%. When the fin tip width increases from 2 mm to 3 mm, the average temperature reduce 6.7 K and the maximum temperature decrease 7.3 K, the average heat transfer coefficient of internal and external heat exchanger increase 3.8% and 3.7% respectively, the heat recovery efficiency increases 0.88%. 相似文献
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A heat transfer model for three-fluid separated heat pipe exchanger was analyzed,and the temperature transfer matrix for general three-fluid separated heat exchanger working in parallel-flow or counter-flow mode was obtained.It was found that the forms of temperature transfer matrix are similar for heat pipe rows with equal or different heat transfer surface area.Furthermore,by using the temperature transfer matrix of the heat pipe exchanger,the relationship between heat transfer effectiveness θ 1,θ 2 and M,NTU,U,Δt i were derived for the exchanger operating in parallel-flow or counter-flow mode,and a simple special example was adopted to demonstrate the correctness of these relationships. 相似文献
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The excessively increasing environmental concerns along with reducing fossil fuel resources introduce the trend of increasing the efficiency of boiler via implementing waste heat recovery. In the present study, the potential of latent heat recovery is investigated in the middle‐size boiler exhaust flue gas using the shell and corrugated tube heat exchanger. The main purpose of the present study is efficiency growth in flue gases using latent heat recovery of the steam energy. The heat recovery analysis is evaluated by a validated computational fluid dynamics model by a commercial software. For this study, the effect of different tube arrangements, number of tubes, and flow direction in the shell on heat transfer and pressure drop were investigated. The results showed that in‐line arrangement of the tubes in the shell presents better thermal performance and also high pressure drop among the other arrangements. As a result, by considering the thermal performance and pressure drop, radial arrangement shows higher performance. According to the obtained results from Section 2 of the present study, by considering the radial arrangement of tubes in the shell, as the number of tube rises, the thermal performance declines. 相似文献
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A new type of gas burner for Stirling engine that can recover adequate heat from exhaust gas was designed based on the plate heat exchanger and low‐swirl combustion technology, which consists of three components: a cyclone, a burner, and a circular plate heat exchanger. The circular plate heat exchanger tightly wound around the combustion chamber plays a high efficiency of heat recovery role. In consideration of the radial symmetry of the burner, a three‐dimensional numerical simulation was carried out by Ansys15. The velocity distribution, temperature distribution, and pressure distribution of the combustion gas were presented respectively. Strong backflow that came from the exhaust gas around the root of the flame in the combustion chamber and a vortex below the inlet of the exhaust gas channel were found, which were beneficial for the combustion and improving the uniformity of temperature distribution. Combustion behaviors of the burner under standard operating conditions were obtained, the highest temperature was about 2200 K in burner and the exhaust gas entered the plate heat exchanger at the temperature of 1375 K and exited at 464 K, with the waste heat recovery efficiency over 65.8%. And, the air‐fuel ratio and combustion power had negligible effect on the waste heat recovery efficiency. 相似文献