摘要
外置式换热器 ( EHE)在大型循环流化床锅炉已被广泛应用 ,而目前国外厂家通常采用的控制进入EHE的物料量的机械阀存在着磨损严重、维护费用高等问题。作者提出一种非机械阀控制进入 EHE的物料量的外置式换热器布置方案。它把外置式换热器和 Loopseal返料机构结合在一起 ,通过控制 Loopseal返料机构和外置式换热器运行时送入的风量来控制进入外置式换热器的高温物料量 ,从而取消机械控制阀。文中对叠置型布置方案的外置式换热器及其连动的 Loop seal返料机构进行了冷态试验研究 ,试验研究结果表明这种布置方案可以实现物料向 Loop seal返料机构和 EHE的分流 ,通过调节运行参数或结构参数 ,可以控制进入 EHE的物料流量及比例 ;同时得到了叠置式外置换热器的压力分布和阻力特性。另外 ,也给出了 EHE换热床内的传热特性。图 1 4表 1参
External Heat Exchanger (EHE) is believed to be a viable way towards the solution of heat transfer surface arrangement and steam temperature control with the scale up of circulating fluidized bed boilers. A new concept of external heat exchanger is developed in this paper. The flow of hot solid particles diverted from the recycle loop is controlled by pneumatic (air flow of recycle device or EHE), not the mechanical valve that is popular used in many CFB boilers. The major feature of this EHE system is avoiding the use of the mechanical vale that exist heavy erosion and high cost. The in series joint way between the EHE and the recycle device, (i.e., the recycle device is on top of the EHE) is proposed. The following aeration air flows may be used as the control parameters of the solid flow diverting from the recycle loop: fluidizing air of overflow part of the loop seal and the fluidized chambers of EHE, aeration air of the standpipe of the loop seal and the first chamber of the EHE. Experiments on the operation characteristics and the control characteristics of solid diverting of the operating parameters have been completed in the cold EHE test rigs. In additional, experiment on th heat transfer of the heat exchanger bundles in the fluidized chambers of the EHE shown the heat transfer coefficient between bed to immersed heat ecxhanger surface is very high. Figs 14, table 1 and refs 7.
出处
《动力工程》
CSCD
北大核心
2001年第4期1324-1331,共8页
Power Engineering
关键词
循环流化锅炉
外置式换热器
非机械阀
试验
circulating fluidized bed boiler
external heat exchanger
not mechanical valve
control
pressure ditribution
resistance characteristics
