摘要
大型循环流化床锅炉广泛采用各种形式的外置式换热器。传统的换热器只能实现换热器(EHE)和返料机构(loopseal)之间的物料流量的调节,此时进入EHE的物料将会全部顺次流过各个换热仓室,很难对外置床中的各种受热面的传热量进行单独调节。本文首次提出了一种全新的非机械阀式外置式换热器布置方式,通过控制流入各个换热仓室的固体物料流量,从而达到对各换热仓室中布置的受热面的换热情况进行单独调节。同时把EHE和loopseal结合在一起,保证向炉膛的返料。文中对这种一体化外置式换热器及其返料机构中的物料流动特性进行了冷态试验研究。试验结果表明,这种外置式换热器有很好的物料分流和流量控制特性。可以通过调节运行参数和结构参数来控制两个换热室、EHE和loopseal以及两个返料口之间的物料流量和比例。同时还得到了物料在换热室的流动特性。通过对可见输送分离高度的测量,提出了分配室和换热室相对隔板高度的设计方法。
Various external heat exchangers （EHE） are widely used with large-scale circulating fluidized bed （CFB） boiler. The solids mass flow rate diverted from the standpipe to the EHE or the loop seal can be controlled and the flow of hot particles into the EHE passes through all heat exchanger chambers in succession. So it is not feasible to control the quantity of heat transfer of different and multilevel heat transfer surfaces in the EHE. A new type of pneumatically controlled EHE was developed in this paper. The major feature of this EHE system was that the solids flow to two heat transfer chambers could be controlled. Thereby the distribution of the quantity of heat transfer could be easily adjusted. Simultaneously, the EHE and recycle device were connected in order to recycle the solid back to the furnace steadily. Experiments completed in the visible cold EHE test rig showed that the solids mass flow rate to the EHE or the loop seal, to two heat transfer chambers, to two exports of solids could be controlled by the aeration airflow into each chamber and geometrical dimension like the height of partition. At the same time, the flow characteristics of solids in heat transfer chambers were investigated. By measuring the visible transport disengagement height （TDH）, the design principle of the relative height of partition of heat transfer and distributing chamber was proposed.
出处
《化工学报》
EI
CAS
CSCD
北大核心
2007年第10期2485-2492,共8页
CIESC Journal
关键词
循环流化床锅炉
外置式换热器
气力调节
物料流量控制
circulating fluidized bed boiler
external heat exchanger
pneumatic control
control of solidsmass flow rate
