常规木材干燥室不同供热状况的 损失分析  

Exergy loss analysis of conventional lumber dry kiln in different heating conditions

作　　者：张璧光[1] 甘雪菲[1] 伊松林[1] 

机构地区：[1]北京林业大学木材科学与工程北京市重点实验室,北京100083

出　　处：《林业科技开发》2012年第1期44-46,共3页China Forestry Science and Technology

基　　金：教育部新世纪优秀人才支持计划项目(编号:NCET-08-0729)

摘　　要：着重分析常规木材干燥室蒸汽管道不同供热状态的损失:当蒸汽管道供热温度一定时,干燥室温度越低,传热温差越大,损失越大;当干燥室温度及蒸汽管道外壁温度一定时,蒸汽管道供热温度越高,传热温差越大,损失越大。传热温差对损失的影响很大,当蒸汽管道供热温度110℃时,传热温差由40℃降到30、20、10℃,其损失分别减少46.08%、77.01%和94.48%,所以要根据干燥室需要的温度尽量减少供热温差,以减少损失。压差流动损失随压差增大而增加,而且压力较高时比压力较低时压降的损失大。蒸汽在管道内压差流动的损失数值比温差传热损失大许多,至少要大1～2个数量级。因此,由锅炉向干燥室供热,应该尽量减少降压节流的情况。Exergy loss of conventional lumber dry kiln in different heating conditions was analyzed. When the steam-coil- heating temperature was constant, lower dry kiln temperature would lead to greater heat transfer temperature difference, meaning more exergy losses. When the temperature of dry kiln and steam coil surface was constant, higher steam-coil-heat- ing temperature would result in greater heat transfer temperature difference and more the exergy losses. The heat transfer temperature difference had a great influence on exergy loss. When the heat-supply temperature was 110~C, the reduction of heat transfer temperature difference from 40~C to 30~C, 20~C or 10~C would lead to 46.08% , 77.01%, or 94.48% de- crease of exergy loss, respectively. Therefore, the heating temperature difference should be reduced as much as possible as long as it meets the need of dry kiln to reduce exergy losses. Exergy loss caused by pressure difference increases with the increase of pressure difference, and was greater in high pressure condition than in low pressure condition. Exergy loss due to differential pressure flow was 1 to 2 orders bigger than that due to temperature difference. Therefore, when the dry kiln is heated by a boiler, throttling should be avoided as much as possible.

关 键 词：木材干燥室 蒸汽供热状况 温差传热[火用]损 压差流动[火用]损失 

分 类 号：U416.168[交通运输工程—道路与铁道工程]