CAJ | 학술논문

针对降膜蒸发器管内结垢问题,提出旋液流态化技术实现自动清洗。由结晶速率等效原理,将饱和溶液在加热面结晶问题等效为在冷却面结晶问题。以0.4m/s平均流速饱和硫酸钠溶液为例进行试验研究。结果表明：近壁面溶液在忽略管壁及污垢热阻的绝对过饱和度Δcsur为4.20%时,与空管连续运行0.5h总传热系数下降80%相比,管内加钢丝螺旋的总传热系数保持不变。Δcsur=5.60%时,钢丝螺旋达到最大清洗速率,超过此值总传热系数下降。Δcsur=6.46%时,加入体积分数1%的粒子,总传热系数未降反升,同未结垢时相比提高6%。降膜蒸发器旋液流态化既能在线自动清洗又可起到对流强化传热效果。其结构简单,便于工业推广。
침대강막증발기관내결구문제,제출선액류태화기술실현자동청세。유결정속솔등효원리,장포화용액재가열면결정문제등효위재냉각면결정문제。이0.4m/s평균류속포화류산납용액위례진행시험연구。결과표명：근벽면용액재홀략관벽급오구열조적절대과포화도Δcsur위4.20%시,여공관련속운행0.5h총전열계수하강80%상비,관내가강사라선적총전열계수보지불변。Δcsur=5.60%시,강사라선체도최대청세속솔,초과차치총전열계수하강。Δcsur=6.46%시,가입체적분수1%적입자,총전열계수미강반승,동미결구시상비제고6%。강막증발기선액류태화기능재선자동청세우가기도대류강화전열효과。기결구간단,편우공업추엄。
To solve the fouling problem of falling film evaporator,a new online fouling removal technology of spiral-flow fluidization is developed.According to the equivalence principle of crystallization rate,the crystallization of supersaturated solution on heating tubes in evaporators is equivalent to that on cooling tubes of heat exchanger in experiments.Saturated sodium sulfate solution flows through the cooling tubes at the average speed of 0.4 m/s.The results show that as the absolute supersaturation near the tube surface（Δcsur） is 4.20%,the total heat transfer coefficient is not reduced under the condition of tubes with steel spiral-insert after continuous operation of 0.5h while it decreases by 80% under the condition of hollow tubes.When Δcsur is more than 5.60%,the total heat transfer coefficient will decrease.However,the total heat transfer coefficient does increase by 6% not decrease under the conditions of spiral-insert and fluidization of 1% volume fraction of particles,when Δcsur is 6.46%.The technology of spiral-flow fluidization can not only remove fouling online and automaticly,but also enhance the convection heat transfer in tube side.With its simple structure,it can be applied in process industry.