卧式喷淋降膜蒸发站在麦草浆黑液蒸发中的应用

Application of Five Body, Four Effect Horizontal Spraying-Film Evaporator in Concentrating Wheat Straw Pulping Black Liquor

针对草浆黑液的物理性能及蒸发浓缩的困难 ,研制了卧式喷淋降膜蒸发器。生产实践表明 ,该蒸发器可应用于草浆的黑液浓缩。以安徽某纸厂亚铵法麦草浆黑液五体四效蒸发站 (单台传热面积 2 50m2 )为例 ,进行了应用结果的分析 ,测试出各效的传热系数为 1 2 357～ 1 4 779kJ/(m2 ·h·K) ,蒸发强度平均为 2 0 88kg/(m2 ·h) (黑液浓度由 7%蒸浓到 53 % ) ,并且具有良好的防垢和除垢性能。

The studies of characteristics of black liquor from wheat straw pulping process show that such type of black liquor has high content of ash (silica), pentosan and high viscosity which will influence the normal evaporation operation. The heat transfer ability of wheat straw pulping black liquor is poor and this black liquor is easy to form scales during evaporating. Recently an industrial scale new type of five body, four effect horizontal spraying-film evaporator was designed and installed by us, the industrial scale trials are proved that the new designed horizontal spraying-film evaporator with heat-transfer area of 250m 2 has extremely high evaporating capacity, high heat-transfer coefficient, the scale formed is easily to be removed. The mean of evaporation intensity for wheat straw pulping black liquor can reach up to 18～22 kg/m 2·h, heat transfer coefficient can reach up to 12357～14779 kJ/(m 2·h·K).