化学机械法制浆废水的蒸发及其物化性质的研究

发布时间：2018-11-16 07:08

【摘要】：研究了P-RC APMP废水的沸腾传热系数,实验在强制循环蒸发器上进行,考察了热通量、流体流速、流体浓度对P-RC APMP废水沸腾传热系数的影响。实验结果表明,在一定的热通量下,随着流体流速的增加,P-RC APMP废水沸腾传热系数增加。浓度不同,流速对传热系数的影响不同,随着浓度的增大,流速对传热系数的影响越大。采用不同的多效蒸发流程,根据测得的沸腾传热系数对其蒸发能耗进行了核算,并与热泵蒸发的能耗进行了对比,结果表明,五效顺流蒸发每蒸出一吨水需要18.52kg标煤,三效顺流蒸发每蒸出一吨水需要26.17kg标煤,而太阳纸业的热泵蒸发生产数据是每蒸出一吨水需要6.81kg标煤,从以上结果可以看出,P-RC APMP废水在2.22～12.40%这个范围内,热泵蒸发具有比较大的优势。研究了废水的各项物化性质,包括波美度,相对密度,粘度,表面张力,比热容,沸点升高值和固形物的元素分析,为废水处理提供理论依据。实验结果表明, P-RC APMP废水和BCTMP废水的相对密度、波美度与浓度都呈很好的正比线性关系,与温度都呈反比线性关系。粘度随着浓度的增大而增大,温度的升高而减小,P-RC APMP废水浓度超过约40%时,粘度急剧增大；BCTMP废水浓度超过约30%时,粘度急剧增大 P-RC APMP废水的表面张力随着浓度的增大,开始变化不大,当浓度超过约35%时,表面张力随着浓度的增大而增大,随着温度的升高而逐渐减小；BCTMP废水的表面张力随着浓度的增大,先略有减小,当浓度超过约15%时,表面张力又随着浓度的增大而增大,随着温度的增大而逐渐减小 P-RC APMP废水和BCTMP废水的比热容与其固形物含量有关,都是随着固形物含量的增大而减小,与固形物含量呈很好的线性关系。 P-RC APMP废水的沸点于升高值与浓度成正比,当浓度超过30%时,随着浓度的增大,沸点升高值增大的越来越快。 C元素在P-RC APMP废水固形物中所占的比例为31.18%,N元素为0.46%,H元素为3.93%,S元素为0.008%。 P-RC APMP废水固形物的无机物含量为30.26%,有机物含量为69.74%,燃烧热为12457kJ/kg; BCTMP废水固形物的无机物含量为25.66%,有机物含量为74.34%,燃烧热为16380kJ/kg。
[Abstract]:The boiling heat transfer coefficient of P-RC APMP wastewater was studied. The effects of heat flux, fluid flow rate and fluid concentration on boiling heat transfer coefficient of P-RC APMP wastewater were investigated. The experimental results show that the boiling heat transfer coefficient of P-RC APMP wastewater increases with the increase of flow rate under certain heat flux. The effect of flow velocity on heat transfer coefficient is different with the increase of concentration, and the effect of flow rate on heat transfer coefficient is greater with the increase of concentration. According to the measured boiling heat transfer coefficient, the evaporation energy consumption is calculated by using different multi-effect evaporation processes, and compared with the energy consumption of heat pump evaporation. The results show that 18.52kg standard coal is required for every ton of water evaporated by five-effect downstream evaporation. The 26.17kg standard coal is required for every ton of water evaporated by the three-effect downstream flow, while the heat pump evaporation production data for the Sun Paper industry is that each ton of water needs the 6.81kg standard coal for each ton of water evaporated. As can be seen from the above results, In the range of 2.22 ~ 12.40% for P-RC APMP wastewater, heat pump evaporation has a great advantage. The physicochemical properties of wastewater were studied, including wave beauty, relative density, viscosity, surface tension, specific heat capacity, boiling point elevation value and elemental analysis of solid, which provided theoretical basis for wastewater treatment. The experimental results show that the relative density of P-RC APMP wastewater and BCTMP wastewater are both proportional to the concentration and inversely proportional to the temperature. The viscosity increases with the increase of concentration and decreases with the increase of temperature. When the concentration of P-RC APMP wastewater exceeds about 40%, the viscosity increases sharply. When the concentration of BCTMP wastewater exceeded about 30%, the viscosity of P-RC APMP wastewater increased sharply, and the surface tension of P-RC APMP wastewater began to change little with the increase of concentration. When the concentration exceeded about 35%, the surface tension of P-RC APMP wastewater increased with the increase of concentration. With the increase of temperature, the temperature decreases gradually. The surface tension of BCTMP wastewater decreases slightly with the increase of concentration. When the concentration exceeds 15, the surface tension increases with the increase of concentration. With the increase of temperature, the specific heat capacity of P-RC APMP wastewater and BCTMP wastewater is related to the content of solids, both of which decrease with the increase of solid content, and there is a good linear relationship between the specific heat capacity of P-RC APMP wastewater and BCTMP wastewater. The boiling point of P-RC APMP wastewater is directly proportional to the concentration. When the concentration exceeds 30%, the boiling point increases faster and faster with the increase of the concentration. The proportion of C element in the solid form of P-RC APMP wastewater is 31.18% and N element is 0.46% and H element is 3.93% and S element is 0.008%. The inorganic content of P-RC APMP waste water is 30.26, the content of organic matter is 69.74, the combustion heat is 12457 KJ / kg, the inorganic content of BCTMP waste water is 25.66g, the content of organic matter is 74.34 and the combustion heat is 16380kJ / kg.
【学位授予单位】：天津科技大学
【学位级别】：硕士
【学位授予年份】：2011
【分类号】：X793

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