蒸汽管网输送过程的热力学特征及凝水量计算分析

Thermodynamic characteristics and condensate calculation analysis of steam pipeline network transportation process

现有文献中,对蒸汽管网输送过程凝结水量计算及降凝措施的研究多局限于传热学层面,缺乏热力学层面的探讨。运用水蒸汽焓熵图来研究蒸汽管网输送过程的热力学特征,可以形象地反映管道热损与压损对凝结水生成与降凝的过程和机理:热损是产生凝结水的源头;压损降低了蒸汽冷凝的起点,有利于实施降凝;凝结水量的计算应该全面考虑这两项因素。在理论实用价值角度,对基于质能平衡原理推导的凝结水量公式进行了验证和完善;对基于压降过程产生的蒸汽冷凝起点焓值变化进行了定量分析,并提出了饱和焓值与管道压损之间的精准拟合方程。分析表明,管网压损所引起的降凝效应主要反映在低压饱和蒸汽区间;据此论证了低压饱和蒸汽无凝输送的可行性和条件。所得研究结果可供蒸汽管网设计和运行参考。

In existing literature,the research on the calculation of condensation quantity and decondensing measures for the transmission process of the steam pipe network is mostly limited to the level of heat transfer,and the lack of to study at the thermodynamic leve.l Use the water steam enthalpy-entropy diagram to study the thermodynamic characteristics of the steam pipe network transportation process,which can reflect the process and mechanism on the generation and reduction of pipeline thermal loss and pressure loss:The thermal loss is the source of the producer water,the pressure loss reduces the starting point of the steam condensation,which is conducive to the implementation of the reduction,the calculation of the quantity of condensation should be comprehensively considering these two factors.From the perspective of theoretical practical value,it is verified and improved for the coagulative water quantity formula derived from the principle of quality balance.A quantitative analysis is performed for the specific enthalpy changes in the steam condensation point generated by the pressure loss processing process.And proposed a precise fitting equation between the saturated specific enthalpy values and pipeline pressure loss.The analysis shows that the lowering effect caused by the pipeline pressure loss is mainly reflected in the low pressure saturated steam interval;it is based on the feasibility and conditions of low pressure saturated steam non-condensation transpor.t The results of the obtained research can be used for the design and operation of the steam pipe network.