|| ANALYSE AND RESEARCH FOR THERMODYNAMIC SYSTEM IN DRYER SECTION OF PAPER MACHINE|
|| paper machine, the dryer section, thermodynamic system, steam ejector, entrainment ratio|
（3）对蒸汽喷射式热泵在纸机干燥部热力系统的应用做了充分的研究，在学习总结前人计算经验的基础上，对比了不同的喷射系数计算方法，得出热力学计算喷射系数较为准确；提出了针对不同汽源热力系统的热泵设计方法；采用计算流体力学（CFD）软件技术对热泵进行了模拟，验证了本文中的设计方法并进行了模型选优，用Pro / E软件进行了结构造型。
（5）按照某造纸厂提供的参数，设计实施了一套3200 / 350纸机的热力系统，并设计一台蒸汽喷射式热泵，使研究与实践相结合。
Energy is a bottleneck of restricting the development. The contradiction of energy supply and demand now becomes more and more obviously. Energy saving has been paid more attention which is an important method to improve papermaking industry’s profit. On all aspects of pulp and paper in terms of energy consumption, the paper machine dryer section is the largest section, so the reasonable design of paper machine dryer section, in particular the thermal system, and to save construction investment, improve productivity, ensure product quality and reduce production cost has a very important relationship.
For a long time, there is a major problem that condensate water can’t be excluded easily in the thermodynamic system, affecting and restricting paper machine’s speed and energy consumption. So the research of thermodynamic system in the dryer section of paper machine has never stopped in the world. For thermodynamic system in the dryer section of paper machine, it develops generally from a single-stage to multi-stage supplying steam system and then now to heat pump supplying steam system. Since the heat pump supplying steam system came out, the vast of paper machines used this method to improve their heat supplying system in our country.
How to design and arrange thermodynamic system, how to make the heat pump’s function best, and how to bring control system in full play, these factors affect normal operation of the paper machine. To build a new paper machine or improve an original thermodynamic system can not only adopt unified model blindly, it is necessary to study a set of machine-specific parameters of the thermal system design. In this paper, the thermodynamic system on the machine, heat pump and dryer installed devices were analyzed with the study as follows:
(1) All areas about drying section were analyzed in this paper. Pointing out that the constraints as well as the advantages and disadvantages, the main parameter of thermodynamic system be analyzed and researched. It should be given a variety of factors, rational and reasonable to use the most applicable technology, to select the most suitable parameters.
(2) The main parameters of the calculation in thermal system were researched to implement the general steps of machine dryer section design. The VB compiled language made the calculation easy and increased the speed of this research.
(3)This paper studied theory and mechanism in-depth of steam ejector used in the dryer section. Based on the grand old men’ experience, contrasts different calculation means to calculate entrainment ratio. The result is thermodynamic mean for steam ejector entrainment ratio calculation is exact. For different thermodynamic system this paper gives different means to design heap pump. Use CFD software to simulate the steam ejector’ fluent flow. Through those simulating we can find the best way to design steam ejector to achieve the purpose of increase pressure-gradient and energy saving. Finally Pro/E software was used to create structure.
(4)The multi-nozzle ejector was studied. Compared the conventional ejector’s model with multi-nozzle ejector’s model, contrast obtained by the simulation that, multi-nozzle ejector has a huge advantage in its structure and function.
(5)On the base of analysis and research above, a set of 3200/350 paper mill’s drying section was designed according to the parameters which a paper mill providing. In addition, a steam ejector to this drying section was designed.
(6)The theory and mechanism of multi-port dryer were analyzed in this paper. The Pro/E software was used to create structure, and the patent ZL2008200295648 was obtained.