伴热管网监控系统的研究

发布时间：2018-02-16 03:28

本文关键词： 化工物料传送伴热管网温度监控模糊控制　出处：《哈尔滨工业大学》2015年硕士论文　论文类型：学位论文

【摘要】：石油化工企业中物料的输送大多是在管道中进行的,为保证物料能够在管道内顺利的传送,需要对物料输送管道进行伴热,以提高其流动性。常用的伴热方式为外伴热管伴热,即将伴热管道安装在物料管道旁,两管道处于平行位置,伴热管内流通伴热介质,伴热介质散发热量为物料进行伴热。通过调节伴热介质的伴热温度以及伴热流量,满足伴热需求。现行的伴热热量调节方式往往为简单的质调节方式,即管网运行过程中伴热介质流量不发生变化,只调节供热温度。这种调节方法虽能保证伴热需求,但往往造成能量的浪费,且容易造成各伴热支路之间的热量分配不均。因此,为了达到节能减排的目的,研究了伴热管网优化控制方法。将伴热网的供热系统分为两级,即一次供热网和二次供热网,热源处将加热后的伴热介质通过一次网输送到各子站,各子站通过流量分配将介质输送各伴热管线。与以往的简单质调节不同,本文采用质调节与量调节相结合的方式,即二次网根据室外温度的变化预测供水温度,制定供热曲线,通过调节热源供热量来调节二次网的供水温度,以此达到按需供热的目的。在管网运行过程中,由于伴热支路较多,各支路之间由于地理环境等因素的不同,会造成各支路的热量不均现象,因此各条伴热支路通过自主调节支路阀门开度,以此调节供热量。对各支路的调节,采用基于回水温度的调节方法。依据伴热系统热量传递的特性,当各支路的伴热回水温度达到工艺指标即可保证被伴热介质得到充足的热量,满足工艺要求。且基于回水温度的调节方法是最直观有效的调节方法,通过监测各支路回水温度,采用闭环反馈的方式,实时调节温控阀开度,从而使回水温度达到工艺指标。由于伴热系统传热过程具有大滞后、大惯性、强耦合的特点,因此,常规的经典控制方法不能取得良好的控制效果,本文采用模糊控制算法,设计了模糊控制器,确定了控制规则,并对模糊控制效果进行了仿真,得到了温度变化相应曲线,并与传统的PID控制进行对比,最终得出本文设计的模糊控制器可以达到良好的控制效果。
[Abstract]:The transportation of materials in petrochemical enterprises is mostly carried out in the pipeline. In order to ensure the smooth transfer of materials in the pipeline, it is necessary to carry out heat tracing in the material conveying pipeline to improve its fluidity. The common way of heat tracing is external heat tracing pipe. The heat tracing pipe is installed next to the material pipeline, the two pipes are in parallel position, the heat tracing medium is circulating in the heat tracing pipe, and the heat released by the heat tracing medium is the material for heat tracing. By adjusting the heat tracing temperature and the heat tracing flow rate of the heat tracing medium, In order to meet the demand of heat tracing, the current regulation mode of heat tracing heat is usually a simple way of quality regulation, that is, the flow rate of heat tracing medium does not change during the operation of the pipe network, and only the heating temperature is adjusted. This regulation method can guarantee the heat tracing demand. However, the energy is often wasted, and the heat distribution is uneven among the heat tracing branches. Therefore, in order to achieve the purpose of energy saving and emission reduction, the optimization control method of the heat tracing network is studied. The heating system of the heat tracing network is divided into two levels. That is, the primary heating network and the secondary heating network, where the heating tracing medium is transported to each sub-station through the primary network, and each sub-station conveys the medium to the heat tracing pipeline through the flow distribution, which is different from the simple quality regulation in the past. This paper adopts the combination of quality regulation and quantity regulation, that is, the secondary network predicts the water supply temperature according to the change of the outdoor temperature, formulates the heating curve, and adjusts the water supply temperature of the secondary network by regulating the heat supply of the heat source. During the operation of the pipe network, because there are more heat tracing branches and different geographical and environmental factors, the heat distribution of each branch road will be uneven. Therefore, each heat tracing branch adjusts the heat supply by adjusting the opening of the branch valve independently. The regulation of each branch adopts the method based on backwater temperature, according to the heat transfer characteristics of the heat tracing system, When the backwater temperature of each branch reaches the technological target, it can ensure that the reheating medium can get sufficient heat and meet the technological requirements. The regulation method based on the backwater temperature is the most direct and effective method, and the backwater temperature of each branch can be monitored by monitoring the backwater temperature of each branch. The closed-loop feedback method is used to adjust the opening degree of the temperature control valve in real time, so that the backwater temperature can reach the technological target. Because the heat transfer process of the heat tracing system has the characteristics of large lag, large inertia and strong coupling, so, The conventional classical control method can not get good control effect. In this paper, the fuzzy controller is designed by using fuzzy control algorithm, the control rules are determined, and the simulation of the fuzzy control effect is carried out, and the corresponding curve of temperature change is obtained. Compared with the traditional PID control, the fuzzy controller designed in this paper can achieve good control effect.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ051.2;TP277

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