Advanced Process Control Of Micro-system For ATR Of Methanol

Nowadays, as the energy crisis intensifying, people are vigorously exploring new energy options that can substitute traditional energy to achieve sustainable development. Hydrogen attracts widespread attentions because of its cleanliness and high-efficient which makes it considered as the future alternative to fossil fuel. However, its direct application is encountered by a series of problems that hard to solve resulting from its special physical and chemical properties. Therefore, using hydrogen-rich materials with stable physical and chemical properties to produce hydrogen becomes a feasible solution. Because of the moderate operating temperature and high conversion rate of methanol reforming, methanol is generally considered to be the most suitable candidate for hydrogen production. Thus, the study of methanol reforming has received extensive attentions, and one of the hot spots is integrated control of this process.Methanol reforming is a typical variable parameter process. Its model always changes without any rule which makes it difficult for classical control theories and methods to achieve good results. Therefore, this study attempts to employ advanced control strategies to achieve the control of methanol reforming. Concrete research contents are as follows:1. As the methanol reforming process involves complex chemical reactions, it is difficult to fully take all the circumstances into consideration during mechanism analysis. To solve this problem, a micro automatic control system for autothermal reforming of methanol (ATR) is built which has actual hydrogen production capacity. This research platform, on the one hand, provides a strong guaranty for model identification by producing large amounts of data. On the other hand, it provides opportunities for the control methods designed to be applied so that we can examine the performance of control strategies and find defects rather than relying on simulation results only.2. Based on the variable parameter characteristic, we design a control method with parameter adaptive capability. This method can still achieve excellent control effect when the process model changes significantly due to the independence of the controller. Taking actual noise into consideration, an improvement as to anti-interference is made which improves the robustness of the system.3. In this study, sliding mode control ideas is utilized in ATR process control for the first time. In order to avoid the inherent disadvantage of shaking, an improvement is made by adding a smooth link between the sliding mode controller and ATR process. Simulation results show that the controller not only retain the advantage of invariance, but also overcome the influence of shaking. This part of work provides a new solution to the control of ATR4. ATR process is a multi-input multi-output process. Reforming temperature should also be paid close attention while the hydrogen output is concerned. A ratio controller with temperature restraint combined with the advanced controller is designed to achieve the coordinated control between the inputs and outputs.Finally, achievements obtained from our researches are applied into the actual ATR system. The running results verify the validity of the control strategies, and also reveal some shortcomings and defects which specify direction for future research.