Design And Realization On Control System Of Large-scale Oxygen Manufacture Equipment With ALC

Based on 2x75000Nm3/h oxygen manufacture equipment in shougang jingtang united iron and steel Co. LTD, the paper expounds how to design and develop a control system under DCS system of YOKOGAWA CENTUM CS3000 in detail, which realizes the monitor and control of the oxygen with automatic load change.At first, the paper introduced the current situation of air separation technology and the development of air separation technology is also reviewed. Then, the air compression system, pre cooling system, air purification system, expansion refrigeration system, air separation system as well as liquid storage backup system are explained in detail. The control requirements of oxygen manufacturing process are elaborated. According to above requirements, the paper achieves the task of the hardware and software platform selection of oxygen manufacture equipment system.At the same time, in order to decrease the rate of oxygen blow-off, the air separation products have to meet the user’s needs to achieve automatic adjustment of production load. Along with the scale of oxygen industries expanding continuously, the plant becomes more and more complex which results in many constrains. However, the process limitation and constraints may perturb the plant form their desired working point and the disturbance entering the plant or new input information from the operator may change the location of the optimal steady state. So how to deal with the optimization and control of the complex system in order to make system running in a more economic state is the main problem of this research.MPC calculation is separated into steady-state and dynamic optimization. Considering the effect of measured disturbance, the steady-state objective is recalculated at each sampling time. When carrying out the steady-state target calculation, the steady-state target calculation and dynamic MPC input rate constraints should be compatible. The difference between the model prediction and the measured output at the current time is introduced into the model to incorporate feedback. Finally, the paper researches and designs a predictive control algorithm to achieve the function of oxygen unit’s automatic variable load.Finally, the whole system is accomplished based on DCS control system of YOKOGAWA CENTUM CS3000. Since the system has been put into practice, the process of production and operation is stable and reliable and the system achieves excellent control effect, which increases production efficiency, reduces operating costs and labor intensity and achieves significant economic and social benefits.