Refining industrial intelligent control system often pressure-relief device solutions
Category:
Smart Factory Integrated Solution
Better Your Technology
Our goal:The maintenance investment rate is above 95%, and the fluctuation of key indicators is reduced by more than 30%, and automatic crude oil switching is realized.
Current Situation, Problem
At present, the problem of atmospheric and vacuum distillation equipment is that domestic crude oil comes from different producing areas, and the variety of crude oil varies greatly. In order to ensure the quality of the products, the operating conditions of the equipment need to be changed according to the switching of crude oil, and the traditional PID-based control. The method can not realize the oil change automation, which leads to the product quality can not be effectively controlled, and the operator frequently operates manually during the oil change, and the labor intensity is large. Therefore, the automatic switching of different types of crude oil in the production process is an urgent problem for refining enterprises.
Atmospheric and vacuum unit solutions
Often pressure-relief devices to be split crude oil by distillation method different boiling range of components, to adapt to the product and the downstream demand for raw materials processing equipment, the main purpose of various fuels derived from crude oil, lubricating oil, chemical raw materials and other petroleum products (such as petroleum coke, asphalt, etc.). Atmospheric and vacuum distillation is the first step of crude oil refinery processing, namely in a crude oil processing, processing in the refinery process always plays an important role, called & other; Leading & throughout; Device. As a result, the operation of the atmospheric and vacuum distillation tower is normal production of crude atmospheric and vacuum device extremely important link, the stand or fall of operation, product quality is directly related to device, pull out rate and unit energy consumption, the size of the reaction device running level. Device including atmospheric and vacuum distillation operation running smoothly, the control of various parameters, raw material properties and operating regulation of environmental change, production plan and the adjustment of the product quality and the processing of abnormal events, etc., which often reduced pressure distillation device running smoothly operation, the basis of the stable operation of fractionating column is the premise of guarantee the quality of the product.
Typical cases
Figure 1 VOA online predictive control process technology co., LTD, zhejiang state industry and the development of zhenhai refining cooperation 1 # set of atmospheric and vacuum device advanced control system, the introduction of the virtual online analyzer (VOAs) to forecast the fractionating column the quality of the products, VOAs can provide higher than the frequency of the laboratory analysis many product quality estimation, and can be connected into the model predictive controller (MPC), feedback control. VOA credible to calibration laboratory tests of the samples, can be used to eliminate the influence of model deviation and unpredictable disturbance and figure 1 structure for VOA realize online predictive control process.
Figure 2 often pressure-relief devices with some quality prediction of zhenhai refining crude distillation product quality soft instrument control system design including the first often do, often a line dry, often three line 95, minus one line of 95 points. Controller according to the oil change period forecast changes of each product quality soft instrument for automatic control in advance, on the premise of guarantee the quality of products, realize automatic switching of crude. The application of this technology in achieving accurate quality control, equipment running smoothly, reduce labor intensity and so on operation has played an important role. Figure 2 below is often do some test sample value and online VOA correct before do some comparison of predictive value.
It can be found that the predicted value before the VOA correction is basically the same as the actual test sample, and there is a big change to the dry point, such as oil switching, which can be predicted in time. This is the condition for MPC to realize online control of product quality.
Fig. 3 The control effect of the constant top decompression point indicator switching control and the advanced control system. After adjusting the dry point index according to actual demand (normal top quality is adjusted from 170 °C to 182 °C), the dry mass controller will automatically adjust the operating variable according to the change of the dry point control range, and the controller operating variable can be found gradually. Adjustment, the dry point quality prediction will return to the adjusted setting range. It is found through the test sample that the actual dry point quality also returns to the set range, indicating that the controller can automatically adjust the dry point index.
Figure 4 shows the effect of the advanced control system on the control of the VDO at the top of the top during crude oil switching. The advanced control system changes the predicted value of the constant top dry point through the signal feedback of the disturbance variable (oil switching). When the oil product changes relatively, the predicted value of the normal top dry point will exceed the control range. The device responds quickly and automatically adjusts the operating variables. It can be found that the predicted VOA of the dry point returns to the control range faster, indicating that the quality of the constant top product is basically maintained within the control range during the crude oil switching process, achieving automatic switching.
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