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In the chemical industry, distillation towers are a common device used to separate and purify various components. The application of computer technology has enabled the automated control of these distillation towers, thereby facilitating process optimization. With the continuous advancement of technology and the increasingly stringent and refined process requirements imposed by quality systems, traditional methods have become increasingly unable to meet the high efficiency and quality standards demanded by today’s industry. To address the aforementioned shortcomings and achieve precise and effective control over the system temperature, an automated temperature control system based on computers was adopted; after appropriate modifications and adjustments, it was applied in the process of distillation separation. Introduction 1. Principles of distillation: The basic principle of distillation is a unit operation in which a liquid mixture is partially vaporized and partially condensed multiple times; by taking advantage of the difference in volatility among its various components (relative volatility, α), separation is achieved. Distillation can be classified according to its operation methods into: simple distillation, flash distillation, rectification, and special rectification, etc. 2. Brief description of the process: Steam enters from the bottom of the tower. The evaporated vapor phase comes into countercurrent contact with the descending liquid. During this contact, the volatile (low-boiling-point) components in the liquid phase are continuously transferred to the vapor phase, while the non-volatile (high-boiling-point) components in the vapor phase are continuously transferred to the liquid phase. As the vapor phase moves closer to the top of the tower, its concentration of volatile components increases; whereas as the descending liquid moves closer to the bottom of the tower, its concentration of non-volatile components increases. This process enables the separation of the various components. The vapor rising from the top of the tower enters the condenser; part of the condensed liquid returns to the top of the tower as reflux to enter the distillation column, while the remaining part is taken out as distillate. The liquid that flows out at the bottom of the tower is sent partly to a reboiler, where it is heated and vaporized to return to the tower as a gas phase; the other part of the liquid is taken out as residue. 3. Existing problems: However, when looking at the overall chemical processing process, it is difficult to achieve precise temperature control in the entire condensation system. This makes it difficult to distinguish the physicochemical properties of certain substances and impurities. That is, when other impurities inevitably get mixed in the system, the purpose of the entire distillation and separation process is undoubtedly greatly compromised. In response to this situation, in actual production it is common to raise the system temperature as a solution. On the other hand, the higher the temperature, the more difficult it becomes for certain useful substances to be completely condensed and returned, which in turn reduces the efficiency of separation. 4. Solution: Based on the principles of distillation and an analysis of the process, the degree of precision in temperature control determines the quality of the distillation results. In the actual production process, variable factors and influencing factors objectively exist. Moreover, there are many variables that need to be controlled, and various combinations of these variables can lead to results that deviate from the desired goals. Therefore, precise and accurate automated system control plays a very important role both in achieving process efficiency and in maintaining the overall quality system. Automatic control 1. Concept: It refers to the use of external devices or apparatuses, without direct human intervention, to enable machines, equipment, or certain working conditions/parameters in a production process to operate automatically according to predetermined rules. Automatic control is in contrast to manual control. 2. Application: Feedback regulation is the core of automatic control. For example, in automatic temperature control, temperature is used as the output value to regulate heating and cooling, thereby achieving a constant temperature. Using automatic control for temperature regulation in distillation towers can **improve the efficiency and quality of distillation. The temperature of the condensation system at the top of the distillation tower is monitored by a temperature control system; sensitive temperature sensors are installed in this system, and their readings change as the composition at the top of the distillation tower changes. The system sets a certain monitoring temperature threshold; if the temperature of the system exceeds this limit, the automatic temperature control system will adjust itself by resetting the temperature and changing the appropriate reflux ratio in order to resolve the issue promptly. If the temperature of the steam system at the distillation tower exceeds the controlled range, that is, if the proportion of uncondensed substances in the system increases, the entire system quickly adjusts the temperature and reduces the reflux ratio. Conversely, automatic control systems adjust the system to ensure that the distillation process always takes place under constant and suitable conditions. In this way, the operation of the condenser control is carried out through automated programs that ensure precise monitoring, eliminating the need for manual intervention to adjust the system temperature and reflux ratio, thereby optimizing product quality. Distillation Columns and Automatic Control 1. Gas-Liquid Equilibrium under Automated Control The operation of distillation processes is essentially a manifestation of three chemical equilibria: those related to materials, phase states, and heat balance, all of which are closely interconnected. For example, when the steam pressure changes, the actual evaporation rate at the bottom of the tower changes rapidly, which directly leads to thermal imbalance within the system, as well as an imbalance in the gas and liquid phases. Therefore, the key to the production process lies in the balance between heat and steam volume. Under other constant conditions, the flow rate is proportional to the evaporation rate as well as the pressure difference across the distillation column; thus, the evaporation rate can be controlled by adjusting the pressures at both ends of the distillation column. In automatic system operations, a cascade control approach is used for feed rate and bottom of tower pressure; the electronic signal representing the bottom pressure is sent to the flow control valve system, which then automatically adjusts the flow rate. Real-time optimal adjustment of the feed rate can achieve relative stability in the pressure at the bottom of the tower, thereby preventing fluctuations in the feed rate from affecting the final separation efficiency of the entire process. 2. Temperature control of the distillation column: (1) The temperature control element for the distillation section is placed at a certain tray in this section, and this is referred to as distillation section temperature control. Suitable for applications where high quality of the product at the tower top is required or where gaseous feed is used. The adjustment method is to appropriately adjust the reflux ratio based on the temperature of the sensitive plate. For example, when the temperature of the sensitive plate rises, it indicates a decrease in the Zn content of the product at the top of the tower; therefore, a signal is sent to increase the reflux ratio appropriately, so that when XD reaches the acceptable value, the temperature of the sensitive plate drops back to the specified level. (2) The temperature control sensor for the stripping section is placed at a certain tray in the stripping section, and this is referred to as stripping section temperature control. It is suitable for applications with high requirements for the bottom product or when a liquid phase is used as the feed; the adjustment method employed is to appropriately regulate the heating power of the reboiler based on the temperature of the sensitive plate. For example, when the temperature of the sensitive plate decreases, it indicates that the liquid phase composition Xw at the bottom of the reactor increases, resulting in substandard product; therefore, a signal is sent to increase the heating power of the reboiler accordingly, raising the reactor temperature in order to maintain it at the specified operating value. (3) Temperature difference control: When the boiling points of the various components in the feed solution are similar and high purity of the product is required, conventional temperature control methods are not suitable; instead, temperature difference control methods should be employed. Temperature difference control is designed based on the principle that the temperature variations between two plates are always much greater than those on a single plate. This approach makes it easier to ensure product purity, as well as to select and use appropriate instruments. 3. In the industrial production process of PVC, the distillation step is carried out using high and low boiling point towers. The most critical technique here is the precise control of the temperature of the condenser system at the top of the distillation tower, and this represents the bottleneck in the entire industrial production of PVC. With the advancement of technology, installing automated control systems in the condensation section of the PVC distillation process offers clear advantages over conventional methods, as shown by actual data. a. VC low-boiling tower system: The VC low-boiling system is used to separate components such as acetylene, which have a boiling point lower than that of VC. In practice, the actual goal of separating low-boiling components cannot be achieved efficiently, as the two substances often exhibit similar properties, and the acetylene component in the liquid phase is miscible with the vinyl chloride liquid phase system. Based on the actual conditions, a computerized automated control system was installed in the condenser system. It enables real-time monitoring of the temperature of the material at the top of the distillation tower, and makes automatic adjustments based on actual conditions in order to achieve precise control over the temperature of the condensation system, thereby avoiding abnormal situations such as excessively high or low temperatures. After automated temperature control, it becomes possible to optimize the reflux ratio and reflux volume at the top of the distillation tower. b. In the VC high-boiling tower system, the VC liquid from the low-boiling tower is further separated into high-boiling-point components through the distillation process in the high-boiling tower system; the high-purity gaseous VC is obtained at the top of the distillation tower and then converted into a finished product via a condensation system. In actual production processes, traditional condensation system control often fails to achieve precise temperature control, ultimately affecting the quality of the products. And once a computer-based automatic temperature control system is installed in the high-boiling-point tower condensation system, the computer monitors in real time the temperatures at the top of the tower and within the condensation system, automatically controlling the reflux volume and reflux ratio to maximize the operational efficiency of the entire process. Supergravity distillation tower: The supergravity distillation technology that has emerged in recent years utilizes a supergravity field with gravity levels hundreds to thousands of times higher due to high-speed rotation, replacing the conventional gravity field. This approach significantly enhances the gas-liquid mass transfer process and reduces the height of the mass transfer unit by an order of magnitude. This transforms the massive tower equipment into an ultra-high gravity distiller with a height of less than 2 meters, thereby achieving higher efficiency and a reduced size. Supergravity distillation changes the traditional distillation mode of tower equipment, allowing for a continuous distillation process to be carried out in an indoor facility. It helps conserve steel resources for societal development and extends the usable life of Earth’s resources ； For the development of enterprises, it can save space and land resources, reduce pollution emissions, improve product quality, enhance management practices, lower the intensity of labor in production, and increase production safety. The combination of a hypergravity distillation column with automatic control allows for an improvement in the distillation efficiency of such columns both in terms of the gravitational field and temperature, **thus facilitating industrial development.