Added control via regulating valve
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It is planned to add two additional DCS control points to the existing process: a new steam control valve to regulate the temperature of the reactor, and a new circulating water control valve to regulate the top temperature. I need help determining how many interfaces are required for a DCS system, as well as what types of instruments are needed. The more detailed the information, the better. Thank you.
If no complex calculations are involved, for two PID controllers, generally two AI elements and two AO elements are required, making a total of four channels. As for the materials, since it is about regulating temperature, two temperature sensors are needed; for temperatures that are not very high, PT100 sensors can be used, along with two control valves
Thank you, but could the materials be more specific? Does it include anything like a magic box that is needed in the DCS control box? I’m afraid the materials submitted may not have been considered thoroughly, and the specifications might be incorrect. (Vapor: 12 Kg, DN50; used to control the kettle temperature between 0-200 degrees; circulating water: 3 Kg, DN40; used to control the top temperature between 0-160 degrees)
For temperature measurement, just specify PT100. As for the insertion depth, it should not exceed half of the diameter; in your case, one is 20 MM and the other is 10 MM. Regarding control valves, the models vary from manufacturer to manufacturer; once you have determined the manufacturer, then specify the model
Your description of the process isn’t very clear. First of all, is there a relationship between controlling the temperature of the reactor and controlling the top temperature? It seems that this kettle has a jacket; does the steam pass through the jacket? What about the circulating water? To achieve effective control, it is necessary to understand the process and the equipment involved. This is a rather general statement; if there is no connection between the two and it’s just a single-loop control system, then it’s quite simple. If electric control valves are used, each valve requires an AO and an AI signal. If temperature measurements for the reactor and the top of the vessel are not already available, then two additional RTDs are needed. As for the power supply for the valves, you need to decide whether it should come from the DCS or from the electrical department. Generally, the power supply for control valves is provided by the instrumentation department. For the software side, a PID controller suffices, allowing for both manual and automatic operation. As for whether additional modules are needed in the DCS, you need to check whether there are any spare points available for those modules; if so, you can use them directly, otherwise you’ll need to add additional modules
Steam supplies heat to the falling film evaporator to control the temperature of the reactor; at the top of the tower, an internal reflux condenser is used to control the top temperature
Then these two controls are not closely related to each other. The issue of temperature lag also needs to be taken into consideration. Observe carefully and adjust the PID parameters to find a suitable set – it’s a single-loop control system
Thank you. The basic idea is to use single-loop control in place of manual operation in order to achieve temperature stability. I currently lack knowledge regarding the materials used for instruments, and I don’t know how to document them; the PID can only be adjusted after the instrument is installed. I also hope you can give some guidance regarding the submission materials
Thank you. The basic idea is to use single-loop control in place of manual operation in order to achieve temperature stability. I currently lack knowledge regarding the materials used for instruments, and I don’t know how to document them; the PID can only be adjusted after the instrument is installed. I also hope you can give some guidance regarding the submission materials