Seeking experts’ help with the selection of control valves and flow meters
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This is a clumsy device; now it is necessary to select the control valve and the flow meter. I have just started working with chemical process instruments. I hope I can get some help with everything I don’t understand. Regarding the control valves on the drawings, how should I choose the right type for them? And for flow meters, under what circumstances should a mass flow meter be used and when should a vortex flow meter be used? Can a pneumatic single-seat control valve together with the ZDP2000 electrical positioner from Xuzhou Aka be used with the control valve in the diagram? Since it is an old project, all control valves and flow meters need to be removed from the discarded equipment.
The selection needs to be re-evaluated based on the process parameters
A mass flow meter uses thermal sensing for measurement, determining the flow rate based on the amount of molecular mass carried away by the gas molecules. Since it relies on thermal sensing, changes in gas temperature or pressure do not affect the measurement results. The structure of an eddy current flow meter consists of a non-streamlined eddy generator placed in the fluid; it is a device in which fluid separates alternately on either side of the eddy generator, resulting in two sequences of eddies that are arranged in a regular, alternating pattern. Mass flow meters are a bit more expensive; choose one based on the actual circumstances.
Mass flow meters are generally used for transporting products, and they are rarely utilized in industrial processes. For process control, vortex flow meters are sufficient. Control valves are determined based on the parameters of your process; these values need to be recalculated before reusing existing valves. As for the brand of regulator, any brand can be used as long as its safety performance is reliable, and the original valve can be installed in place
Does the original poster understand? If one can figure all this out in just three to five days, then it won’t be possible to manipulate the instruments. It’s recommended that you hire a designer for this task.
This is a benzene extraction unit, right? For the flow meters used in such units, orifice plates combined with differential pressure flow transmitters will suffice. It seems that a mass flow meter could be used if measurement of the injected fluid is required. The selection of instruments for extraction units is relatively simple; it’s best to let the manufacturer make the decision. The only issue is that the medium may contain benzene, so attention should be paid to the sealing materials and their type. Your question isn’t clear enough. Additionally, it’s quite troublesome to recalculate things for reuse projects – the valve sizes and their regulating capabilities need to be matched, and design firms or manufacturers have to do a lot of calculations. Also, practice typing regularly if you have time
Great reply! Give it a like! Original poster, in our factory, what matters for reusing existing equipment is that the diameter matches, and if the flow coefficient is higher than that of the new projects you’re using now, then it can be utilized. It doesn’t work well, so just buy a new one. Reusing old ones isn’t feasible either – the diameters aren’t the same, and the maximum flow rate isn’t even half of what it should be; that would be a disaster……
Control valve: Check the CV value of this control valve. Consider the design conditions, temperature, pressure, pipeline class, material, and process conditions; in other words, look at the pressures before and after the valve as well as the flow rate. The CV value can be calculated based on the design conditions and then compared with that of the old valve