Investigation, Analysis, and Improvement Discussions on the Use of Programmable Valves for Pressure Swing Adsorption Carbon Removal (Prizes for Participants! ）
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Recently, I’ve seen many posts on Haichuan regarding decarbonization. When discussing pressure swing adsorption for decarbonization, it is mentioned that the main problem with this technology is the high frequency of failures in the programmable control valves. Whether these valve problems represent the biggest issue associated with this process remains to be determined. There are likely quite a number of companies using this technology at present. What material is used for the sealing of the valve plates in your company or in any companies you are aware of? How is pressure swing adsorption being used in your organization? How to resolve problems with programmable control valves? How has your organization made improvements? How is it performing after the improvements? Many issues need to be discussed together by all of us. To get things started, let me talk about the situation at my company: We have been using pressure swing adsorption for carbon removal for 8 years now. The first 6 years were fine – the system was very stable. But starting from the 6th year, the programmable valves used in the rough purification process began to fail; mainly, the sealing gaskets of these valves (made of modified tetrafluoroethylene material) got damaged. Even after replacing them with new ones, those gaskets would fail again within less than half a year, which is really problematic! There have also been individual cases of the valve frame becoming detached from the valve body due to welding issues! There’s no good solution at the moment; just replace it when it breaks! But at some point, a problem suddenly arose, causing the system to stop and require maintenance! Headache! Those who reply promptly are kindly requested to have bonus points awarded by BZ! This post was last edited by ddfmy on 2009-3-30 10:38]
The enthusiasm for discussion isn’t high! Are there not many questions from everyone? That’s why we need everyone even more to share their experience!
All three of our units use hydraulic stop valves; the earliest unit was put into operation in 2003 and has been running continuously ever since； The sealing of a programmable valve consists of two main parts: one is the main passage section, and the other is the hydraulic cylinder section ； The main channel is sealed using a valve plate along with a PTFE sealing ring, while the hydraulic cylinder is sealed with a stuffing seal (skeleton oil seal and O-ring) ； In the initial stage, due to inadequate purging and cleaning of the oil circuits, there were frequent leaks in the hydraulic cylinders; these leaks could be largely eliminated after operation for some time ； A few seals in the main channel have been replaced, and no severe internal leakage has been detected yet. The three systems share approximately 220 programmable valves; I hope no serious problems arise, otherwise it will be a big hassle.
Our programmable valves never close properly; when there is a vacuum condition and they fail to close, it causes problems during adsorption, and in severe cases the only solution is to shut down the system.
The valve disc sealing material we use is also a modified tetrafluoro material, based on Sichuan Tianli’s technology. Oil leakage from the supports is quite severe, especially in the programmable valves used for purging and reverse operation; the same issue is apparent with the common valves as well. Some solenoid valves are leaking oil quite severely; I’m not sure what good solutions there are
We use the technology from Sichuan Tianli; the oil doesn’t leak. The problem of oil leakage is mainly caused by scratches on the valve stem or poor-quality dust seals in the hydraulic cylinders. Additionally, regular cleaning and filtering of the oil system are also crucial. Replacing the seals alone won’t solve the issue if there is oil leakage – it’s also necessary to check the oil. Examine the valve stem carefully; if it indeed has scratches, it will have to be replaced. In our case, the problem lies in damaged seal plates. I wonder what oil pressure levels everyone maintains?
We have eight oil pumps; three of them are in use. The oil pressure is generally kept above 4.5 MPa, and not higher than 6.5 MPa.
More or less; ours is also between 4.5 and 5.5. Too high oil pressure can easily cause damage to the valves!
I wonder how everyone is using their energy storage devices – have you checked the nitrogen pressure?
The accumulator can be used; there is no equipment for checking the nitrogen pressure, and nitrogen is filled only once a year.
Points to note when using a accumulator: · Before inflating the air bag, a small amount of hydraulic oil should be injected through the oil filling port to lubricate the air bag； ·It should be inflated to the specified pressure; the inflation pressure for the accumulator can range from 25% to 90% of the system’s maximum pressure, with a typical value being 85% to 90% of the system’s minimum operating pressure ； ·During use, it is necessary to regularly check the airtightness of the airbag; at the beginning of use, this should be done once a week, and thereafter once a month. If the pressure falls below the specified level, it must be inflated promptly. Bring it to a normal state ； ·When not in use for an extended period, the inlet and outlet valves must be closed tightly ； ·During use, it is also necessary to regularly check for air leaks, and any leaks detected should be addressed promptly. If oil leaks from the upper air valve, it indicates that the bladder is damaged, and a new accumulator should be replaced ； ·The accumulator is an essential component and emergency measure in the system, and it should be in good working condition