The vacuum system in the solvent recovery device undertakes the two tasks of distillation decompression and membrane separation transmembrane pressure difference. The vacuum degree is unstable, the distillation temperature does not go up, the membrane flux falls down, and the recovery rate is affected. The maintenance of the vacuum system is easily ignored as an auxiliary machine. It is listed as an independent unit management in the operation ledger, and the long-term operation of the device will be much more stable.
The problems of vacuum system are cumulative: the quality of sealing water, the slight leakage of pipelines and the wear of pump clearance are all developing slowly, and the slight drift of daily parameters is more worth watching than sudden failure. If trend management is done on a daily basis, the passivity of device maintenance and repair costs will be much smaller.
The daily management of the water ring pump revolves around the sealing water: in areas with high water hardness, scaling is the first reason for the slow decline of vacuum degree. The sealing water is regularly tested for hardness and replaced, and the heat exchanger is cleaned according to temperature rise. The liquid level and makeup water temperature are recorded shift by shift. High makeup water temperature will directly reduce the pumping capacity. The focus of rotary vane and screw pump is on oil circuit and filter: oil level and oil quality shall be checked periodically, and the pressure difference of exhaust filter shall be changed upon limit.
The operation sound and temperature rise of the pump are included in the patrol inspection: the abnormal sound and bearing temperature rise are the precursors of mechanical failure, and it is better to arrange planned maintenance if it is found early than to wait for the car to jump. The regular switching of standby pumps should also form a system: the main and standby pumps operate alternately, and the standby pumps are not idle for a long time-the pumps that do not rotate for a long time will have dry packing and jammed impellers, which will cause problems when switching. The rotation cycle is weekly or monthly. After switching, check the vacuum degree and current, and confirm the normal state before handing over.
Regularly check the pumping capacity: after shutdown and isolation, the time from normal pressure pumping to assessment vacuum degree of the pump is compared with the commissioning reference, and the capacity decreases when the time is prolonged; The corresponding relationship between the current and vacuum degree of the nuclear pair pump during operation, the same vacuum degree current increases, indicating that the efficiency is decreasing. Check the attenuation found, first check the external causes of the system-pipeline leakage and sealing water quality, then judge the internal wear of the pump, and then start the pump after the external causes are eliminated.
The system has rules for leak detection: segment isolation and pressure maintenance, segment with fast pressure drop and subdivision, and leak detection liquid is used to check micro leak points one by one. Flange gasket and valve packing is the high incidence of micro leakage. Leak check records are kept according to the pipe section number, and one pin number is processed, so that the target of system leakage rate decreasing year by year can be based on.
| Fault phenomenon | Common causes | Handling method |
|---|---|---|
| Vacuum slowly decreased | Scale or slight leakage of sealing water | Check the water quality and then check the leakage in sections. |
| sudden drop of vacuum degree | Sealing water interruption or pipeline breakage | Shutdown, troubleshooting and recovery |
| Temperature rise of pump noise | Bearing wear | Planned Overhaul Replacement |
| Current rise | Wear in pump or abnormal medium | Overhaul after efficiency verification |
| decreased membrane flux | Insufficient transmembrane pressure difference | Check vacuum side parameters |
| Exhaust filter clogged | Differential pressure to limit | Replace by cycle |
First, check the external factors: temperature and flow rate of sealing water, whether there is a new discharge port in the pipeline, and whether the feed on the process side is supplied with gas. External causes are normal to look at the pump itself, and when fluctuations are accompanied by current pulsation, the possibility of problems in the pump increases.
Softened water scales slowly, but the cost and water treatment burden should be calculated. Circulating water with low hardness can also control scaling by strengthening the monitoring of sewage discharge and water replenishment. The key is that the water quality is tested and recorded, not what kind of water is used.
The operating hours shall be given to the basic cycle, and the state data shall be corrected: when the pumping capacity verification and current trend are normal, it shall be arranged according to the cycle, and if the index deteriorates in advance, it shall be overhauled in advance according to the state. Fixed period plus state correction, than only by hours.
This article by LuoyangWohong PetrochemicalEquipment Co., Ltd. arranges that the company provides design, manufacturing and operation and maintenance services for condensation recovery, membrane separation recovery and complete solvent recovery devices for chemical and pharmaceutical enterprises. If you need process evaluation or scheme configuration, please contact and exchange.
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