"After replacing the molecular sieve, the pressure difference of the condensate dryer B was reduced from about 120 kPa before the replacement to a normal 75 kPa, and the subsequent analysis of the sample content of the carbon three hydrogenation system was qualified." March 3 At the meeting, Wang Jun, a technician of the ethylene plant compression process at Guangzhou Petrochemical Industry, reported on the operation of the condensate dryer after the online replacement of the molecular sieve. Clutch Disc,Clutch Disc Assembly,Custom Clutch Disc,Automobile Clutch Disc ZHEJIANG LINGFENG TECHNICAL CO.,LTD. , https://www.boxnclutch.com
The function of the condensate drier is mainly to remove the trace amount of water entering the deprotonation material, prevent the carbon three hydrogenation catalyst from being temporarily poisoned, and satisfy the water content regulation in the propylene product. There are two A/B dryers, one for operation and one for regeneration. Each unit has a 48-hour operating cycle.
Starting in June 2016, the operating pressure at the B station rose from a normal 75 kPa to 115 kPa, and there was a shortage of regeneration gas flow during the regenerative operation. Failure to deal with it in time could easily lead to exceeding the standard in the subsequent separation process.
"Although measures such as increasing the regeneration gas cross-over line effectively alleviate the problem of small regeneration gas flow, they still do not completely solve the problem and pose a threat to the safe and smooth operation of the plant," said Liu Lixin, chief technician of the compression process.
If the work is stopped and replaced, the impact on the device and the downstream will be enormous. Through repeated research by technicians, they decided to replace B's molecular sieves and porcelain balls online. However, the normal operating cycle of the A-station is only 48 hours. Replacement of a molecular sieve requires the replacement, unloading of the molecular sieve, and the application of the molecular sieve. The time is not enough.
How to successfully complete the replacement of dryer molecular sieve in the shortest time? The technicians boldly proposed that the molecular sieves be qualified for dryness in the manufacturer, sealed and packaged, and no longer be scheduled to regenerate after on-site filling, and that the molecular sieves be directly put into operation to save about 20 hours of molecular sieve replacement time.
In order to ensure that the replacement work is foolproof, the craftsmen will continue to refine the replacement plan, and provide training and training to the team members in advance so that everyone in the replacement plan will have a good idea. In the process of replacing the molecular sieves, they increased the temperature of the condensate stripper sensitivity plate, increased the frequency of bottom draining, reduced the water content taken to the subsequent system; properly reduced the device load, and strengthened the monitoring of the water content at the feed station of the carbon three hydrogenation system. To ensure the stable operation of the carbon three systems during the replacement process. In addition, they also performed sample analysis on the dew point from the C3 hydrogen inlet, propylene product, etc. after 36 hours of operation at the A station. If the C3 hydrogenation inlet dew point exceeded the limit, the feed to the depropanizer was stopped to avoid the propylene product. influences.
With the joint efforts of everyone, the online replacement of the condensate dryer molecular sieve was successfully completed. Replacement of the molecular sieve condensate dryer has not only thoroughly solved the problem of long-period operation of the control device, but also accumulated experience for on-line replacement of other dryer molecular sieves.