What issues in the operation are indicated by this set of MTBE product data?
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Sample Name, Analysis Items, 0:00, 8:00, 16:00, Unit, Upper Limit, Lower Limit. MTBE Product, C4 Components, 000% (m/m), 0.5; C5 Components, 0.19, 0.19% (m/m); Components with Molecular Weight over 8, 6.49, 6.26, 5.25% (m/m); n-Butylene + Isobutylene, 0.01, 0.02% (m/m); Methanol, 000% (m/m), 0.2; tert-Butanol, 0.11, 0.12, 0.15% (m/m), 0.6; Methyl tert-butyl ether, 92.82, 93.07, 94.35% (m/m); Methyl sec-butyl ether, 0.19, 0.15, 0.16% (m/m); Methyl tert-pentyl ether, 0.02, 0.03, 0.08% (m/m); Unknown Components, 0.17, 0.16, 0.01% (m/m); Methyl tert-butyl ether + Methyl sec-butyl ether, 93.01, 93.22, 94.5% (m/m); 98
How can there be such a high C8 level? Could it be that the proportion of methanol is too low, causing isobutylene to undergo dimerization?
Based on sampling analysis, with a methanol content of 0 in MTBE and a high amount of C8, it is likely that the alcohol-to-olefin ratio is on the low side. In terms of operation, the isobutylene concentration can be monitored using online instruments, or the isobutylene concentration in the raw C4 material can be determined through sampling analysis; additionally, the bed temperature can be observed to make a judgment. All other components are within normal ranges
The low alcohol-to-olefin ratio is caused by the high temperature in the etherification reactor.
This is due to an excessively low alcohol-to-olefin ratio after the catalyst was replaced; increase the amount of methanol used.
After replacing the catalyst, methanol immersion does not cause problems; the alcohol-to-olefin ratio is low during the startup phase
I’ve never seen such a high C8 content; increase the control of methanol
Isobutylene has a high likelihood of self-polymerization as the alcohol-to-olefin ratio is gradually increased.
1# chengkang has an excessively low alcohol-to-olefin ratio, resulting in the autopolymerization of isobutylene.
If there is no problem with the upstream equipment, it is caused by an excessively low alcohol-to-olefin ratio; increasing this ratio should resolve the issue.
Carbon 8 should be a dimer; this is caused by a lower alcohol-to-xylene ratio during processing, and the issue can be resolved by increasing the purity ratio appropriately