The solid content in heavy oil catalytic slurry varies from high to low
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Over the past half month, the solid content in the slurry in my workshop has sometimes been as high as >25 g/L, and at other times it has dropped to <2 g/L. The operating conditions of the riser settler remain stable, and the feed rate is constant; the fresh catalyst used is the same as before. During this period, the amount of slurry sent outside has been high, with the solid content fluctuating. The ash content of the slurry is around 0.05%. All of our slurry is sent outside for disposal, without being reprocessed. Please give me some guidance, seniors! ! !
Could it be that the centrifuge has failed, or that there is a leak in the feed pipe? Once before, a crack appeared in the leg of the centrifuge, which resulted in an excessively high solid content. . .
If there is a problem with the centrifuge, could the solid content drop below 2 as well? We have a system with both high and low pressure units, with the raw slurry/tilted tubes located outside
I’m really not very familiar with parallel configurations; I’ve only worked with coaxial ones. .
Adjust the trend of the coarse spinning pressure drop of the descender and see if the fluctuations are large
The fluctuations are significant, but the overall trend remains the same. Moreover, the opening degrees of the control valves at all steam injection points, feed nozzles, and terminator nozzles in the riser and settler, as well as the flow meters and pressure gauges, have been checked and are all stable with no fluctuations
The reasons for the large fluctuations in the pressure drop of the centrifuge are under investigation; no results available for now
Because it gets big sometimes and small other times. So it’s as if there’s a problem here!
Personal opinion: 1. First, determine whether the solid content of the slurry subjected to analytical testing is indeed catalyst powder, before proceeding with further assessment； 2. Check for reasons in the operation process – could it be that the operating pressure fluctuates significantly? ； 3. Next, look for the cause within the catalyst itself – could it be due to fragmentation or thermal expansion? ； 4. Further analysis of the equipment shows that the first issue is the pressure drop in the cyclone separator, as well as the material leg of the cyclone separator. In our case, we encountered a situation where the material flow rate through this leg was too high, resulting in poor separation efficiency; as a consequence, the catalyst ended up in the distillation tower, which led to an excessive solid content. The operation was stopped for maintenance, and things returned to normal after that. Furthermore, you can’t wait any longer now; hurry up and confirm the situation before making a decision. If the solid content is indeed too high, the pipelines and equipment won’t be able to withstand it for long, so it’s best to be cautious and take action promptly to prevent accidents.