Why is the catalyst loss in catalytic cracking higher after maintenance than before?
Thread Content
After the maintenance this year, the DCC reactor underwent major repairs; the settlers and expansion joints in the three-rotor and four-rotor systems were cleaned and replaced. After it started operating again, the processing volume remained around 150, with no significant changes. However, when the processing volume increased to 165, the pressure drop in the reactor also rose, and the vibration of the smoke extractor became more severe. Has anyone encountered this situation?
There isn’t much information available, but you can calculate things such as the linear velocity in the cyclone separator and other relevant parameters
We have encountered this issue with paraffin oil catalysis: when the processing volume is increased to its limit, the pressure drop across the settler decreases, leading to agent leakage. It might be exceeding the centrifugation load.
That’s not the main reason, right! Is it okay now after you reduced the volume? A preliminary analysis suggests that the distribution plate might be partially blocked, leading to severe catalyst wear. The processing volume has decreased now, and so has the main output level. Let’s see how it goes; if it doesn’t improve, then we’ll really have to take drastic measures
There are many reasons for material leakage in cyclones. One reason is a fault within the cyclone itself, while another is related to operational issues. A processing capacity of 150 is no problem; however, if material leakage occurs at higher capacities, it might be due to an inappropriate inlet linear speed. Additionally, if a balancing agent is used during operation, check whether the content of fine powder is too high
The increase in vibration of the exhaust fan is usually caused by an imbalance resulting from catalysts on the blades. As the processing volume increases, the main air flow rate also rises; has there been any change in the vibration of the main fan?
I’m sorry I wasn’t able to reply to you in time these past few days as I was on a business trip; also, the smoke extractor stopped working
The inlet velocity for the primary cyclone is required to be 18–25 m/s, while that for the secondary cyclone should not exceed 35 m/s.
It’s possible that there is an error in the installation angle of your flap valve; what is the installation angle for yours?
The angles have all been measured and calculated correctly; now it’s possible that the issue lies with the nozzle or the distribution plate
If the wing valve was not replaced during device maintenance, the installation angle can be ruled out as a cause.