【JST-026】One-on-One Q&A Office for Continuous Reforming Units (UOP)
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This post was last edited by Firefly on 2015-4-10 08:26. To better share knowledge and skills with everyone and as a challenge for myself, a dedicated Q&A thread has been created. My areas of expertise include the operation of continuous reforming processes and accident analysis (mainly UOP processes). Work experience: over 8 years of experience in the operation and management of continuous reforming units. Regarding the questions raised, I will do my best to provide answers. Note: + F9 b: {* g% h8 @* U 1) This post is mainly focused on issues related to the operational procedures and accident analysis of continuous reforming units, with the aim of facilitating mutual exchange and joint improvement. 2) This post is intended for one-on-one discussions between those seeking help and me; other forum users are also welcome to participate in the discussions. If you are not satisfied with the responses, please create a new topic in the Catalysis/Coking/Reforming/Oil Blending discussion area. Thank you for your cooperation! 3) Due to work commitments, I may not be able to respond promptly; please understand!
This post was last edited by naruto on 2013-4-4 15:08
In the reduction section, from top to bottom, the temperature of the second thermocouple is the lowest; this is the case for most of them, with only very few exceptions. For heating the hydrogen supplied to the closed hopper, medium-pressure and low-pressure steam as well as electric heating can be used, with the temperature being controlled at 180 degrees? The differential pressure control for the nitrogen-sealed tank and the closed hopper is set at a few KPA; there are often alarms related to this, and it is the most difficult parameter to adjust properly.
The differential pressure between the nitrogen-sealed tank and the closed hopper is controlled at 5 kPa; fluctuations in this parameter are related to the pressure in the reformate separation tank and the pressure in the regenerator
For heating the hydrogen supplied to the closed hopper, medium-pressure and low-pressure steam as well as electric heating can be used, with the temperature being controlled at 180 degrees? There’s no real need for this; heating with low-pressure steam is sufficient. It’s not necessary to keep the temperature at 180°C – a slightly lower temperature has little impact, and there’s no major problem even if the temperature is above 150°C
The temperature in the reduction section, from top to bottom, is lowest at the second thermocouple; this is the case for most of them, though there are a few exceptions. This is related to the characteristics of the reduction section as well as the location where the thermocouples are installed. You can check your equipment’s manual for more details
May I ask the original poster: The reduction reaction is an exothermic reaction. But why is the actually measured temperature of the reduction section lower than the temperature of the reducing hydrogen?
You can consider this from two aspects. First, the temperature of the gas raised by the regenerator is generally around 170°C, and the flow rate varies depending on the regeneration capacity, but it is usually around 500 Nm3/h. Due to heat losses in the riser, the temperature of this gas is still around 110°C when it reaches the inlet of the reduction section; this cooler gas causes a decrease in the temperature within the reduction section； The second reason is the catalyst; when the catalyst enters the reduction section, the temperature is usually around 110°C, and part of the heat from the reducing hydrogen is used to heat the catalyst
The differential pressure setting for the nitrogen-sealed tank and the closed hopper is 5 Kpa; have you set it at the maximum value? UOP has always wanted to set it at 2.5 Kpa; if that’s not possible, then… It was set at 4 Kpa, and a damper was added to the differential pressure gauge (based on our recommendation). UOP tried hard to adjust the PID parameters without success, and changing the curve for the balance valve also did not lead to any improvement.
After the major overhaul of my unit last year, the startup isolation valve bank keeps closing frequently! I only increased the temperature of the replacement gas a little! It got much better after that! But there are still times when it shuts down! Can I increase the flow rate of the replacement gas? Will increasing the flow rate have an impact on the flow? Some sources say that the dust generated after removing the agent and then adding it affects flow! Is there a good way to remove it?
OP, are you proficient at semi-regeneration? Can I ask about semi-regeneration in the future?