How to control C2 in reformed liquefied gas?
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I would like to ask the experts: how can C2 levels in continuously reformed liquefied gas be kept below 3, and how should the stabilizer be operated?
In my opinion, C2 in liquefied gas is related to the reforming reaction; we also often experience excess levels of this substance. When that happens, we increase the temperature of the water cooling system in the stabilizer tower, and we redirect the overhead gas from being reprocessed to being discharged at a lower pressure
Bro Yu, aren’t you controlling it pretty well?
There is no water cooling – only air cooling. How do I adjust it? With air cooling turned on to full capacity, it doesn’t get cold enough
It’s not at full capacity either; the temperature should be slightly higher, so that the lighter components in the gas at the top of the tower can be removed through the low-pressure outlet, rather than staying in a state of continuous recirculation through re-contact. That’s how I understand it – I’m not sure if that’s correct
Increase your cold-end temperature slightly to prevent C2 from condensing as much as possible
The approach of releasing the gas at the top of the tower to adjust the fuel gas amount is flawless; relying solely on increasing the temperature after cooling and the temperature at the top of the tower can be effective, though the effect isn’t particularly significant. As the temperature after cooling and the temperature at the top of the tower increase, it is also necessary to increase the amount of fuel gas supplied, while making sure that the amount of C5 extracted remains within the specified range.
Previously, the opening degree of the vent valve at the top of the tower here was very low, only a few percent; it was later adjusted to around 40, which was slightly better. However, the operation of this vent valve has always been carried out in accordance with the instructions from management, and the shift team made no adjustments. There are many factors at play, and the carbon pentane content in the liquefied gas is quite acceptable
For the raw material, our reformed and stabilized liquefied gas has a C5 content of no more than 2. Then, stable dry gas is sent out from the stabilization reflux tank, and the fuel gas lines within the unit are installed. The operation of the stabilizer is primarily aimed at controlling the saturated vapor pressure of the stabilized gasoline.
The overhead gas is sent forward and then comes into contact with C2, forming a cycle; the overhead gas is not combined with the fuel gas, making it difficult to control the C2 content
Let’s take a look at the reforming reaction then. In our unit, the proportion of C2+C5 in the liquefied gas is no more than 5%; the temperature at the bottom of the tower is not high, and the C5 content is low. It’s mainly the C2 content that matters, which remains around 4.5%. If this value is too high, it’s likely due to issues with the reforming reaction