Hi,
Does anyone know of a process in the industry where a multi-tube catalytic reactor is used for a heterogeneous G-S reaction at low pressure (<5 barg)?
I'm working on a project for the partial oxidation of a hydrocarbon. The reaction is highly exothermic and takes place at 380-450 C and around 2 barg.
I'm finding it extremely hard to come up with a design for this application. The reasoning behind my design is the following:
- Reactors with larger tube diameter are more cost effective than those with small diameter for the same capacity.
- Tube heat transfer area decreases when the tube diameter increases, making more difficult to remove heat of reaction.
- Limit pressure drop of reactor to 0.5 bar because of high cost of compression and recycle.
- High space velocity increases selectivity to desired product (according to experimental data).
Basically, I'm trying to find the maximum tube diameter that allows to remove the heat of reaction, and a tube length that will give me a reasonable pressure drop and number of tubes at a given space velocity (I'm assuming 40,000 max). Obviously this two trade-offs are dependent and have an effect on each other, but I wanted to state it like this for matter of simplicity.
The only way I can achieve this is at a very low space velocity, that results in a sharp decrease in selectivity to the desired product and increase in selectivity to undesired products (CO2 and CO that result from a total oxidation).
I suspect the biggest issue is the low operating pressure and pressure loss limitation that does not allow me to operate at higher space velocities. This is why I ask if anybody knows of this kind of reactor being used in a similar low pressure application.
Maybe a fluidized reactor is a better choice in this scenario?
Looking forward to hear your comments,
Thanks,