Those numbers don't make "common sense" to me.
230 tubes 6.3mm diameter have a total area of 7400mm^2.
You have 9000mm^3 /s of fluid flow
That is a flow velocity of about 1.2mm/sec. How long is your fluid going to take to pass through the exchanger ???
For good heat transfer you don't need a big cross section area. You need a big surface area. I would forget about round tubes and start brainstorming for a completely different geometry of heat exchanger.