ENGMechanical,
Assuming you know all about ammonia production on a large scale (safety, control, operability, metallurgy, equipment process and mechanical design and so on - in other words more than google and a couple of weeks reading), I'd suggest looking at the literature around process scale up. Most of the problems you'd encounter are effectively the reverse of what most of us try to do when developing a new process.
As a starting point, the obvious issues are:
Heat losses become more significant as equipment gets smaller
The process volume in pipework will be a significant fraction of the overall plant inventory.
Small scale equipment often isn't an exact analogue of the larger commercial equipment, is disproporionately expensive or simply not available.
Heat integration is much more difficult
Different technologies may be better - electrical heating may be better than steam for example.
There are a few companies out there that build this sort of plant for a living. As a wild guess, assuming a team experienced in small scale design, maybe a project cost in the high tens of millions of dollars for something like this.
Regards,
Matt