Pump Seal Make-Up Package

"2. We are adopting plan 53-modified, is there any requirement for cooling the barrier fluid?"

Normally yes (API682 indicates a cooler in the Plan) - you need to remove the heat added to the buffer fluid by the two seals. Where possible finned tubes cooled by the atmosphere are the most maintenance friendly and the cheapest, however this depends on the cooling required and atmospheric conditions. You do not give many details but I assume condensate at about 45 deg C?

Where does the 15 meter requirement in your first question come from?

Normaly you would try to have the unit as close as possible because the pumping mechanism on the seal develops very low head.