I think the 60 ft is good. I'm not sure you want to operate glycol hot enought to keep sulfur molten.
If you need to jump over sections for flanges, valves, etc, the jump over pressure drops will be very high because the csa in the jump over is far less than the jacket.
Steam presents a...
I think plumbers use about 25-50 gal/day/person. This may be for homes and include cooking, toilets, and bathing so you may want to use the lower number for a plant situation.
You might also check local plumbing codes or do a Google search.
The purpose of a relief device is to prevent a pressure vessel from catastrophically rupturing. I don't think a Plate & Frame Heat Exhanger is even a pressure vessel. Does it have an ASME Stamp/Design?
As the plates will leak and prevent a catastrophe, I see no reason to add relief protection...
It is normal to see weld lines but you should not see discoloration. Discoloration is indicative of poor welds.
The only way to fix poor welds is to cut them out and redo them. Automatic orbital welding is the preferred method of welding sanitary pipe. Welders must be qualified and it is...
