Steam leaks will entrain air - at whatever temperature - from countless tiny vortices, 360* in the steam plume, along it's length. This cools the steam VERY rapidly. I have direct experience in the type of situation described by the initial poster. There was a steam leak in a 30 PSIG (2 barg)...
In your initial question, you write: "... as I believe that the Gas Hot side should have a much higher temperature than this."
Why? Is there a downstream process issue arising from the HX outlet gas temp?
I might suggest using terms like 1/ hot side inlet temp and hot side outlet temp and 2/ cold side inlet temp and cold side outlet temp.
What cold side outlet temperature was specified on the design?
Spirax Sarco has (had?) some excellent literature on steam systems, one of which is "Steam Heated Tracer Lines", which was a booklet (11 titles in the set - but I only have 3, courtesy of a Scottish salesman what worked in the UK before coming to Canada) published in the UK. The section on...
Companies like Spence, Spirax-Sarco and a number of others make temperature control valves for applications exactly like this. The control valve is installed in the steam line, and the sensing element for the valve is installed in the outlet of the water side of the HX. As well, these companies...
Regardless of whether it is a hot water boiler, or a steam to water heat exchanger - both require the same kind of over-pressure protection on the water side.
I didn't word my post very well - hot water boiler makers will provide the relief valves for the rating of the boiler specified. I have seen hot water systems that ran at 350 PSIG. But the boilers were the boilers, and the system had any overpressure protection required that was separate.
The...
I would look at it like this: If this system had it's own stand-alone hot water boiler, that boiler would have shown-up with whatever relief valve(s) were required as determined by the manufacturer, in order to protect the boiler. The boiler manufacturer has no idea what the system volume may...
The steam-side safety valve is SET for 15 PSIG, or the steam service to the building OPERATES at 15 PSIG? If the steam system OPERATES at 15, that means that the safety valve setting is some higher pressure.
What kind of corrosion are you experiencing? If it's pitting, then that is likely from dissolved oxygen in the feedwater and with feedwater at 140*F, you obviously don't have a deaerator. Note that simply heating the feedwater more will not solve a dissolved oxygen problem, you must vent it.
Not sure where you're getting your numbers. My steam tables say that 600 PSIG saturated steam has 1203 BTU/lb. 228*F feedwater will have about 196 BTU/lb.
The boiler efficiency cannot count the heat value of the feedwater, so that must be subtracted from the heat output. What is the BTU/lb of steam leaving the boiler? What's the temperature of the feedwater entering the boiler? Get the heat values for each off the steam tables to see what the...
What is the fuel input to the boiler to make 1,000 lbs of steam? You can figure that off boiler efficiency (you've posted the annual numbers). What is your cost of a million BTU of fuel? Once you have that, then you can calculate the savings on each 1,000 lbs of steam not required by your...
Ian - Does your boss realize how pipe is insulated? Pipe insulation typically comes in 3 foot half-sections that get wired, taped or banded to the pipe. There are what amount to "cuts" EVERYWHERE after it's installed. That's why insulators cover these joints between the sections (that are...
Order on of these - note that the mini one only does up to 6" pipe. The next 3 to the right all have the same scales, and will measure up to 16" pipe. Note that there are 2 scales, one one for nominal pipe diameter, and one for actual diameter. Cut a slit in the pipe insulation, measure the...