I want to build a monotube boiler. I have plenty of muffler pipe in the garage, and its thickness complies with the ASME formulas for the design pressure, but the type of steel may not be boiler type. What do you think?
I would think muffler material would work for a boiler since it sees fairly hot temperatures when in service. To me the question is what pressure will you be operating at and what safety devices will you have to prevent over pressure. If the tube was to fail, it is likely to split and not explode. Is the muffler pipe seamless or erw? If erw then you need to be concerned about the quality of the welded joint. I would do a serious pressure test before I used it for a boiler. Probably at least twice the operating pressure.
No for the following reasons. 1) the thickness may meet ASME requirements but what type of steel is it? 2) I'm sure the grade of steel is NOT sufficient for boiler tube applications, 3) the muffler tube is seamed and is NOT sufficient for boiler tube application, 4) is the muffler tube aluminized or galvanized because the coating may react with your fluid at higher temperatures, 5) the corrosion of the muffler tube may be accelerated at elevated temperatures when in contact with your fluid. You need to consider operating pressures, the ease of overheating, appropriate materials, heat flow, adequate safety valves, etc. Sorry, but don't take this too lightly and get yourself or others hurt. Good luck.
