Aluminum pipe, cost

Properly coated aluminum pipe has performed well in this environment for more than 40 years. This alloy requires active monitoring, but the added benefits of low-cost installation and lack of product contamination provide cost-effective systems. 

Appendix A contains a materials selection guide for aerated freshwater systems. As indicated in Note 27 of Appendix A, in freshwater systems, admiralty brass should be limited to a maximum pH value of 7.2 from ammonia and copper-nickel alloys and should not be used in waters containing more sulfides than 0.007 mg/L The materials selection guide is also satisfactory for seawater, although pump cases and impellers should be a suitable duplex stainless steel or nickel-aluminum-bronze (properly heat treated). Neoprene-lined water boxes should be considered. For piping, fiber-reinforced plastic (up to 150 psi [1,035 kPa] operating pressure) and neoprene-lined steel should also be considered. Titanium and high-molybdenum SS tubes should be considered where low maintenance is required or the cost can be justified by life expectancy. 

Cost and installation time for aluminum welded pipe and fittings. 

Reconsider Prob. 9-32, To reduce the heating cost of the pipe, it is proposed to insulate it with sufficiently thick fiberglass insulation (fe = 0.035 W/m C) wrapped with aluminum foil (e = 0.1) to cut down the heat losses by 85 percent. Assuming the pipe tempeialuic to remain constant at 25 C, determine the ihickne.ss of the insulation that needs to be used. How much money will Ihe insulation save during this 10-h period Anmers 1.3 cm, 22.3... 

With respect to the older Monsanto/Lummus AlCl3-catalyzed EB process the advantages are the lower costs and risks (i) in the handling and disposal of the aluminum chloride catalyst and waste and (ii) for equipment and piping corrosion and fouling (major equipment pieces needed to be replaced on a regular schedule because of corrosion). 

If low or intermediate-chromium steel pipe will not resist corrosion adequately in refinery streams it will be necessary to use aluminum-coatings or high-chromium ferritic (Type 400) or austenitic (Type 300) stainless steels. Do not try to justify anything more expensive. It is almost impossible. When trying to choose between these possibilities, look at the over-all picture. Do not even consider corrosion resistance. The difference is slight. As a matter of fact, the difference in cost may also be less than expected. 

GRE containment piping promises to be substantially more economical than aluminum-lined stainless steel piping. Marshall and Brandt [ ] have shown that the installed cost of fiber-reinforced pipe is near that for mild steel for a number of noncryogenic applications where corrosion resistance is of primary importance. 

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