Sulfuric acid corrosiveness

Materials of Construction. Resistance of alloys to concentrated sulfuric acid corrosion iacreases with increasing chromium, molybdenum, copper, and siUcon content. The corrosiveness of sulfuric acid solutions is highly dependent on concentration, temperature, acid velocity, and acid impurities. An excellent summary is available (114). Good general discussions of materials of constmction used ia modem sulfuric acid plants may be found ia References 115 and 116. More detailed discussions are also available (117—121). For nickel-containing alloys Reference 122 is appropriate. An excellent compilation of the relatively scarce Hterature data on corrosion of alloys ia Hquid sulfur trioxide and oleum may be found ia Reference 122. 

The connection box cooler receives regenerator flue gas after it has been reduced to essentially atmospheric pressure. This arrangement is not limited to the production of saturated steam. Any number of coils can be installed in the box, and normally both steam-generating and superheater coils are present. The tube temperatures within the box must be maintained above the SO dew point of 150—175°C to prevent sulfuric acid corrosion (63). 

A more obvious energy loss is the heat to the stack flue gases. The sensible heat losses can be minimized by reduced total air flow, ie, low excess air operation. Flue gas losses are also minimized by lowering the discharge temperature via increased heat recovery in economizers, air preheaters, etc. When fuels containing sulfur are burned, the final exit flue gas temperature is usually not permitted to go below about 100°C because of severe problems relating to sulfuric acid corrosion. Special economizers having Teflon-coated tubes permit lower temperatures but are not commonly used. 

Ammonia H,S/SO, with 02 present. Ammoniacal corrosion. Sulfurous acid corrosion. 

Acid neutralizers are alkaline materials that produce active components designed to absorb and neutralize S03 in the gas stream during combustion. The effect is to reduce sulfuric acid corrosion on heat-exchange surfaces (such as economizers and air heaters), which takes... 

OLEUM Fuming Sulfuric Acid Corrosive Material 3 0 2 W... 

For example, the acid will uniformly corrode a piece of mild steel sheet immersed in dilute sulfuric acid. Corrosion by uniform attack accounts for the greatest loss in practice. The incidence of this kind of corrosion can easily be detected and remedial measures taken. 

F.G. Hodge and B.E. Wilde, Effect of Chloride Ion on the Anodic Dissolution Kinetics of Chromium-Nickel Binary Alloys in Dilute Sulfuric Acid, Corrosion, Vol 26, 1970, p 146-150... 

Sulfuric acid — corrosive. If the battery case is broken acid leaks can damage skin and eyes on contact. Damage will also occur if in contact with materials and clothing. 

Incompatibilities and Reactivities Strong oxidizers, ammonia solutions [Note Decomposes in water to sulfuric acid corrosive to metals.] ... 

Colorless syrupy liquid (containing sulfuric acid) corrosive decomposes at 45°C (113°F), decomposes in cold, and hot water soluble in H3PO4. 

Determination of resistance to intergranular corrosion of stainless steels—Part 2 Ferritic, austenitic and ferritic-austenitic (duplex) stainless steels—Corrosion test in media containing sulfuric acid Corrosion of metals and alloys— Determination of dezincification resistance of brass Copper alloys— Ammonia test for stress corrosion resistance Corrosion tests in artificial atmosphere—General requirements... 

Figure 4-8. Sulfur cycle in sewage systems - biogenic sulfuric acid corrosion.

Figure 4-9. a) Principle of the simulation device for testing the resistance of concrete and other building materials to biogenic sulfuric acid corrosion, b) View of the open test chamber filled with test blocks. 

Figure 4-10. Two concrete specimens of different resistance from the test chamber after exposure to two test cycles of biogenic sulfuric acid corrosion, where PC is Portland cement (left) and HC is blast furnace cement (right).

B.J. Fitzgerald, T.L. Yau, and R.T. Webster. 1992. Stress corrosion cracking of zirconium and its control in sulfuric acid. Corrosion 92, Paper No. 154, Houston, TX NACE Intemational. 

The cause of the tube leaks is cold flue gas. But the cause of the cold flue gas is tube leaks. The real cause of the tube leaks is sulfuric acid corrosion. The sulfuric acid condensation is the result of the low temperatures of the flue gas. To avoid this problem, the flue gas must not be cooled too much by the cold air. 

Fontana, M.C. (1968). Corrosion by Sulfuric Acid. Corrosion Course Module 14, Metals Engineering Institute, ASM. 

Mechanical and Metallurgical Control of Sulfuric Acid Corrosion in Petroleum Processes, Trans. ASMS, 1946. 

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