Sulfur corrosion test components

Attack on metals can be a function of fuel components as well as of water and oxygen. Organic acids react with cadmium plating and 2inc coatings. Traces of H2S and free sulfur react with silver used in older piston pumps and with copper used in bearings and brass fittings. Specification limits by copper and silver strip corrosion tests are requited for fuels to forestall these reactions. 

Asarco tested components of sulfur concrete, both precast and poured in place, in corrosive environments of sulfuric acid. Favorable endurance of these samples led to a full-scale cooperative demonstration project. The project selected was the rehabilitation of an electrolytic zinc cellhouse basement floor of approximately 21,000 square feet. 

Some sulfur compounds can also have a corroding action on the various metals of the engine system, varying according to the chemical type of sulfur compound present. Fuel corrosivity is assessed by its action on copper and is controlled by the copper strip test (ASTM D-130, IP 154), which specifies that not more than a slight stain shall be observed when the polished strip is immersed in fuel heated for 2 h in a bomb at lOO C (212°F). This particular method is not always capable of reflecting fuel corrosivity toward other fuel system metals. For example, service experience with corrosion of silver components in certain engine fuel systems led to the development of a silver corrosion test (IP 227). The mercaptan sulfur content (ASTM D-1219, ASTM D-3227, IP 104, IP 342) of jet fuels is limited because of objectionable odor, adverse effect on certain fuel system elastomers, and... 

Corrosion occurs when all components of the process are present and capable of reaction (see preceding section). Basic test conditions include exposure of the coatings systems to an electrolyte containing reducible species (typically oxygen or hydrogen ion). More sophisticated testing would include closely replicating known corrosive conditions such as wet/dry cycles and multicomponent and multiphase chemical environments. Immersion, salt spray, and a partial pressure of sulfur dioxide corrosion tests correspond to water tank, marine, and combustion exhaust service environments, respectively. An important relationship exists between the corrosive environment used in the test procedures and the product s intended service use. 

Presence of small amounts of some sulfur compounds in certain refined products (gas and liquid) can have a corrosion effect on copper alloy components of users equipment that adversely affects their function. For example, copper corrosion products could cause plugging of metering and pilot valves. Consequently, product specifications may call for the product to pass a copper corrosion test such as ASTM D 1838, Test Method for Copper Strip Corrosion by Liquefied Petroleum (LP) Gases, or ASTM D 130, Test Method for Detection of Copper Corrosion from Petroleum Products by the Copper Strip Tarnish Test, or ASTM D 4048, Test Method for Detection of Copper Corrosion from Lubricating Grease. 

Commercial success of sulfur-iodine hydrogen production depends largely on the capacity to identify materials of construction that can handle the corrosive environments and on the ability to manufacture process components with these materials economically. This chapter has reviewed a cross-section of materials data generated by testing in the various process settings within the cycle. Ta alloys and SiC have been shown to have good corrosion characteristics in all the liquid environments, but individual candidates have also been suggested for use in particular conditions. Both of these materials have unique mechanical properties, and much effort is needed in order to use them for component fabrication. 

Free, or corrosive, sulfur in an appreciable amount could result in corrosive action on the metallic components of an appliance. Corrosive action is of particular significance in the case of pressure burner vaporizing tubes that operate at high temperatures. The usual test applied in this connection is the corrosion (copper strip) test (ASTM D-130, ASTM D-849, IP 154). 

Corrosion of heating equipment can occur if the sulfur oxides formed on combustion of fuel oil are allowed to condense in the presence of moisture on the cooler parts of the flue system. Corrosion of metal parts of the fuel system may also reflect the presence of corrosive sulfur components in the fuel. The corrosive tendencies of the fuel may be detected by the copper strip test (ASTM D-130, ASTM D-849, IP 154), the effect of these sulfur compounds being indicated by discoloration of the copper strip. 

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