Gases corrosion tests

Smith, G. R, Ganesan, R, Tassen, C. S., Conder, C. (1995), in High-Temperature Gases (Corrosion Tests and Standards Application and Interpretation) Baboian, H. (Ed.). Washington ASTM, p. 359. 

Environmental testing—Part 2 Tests— Test Ke Flowing mixed gas corrosion test... 

Specifications for the principal LPG products are summarized in Table 4. Detailed specifications and test methods for LPG are pubHshed by the Gas Processor s Association (GPA) (3) and ASTM (4). The ASTM specification for special-duty propane and GPA specification for propane HD-5 apply to propane that is intended primarily for engine fuel. Because most domestic U.S. LPG is handled through copper tubing, which could fail if corroded, all products must pass the copper strip corrosion test. A test value of No. 1 represents a LPG noncorrosive to the copper. 

Carbonyl sulfide reacts with chlorine forming phosgene (qv) and sulfur dichloride [10545-99-0] and with ammonia forming urea and ammonium sulfide [12135-76-1]. Carbonyl sulfide attacks metals, eg, copper, ia the presence of moisture and is thought to be iavolved ia atmospheric sulfur corrosion (27,28). Its presence ia propane gas at levels above a few ppm may cause the gas to fail the copper-corrosion test. 

FIG. 28-15 Sch( niatic diagram of the (icctrochcmical cell used for crevice corrosion testing. Not shown are three hold-down screw s, gas inlet tiil)e, and external thermocouple tiil)e. 

VFO works well in gas turbines. In a nine-month test program, the combustion properties of VFO were studied in a combustion test module. A gas turbine was also operated on VFO. The tests were conducted to study the combustion characteristics of VFO, the erosive and corrosive effects of VFO, and the operation of a gas turbine on VFO. The combustion tests were conducted on a combustion test module built from a GE Frame 5 combustion can and liner. The gas turbine tests were conducted on a Ford model 707 industrial gas turbine. Both the combustion module and gas turbine were used in the erosion and corrosion evaluation. The combustion tests showed the VFO to match natural gas in flame patterns, temperature profile, and flame color. The operation of the gas turbine revealed that the gas turbine not only operated well on VFO, but its performance was improved. The turbine inlet temperature was lower at a given output with VFO than with either natural gas or diesel fuel. This phenomenon is due to the increase in exhaust mass flow provided by the addition of steam in the diesel for the vaporization process. Following the tests, a thorough inspection was made of materials in the combustion module and on the gas turbine, which came into contact with the vaporized fuel or with the combustion gas. The inspection revealed no harmful effects on any of the components due to the use of VFO. 

Test method for porosity in gold platings on metal substrates by gas exposures Test method for half-cell potentials of uncoated reinforcing steel in concrete Method for detection of copper corrosion from petroleum products by the copper strip tarnish test... 

Nickel-based alloys-Determination of resis-ance to intergranular corrosion Corrosion tests in artificial amospheres at very low concentrations of polluting gas(es) Test /. .-sulphur dioxide test for contacts and connectors... 

Corrosive sulfnr componnds can be detected by their effect on copper and the form in which the general copper strip corrosion test (ASTM D1838) for petrolenm prodncts is applied to liqnefied petrolenm gas. Hydrogen sulfide can be detected by its action on moist lead acetate paper, and a procedure is also used as a measure of sulfur compounds. The method follows the principle of the standard Doctor test. 

A dense and electronically insulating layer of LiA102 is not suitable for providing corrosion resistance to the cell current collectors because these components must remain electrically conductive. The typical materials used for this application are 316 stainless steel and chromium plated stainless steels. However, materials with better corrosion resistance are required for longterm operation of MCFCs. Research is continuing to understand the corrosion processes of chromium in molten carbonate salts under both fuel gas and oxidizing gas environments (23,25) and to identify improved alloys (29) for MCFCs. Stainless steels such as Type 310 and 446 have demonstrated better corrosion resistance than Type 316 in corrosion tests (29). 

Copper and copper-containing alloys are susceptible to attack by elemental sulfur and hydrogen sulfide as well as organically bound sulfur. Active or elemental sulfur and hydrogen sulfide gas can attack copper to form copper sulfide, a dark-brown to black compound. This can be seen through ASTM D-130 copper corrosion testing. 

From the literature it is known [I, 2, 4] that the stability in aggressive environment is naturally connected with the structure and condition of titanium. Therefore, performing the corrosion tests has allowed deeper understand a nature of gas saturation of titanic powders of different kinds of manufacturing, and to obtain new results. 

Schedule 40, 347 SS, 4-inch pipe, a 500-gallon-per-minute sodium pump, a corrosion test section, and a 35-gallon expansion tank. Each and every part was electropolished, pipe ends were taped dust-tight before welding, inert arc gas back welds were made, and every effort was made to complete, in the field, a chemically clean sodium system. Figure 22 shows the dirty sodium surface which resulted after clean sodium was filled into the loop. This experience demonstrated very conclusively the importance of being practical in sodium system construction. 

The gasifier atmosphere used for most Phase I corrosion tests is given in Table II. During testing, only the inlet gas composition shown was controlled. 

INLET AND EQUILIBRIUM GAS COMPOSITION OF PHASE I CORROSION TESTS ... 

Phase II - Pilot Plant Testing. This phase of coal gasification materials evaluation involves exposure of metals and refractories in selected test locations in current pilot plants. Corrosion testing in this effort began during 1974 with four pilot plants and now involves six HYGAS, CONOCO COAL, Synthane, BI-GAS, Steam-Iron, and Battelle. 

For hot corrosion testing burner rigs can be applied [26]. The agent is injected into the flame of the burner and the sample is held or agitated at a distance, which allows deposition of the corrosive agent from the gas phase at a constant rate. 

In the ordinary furnace test for gas corrosion the samples are placed in a furnace for a given time in the atmosphere of interest. The advantage of the furnace test is that many different samples can be tested in one set of conditions, the drawback that it gives only one data point in time per experiment. The pitfalls are apparatus related Temperature and atmosphere constancy have to be guaranteed, crosscontamination must be avoided, and interaction with furnace linings and crucible material minimized. The danger of those points is often underestimated there are reports of different results from a mere change in the furnace size [27]. 

One-year test results on zinc and cadmium are in Table 2.22. The results of long-term atmospheric corrosion tests on zinc and cadmium coatings (Fig. 2.35) are compared with those of accelerated corrosion tests (Fig. 2.36) on the same coatings in three cabinets warm and humid, SO2 gas, and sea mist (Strekalov and Berukshtis, 1965). 

Fig. 2. 36 Accelerated corrosion tests (for comparison with Fig. 2.3S) on (a) zinc and (b) cadmium I = SO2 gas 2 = sea mist 3 = warmth and humidity solid lines = nonchromated coatings dashed lines = chromated coatings (Strekalov and Be-rukshtis, 1965).

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