Reduction reactor materials samples

Figure 13. Corrosion behavior of reduction reactor materials samples in anhydrous environment (O), Hastelloy C276 Cartech CB3 (V), Incoloy 825 (A), Inconel 625 (O), SS 310 and (0), SS 18-18-2. Furnace temperature, 482°C (900°F) anhydrous S03 12 cc/min argon 128 cc/min. Erratic erosion rate behavior of SS 310 and Cartech 20CB3 is caused by the spalling of the corrosion product. Negative values indicate weight gain per unit area.

Figure 14. Corrosion behavior of reduction reactor materials samples ( 7), Inconel 625 (O), silicon (Q), silicon nitride (%), alonized Inconel 62 (M silicon carbide and ( f), Inconel 657. Furnace temperature, 482°C S03, 25 see/min steam, 58 see/min argon, 78 see/min.

Calibration is usually done with ultrapure acetanilide [36] as the ratio between carbon and nitrogen of this standard is similar to that of phytoplankton. The efficiency of the oxidation-reduction reactors has to be frequently checked by analyzing standards or reference materials every 10-12 samples. 

Temperature programmed reduction (TPR) experiments. TPRs were performed for each material using a quartz reactor tube (4 mm i d ), in which a 100 mg sample was mounted on loosely packed quartz wool. Samples were predried overnight at 120 °C. The sample was heated at 5 °C /min up to 700 °C under 20 mL/min flow of a 2 1 mixture of H2 Ar. 

The amounts of material in the samples were calculated from element mass fractions and the absorption coefficients of the constituent elements [17] just above the absorption edge to give an absorber optical thickness close to 2.0 absorption lengths. The samples were loaded into a Lytle in situ reactor-cell [18] and reduced in a mixture of H2 (5%) in He (purity 99.995% flow rate 30 ml/min) by heating at a rate of 5 K/min from ambient temperature to 673 K. The samples were kept at 673 K for 3 h. Two EXAFS scans were recorded and summed for each sample before and after reduction. XANES scans were taken continuously during reduction. 

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