Selective methane oxidation over promoted oxide catalysts. Quarterly technical progress report, March 1, 1993--May 31, 1993

Technical Report · Tue Jun 01 04:00:00 EDT 1993

DOI:https://doi.org/10.2172/10176534· OSTI ID:10176534

Klier, K; Herman, R G; Sarkany, J; Sun, Q

A 1 wt% SO{sub 4}{sup 2{minus}}/1 wt% Sr/La{sub 2}O{sub 3} catalyst has been shown by us to be one of the most active catalyst for the oxidative coupling of CH{sub 4} to C{sub 2} hydrocarbons. One of the by-products is CO{sub 2} and this is a potential strong poison for the formation of C{sub 2}{sup +} products. Hence, various pretreatments of this catalyst were studied in terms of effect on the catalytic performance. Before the reaction was carried out at 500 or 550{degrees}C, the catalyst was pretreated in flowing air or He at 500, 700, or 800{degrees}C. Relative to the 500{degrees}C treatment, the pretreatment in air at 700{degrees}C only slightly decreased the C{sub 2}{sup +} selectivity while the CO{sub x} selectivity increased. This effect was larger when the pretreatment was carried out at 800{degrees}C. It was observed that the deactivation effect was slightly smaller when the pretreatments were carried out in He instead of air. For both air and He, the CH{sub 4}, conversion and the C{sub 2} %yield showed more or less parallel changes (small decreases) with increasing pretreatment temperature. After a standard pretreatment (air, 500{degrees}C, 1 hr), the reaction temperature was increased stepwise from 500 to 700{degrees}C and then lowered to 550 (or 500){degrees}C. It was observed that the catalytic performance showed deactivation towards the C{sub 2}{sup +} products. Decreasing stepwise the total flow rate (GHSV) of the reacting gas mixture (CH{sub 4}/air = 1/1) from 70,175 to 5,388 {ell}/kg catal/hr at a reaction temperature of 550{degrees}C caused large changes in both the activity and selectivity. After going back at 550{degrees}C to the original GHSV = 70,175 {ell}/kg catal/hr, the temperature was increased stepwise up to 600{degrees}C. Up to 580{degrees}C, the catalytic activity and selectivity did not change very much.

• Research Organization: Lehigh Univ., Bethlehem, PA (United States). Zettlemoyer Center for Surface Studies
• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: FG21-92MC29228
• OSTI ID: 10176534
• Report Number(s): DOE/MC/29228--3408; ON: DE93040001
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
010408
10 SYNTHETIC FUELS
100200
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201
AIR
C1 PROCESSES
CATALYSTS
CATALYTIC EFFECTS
CHEMICAL AND PHYSICOCHEMICAL PROPERTIES
FORMALDEHYDE
LANTHANUM OXIDES
METHANE
METHANOL
OXIDATION
OXYGEN
PRODUCTION
PROGRESS REPORT
SPECIFICITY
STRONTIUM
SULFATES
TEMPERATURE DEPENDENCE