甲烷和富氧空气催化氧化制合成气

Catalytic oxidation of methane with air to syngas

采用固定床流动反应装置，考察了３种不同氧化气氛下甲烷催化氧化制合成气的反应性能。在空速为５×１０５ｈ－１、ＣＨ４／Ｏ２＝２．０、外控温度为８００℃时，富氧空气（３４．５％Ｏ２＋６５．５％Ｎ２）具有和１００％Ｏ２气氛基本接近的反应性能，而且用空气或富氧空气取代纯氧明显减轻了催化剂床层的“热点”现象。针对富氧空气（３４．５％Ｏ２＋６５．５％Ｎ２），考察了空速对反应性能的影响。结果表明，空速在３×１０５～８×１０５ｈ－１范围内ＣＨ４转化率＞９０％，ＣＯ选择性＞９０％，Ｈ２选择性接近１００％；合成气中（Ｈ２＋ＣＯ）／Ｎ２比值接近３．０，ＣＯ经水蒸汽变换后得Ｈ２／Ｎ２比值接近３．０。

Catalytic oxidation properties of methane to syngas at three different oxidation atmospheres have been investigated in a fixed bed flow reactor. It is found that the reaction of methane with oxygen enriched air(34.5% O 2+65.5% N 2)exhibits the same activity as that with 100% O 2 under the conditions of high GHSV(5.0 x 10 5h -1 ),CH 4/O 2 ratio of 2.0,and 800℃,and that the 'hot spot' in the catalyst bed is significantly reduced when 100%O 2 is replaced by air or O 2 enriched air. The effect of space velocity on catalytic activity is also studied for 34.5%O 2+65.5%N 2.When the space velocity is in the range of 3×10 5～8×10 5h -1 ,CH 4 conversion is>90%, and the selectivities to CO and H 2 are>90% and near 100% respectively.Both the molar ratio of (H 2+CO)/N 2 in the product gas and that of H 2/N 2 after CO conversion with steam are close to 3.0 , which can essentially meet the requirements of ammonia synthesis.