Abstract:

A concentric self-thermal reactor, in which ammonia decomposition is carried out in the center tube and hydrogen combustion takes place in the annulus was analyzed by modeling and simulation. The performance of the reactor with hydrogen-air flow co-current or counter-current to the ammonia flow was investigated and compared with that under isothermal condition. In the co-current mode, the high concentration of ammonia corresponds with the high heat generation rate of hydrogen combustion, while in the counter-current mode, the combustion heat is firstly used to increase the temperature of the hydrogen-air flow then used by ammonia decomposition. Therefore, the reactor with co-current flow is much more efficient in terms of the high conversion and the full use of hydrogen combustion heat. The co-current flow reactor performs as well as an isothermal reactor when a high conversion is realized.

Key words: chemical reactor, mathematical modeling, hydrogen production, ammonia decomposition, co-current flow pattern

摘要：

建立了管壳式自热型氨分解反应器,其中管内为拟均相催化反应,管外壳程为考虑气膜传递阻力的非均相催化反应。通过模拟比较和分析了氨气和氢气-空气混合物并流与逆流操作的反应结果。在并流操作中,氢燃烧产生的高温正好与高氨气浓度对应,氢燃烧热被充分用于氨分解反应,因此反应效率要显著高于逆流操作。与等温反应器的比较分析表明,在自热和高转化率条件下并流操作的效率与等温操作效果很接近。

关键词: 化学反应器, 数学模拟, 制氢, 氨分解, 并流操作