板状镍催化剂上氨分解和氨部分氧化制氮氢气的研究

研制了一种 Ni/Al₂O₃多孔板状催化剂.该催化剂在反应温度高于750℃,氨分解率高于99.5%时,允许反应空速达10000—40000h^-1.用该催化板组装的反应器可采用内加热形式,和一般的外加热反应器相比可节约能耗约30%.在催化板上氨分解的经验动力学方程是γ=kp²NH₃,表观活化能为153.0kJ/mol.将该催化剂用于氨部分氧化时,在空气和氨比为1.0—1.7,680—750℃,氨空速10000—40000h^-1条件下,在氨点火后无外加能源情况下,能制得含氢30～43%,残氧小于0.1%的氮氢混合气,氨的转化率>99.5%,连续250小时反应表明,催化剂活性稳定.宏观动力学研究得出,反应对氨呈零级,表观活化能为37.2kJ/mol.

STUDY ON THE DECOMPOSITION AND PARTIAL OXIDATION OF AMMONIA ON POROUS Ni/Al_2O_3 CATALYST PLATE

A porous Ni/Al₂O₃ catalyst plate was prepared.It gives NH₃ conversion more than 99.5% at 750℃ and space velocity of NH₃ 10000-40000h^-1.An internal heating type was adopted Which saves 30% energy in comparison with the external heating type.The results of reaction kinetics showed that the rate equation of ammonia decomposition on the catalyst plate is γ=kP²NH₃ and the apparent activation energy is 153.0kJ/mol. The partial oxidation of ammonia on the catalyst plate was also investigated at the conditions of 680—750℃,air/NH₃=1.7-1.0 and space velocity 10000-40000h^-1.The results showed that a gas mixture containing 30-43% of H₂ and less 0.1% of O₂ was obtained without external heating after NH₃ combustion.A duration test for 250h indicated that NH₃ conversion was over 99.5%.The reaction kinetics showed that the rate equation of partial oxidation of ammonia was of zero order and the apparent activation energy obtained was 37.2kJ/mol.