The unstable measuring system of raw material,the jam of granulator entry trough,return material of off-gas pipeline,water balance in drying system and so on in urea-based compound fertilizer process designed by Wuhuan Science & Technology Co.

Through the analysis of the structure of the off-gas pipe and the loads acting on it,it is indicated that the improper structure is the main source to cause the buckling of the inner pipe in off-gas pipe.