This paper makes a brief summary of the measures for technical t ra nsformation and practicing situation of many small urea units and their supporti ng works such as the decarbonizing workshop section, CO2 compressing and purifyi ng workshop section, N- H- aerostatic press, and main urea workshop building, etc.

Expounds the steel selection for large scale urea plant and its corrosion,presents the application and development of stainless steel in large urea plant,discusses and analyzes the challenges,competition and opportunities for domestic stainless steel in this area.

Successful application of my company's patent technique on modification of urea plant with aqueous solution total cycle process;

Technology Progress of revamping urea process of solution full recycle with pre-separation & pre-distillation in urea plant;

Modifying the bottle-neck equipment to increase the urea plant capacity;

Dynamic simulation of 130 kt/a urea unit;

Dynamic analysis and optimizing operation of urea unit under circulating evaporation

The Application of Poisonous Medium Leakage and Diffusion Model on Safety Evaluation of Urea Unit