Snamprogetti ammonia process

Figure 3.10 A schematic of the Snamprogetti ammonia stripping process. Source [9],...

A three-step process developed hy Snamprogetti is based on the reaction of acetylene and acetone in liquid ammonia in the presence of an alkali metal hydroxide. The product, methylhutynol, is then hydrogenated to methylhutenol followed hy dehydration at 250-300°C over an acidic heterogeneous catalyst. 

The second reaction represents the decomposition of the carbamate. The reaction conditions are 200°C and 30 atmospheres. Decomposition in presence of excess ammonia limits corrosion problems and inhibits the decomposition of the carbamate to ammonia and carbon dioxide. The urea solution leaving the carbamate decomposer is expanded by heating at low pressures and ammonia recycled. The resultant solution is further concentrated to a melt, which is then prilled by passing it through special sprays in an air stream. Figure 5-3 shows the Snamprogetti process for urea production. ... 

Snamprogetti granulation technology has been applied in a 1,650-tpd plant operating since 1990. The plant is completely free from pollution problems. All vents are efficiently treated so that they are discharged to atmosphere practically free of ammonia and urea. Process wastewater is hydrolized within the plant to achieve boiler feedwater specification and recover ammonia and carbon dioxide. 

Snamprogetti Spa Urea Ammonia and carbon dioxide Process is pollution-free, and energy efficient 98 2000... 

Integrating the ammonia and urea process into a single train was proposed by Snamprogetti to reduce investment and operating costs [1099] (see also Chapter 7). 

The Snamprogetti process is based on using ammonia to strip CO2 and NH3 out of the urea reactor effluent. One of the impurities that affects the performance of urea as a fertilizer is biuret. To avoid a yield loss and minimize product contamination, it is important to minimize biuret formation. The con-... 

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