Application of structured packing in nitrogen fertilizer plants

Application of structured packings in nitrogen fertilizer plants

Nitrogen fertilizer industrial mass transfer and separation equipment has always been the dominant role of granular fillers and plate towers. In recent years, structured fillers have been gradually applied in small and medium-sized nitrogen fertilizer plants.

1 Main application types and features

1.1 Metal mesh corrugated packing

It is composed of corrugated plate pressed by metal wire mesh, with small wave height, large specific surface area, good surface wetting performance, high separation efficiency, and the separation efficiency of 10 or more theoretical plates per meter of packing layer. However, because its manufacturing materials such as stainless steel wire mesh is expensive, the cost per unit volume filler is high, and the strength is low, it is generally suitable for difficult to separate and heat sensitive matter system of vacuum distillation, atmospheric pressure rectification and absorption, the tower diameter is not large (less than 2m), not easy to plug and corrosion occasions. Divided into single and double metal wire mesh corrugated packing. Single-layer metal wire mesh corrugated packing has 250 type, 500 type, 700 type, 500 type is the most widely used.

1.2 Mesh (plate mesh) corrugated packing

Mesh corrugated filler is a new type of corrugated filler recently developed successfully, is directly stainless steel and other thin strip is properly processed into a specific specification of diamond mesh plate, the cost is significantly lower than the wire mesh at the same time has the excellent performance of wire mesh corrugated filler, industrial applications are expanding, the scope of application is similar to the application of wire mesh corrugated filler and special conditions.

1.3 Corrugated metal orifice packing

It is mostly composed of stainless steel corrugated plates, and there are many small holes of about 5mm on the plates. Its performance is between metal mesh corrugated packing and scattered packing. Due to reasonable structure, high strength, low cost than metal mesh corrugated filler, good corrosion resistance, strong anti-pollution ability, pressure reduction, large flux, it is especially suitable for atmospheric pressure and medium vacuum and pollution risk of organic distillation, and suitable for atmospheric pressure and pressure countercurrent absorption process. In the design of new towers and the renovation of old towers, it is used to replace scattered packing such as Pall rings and certain plate towers. Especially in the transformation of large tower, it has obvious economic effects on improving the output and quality of products and reducing energy consumption.

1.4 Plastic orifice corrugated packing

The structure is similar to the corrugated metal plate filler, and the material is polypropylene, polyvinylidene fluoride, polyvinyl chloride and so on. The main advantages are corrosion resistance, light weight, low price, low resistance, high efficiency and small amplification effect. At present, there are mainly 125Y and 250Y two specifications, they are suitable for a variety of absorption and desorption processes, but also for waste gas purification and large liquid load and high operating pressure processes and improve the production capacity of the existing tower, but also suitable for foamy material systems. Good results have been obtained in chemical fertilizer and environmental protection departments.

2 Engineering application examples and effects In recent years, small and medium-sized nitrogen fertilizer plants have achieved great success in applying structured fillers when they are undergoing technical transformation and expanding capacity.