POSSIBILITIES FOR DECREASE OF THE ENERGY CONSUMPTION IN THE TRISUPERPHOSPHATE MANUFACTURE

摘要

Phosphoric fertilizers have tremendous importance for development of plants and most widely used of them are superphosphates. The phosphoric fertilizer with greatest application in agriculture due to its high phosphorus content and respectively greatest industrial manufacture is the trisuperphosphate. The process of manufacture of trisuperphosphate comprises the following steps: decomposition of natural phosphates with phosphoric acid at 90 - 100°C, drying and granulation of the product. The main problems of this manufacture are connected with the considerable energy losses. One of the modern methods for evaluation of the energy effectiveness of complex chemical - technological systems is the exergy method of thermodynamic analysis. Exergy analysis of the trisuperphosphate manufacture is made and the internal and external exergy losses were determined. The exergy efficiency coefficient of the system as a whole - 12.31% and of it elements were calculated. This low value is due to the incomplete utilisation of heat in the system and great consumption of natural gas. The most considerable exergy losses can be observed during the drying process of trisuperphosphate.