Close-loop Treatment Of Coke Cooling Water In Delayed Coking Unit

The offensive odours of coke cooling water can pollute environment seriously. Then the formation of coke cooling water and the source of the odours and it's harm were set forth. By investigating the current treatment processes of coke cooling water and their offensive odours treatment, the advantages and disadvantages of various methods were elaborated. Furthermore, by inspecting the treatment process of coke cooling water in delayed coking unit of Shengli petrochemical corporation, the problems in the treatment process were pointed out, and the solutions were proposed. Close-loop treatment process of coke cooling water in delayed coking unit was designed in this paper.By analyzing the cause of the offensive odours explosion in several refineries on the basis of the explosion theory, it is pointed out that there was breathing space in coke cooling water tank and flammable FeS generated in the process of offensive odours treatment. These two aspects are the main causes for the explosion. And according to the characteristic of delayed coking unit of Shengli petrochemical corporation, So the dual insurance approach of preventing the explosion are developed, the Pot-coke cooling water tank with simple structure are designed. Then a new method of wet desulphuration that not generates FeS in the process of odours desulphuration is found.The offensive odours was collected when coke tower drained coke cooling water in Shengli petrochemical corporation. The analysis result of the composition of odours shows that it mainly contains toxic sulphide. Then the experimental study was carried on the ferric chelated law to remove the sulphide. The result indicates that ferric citrate can effectively desulfurizate in the treatment of offensive odours of coke cooling water. The process parameters are, the ferriccitrate concentration, 0.2mol/L, tem-prature, 313K, fluid column, 50cm, and in blist bed reactor. H₂S removing rate is nearly 100%.The laboratory apparatus were established and different structural pot-nozzles were designed. Nitrogen and water have been used to simulate the two-phase flow. In the exhaust gas rate of Pot-coke cooling water tank's experiment, the exhausting gas rate is relation to the different feeding methods and the different heights of pot-nozzle. On the conditions that the launder height is 6.7m, the pot-nozzle heights vary from 1.1m to 1.6m, the gas flow rates vary from 0.024m³/h to 0.06m³/h, and the water velocities vary from 0.4m/s to 0.7m/s, the exhausting gas rates remain 85%.Then the enlargement experiment of Pot-coke cooling water tank has been carried out in order to check the exhaust gas rate of Pot-coke cooling water tank. Further check the relation between exhausting gas rate the different feeding methods and the different heights of pot-nozzle. On the conditions that the launder height is 6.7m, the the gas flow rates vary from 0.024m³/h to 0.06m³/h, and the water velocities vary from 0.4m/s to 0.7m/s, the exhausting gas rates remain 86%. Provid the theoretical base and technology reference for industry application.