Employs the division of heated product flow coming from the external heat exchanger into two:
• external circuit – part of the flow is diverted to the lowering pipes of the oil jet block in the area of elliptical heads of the rail tank car.
• internal circuit–part of the flow is diverted to the recovery zone from the rail tank car to the circulation system.
External circuit provides heated product input into the rail tank car and cold product recovery from the rail tank car to the circulation system.
Internal circuit provides only heated product input to the recovery zone of the cold product from the rail tank car in order to reduce the product viscosity.
Flow-ratio control within both internal and external circuit is maintained via control valves. Product flow set within the internal circuit is defined by physical condition of the product in rail tank car. The higher viscosity or setting point of the product in rail tank car the bigger flow of the heated product within the internal circulation is required. During the course of the circulating heating system operation cold product is constantly being recovered at the bottom of the rail tank car and the same amount of heated product is being fed into the rail tank car for jetting and diverted to the upper area of the rail tank car.
There is an interface between the hot and cold product being established within the rail tank car that is constantly decreasing during the course of cold product recovery. Constantly increasing upper layer of hot product melts the cold product on the tank walls entirely leaving them absolutely clean after the discharge.
The use of the oil jet block with lowering pipes allows to exclude so called “cleanup” stage that is employed by different open jetting technologies and violates fire safety regulations and contributes to significant environment contamination.