The project of construction of the newly constructed plant in oil refinery in Pancevo, MHC/DHT, which was planned to produce jet fuel and euro diesel didn’t include the installation of systems for the dosing of antioxidants in jet fuel and diesel fuel additives for the euro diesel. Dosage of antioxidants is regulated in the "Official Gazette of RS", no. 64/2011, Annex II, and dosing the additives for required lubricity and electrical conductivity in euro diesel is regulated in accordance with the Standard EN-590. For this reason, it was necessary to set up a project for the construction of installations for the dosage of antioxidants in jet fuel and dosing the additives for euro diesel fuel. Therefore, NIS Serbian oil industry owned by GaspromNEFT released the tender which was after the bidding phase awarded to WIG.
System for additives dosing is supplied from a single cylindrical horizontal tank divided in two parts with the volume of 60 m3 and 40 m3 for each part of the tank. Tank consists of two different types of additives. The first part of the tank, with the volume of 60 m3, consists of the additive for dosing the diesel metering line. The second part of the tank, with the volume of 40 m3, consists of the additive for dosing the jet fuel metering line. Below the lowest level of the tank, 4 self-priming gear pumps for pumping the additives are placed. The capacity of the pumps is 19 l/min. Bypass valve is installed before the entrance of the injection block, which will set the inlet pressure in the injection block. Pressure should be about 5 bars higher than the pressure in the main line. For optimal performances, additive is injected down the course of the fluid. A static mixer is installed in the main pipeline.
As per the technical requirements, the system adds additives in two lines, diesel and jet fuel, as well as two independent entities. Each dosage unit is made out of two completely separate metering lines. This provides continuous additives dosing at all operating conditions and at the high redundancy of the system. The solution is based on a specially designed module connected to a control unit that can be controlled by adding additives for each line. The modular system consists of an injection unit which containing PD flow meters, solenoid valves and filters, injection controller connected to the main line standards and depending on the fluid flow in the main line and prediction formulas. Pulse signal opens and closes the valves in the injection block.
System for additives dosing can be controlled via local display remotely from the control room. This type of system control is considered redundant. In case of a communication breakdown between the control room and the system for additives dosing, locally configured HMI takes the main role in controlling the system.
The system operates in a redundancy. There are installed two SMAR controllers, type DF73, which are working in a full redundancy. There is a high degree of security of the system in the event of a potential failure of one of the controllers. Namely, if one controller fails, its role as the primary takes another one, redundant controller.