Abstract: Recently, furnace discharging is performed by opening the emergency relief valve and drain oil into the sump oil pool, which is not a favourable solution. For this reason, a 50m³ horizontal tank, after being renovated, can be used as a temperary venting tank to replace the sump oil pool with an emergently discharged sump oil system added to the furnace.In this way, sump oil can be stored in the 3000m³ tank.The authers introduce in the paper the process flow of sump oil discharge and recovery system with the reason analysed why the furnace relief system is necessary to be improved. The position of the tank is clearly stated from safety point of view together with points for attention if the system is applied.