Oil dewatering system VOD 16 and electrostatic oil cleaning system D2 in the cement industry Electrostatic oil cleaning from FRIESS

A wide variety of aggregates are required for cement production. These aggregates often have to be ground for further processing. Depending on the use of the cement, ground blast furnace slag may be used as an additive. A large cement manufacturer has therefore set up a blast furnace slag processing plant in the immediate vicinity of a large steel plant in Germany. The blast furnace slag is delivered directly from the steel plant to the cement manufacturer. The delivered blast furnace slag is ground in the plant to achieve the desired grain size. The decision was made to use a mill from a world-renowned German manufacturer. In order to maintain the desired precision in the grain size distribution achieved, the mill wheels are continuously adjusted during operation using large hydraulic cylinders. Despite the very high forces needed and a very small adjustment in the millimeter range, the adjustment of the hydraulic cylinders must be extremely precise.

Despite very good extraction systems, there is considerable dust pollution in the facility during operation. Although the hydraulic unit for operating the adjustment cylinders was provided with a separate enclosure, dust particles enter the hydraulic oil both via the air filter and the cylinder seals. The high level of dirt in the hydraulic oil caused the servo valves in the hydraulic control system to malfunction. Due to the malfunction of the hydraulic system, the particle size distribution no longer met the specifications.

The operations manager of the new plant was the first to recognize the connection between contaminated hydraulic oil and the resulting malfunctions.The company contacted Friess GmbH and after the oil was checked by the responsible Friess GmbH sales representative, it was determined that the hydraulic oil was clearly too dirty for the operation of servo valves. At the same time, the oil sample showed that condensation had already formed in the hydraulic oil. As the hydraulic system was repeatedly shut down for long periods during the commissioning phase and the facility is unheated, there were large temperature fluctuations in the hydraulic oil reservoir. This caused condensation to enter the hydraulic system. Based on the results of the oil analysis, the decision was made to use a model D2 electrostatic oil cleaning system and a model VOD 16 oil dewatering system to improve the quality of the oil.

After the VOD 16 oil dewatering system had removed over 1 liter of condensation water from approx. 1500 liters of hydraulic oil within a very short time, the D2 electrostatic oil cleaning system was put into operation. After just four weeks of continuous operation, there was a considerable improvement in the degree of cleanliness of the hydraulic oil.