During the processing of concrete (fresh concrete), large amounts of heat are released during the hardening process of this building material, since this chemical process is an exothermic reaction.
To achieve the functionality of structures and components, it is necessary to limit the maximum fresh concrete temperature during the manufacturing process. In that way cracks due to thermal stresses during the setting process should be prevented.
Depending on the weather, the concrete temperature must be lowered by 1 to 20 °C (Average: 5 °C).
Fresh concrete can be cooled down in a number of ways using cryogenic gases. This is done in direct contact (e.g. lance cooling in a truck mixer) or by cooling the starting materials (cement cooling, rock, grit cooling, water cooling)
In cement cooling, the cement delivered in the road tanker is cooled down to the desired target temperature during storage in the local cement silos. A special nozzle system is installed in front of the riser to the cement silo, which enables the mixing of cement and LCO2 or LIN. For this purpose, the cross section of the cement stream is reduced, on the one hand to create homogeneous mixing with the cooling medium and on the other hand the necessary pipe volume for the exhaust gas.
The cooling medium evaporates in this process and the resulting gas moves with the cement in the silo. In this way, the gas continues to cool the cement, thus exploiting the cold energy of the gas.
The discharge of the gas takes place via the existing filter system of the cement silo, which, however, must be designed for the increased gas quantities. In most cases these filter systems have to be extended or several filter systems can be combined on the construction sites.
The adding of the cooling medium takes place via a two-stage control. For this purpose, appropriate installation options for the temperature sensors must be provided by the customer.
Your benefits at a glance
- Easy installation in existing plants
- Controlled supply of large amounts of cold in a short time
- Very high utilization of the used cooling energy (> 98%)
- No influence on the quality of the concrete
- Control of the concrete temperature possible by mixing hot and cold cement
- High profitability