Energy Saving in Salt Production
The establishment of a salt production facility can save up to 1.6 GWh of electrical energy annually with the use of a conventional fan.
Task
The British company Salt Union uses specialized drying drums to produce millions of tons of salt each year. One such drum processes coarse granulated salt, which is used in dishwashers. However, a significant amount of electrical energy is wasted unnecessarily.
Previously, the fan that extracted air from the drying drum was controlled by a damper in the duct that operated based on the difference in air flow rates. During salt production, this damper was closed 95% of the time, which led to the fan using maximum electrical power to draw air through a restricted space.
The drying drum fan was large since the apparatus for drying salt was initially used to vacuum the salt crystals. Previously, the crystals were smaller, whereas granulated salt requires crystals with a diameter of 2-3 mm. The ideal crystals created more pressure on the drying apparatus compared to the coarse product, complicating the drying process.
Thus, Salt Union was tasked with developing a technology to optimize energy consumption during salt production.
Solution
With the support of partners from ABB Drives Alliance, a solution for saving electrical energy was developed and implemented. An electric motor with a power of 337 kW was installed on the system. Calculations performed by ABB showed that only 132 kW of power for the motor with the fan was sufficient to achieve the required airflow efficiency.
Benefits of the New Technology
After implementing the technology to reduce the size of the drying drum fan, the energy savings amount to 1.6 GWh annually. This allowed for a saving of over 60% of electrical energy compared to previous approaches. The project, costing about £20,000, enabled Salt Union to save over £100,000 in the first year. It was also found that even a small amount of heat from the drying drum drive can warm the air in the equipment during the winter period, which became an additional advantage for the salt producer.