Material build-ups in the production process often lead to reduced plant productivity and higher cleaning costs, as well as increased safety risks to maintenance staff. Such issues can be avoided by undertaking measures including:
• blockage and build-up removal
• silo and hopper cleaning
Having developed expertise in both these areas, here Laurent Moret, Technical Director of Standard Industrie discusses one particular process that has helped plants across the world improve their productivity, reduce cleaning costs and lower accident risks.
Using air cannons to avoid the creation of build-up in silos
The function of an air cannon is to release regularly and instantly a volume of compressed air of between 4 and 400 litres, through an adapted outlet port (from 25 to 300 mm) to achieve a deflagration.
In this way, the air cannon acts directly on the material, thus avoiding any damage to the structure. Air cannons can be applied to various locations in a process, any time when clogging or build-ups appear.
Let’s see examples of air cannons application: In the batch house where raw materials are mixed, air cannons can be installed in bulk material silos. Specific silos or hoppers containing cutlets can also be equipped with declogging devices in order to help material flow.
Another unexpected location where such devices can be used is the smoke treatment plant and smoke evacuation, these plants where gases are treated can clog and an easy way to remove the soft build-up is to blow air on a regular basis.
This regular planned airblow removes the dust and avoids the formation of harder build-ups which could lead to total blockage. This is a smart soft easy and preventive solution against the worst. In the furnace, you will find them on the hopper, feed chute and furnace arch’s.
In the cement process, the raw mill travels initially by the preheater tower before being sent into the kiln for the manufacturing of clinker.
The problem is often at the preheater tower’s level where the material clogging started.
The temperature around the tower area can reach 900 °C (1652 °F) and the maintenance interventions can last several hours. Thus this clogging leads to a loss of productivity but also to an increased risk for the maintenance staff.
In addition, if a concretion comes loose, it could fall on the kiln inlet area and consequently cause a breakdown; this could cost the plant several million pounds.
The fields of application are varied. Air cannon installation is also the solution to problems of:
- Hopper clogging in quarry
- Bridging and rat holing in dust hoppers in steel waste treatment plant
- Bridging and rat holing in brick shale hoppers
- Obstruction of the ventilation ducts cyclone inlet at a metal recycling plant
- Maintenance of weighing silos in glass factories
- Kiln inlet concretions in cement works
- Obstructions related to dust accumulation in cement works
- Supply hopper clogging in mine ores
- Material flow after combustion in lime kiln
- Clogging of sand, moisture sensitivity in foundry
The below video is an example of how an air cannon such as the AIRCHOC®, when placed on storage units, releases compressed air into the silos or hoppers, in order to prevent clogging or material build-up:
