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Dust Control

There are many ways to control dust in dry bulk material handling applications and all have their place.  ADSTM Dry Fog is particularly well suited to most containable dust sources, its sometimes the only choice that has a chance of success, and it sometimes cannot be used.  In most plants, a well thought out combination of technologies is the best solution.  


Jay Venter

Dry Cargo International's North American West Coast Regional Report 
 

 

Reference:        ADSTM Dry Fog Dust Control

 

In our lives, we can find dust almost everywhere, in our homes, cars, yards and in many other places you can imagine. Although there are different levels of dustiness which basically depends on two main factors: Lack of moisture and wind. When dirt is dry it is easier that its fine particles become airborne because it is difficult for them to stay together and to be heavier as a whole bulk. The second factor is how the dirt is exposed to wind. If the dirt is dry and exposed to wind, dust emissions will be seen.

On industrial facilities and specifically on the material handling, we can see the same effect we see on our lives. On these facilities the effect is more dramatic than in our ordinary lives because the amount of dirt (ore, coal, chemical products, grains, wood by-products and others) being moved is massive, the can contain components dangerous to the human being health, and most industries are located in isolated place where the winds are heavier, and it is always difficult to protect the dirt from the winds.

Dust Control is a combination of two elements, Passive and Active. The Active dust control systems are those that uses energy to operate, there are several options and suppliers who can take care of this important part which can be done by Dust Suppression, Extraction or Scrubbing. Regarding the Passive dust control system, we can say that it is as important as the Active one, and they cannot work apart. The Passive dust control system is the key element that creates a controlled volume to isolate the point where dust is generated allowing the Active one to do its job.    

At the Raring Corp we have been designing, manufacturing and supplying both Agglomerative Dust Suppression Systems (ADSTM) and Water Spray Systems (WSS) for the last 34 years and we are convinced that our systems couldn’t be as successful without the Passive Dust Control features.

There is a huge difference between the two technologies that we offer to our clients for controlling the dust on industrial facilities, ADSTM Dry Fog is intended to control the dust where it is generated and WSS is an accumulative process which increases material’s moisture in order to reduce its capacity to generate dust downstream.

ADSTM Dry Fog technology applies to crushing, screening, conveying, loading, and unloading of dry bulk materials.  When done properly, it is as effective as dust extraction with bag houses and much less expensive to implement, operate, and maintain. ADSTM Dry Fog uses the Raring Corp special acoustic nozzles to fracture water into a cloud of extremely small droplets that are in the same size range as the airborne respirable dust.  These devices use compressed air to create high frequency sound waves that shatter water into the fog sized droplets needed while retaining adequate kinetic energy to project the fog where it’s needed and penetrate through opposing air flows.  The nozzles incorporate relatively large liquid ports which act along with the acoustic nature of the nozzles to resist plugging. Acting in the same way that clouds cleanse the atmosphere of dust, the water droplets agglomerate with the dust particles, become heavier, and settle back to their source. Successful application of ADSTM Dry Fog technology to industrial dust control requires three design elements on top of fog application: containment, retention time, and collection surface. As it was mentioned previously on this article, containment (Passive) is the most important one. Transfer enclosures need to be a little larger than the norm, truck and rail dumps require features to contain the displaced air by rolling it back into the hopper, and bins need protection from wind and other outside influences.

There are many ways to control dust in dry bulk material handling applications and all have their place.  ADSTM Dry Fog is particularly well suited to most containable dust sources, its sometimes the only choice that has a chance of success, and it sometimes cannot be used.  In most plants, a well thought out combination of technologies is the best solution. 

Going back to the size of the water particles, if the water and dust particles are very much different in size, the slipstream created by the larger one carries the smaller one around it and impact is prevented.  This simple principle explains why plain Water Spray Systems are not a good solution for controlling the dust at the source, material’s fine and water don’t get together and we are just wetting the first layer of the material. At TRC we do use plain Water Spray Systems and sometimes together with the ADSTM Dry Fog, in order to give our clients overall solutions for their problems. Nevertheless, what TRC is looking to achieve by using Water Spray Systems is getting the bulk material moisture close to the its DEM factor. The DEM factor (Dust Extinction Moisture) is the moisture where the material stops generating dust and at TRC we design our WSS to make a step-by-step process to create a homogeneous material in terms of moisture. This way, we force the material to start gradually losing its capacity to generate dust and when it finally reaches the stockpile the dust generation is minimized.

Under our long term working on dust control, we can say that these technologies required both technical and experience to be used and implemented properly, but when we get to apply them together good dust control systems can be implemented which contributes to the environment and to the people health.    

 

    Gonzalo Campos Canessa

TRC CEO

 

Recent news

TRC participating at the Pimasa Group's annual planing summit.

Through our local Representative in Chile, PIMASA we have commissioned the Dust Suppression Systems we supplied for the Chuquicamata Subterraneo project.

After 13 years of continuous operation, the TRC FP stems are still producing great fog. The photo of the stems in use was taken during the last maintenance service, we do quarterly at ADM.

Yesterday we started up the fog system at the truck dump at Buzzi in the USA. The plant did a good job mounting the system, which facilitates our job at starting up this dust suppression system.

The Fog system we sold to buzzi for controlling the dust at the truck dump is already installed and we will be commissioning it after Thanksgiving weekend.