Dry ice blasting in the pulp mill industry
Dry ice blasting is a carbon dioxide cleaning method where a solid form of carbon dioxide, dry ice, is accelerated in a pressurized air stream, directing it to the surface in order to clean it. It is a new cleaning process which is replacing the traditional blasting materials like water, glass, sand and plastic.
Three steps are involved when cleaning using dry ice blasting method. these are:
Step 1: Energy transfer.
This is where the dry ice is propelled at a high speed through the blasting gun. The force generated knocks off the contaminants from the surface.
Step 2. Micro-thermal shock.
A micro-thermal shock is created by the cold dry ice hitting the contaminants making the contaminants crack leading to the further elimination of the contaminants.
Step 3. Gas pressure
This is the phase where the dry ice explodes on impact and converts into CO2 due to warming process. CO2 expands underneath the surface of the contaminants forcing the contaminant relocation and falling off the ground. The dry ice evaporates leaving the contaminant to fall off the ground.
BENEFITS OF USING DRY ICE BLASTING IN THE PULP MILL INDUSTRY.
1. Decreases downtime of the equipment.
Dry ice blasting method does not need the equipment to be disassembled when cleaning. The time consumption in disassembling the equipment is eliminated. The ability to clean the equipment in place without disassembling also eliminates:
-The process of transporting the equipment to the cleaning area.
-Cooling down time
The dry ice cleaning method reduces the downtime period from days to hours.
2. Faster and more thorough cleaning.
Superior cleaning is achieved and at the same time reducing the cleaning hours compared to other scrubbing methods. It also cleans areas that can not be reached by hand.
3. Reduction of waste disposal.
Other methods of cleaning lead to secondary contaminants which are the cleaning agents used in the process. This does not apply in the case of dry ice cleaning/blasting method since the CO2 evaporates upon contact.
4. Increased safety.
The CO2 is nonhazardous and nontoxic giving an advantage to employees, environment and for the equipment.
5. Elimination of equipment damage.
Other methods such as sandblasting can lead to the removal of the surface due to aggressive and abrasive effects whereas the dry ice cleaning/blasting method takes care of the surface by lifting the contaminant away. The cleaning without disassembling also eliminates the possibility of damage to the equipment during relocation from and to the cleaning dedicated cleaning area.
6. Lower cost.
The cost incurred in dry ice cleaning/blasting method is considerably lower compared to other methods which use cleaning agents and are more labor intensive.
Dry ice cleaning method has not only revolutionize the cleaning process of the pulp mill industry but in all industries. It has made most of the equipment to operate at peak efficiency with minimal downtime.