The emission of HCl from the pre-treatment section in a Hot Dip Galvanizing plant causes several corrosion inside the building and has major environmental impact to the surrounding air. Secondly, it has also impact on the labor working conditions and its health.
So there is no option to avoid the emission. This is done by a combination of gas scrubber and the engineering of the pre treatment enclosure.
The component that must be removed from the air flow has a strong preference to dissolve into the gas scrubbing liquid. After dissolving in the gas scrubbing liquid it immediately reacts with the chemical present in the solution and is therefore not able to go back into the air flow.
The reaction speed and efficiency of the process depends on several parameters as mentioned below:
- The nature and properties of the air contaminant
- The gas scrubbing liquid
- The process conditions like concentration and pressure
- The present of other elements in the air flow
- The efficiency of the scrubber
Because of the fact that the contact between the air flow and the scrubbing liquid is so intense beside mass transport also heat transport will take place that will lead to an evaporation of water. This however depends strongly on the process conditions.
CIC International is ISO 9001 certified. The equipment is build according to CE. During production and installation the latest state of the art technologies are used.
CIC International has an enormous amount of experience in the field of air treatment that goes back many, many years. The impressive reference list together with great experience were the basis for the continuous improvement and modification of the units to the stringent legislation.
The CIC International gas scrubbers are unique in its kind and have the following advantages:
- Compact construction and therefore small surface area requirement.
- Extreme high efficiency due to a special construction and own development of the packaging material.
- Low operational cost.
- Low investment costs by the unique Construction designed by CIC International.
Besides this CIC International uses a very sophisticated computer modelling system as the basis for its design developed based on its many years of experiences.
The CIC International gas scrubbing systems consists out of the following components:
- Gas scrubbing system
- Connecting piping
- PLC unit and control cabinet
Depending on the demands and wishes of the customer the following units can installed optionally:
- Demister unit for higher removal efficiency
- Automatic pH controlling unit
- Automatic conductivity unit
- Chemical addition and storage unit
- Visualisation Software and controlling unit.
- Remote Controlling System in order to carry out service activities, modifications, trouble shooting,
The gas scrubber are available in different materials like:
- Standard housing of thermoplastic such as polypropylene specially for indoor units.
- In case of outside operating units polyethylene (HPE) with an air inlet temperature of max. 60ºC.
- For gas inlet temperature of more than 60ºC a polyester system with a liner made out of polypropylene or glass fiber is also possible.
- For specific application a design in AISI 304/316L is also possible.
In an open pre-treatment system the amount of air to be removed is extremely high and therefore will increase cost and waste.
To prevent polluted air to escape from the pre-treatment area, a small vacuum pressure will be maintained in this enclosed area. To do so we have to pull a certain amount of air out of the pre-treatment area and suck fresh air into this area. The balance between ventilator capacity and the inlet of air must be balanced and therefore carefully engineered.
In this way the acid air cannot escape from this enclosed pre-treatment area.
The principle of the system is that a minimum amount of air is removed from the enclosed pre-treatment area and blow through a Gas scrubber or fluidized bed system. In both systems the acid from the air is absorbed and removed from the air.
After leaving the gas scrubber or the fluidized bed system the air is clean and can be ventilated to the environment without causing pollution.
Our air cleaning systems have the highest requirements and met:
- Standard level will be average < 5 mg HCl per m3 emitted air out of the chimney (TÜV – Germany).
- Exhausting capacity depends on the final dimensions of the pre-treatment area but will be approximately 5.000-35.000m3 per hour.