Combat the corrosion and irreversible damage caused by pollutant by-products at pulp and paper mills. Prevent equipment failure with Camfil’s molecular filters in a variety of applications.
Even in the digital age, paper and cardboard are essential global commodities. Processing wood and reclaimed waste paper to make pulp and new paper requires the use of aggressive chemicals. These chemicals can corrode process equipment, especially sensitive electronic and electrical process control systems.
When these fail, the result is unplanned shutdowns and loss of process efficiency and profitability.
The primary papermaking processes – pulp and wastepaper bleaching, lignin removal and wastewater treatment – are the source of the following contaminant gases that warrant corrosion control:
The rooms containing electrical and electronic control equipment are ventilated with temperature and humidity conditioned air to achieve the environmental conditions required by the warranty conditions imposed by original equipment manufacturers.
The supply or make-up air will be taken from an external location and the outdoor air may be heavily contaminated with acidic gases. If these gases are not removed before the air enters the room, then the control equipment will be susceptible to damage and, ultimately, failure due to corrosion. Molecular filtration can remove these gases.
The gas concentration in the inlet air may be high – perhaps tens of parts per million (ppm). However, the manufacturer’s warranty typically requires in-room gas concentrations in the very low parts per billion (ppb) range to comply with corrosion class G1 under ISA 71.04-2013. A molecular filter installed in the outdoor supply air system must operate with very high efficiency on a single-pass basis. Importantly, this air, which may account for up to 40% of the total room ventilation rate, is used to positively pressurise the control room to prevent the ingress of fugitive gases. The level of pressurisation can be compromised by unnecessary opening of doors and windows, leaks due to construction defects and leaks at cable entry points.
To provide additional protection from fugitive gases, additional molecular filtration can be installed in the return/recirculation air system. Concentrations of gases are much lower in the return air and a filter will operate on a multi-pass basis. A lighter duty filtration solution than that used in the outdoor air system makes a good choice. Sometimes industrial air cleaners make a good choice for both room pressurisation and as recirculation systems.
Here’s what Camfil can do for you to meet the challenges of your pulp and paper operations.