PULP & PEPER

Clean air solutions to support mill operations

Pulp and paper operations present a unique combination of challenges in air filtration. Electronic process control systems are susceptible to corrosive elements in the pulp mill environment. Byproducts such as fly-ash, fiber and dust can interfere with plant machinery, while airborne contaminants can affect employee health and wellbeing. AAF’s complete range of clean air solutions are designed to address the complex needs of the pulp and paper industry — helping protect the electronics, equipment and people involved in production and other daily operations.

Pulp and paper operations present multiple challenges for air pollution control. Steam boilers produce fly-ash, process equipment creates salt cake accumulation, and in-plant processes create various kinds of dust and fumes.

The primary source for gaseous contamination in pulp and paper mills is the pulping process. In the Kraft pulping process, highly malodorous emissions of reduced sulfur compounds are produced. These compounds are measured as total reduced sulfur (TRS) and include hydrogen sulfide, methyl mercaptan, dimethyl sulfide, and dimethyl disulfide. These sulfur compounds are often described as smelling like rotten cabbage. In the sulfite pulping process, sulfur oxides are also emitted in fairly significant concentrations. Other pulping processes, such as the mechanical and thermomechanical methods, generate significantly lower quantities of air emissions.

In addition, steam and electricity-generating units using coal or fuel oil emit fly ash, sulfur oxides, and nitrogen oxides. A secondary source of corrosive gases in the pulping process is during the bleaching step. These bleaching chemicals, which often include lime, are caustic and cause corrosion to occur.

Optimize Your Filtration and Improve Your Environment

For particulate filtration, several stages of HVAC-type air filtration products are employed to help keep the wood fiber and associated dust to a minimum. Ensuring that this dust is removed is extremely important to both the paper quality and the maintenance of the pulping equipment and paper production machines. 

At a minimum, protection of the control room includes pressurization with purified air. This prevents corrosive gases from infiltrating the control room and causing corrosion problems. Additionally, recirculation air may require cleaning, if the room is a high traffic area or there are other internal sources of contaminants.