Paper industry treatment of wood and road in the process

The bark step produces a residual product called bark press filtrate. This is very acidic and therefore corrosive but also abrasive. Here we are happy to offer a displacement pump, in the form of hose pump, membrane pump or piston diaphragm pump.

The chips go on a conveyor to a screening house, where the chips are sorted/grated. From the screening house, the chips are blown to the coking plant. This transport is very labour intensive and therefore ceramic hoses and ceramic tubesespecially bends, good to use.

After boiling, white liquor is added to boil out the lignin. White liquor/Sodium liquor (NaOH) has a high low pH and plastics are normally not an option.

If the goal is a white mass, a bleaching step follows the boiling process. Different oxygen steps are used here, hydrogen peroxide and chlorine dioxide. Hydrogen peroxide and chlorine dioxide are corrosive and we therefore have a wide range of products that can handle this. Above all, we have good linear control valves, on/off valves. In the case of particle-free media, we can offer magnetic drive pumps.

The chlorine dioxide that may be used is produced from chlorates that are coated with a lot of particles. Here we can offer in particular a ceramic pump to pump this flow. Chlorine dioxide is usually produced at the mills in a separate process at the mill.

If hydrogen peroxide is used in the process, it should be circulated to prevent it from decomposing and reverting to hydrogen. Here we use acidic solids centrifugal pumps.

The pulp is then pumped onto the paper web. In this step, the pH value may need to be lowered, which is done by adding, for example, sulphuric acid (H₂SO₄). The process uses equipment such as pumping, plastic tubes, plastic valves and tanks. The dewatering of the pulp then begins, removing water to mould the paper.

When the paper is to be coated, different media are applied to coat the pulp. When applying a coating adhesive, for example, a linear diaphragm pump. are used. The choice of coating material varies depending on the product to be manufactured, but often involves highly viscous substances. Therefore, in this step, different types of displacement pumps

Process water in the mill

Usually, fresh water is drawn from a lake or river and used in much of the process. The sand trap removes coarse particles and humus. Further water treatment aims to eliminate living organisms, which can be done by adding, for example, hydrochloric acid (HCl). In this step, we can offer equipment such as tube, tanks and ventilate.

Coke oven

When pine is used in the process, you want to split the soap out of the wood, this is done in the pine oil boiler. Here, sulphuric acid is used in the process. This process is very hot, and lined steel products such as ventilate and tube are therefore very useful here. The residual acid can be up to 100 °C hot. A static mixer can be used for the mixing of H₂SO₄.

Black liquor and soda pan

To convert the residues from the digester back into white liquor, the black liquor, i.e. the spent liquor, is treated in a combustion process in the recovery boiler. The result is white liquor that can be returned to the process. The recovery boiler process uses lime and milk of lime, which means that ceramic hoses, tube and centrifugal pumps are appropriate solutions.