We think a lot about wood utilization from both a cost and sustainability perspective. At Mercer, our operations focus on increasing the utilization of the raw materials in our process while minimizing waste. Full utilization starts in the forest and continues through every step of the pulping process in our large, modern facilities.
The idea behind full-cycle utilization is reducing our carbon footprint on the landscape by using responsible forestry practices where we use, reduce, and/or recycle our fibre and residuals (branches, bark, and pulping liquor) in the making of our pulp and bioenergy processes.
Our Mercer Holz wood procurement team in Europe is dedicated to buying a range of wood products from the forest with an array of quality; be they high-quality sawlogs to basic pulpwood. We merchandise this material to ensure that it is utilized and ends up in a process that gains the greatest value from that material.
In Canada, we have custom machinery to enter forest sites harvested by others and recover the material left behind that was otherwise destined for burning. By focusing on the increased utilization of the fibre, such as the portable chipping processes used by Mercer Peace River, we have been able to achieve 120% higher utilization in comparison to Alberta Provincial standards.
We pay for waste material that other producers in the region discard. This practice results in greater utilization of the resource and eliminates a source of particulates when the material would otherwise be burned in slash piles.
We are in the midst of a $70 million upgrade to our sawmill at Friesau in Germany; this will include an upgrade to primary breakdown equipment to increase the percentage of each log recovered to make lumber by 2 – 3%. In our pulp mills, new chip screen facilities and chip handling equipment help reduce damage to wood chips and recover more wood to make value-added products. These are small, but important improvements, to achieving full utilization of a scarce but renewable resource.
With a few isolated exceptions, our manufacturing facilities are fully electric: electric pumps, agitators, vacuums, conveyors, and control systems. Those pieces of equipment that remain driven by fossil fuels are targets for electrification. We have introduced electric locomotives, shunting robots, cranes and log loading equipment, and we constantly focus on electricity and steam conservation to optimize the amount of steam that is available for electricity generation.
In our kraft process, efficient recovery and regeneration of our pulping chemicals are essential. We work continuously to improve our manufacturing processes that not only cut down on our emissions but also increases productivity and decrease costs. Wood components dissolved in our pulping processes are converted to useful bioproducts, such as tall oil, turpentine and methanol, or used to create electrical energy through combustion. As a result, our processes are cost-effective, and the recovery cycle allows us to not only be energy self-sufficient but provide electricity to our local energy grids as we convert dissolved organic and other waste materials into steam for our turbines.
The majority of the energy input to our mills comes from the wood dissolved in the white liquor, bark, and other fuels burned in the boilers and lime kilns. This energy ends up producing high-pressure steam from the boilers that allow us to produce electricity through our turbines and lower pressure steam to be utilized throughout the pulping processes.
We take warm water from the evaporator supply and use it as cooling water to the digester heat recovery system, thereby producing twice the volume of high-temperature water versus supplying the digester system directly with cold process water. The low-pressure steam freed up in this way can be diverted to a turbine generator condenser for higher electrical power production.
To further increase our efficiencies, we use warm water wherever possible as a medium in the fibreline process to produce hot water, which reduces our need to use energy. The hot water is utilized throughout the process which frees up steam otherwise needed to heat water. The use of less low-pressure steam allows more steam to be turned into electrical energy through a condensing turbine.