If you look at a pulp mill, you’ll see large stacks coming up from the building with billowing clouds of low-pressure steam. As part of the pulp-making process, natural gas is used to heat water and create steam vapour, and that steam is used to help break down wood chips and is eventually released via the mill stacks once we’ve captured all of the available energy.
In the mechanical pulping process, large refiners use electricity to grind wood chips into pulp, and a by-product of this process is steam laden with fibre. The efficiency of fibre removal directly influences the reusability of the generated steam. If we’re unable to recover much of this steam, the energy must then be supplemented by steam produced in a natural gas-fired boiler.
A few years ago, the operators at Quesnel River Pulp saw an opportunity. What if the mill could use more steam generated in the mechanical pulp process to heat the water needed in later steps? Perry Ghuman is an energy engineer, and he studies mill systems to figure out ways the mill could save energy. The engineering and operations team at QRP found a solution by installing a pressurized scrubber designed to clean the steam of wood fibre. The “scrubbed” steam will now be clean enough to be reused for other purposes.
“The new technology will essentially allow us to upcycle steam, which reduces the amount of “clean” steam we need to produce up from scratch. And that means we’re using less natural gas to heat our steam,” says Ghuman.
The idea first came up in 2016, and it’s taken four years to see the project come to fruition. During the next major shutdown on the first of October, Quesnel River Pulp will install the final parts of the project. Then, by the end of the year, the entire new scrubber system will be optimized for mill operations. The mill estimates it will reduce CO2 emissions by 10,000 tonnes each year.
Quesnel River Pulp received some financial funding to support this project. Because of the emissions and energy-saving potential, the mill received a two-million-dollar grant from the CleanBC Industry Fund and another two million from Fortis BC, with one million coming from West Fraser. West Fraser has committed to a minimum of 25% of the project cost per the agreement of the CleanBC Industry Fund.
To finally see this come together, it’s pretty exciting for the crew.
“It came from our operators identifying deficiencies, so it’ll be really awesome to see them finally use the technology and to see their concerns being addressed,” says Ghuman.