help us extend the time between major outages,” he added. About 78.5 t of wet liquor at 50% dry solids can be burned each hour. This equates to 942 tds/d producing 222 t/h of high- pressure steam. Ammonium bisulfite is recovered in the flue gas cleaning plant. Currently, due to limitations in the fibreline and evaporation plant, the red liquor is responsible for about 80% of the capacity of the SulfitePower boiler. Natural gas is now the supplemental fuel to achieve the steam capacity needed, but the boiler is designed to burn red liquor without supplemental fuel and sized to allow for upgrades in pulping capacity.

“We have room for expansion in our pulping operation,” said Dottori. “We started replacing our refractory-lined digester vessels with duplex stainless steel, which will give us additional capacity in each of the 11 units.”

Much-needed project Trevor Turner and Dan Guénette, now both Head Operators, were appointed Operating Commis-

sioning Co-ordinators and were involved with the project from the very beginning. The fact that the Andritz boiler replaces three units creates a new mindset, according to Guénette. “When this boiler is down, the mill is down,” he

states. “So, we are training every operator to be at a high level to match our best people.” Turner added, “Any large pro- ject requires a little time for the operators to get accustomed to it, but our operators have been up to the challenge. We are making adjustments day-to-day to further improve the boiler’s performance. Now that the operators are learn- ing the boiler, we are giving them more flexibility”.

Turner and Guénette agree that the boiler is a much-needed ad- dition. “The SO2 emissions from any sulfite mill must be tightly controlled,” they say. “This boiler does that superbly. This is a great thing for the environment and the local community. The boiler runs well and stabilises quickly. We can adjust liquor flows and air ratios based on pulp mill needs, with most of the operation in automatic mode.”

Inside the boiler, liquor is sprayed into the furnace and atomised by steam.

14 14 Spring 2017

Marc Barrette, Mill Manager of the Specialty Cellulose mill, said: “The entire steam plant team was involved in making this project a success”. Barrette was Project Owner for the boiler project, re- sponsible for commissioning and start-up. “Our operators and the commissioning team worked long hours on many consecutive days during the training and commis-

Christoph Gruber, Andritz Commissioning Manager (standing) with Trevor Turner, Head Operator, in the control room.

sioning phases,” he added “The project is over; the boiler is built,” stated Dottori. “Now it is Operations’ job to turn the page and look forward to the next 30 years. That is how we are working with Andritz – shifting from project mode to operating mode: maintaining, optimising and then looking at future op- portunities.”

Dottori says the team made a lot of very good decisions in terms of equipment selection. “You can see that in the way that the mill is operating today. Our digest- ers and the board machine are performing better because of the solid and stable steam supply we are delivering to them. The boiler is big and robust, with spare capacity at the moment. It burns difficult liquors quite effectively. We’re still optimising, but overall we are happy.”

Cousineau agrees. “I would definitely do another project with Andritz,” he said. “That’s the bot- tom line.”

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