A new phase will begin in Metsä Group's Äänekoski bioproduct mill project during the first quarter of 2017, as the focus of work shifts from installing equipment to commissioning – in other words, the testing and test run phase.
“The commissioning will begin department by department as the installation work is completed, and it will end when the mill is engaged in continuous, commercial pulp production,” explains Pertti Lehmonen, Technical Director of the bioproduct mill project.
The installation inspections and the pressure and leak tests will be conducted before commissioning. The tests related to commissioning will begin in January, when the central control room located in the new office building is finished and the automation system software has been installed.
“We'll start commissioning the water plant in February. On a wider scale, commissioning in the process departments, such as the fibre line and the recovery boiler, will begin in March. In terms of the wastewater treatment plant, this phase will occur in April.”
The installation inspections and the pressure and leak tests will be conducted before commissioning.
From cold comissioning to production start-up
In the initial phase of commissioning, the bioproduct mill's equipment will go through cold tests, i.e. mechanical test runs.
“The functioning of every valve and electric motor, for example, is tested. When everything is in order, we'll start testing the equipment in various usage group configurations. Testing has also been performed prior to installation in factory acceptance tests,” says Lehmonen.
In the second phase, the testing will be performed with mediums at sites where the use of water, for instance, is possible.
“The equipment will be grouped into water run groups, and their operation will be tested with cold water. Air can also be used as a medium in the testing of flue gas fans, for instance.”
After the cold comissioning phase, there will be a smooth transition to the mill's hot comissioning, and after that to production test runs and from thereon over to continuous commercial use, during the third quarter of 2017.
“The cold comissioning phase will also include the mill's start-up chemical fill.”
A carefully planned process
As the technical director of the bioproduct mill project, Lehmonen is responsible for monitoring that the commissioning progresses systematically, safely and according to schedule. In practice, the tests are carried out by the main equipment suppliers in charge – Valmet and Andritz – who report on their progress to Metsä Fibre.
“The testing phase involves long hours. The big departments, such as the recovery boiler, pulp mill, evaporation plant and causticising plant are the most challenging and labour-intensive sites.”
According to Lehmonen, the testing phase follows carefully prepared safety instructions, because the work involves different kinds of occupational safety risks than construction and installation.
“We are also carrying out installation work simultaneously with the testing. This is why we have to be particularly careful in ensuring that occupational safety has been taken into account in all activities.”
The testing phase follows carefully prepared safety instructions.
The blowing of stacks during the mill's test run and testing phase will generate noise, and the relevant communication will be carried out separately before they begin. The test runs and testing will have no impact on waterways or air quality.
Prior to the start-up phase of the bioproduct mill, the new wastewater treatment plant will have been fully tested and started up with the wastewater of the current mill.
“In terms of the wastewater treatment plant, the start-up phase will begin in the spring of 2017,” says Lehmonen.