Historically, the chemicals used for pulp production were used once, then discarded. This costly way of making pulp and paper required that a steady stream of chemicals be shipped to the mill. Today, to reach production goals in an economically competitive and more sustainable way, these chemicals are recovered and steam is generated in the black liquor recovery boiler (BLRB). By recovering chemicals and generating steam, the mill’s operational expenditure is greatly reduced. In fact, now, in many cases, mills are net positive producers of renewable electricity for the grid, generating revenue and offsetting fossil power.
The BLRB is so integral today that, without it, most pulp mills would have to shut down operations due to high chemical and electricity costs. That’s why maintaining the high availability and efficiency of boilers is a top priority for pulp mill production managers. If the recovery boiler is down, pulp production halts and costs start to accumulate to the tune of $20,000-$100,000 per hour, depending on mill size. This is expected to occur once per year during the planned pulp mill maintenance outage. It’s the unplanned outages that are detrimental in terms of both cost and the lifetime of the pulp mill equipment.
The cost of boiler availability for a pulp mill
The tool traditionally used to maintain high availability of the BLRB in a pulp mill has been the long retractable steam sootblower (LRSB). This piece of equipment is started up with the recovery boiler and only stopped once the boiler is down. The cost of steam sootblowing is 5-10% of the steam generated in the BLRB. This directly affects the key performance index of energy consumption/ADMT and water consumption/ADMT. The alternative cost of sootblowing is to consume more fuel in auxiliary boilers or generate renewable power.
The cost of the steam itself depends on the size of the pulp mill, but is generally around $10 per ton. For a BLRB generating 300 t/h of steam, this means the steam sootblowing costs $1.3-$ 2.5 million per year.
Combined with the cost of maintaining the system, the average annual cost of boiler availability for a pulp mill is well above $2 million, meaning the system must be operated as efficiently as possible in order to reduce costs without affecting availability.
Sootblow more, with less steam
To improve pulp mill sustainability while staying ahead of the competition, many mills are adopting a holistic approach that balances availability with the cost of steam sootblowing.
The patented solution by Heat Management is called a High Impact Sootblowing System (HISS), and simply reduces the operational expenditure of the sootblowing system while improving the availability of the BLRB to enable increased production.
Using HISS, pulp mills can enjoy a guaranteed savings of 30% lower steam consumption with the same or better BLRB availability. For the example above, this means a guaranteed annual savings of $400,000-$750,000 in steam. The result is lower energy cost/ADMT and lower water cost/ADMT. The short return on investment of 1.5-2 years makes HISS the go-to solution for mills seeking to take control of BLRB availability while comfortably moving production beyond technical specification.
Better for pulp mill productivity and the environment
Improved BLRB availability from dynamic operational and strategic sootblowing capacity plus millions in savings from increased and safe production levels adds up to a huge competitive advantage for pulp mills. What’s more, the resulting energy and water savings per ADMT contributes directly to more sustainable and circular operations—making solutions like HISS ideal for pulp mills reaching for higher productivity and sustainability goals.