Schreyer Award: Solvay Paperboard Machine

CATEGORY: INDUSTRY

AMEC E&C SERVICES

Solvay Paperboard took over an abandoned chemical factory site in a suburb of Syracuse, New York 10 years ago. Since then the company has grown to be one of the most successful producers of corrugated and linerboard carton packaging.

In November 1999, the company began to plan for its third paper machine and searched worldwide for proven technologies that would use 100 per cent recycled fibre as feedstock. In June 2000, the company selected AMEC’s Montreal office to provide the detailed engineering design for the “PM3” project and construction began the next year.

Working in conjunction with Solvay’s construction management team, AMEC designed a highly automated complex that is designed to run on 100% recycled fibre and uses the latest technologies. With a design capacity of 500 tonnes per day (tpd), the project consists of an old corrugated container or “OCC” stock preparation system, a sophisticated rejects disposal system, and a Metso corrugated medium machine with the latest pressing technology. Other elements are fog remediation equipment for paper machine exhaust, an automated roll wrapping line, primary wastewater treatment and a warehouse.

While many industry experts considered the U.S. $125 million budget to be low for this type of complex facility, the project was completed under budget and six weeks ahead of schedule by June 2002. As a result of the design, the total effluent from the facility has been reduced by 400,000 gallons per day and energy is reused within the plant. Solvay has a machine that is highly efficient and is able to deliver just-in-time time products for its partners and customers.

Structure and machinery

The marrying in this project of a structural steel frame design with a pre-engineered building design is an unconventional approach for the paper industry. However, it has worked well for Solvay and has contributed to their ability to build world-class installations at a cost below the industry norm.

A conventional steel frame design was used up to the operating floor level, and, in some cases, up to the mezzanine level when heavy loads were involved. The building was then “topped off” with a pre-fabricated building, resulting in major cost savings.

Because of a long waiting time for steel deliveries, the project was driven by the construction schedule and engineers were forced to deviate from a more conventional approach. Usually, when paper mills are being designed, first the process is established, mechanical layouts are prepared, and then civil and structural engineers complete their detailed design. In this case, the detailed civil design went ahead based on very preliminary mechanical layouts. After the civil design was completed, the mechanical group finalized their layouts and “made things fit” in the space that was available. Despite this unconventional approach, the final layout worked out well and is perhaps among the best possible layouts for a paper mill of this type.

The new machine room was designed in line with the existing paper machines, creating a building that is over 500 metres/1,700 feet long. This arrangement allowed the machine room crane to be designed in line with the other machine room cranes, and meant a second crane could be borrowed from the adjacent machine room during construction. The layout also makes the maintenance of the facility easier.

Though the machine was designed to produce 500 tpd, by using “smart” design techniques during the selection and purchase of process equipment, extra capacity was built in. This has permitted the machine to run up to 700 tpd, with monthly averages nearing 600 tpd. Operating efficiencies are very high and “off-spec” paper is less than expected.

The plant for preparing the paper stock in this facility is very complex, using equipment from many different suppliers. Each piece of equipment is a link in the process chain that takes the recycled paper from the warehouse storage and makes it into a clean pulp slurry for use on the paper machine. The process is highly automated. Whereas normally flow control valves are used to maintain operating variables, here flow control valves were eliminated wherever it made sense, and variable speed pumps are used to control flows. The variable speed drive provides better reliability than a control valve, while reducing the power consumption. It was also found that total installed costs, in many cases, were lower.

In most paper mills of this type, the rejects coming from the stock preparation line are simply dumped on the ground to be picked up by a front-end loader, loaded into a truck and transported to a landfill site. In the PM3’s system, 10 different rejects streams are collected and fed via chutes and collectors to a battery of waste compactors. The compactors are automatically filled in turn, and scheduled trucks pick up the filled bins for disposal. No fuss, no mess!

Water and energy conservation

The new machine was designed to use wastewater coming from the two existing linerboard machines as the main source of process water. Only a minimum amount of fresh water is used by the new machine. As a result, Solvay installed the new machine on the existing site and yet decreased their total fresh water use in the facility as a whole by 400,000 gallons per day. Solvay now has one of the best specific water consumption rates in the industry.

Paper machines require large amounts of vacuum to form a paper sheet. The liquid ring vacuum pumps used need large amounts of seal water to operate. Traditionally, fresh water is used as seal water and it ends up in the sewer. In this case, the vacuum seal water system was designed on a closed loop system using glycol to provide the necessary cooling. The system virtually eliminates the need for fresh water. Also, to cool the paper machine’s many hydraulic units and air compressor system the engineers designed a closed loop using the same glycol system. The icing on the cake is that this glycol system is used during the winter months to heat the 75,000 s.f. warehouse, providing “free heating” and great energy savings.

Fog remediation

Paper mills are notorious for their large vapour plumes coming from the machine rooms. In urban environments, the vapour often causes ice and fog on highways that pass close to the mill, particularly during the winter. To eliminate this hazard in the Solvay design, a fog remediation system was installed. The vapours coming from the paper machine, more than 130,000 cfm, are collected and passed through a glycol cooling system that condenses the moisture in the air stream to a point where the “fogging” condition is eliminated. The water removed from the system is returned back to the process, again reducing the need for fresh water make-up.

The heat that is picked up by the glycol is then used in heating coils on the make-up air units that are distributed throughout the mill — again providing free heating. During the summer months, the fog remediation system is not required and is by-passed.

Even though the use of fresh water in the mill has been minimized through many design innovations, there is still a need for a small amount of fresh warm water for certain process applications. In most paper mills the fresh water is heated using steam, which has a high energy cost. In the Solvay design, a series of heat exchangers was installed on the waste effluent leaving the mill. The fresh water supply was routed through these exchangers, providing warm water for the process — another great energy savings.

Social, economic and environmental benefits

Solvay village was hit hard when Allied Chemical shut down years ago, causing unemployment and leaving the contaminated site abandoned for several years.

Solvay saw the potential of the site and built its first linerboard machine there in 1994. Since then, the company has prospered and become the backbone of the village. Besides bringing the environmental benefits of cleaning up and re-using an industrial site, its operation uses 100% recycled paper,
thereby removing 700,000 tonnes a year from the waste stream going to landfills.

In building paper machine No. 3, Solvay added 65 new permanent jobs as well as thousands of construction jobs in the region. The company is now planning for a possible fourth machine, and the installation of a fluidized bed boiler that will use non-recyclable pre-consumer waste as its main fuel source. It will also burn a synthetic fuel derived from lagoons of chemical waste that were left on the site.

Name of project: Solvay Paperboard PM3 New Corrugated Medium Machine, Syracuse, N.Y.

Award-winning firm: AMEC E&C Services, Montreal (Don Blenkhorn, P.Eng., Tad Granosik, P.Eng., Tony Tuccia, P.Eng., Sylvain Labrche, Arthur Harding, Michel Sanche, Ral Par)

Owner/Client: Solvay Paperboard