Plant-expansion project keeps packing operation up and running.
Morning Star Packing Co. (Los Banos, CA) is a major producer and packager of tomato-ingredient products. As part of a plant expansion initiative, it recently installed new boilers, combustion systems, and a selective catalytic reduction (SCR) system at its facility in Williams, CA. According to Jon Ikerd, Morning Star’s project manager, the equipment not only increased steam-generation capacity at the plant twofold, it also lowered NOx (nitrogen oxide) output.
Tomatoes = big business
California is an agricultural-production juggernaut. Within the U.S., it far exceeds the output of any other state. In tomatoes alone, it produced 14 million tons in 2015 (98.5% of the nation’s overall output).
Morning Star began in 1970, with founder Chris Rufer working as a one-truck owner/operator hauling tomatoes to canneries. From those humble origins, the company has expanded to account for more than 25% of California’s tomato-processing production. Today, it supplies 40% of the U.S. ingredient-tomato-paste and diced-tomato markets (including food giants such as Heinz), with sales of approximately $350 million.
The company’s rapid growth was triggered by the establishment of a tomato-paste-processing plant in 1982, that introduced two industry innovations: the dedicated production and marketing of industrial tomato paste for major food producers and the marketing of tomato paste in 300-gal. containers.
In 1990, Morning Star added another facility in Los Banos. Although this new site was capable of processing 530 tons of tomatoes (producing 180,000 lb. of tomato paste) per hour, soaring demand led to the opening of another plant in 1995. Located in Williams, CA, its ability to handle approximately 630,000 tons of tomatoes (producing 200,000 lb. of tomato paste) per hour makes it the largest tomato-processing facility in the state.
Earlier boiler issues
“Morning Star revolutionized the tomato-processing industry by being a primary processor,” said Lou Brizzolara, a sales engineer at AHM Associates (Hayward, CA). A division of Bay City Boiler & Engineering, AHM is a manufacturer’s representative serving energy users and producers in California, Nevada, Arizona, and Hawaii.
After issues had arisen with a boiler at another Morning Star plant, AHM assisted in the selection of new boilers for the Williams site. As Brizzolara explained, the previous problems were related to installation and welding of the other boiler’s steam drum. This meant the system didn’t initially meet its guaranteed production levels.
At Williams, Morning Star opted for a solution incorporating multiple elements: two boilers from Rentech Boiler Systems (Abilene, TX), and register burners and an SCR system by John Zink Hamworthy (Tulsa, OK). All of this equipment plays a vital role in the facility’s production processes that use steam to boil, dehydrate, and concentrate the paste.
As Ikerd described the process, steam is used to cook the moisture off the product under vacuum, which keeps the boiling point low. “The boilers have been wonderful,” he noted, “but the success of the installation was very much a collaboration between our burner representatives and Rentech.”
Personnel from AHM and Rentech worked closely with burner and fan engineers Steve Bortz and Craig Biles of John Zink Hamworthy to ensure project success. Bortz and Biles had been involved in the previous boiler project. “While earlier boiler installations had not been as successful and didn’t meet their performance guarantees during the first year, they eventually achieved them due to the work of these engineers,” said Ikerd.
The team brought many lessons learned from previous installations, coupled with a solid understanding of the tomato-processing industry. This insight proved invaluable in avoiding the same errors that had occurred in the earlier boiler project, including, for example, challenges associated with ultra-low NOx burners.
While those burners had been effective in narrowing the window of combustion and reducing NOx to below 15 ppm, Ikerd said this made boiler operation more finicky and less reliable. If ultra-low NOx burners were to be avoided, the Morning Star Williams operation had to find a suitable alternative. California, after all, is known for its rigorous environmental regulations. Areas of the state where air pollution levels persistently exceed Ambient Air Quality Standards (AAQS) are designated non-attainment. The standards for non-attainment counties are tough for a reason: to protect public health, safety, and welfare. Counties falling outside of such standards are still required to meet emissions levels that fall far below those of most other states.
While the Williams plant is not in a non-attainment district, it still has to satisfy stringent requirements. The county air-quality control office set a strict limit of 25-tons/yr. of NOx for Morning Star. This made it difficult for the company to execute its expansion strategy. If it had opted for the same boilers and burners as usual, it would have greatly exceeded its NOx quota. However, the combination of the John Zink Hamworthy register burners and SCR, along with Rentech boilers meant that capacity could be greatly increased while remaining in compliance on emissions levels. The register burners selected for Williams brought NOx levels down to less than 30 ppm, which the SCR then reduced to 5 ppm.
The expansion project effectively doubled steam-generating capacity at Williams. Previously, capacity was around 680,000 lb./hr. The new boilers have raised that to 1,360,000 lb./hr. Increased capacity and lower emissions are only half the story.
“These larger Rentech boilers can go from minimum fire to full fire at the same speed as the smaller units we already have, which allows us to have much more flexibility,” observed Ikerd. “If the larger units are not at full fire, we can simply shut down one of the smaller boilers, without fear of causing an upset in our processes that we cannot recover from. Thus the plant’s stability has been greatly increased.”
Boiler efficiency has also been raised: from below 80% to around 85%. For a business whose highest operating cost is fuel, this equates to a welcome reduction in the cost of steam. Due to their size, these D-type boilers with a full-membrane furnace had to have the steam drums shipped separately. The sections were then assembled on site. The reassembly and welding of the boiler components may have proven problematic during an earlier boiler installation project, but not this time.
“Rentech helped us reach our capacity guarantees within the first year while our other boilers took a few years to achieve them due to startup problems,” said Ikerd. “We have now used them for a complete season, during which they’ve run 24/7 for three months straight, without a hiccup.” MT
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