Fremont Case Study

As in most thermal processes involving food, Heinz North America’s Fremont, Ohio, plant uses water to cool the ketchup made on eight production lines. Because Heinz is focusing on sustainability more than ever and water is a vital natural resource, the feasibility of installing a robust reclamation system to save water and natural gas was explored.

A two-day examination of the plant determined that its heat reclamation system was capturing only 25% of the city water being used for cooling. This finding was an obvious place to start to conserve water and energy that would ultimately help meet energy reduction and return-on-investment project goals.

The first part of the solution involved reclaiming the cooling water and sending it into a closed loop system. This initiative alone had the potential to save 100 million gallons of city water per year. Additionally, a system was implemented for recovering heat from the cooling water that was previously going down the drain. The cooling water was 50°F when it entered the system and 160°F when it came out of the coolers. 

Heinz is now using the 160°F recovered waste heat to preheat ketchup ingredients before entering the cookers. Under the old system, the ingredients started at 60°F and had to be heated to 212°F. Now those ingredients measure at a much higher temperature than 60°F at the start of the cooking process. The new system is projected to save more than 37,000 MMbtus of natural gas per year.

Seasonal differences in outdoor temperature also affected the temperature of the water entering and coming out of the system, which, in turn, affected the amount of water usage and energy reclaimed. Engineers discovered they could increase the water savings by equalizing the water temperatures season to season. The resulting system is constant in its delivery of hot water, making it much more efficient. 

Heinz and its partners continued to seek more opportunities to transform Fremont into a model of water conservation. This led to a review of pumps on the plant’s second and third floors whose bearings were routinely flushed with city water. The water traveled across the floor and down a drain. Over time, the water damaged concrete and steel parts of the old structure. The solution was to install a special hub drain that channeled the water used for flushing the bearings into a recirculation system that eliminated one more source of wasted water.

A similar water-saving solution involved the homogenizers that were cooled with city water. Now that water is also being collected and entered into the recirculation system. These accumulated water savings generated a secondary benefit for Heinz – a decreased impact to the water treatment system, along with lower rates for sewer usage.

Yet another system improvement allowed for more efficient use of Fremont’s several onsite wells. The water wells had the capacity to cool two to three of its 11 coolers. However, using this water for cooling was inefficient because its pressure was too great for the existing piping. A valve had to be left slightly open to release the pressure, resulting in water being lost down the drain. As a better alternative, the well water is now being piped to one large heat exchanger where it is used to pre-cool all the water before it goes to the chillers for a final chilling. A steam recovery system now funnels excess steam into a heat exchanger that is in series with the newly installed heat exchangers being used to pre-heat the ingredients.

Because system measurement is critical to determine the impact of the plant improvements, the complex controls system that runs the plant has the ability to calculate how much heat is being saved and to create benchmarks for future improvements. The numbers are proof of the project’s success. Water usage at the plant is down 35 to 40% and the system improvements are recovering 6 million BTUs per hour.