Ammonia Plant System Upgrades Study

The Wabash Valley Produce facility in Farina, Illinois utilizes a central ammonia refrigeration system to provide cooling for multiple functions across the facility. Those functions include walk-in coolers, walk-in -10°F freezers, cooling tanks, and process heat exchangers. Most of the major components and piping that make up the central ammonia system are estimated to be 40 – 50 years old. The Owner’s goal was to make the system safe and reliable for another 20+ years of operation by developing a plan, budget estimates, and schematic design documentation to renovate and upgrade the central ammonia system.

McClure Engineering approached this project with the Owner’s realities in mind. The condition and age of this system could lead one to say it needed to be removed in its entirety and built back up from scratch. That would not be a realistic answer for the Owner and would negate the purpose of this study. The Owner had performed studies and assessments before, but the results of those efforts were never anything the Owner could take action on. We intended to give them a realistic plan that could be carried out with the help of McGrath & Associates.

The Owner in this case was a company that did not typically have a large capital projects budget in a given year. This presented a challenge in coming up with a solution for a system that had significant issues that were realistic from a financial standpoint. The approach taken of creating a master plan with cost estimates for each step of the process was intended to provide a road map that wasn’t as daunting from a financial standpoint as a one-time, all-in dollar amount. This approach would allow the Owner to do some capital planning over a few years to make the project feasible. McClure created a master plan document outlining a recommended path to making the necessary system upgrades over three years. The master plan included line-item lists of project scopes to be completed each year of the plan. The order of the work was prioritized based on risk, from both safety and business standpoints. In conjunction with McGrath & Associates, budget cost estimates for both design and construction were developed and included for each scope of work.

The central ammonia system was critical to the operation of the plant. Taking this system out of operation essentially means shutting down operations of the entire facility. Taking the system out of service for even a short period would not be feasible from a business standpoint. The challenge was developing a plan that would allow the system to remain operational and limit the downtime of the plant. At the same time, not making these much-needed upgrades would leave the plant at significant risk of system failure, which would certainly have an impact on the business and could quite possibly have safety implications. The plan for the eventual construction projects had to be developed with phasing in mind. All portions of the work would be completed with the system remaining in operation, other than for short-duration outages to make necessary switch-overs. While some short shutdowns would be impossible to avoid, they would be minimized to the extent possible.

Existing plan drawings showing the extent of the existing ammonia system did not exist. McClure performed the necessary fieldwork to document the existing system and created a set of plan drawings in CAD showing the system. These plans included major pieces of equipment as well as all system piping running on the exterior of the building. The vast majority of existing system piping was located outside in the service-yard area or on the plant roof.

McClure considered and presented to the Owner an alternate approach to “fixing” the existing central ammonia system. This approach was based on the concept of replacing the central system with smaller, more local systems for each function currently served by the central system. Each new system would be specifically designed to address the needs of that particular function. In this approach, much of the load currently served by the central ammonia system would be served by new equipment utilizing more modern refrigerants that do not present the same level of a safety hazard as an ammonia system. A new packaged ammonia system would be designed and installed to serve those functions where ammonia still makes sense. This alternate approach was presented in a high-level schematic design narrative accompanied by manufacturer cut-sheets for the new types of equipment & systems being proposed. While the Owner decided not to go down this path, it was important to consider all possible solutions and present the Owner with options.