Oil Seed Crush Plant Study Reduces Energy Usage and Increases Capacity
With more than 500 projects completed with less than one year to payback, Cargill Optimizing Services understands how to decrease costs and increase yields in the food and beverage industry.
Recommendations to reduce energy use per mass of product by 10.5% and increase production capacity by 8%. Predicted results verified through audit of operations.
Cargill soybean crush plant operated in the Midwestern United States.
Soybean crush plant used to convert soybeans into crude vegetable oil. The process involves using hexane to recover crude vegetable oil from flaked soybeans. Hexane is evaporated from the oil under vacuum, and hexane remaining in the flakes is stripped using steam. Spent flakes are then roasted and cooled. The hexane/water mixture is condensed in a three phase flash. Hexane is recycled and the water is stripped of residual organics before being purged.
Cargill’s corporate goals for Sustainability (20% energy reduction on a production basis from 2001 to 2010) and Reduced Carbon Emissions (6% on a total basis from 2001 to 2010) require operating plants to make sustainable improvements in energy consumption. In order to meet these goals, the soybean crush facility needed a holistic evaluation of its current operational approach and pragmatic recommendations for efficiency improvement.
The crush plant operations team requested a complete efficiency evaluation. The modeling team executed the project in the following steps:
- Audit site to identify areas of opportunity and gather data
- Collaborate with site and process experts to gather details of process design and operation
- Develop process model based on Cargill’s proprietary agrifood library
- Validate model with site personnel
- Analyze opportunities using model and brainstorm results to identify novel opportunities
- Review opportunity analysis results with site
- Provide follow-up modeling to support detailed engineering design
- Support/troubleshoot ongoing operation
- Find new opportunities for process redesign and “intelligent” benchmarking across sites with different designs but similar products.
Use of the process model enabled Cargill to design a robust and efficient set of enhancements to the existing heat recovery system for the crush plant. In this design, the closing of material and energy balances around the plant was a foundational action. Material flows and compositions were calculated, along with temperatures, vacuum levels, heat duties and operational costs.
The overall project was executed in two phases: an initial modeling/optimization phase, and an implementation phase, during which detailed equipment designs were reviewed, and recommendations tested in light of other process modifications. The model was developed and validated in summer 2004.
Four process modifications were identified and model predictions used to meet economic payback, safety and quality constraints.Equipment was purchased and installed by summer 2005.Operations since 2005 confirm the projected improvements.
Plant steam use per mass of product was reduced by over 10% resulting in significant savings.
Additionally, reducing energy consumption resulted in lowered duty for the cooling tower. This reduction was exploited through lowering the cooling water temperature and increasing vacuum on the evaporators. Deeper vacuum resulted in a capacity increase of almost 8% in a high demand market. Payback on capital invested was significantly less than 2 years based on energy savings alone.
Cargill Optimizing Services uses a uniquely holistic approach to identify operational efficiencies that others often miss. As an industry leader, we offer high-end engineering talent, a proprietary software library of agrifood unit operations, and over a decade of experience modeling and optimizing complex processes.
With more than 500 projects completed that have less than one year to payback, Cargill Optimizing Services understands how to decrease costs and increase yields in the food and beverage industry.