KWS Manufacturing

Heavy Duty Screw Conveyors for Conveying Corn Stover for Biofuel Plant

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Plant Location

Nevada, IA

General Description

DuPont is one of the world’s largest chemical companies and is at the forefront of innovation for ideas to nourish a growing population, build a secure energy future, and make the world a safer place. DuPont is currently constructing a new biomass facility in Nevada, Iowa that will be among the first commercial scale production facilities for corn stover-based biofuels. Corn stover is the byproduct of harvesting corn and consists of the leaves, stalks and husks. Corn stover has typically not been utilized in the biofuels manufacturing process. DuPont has recently developed new technology for converting the corn stover to biofuels. Corn stover along with other residuals provides a potential 1.3 billion tons of raw materials that could produce future fuel in the next 50 years. For this project, multiple screw conveyors were required to transfer both wet press cake and dry biomass. The wet press cake is conveyed from filter presses to storage. KWS designed the wet press cake conveyors to serve as overflow devices that would convey excess material to silos when the downstream equipment became too full or clogged. The dry biomass conveyors conveyed product from the dryers and screeners to storage. KWS worked directly with the Customer’s engineering firm, KBR, to develop an excellent solution on this project.

Design Parameters

  1. Product Type: Corn Stover Biomass
  2. Material Density: 35 Lbs. per Cubic Foot
  3. Capacity: 3,800 Cubic Feet per Hour
  4. Duty: 24 Hours per Day, 7 Days per Week

KWS Advantages

DuPont and KBR were seeking an experienced screw conveyor manufacturer to design and build multiple heavy-duty screw conveyors that were cost effective, high quality and engineered for the application. During the design process, engineers at KWS provided valuable expertise to help KBR determine the exact requirements for the screw conveyors. KWS designed the inlet of the wet press cake conveyors to be part of the chute from the filter presses to the downstream process equipment. Once the chute would fill up to the level of the screw, the excess wet press cake would be conveyed down to one of three storage silos. The dry biomass conveyors were designed for an internal nitrogen purge to prevent the dusty product from igniting. This project was a cooperative effort between DuPont, KBR and KWS. The engineers at KWS have the tools and knowledge to transfer engineering information to the various stakeholders and ensure an end product that met all of their needs.

Special Features

KWS engineers designed the conveyors to meet the requirements of the project. The conveyors were designed with purgeable intermediate bearings to reduce maintenance. A constant nitrogen purge is kept on the bearings to eliminate any contamination from the product being conveyed. Each conveyor was also designed to hold up to 5-psig internal pressure in order to contain the nitrogen purge. KWS also provided manually operated slide gates to help regulate the discharge of product to the storage silos.


"Thank you for all of your help on this project. The KWS equipment looks great and operates completely in accordance with our requirements."

John Dadisman, Principal Technical Professional – KBR


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