Screw Conveyor System for Straw for Process Applications

Screw conveyor system for straw for process applications, developed and designed by BEMA.

Customer and Requirements

An international producer within advanced bioenergy required a conveying system capable of handling large volumes of chopped straw as raw material for a continuous process line. The customer works with biomass-based conversion technologies, where stable and precise material feeding is crucial for both process economics and uptime.

The customer requested a solution that could:

• Ensure uniform and controlled feeding of straw to the process
• Handle a fibrous and easily compacting material without blockages
• Be integrated into an existing process with high demands for operational reliability
• Minimize maintenance and ensure 24/7 operation
• Document performance and capacity in a demanding industrial environment

BEMA’s Solution

BEMA developed a complete screw-based conveying system, optimized specifically for straw and other low-density biomasses. The system combines a receiving hopper, dosing screws, a transport screw, and a feeding screw, which together ensure a stable flow from reception to process inlet.

The feeding screw is unique because it has a small diameter relative to the chopped straw it transports. To ensure a stable material flow, the feeding screw is force-fed along its length via three push screws.

The feeding screw is manufactured in 1.4835 / 253-MA to withstand temperatures up to 600 °C.

The system is pressure-rated for 10 barG, and pressure-bearing components are pressure tested to 16 barG during manufacturing.

Technical Highlights

• Optimized geometry for fibrous biomasses
• Capacity for large volumes of chopped straw
• Low energy consumption and high operational reliability
• Designed for 24/7 industrial operation
• Designed to withstand pressures up to 10 barG

Results for the Customer

• Stable and predictable material feeding to the process
• Minimal risk of downtime and blockages
• Reduced maintenance requirements – screw conveyors have very low service needs
• Higher overall plant utilization
• A more efficient and economical process

The system has proven particularly suitable for bioethanol production, pyrolysis, thermal gasification, and other industrial biomass processes where straw is used as the primary raw material.

FAQ – Screw Conveyor System for Straw

What types of straw can the system handle?

The system can handle wheat straw, barley, rapeseed, corn stalks, and other fibrous biomasses – provided they are chopped and dry.

How does the system avoid bridging in the feeding hopper?

The feeding hopper is designed with negatively inclined sides and equipped with two dosing screws at the bottom that fully cover the entire base.

Can the system be adapted to existing plants?

Yes. BEMA’s modular design makes it possible to integrate the system into both new and existing plants. BEMA has its own design department that can adapt individual machines to existing geometries.

How much maintenance does the system require?

Screw conveying is generally a low-maintenance technology. The system is designed for 24/7 operation with minimal service requirements.

Can the system handle pressurized processes?

Yes. All transport and feeding screws after the rotary valve are designed to withstand a pressure of 10 barG.

Advantages of Choosing BEMA as System Supplier

1. One Responsible Partner

The customer gets a single supplier responsible for the entire material flow – from reception to process inlet. This reduces complexity, minimizes interfaces, and ensures more stable operation.

2. Optimized System Design from Start to Finish

BEMA designs all components to work optimally together. This means:

• Fewer bottlenecks
• Better flow
• Lower energy consumption
• Higher operational reliability

The system is not a collection of components – it is a complete solution.

3. Proven Experience with Biomass and Straw

BEMA has many years of experience with fibrous biomasses, including straw, beet pulp, wood chips, and residual products. The customer receives a solution based on practical operational experience, not theoretical assumptions.

4. High Flexibility and Adaptability

BEMA’s modular systems can be adapted to:

• Different types of straw
• Changing capacity requirements
• New process steps

The customer receives a solution that can evolve with their production.

5. Seamless Integration into Existing Plants

BEMA has extensive experience integrating into complex process environments. This ensures the customer receives a solution that fits into their existing setup – mechanically, electrically, and in terms of control systems.

6. Strong Technical Support and Service

The customer gains access to BEMA’s specialists, who know the system in detail. This ensures fast support, efficient troubleshooting, and reliable operation.

7. High Quality and Danish Production

All key components are produced in Denmark with a focus on robustness, precision, and long service life. Customers receive a solution built for industrial 24/7 operation.