Wood Chip Storage and Metering System for Pyrolysis

General Description

A research and development laboratory created a new process for converting wood chips into fuel using pyrolysis. Pyrolysis is the thermal decomposition of materials at elevated temperatures. A pilot plant was built to test the new process in a cost-effective, accurate and small-scale production environment.

KWS provided bulk material handling equipment for storing, metering, elevating and heating wood chips. The wood chips were stored in a large hopper that was continuously fed by a cyclone. Due to space constraints, the wood chips were then metered and lifted vertically to another hopper by a screw feeder and bucket elevator. After storage, the wood chips were metered to a KWS thermal screw processor to elevate the temperature of the wood chips for the start the pyrolysis process. The pyrolysis industry is growing rapidly, and the need for better technology to achieve better results is a challenge that KWS has successfully tackled.

Design Parameters

Wood Chip Storage and Metering System for Pyrolysis - KWS Manufacturing

KWS Provided a Complete Bulk Material Handling System for Wood Chips

Product Type: Wood Chips
Material Density: 9 to 11 Lbs. per Cubic Foot
Capacity: 36 to 46 Cubic Feet per Hour
Duty: 24 Hours per Day, 7 Days per Week

KWS Advantages

With KWS at the forefront of unique design solutions for the growing pyrolysis industry, the customer knew there was no better choice than KWS. The pilot plant had unique and very tight space constraints. By sharing 3D models of the system with the customer, KWS provided a custom support structure layout that fit seamlessly into the customer’s existing platform structure. KWS provided inspection door locations, footprints for the supports, and indicated bracing locations of the bucket elevator to help the customer with ease of installation and maintenance. The large KWS engineering department interact easily and spoke the “engineering language” that the customer required every step of the way.

Special Features

The storage hopper at the beginning the process was deliberately oversized to make room for future production ramp up and designed in a pyramid shape to avoid bridging of the wood chips, which is a common problem. The hopper was equipped with a live bottom quadruple-screw feeder to accurately meter wood chips. The screw feeder was designed with special variable pitch screws and independent drive units for maximum feed rate variation. The bucket elevator was a very cost-effective method of elevating bulk materials and equipped with digger buckets to help eliminate product buildup at the bottom the elevator and utilized a heavy duty discharge transition to match the heating screw thermal processor inlet. The KWS thermal processor was designed to ASME Boiler & Pressure Vessel Code requirements and could easily preheat the wood chips to approximately 250-degrees F using hot oil.