SPINIFEX TO BIOCHAR - WASTE REDUCTION
North West AustraliaBackground
Spinifex grows abundantly and encroaches on the Client’s oil and gas operations. Currently, the spinifex is removed and stockpiled, this process poses a significant fire risk and a legacy issue. Because of the environmental significance of the site, normal control methods such as spraying with chemicals and burning are not an option.
Objectives
The Client engaged Energy Farmers to conduct a number of trials to look at pyrolysis as a means to reduce the volume of spinifex stockpiled and collected on an annual basis. The trial comprised of three distinct operations:
- Preparation of spinifex for pyrolysis
- Pyrolysis of spinifex
- Emissions from process
After successful completion of the first trial the scope was widened to include dehydrated food waste that is produced on the island and further trials were carried out.
Outcomes
Outcomes of the trials concluded that:
- High speed grinding of spinifex was excessively dusty and resulted in a product that pulverised and unsuitable for pyrolysis through the Energy Farmer biochar kiln
- Pulverised spinifex does not feed via an auger
- Food waste and spinifex can solidify and potentially “plug” augers
- Light, fluffy spinifex material enables air to enter the pyrolysis zone, resulting in combustion of the material and reduces char yield
- A high level of particulate was measured in the flue gas, otherwise emissions were acceptable
- Biochar that was produced exhibited a high pH when produced at high temperatures.
- Explore alternatives for pre-processing of spinifex to produce a more uniform feedstock
- Modify the existing kiln to a design specifically tailored to spinifex
- Design and develop an end to end solution including preprocessing, storage and pyrolysis of spinifex into biochar.
Based on learnings from the previous trials, EFA proposed to:
Status
Ongoing – The first stage of this project was initiated in March 2020. This stage involved inserting a WT40120 Single Shaft Shredder sourced from Waste Initiatives into a 20ft sea container. We also designed and manufactured a feed in hopper and feed out augers. This unit will be commissioned in Jan 2021 before being moved to site. We expect the second stage to begin in the first quarter of 2021.
