EAI presents Cleantech Snapshots: a quick summary of some of the most interesting and innovative areas in clean technology that will drive the sustainability movement in future.
This snapshot focuses on Biomass gasification. Within this page you will find
- An overview of Biomass gasification
- How it works
- Types of gasifiers
- Advantages
- End applications
- Latest innovations
Overview
- Biomass gasification means incomplete combustion of biomass resulting in production of combustible gases consisting of Carbon monoxide (CO), Hydrogen (H2) and traces of Methane (CH4). This mixture is called producer gas
- A diverse range of crop, wood and forest waste can be used as feedstock for biomass gasification
- For India with large amounts of biomass waste generated annually, gasification could be an effective way to provide rural electricity
- Biomass gasifier can be used for operating pumps in remote rural areas, lifting water, operating saw mills, flour mills and for generating electricity
Biomass gasification(Image source)
How it works
Biomass gasification works just like coal gasification: A feedstock enters a gasifier, which cooks the carbon-containing material in a low-oxygen environment to produce syngas. Feedstock generally fall into one of four categories
- Agricultural residues left after farmers harvest a commodity crop. They include wheat, alfalfa, bean or barley straw and corn stover. Wheat straw and corn remnants make up the majority of this biomass
- Energy crops are grown solely for use as feedstock. They include hybrid poplar and willow trees, as well as switch grass
- Forestry residues include any biomass left behind after timber harvesting. Deadwood works well, too, as do scraps from debarking and limb-removal operations
- Urban wood waste refers to construction waste and demolition debris that would otherwise end up in a landfill
Types of gasifiers
- Updraft
- Downdraft
- Crossdraft
Advantages
- Good thermal efficiency
- Flexible adaptation of gas production to load
- Low sensitivity to charcoal dust and tar content of fuel
- Very fast response time to load
- Little tendency towards slag formation
End applications of biomass gasification
- Producer gas can be used to run internal combustion engines (both compression and spark ignition), which can be used as substitute for furnace oil in direct heat applications
- Since any biomass material can undergo gasification, this process is much more attractive than ethanol production or biogas where only selected biomass materials can produce the fuel
Latest innovations
- The gasifier unit which generates producer gas is now used to run diesel engines of 30 HP for one hour
- The furnaces of the gasifier are now built according to various specifications as per the availability of residual biomass and agricultural residue
