Batch Pyrolysis Technology & By-Product Wood Vinegar
Batch Process Technology
Exhaust Flue Gas Purification & By-product Wood Vinegar
The mixed exhaust gas is generated during the high temperature pyrolysis. This exhaust gas is comprised of combustible gas, water vapour and tar gas (bio oil gas), which is produced in the furnace (1) in an oxygen-deprived environment
The mixed exhaust gas is then pulled from the furnace through an inducted draft fan at the top of the furnace and is channelled into the nozzle of an Impacting water spray separator (2) with considerable speed, making an impact on the water layer before re entry (the red arrows showing the flow). Some of the solid particles and tar enter the water (part of the tar is soluble in water), the rest is mixed with the water droplets and bubbles splashed by the impact and is further separated by the effect of the water shield plates when it turns upwards.
The mixed exhaust gas goes through the water shield plates and enters the bottom of the exhaust gas condenser (3) and flows upwards along the bundle tubes.
As a result of the cold fluid cooling effect, the majority of water vapour and tar gas condenses into liquid drops, falling to the bottom of the exhaust gas condenser and form a tar solution. The purified combustible gas then rises to the top of the condenser
When the furnace temperature is below 300°C, the operator opens valve 1 and closes valve 2. This allows the clean gas at the top of the exhaust gas condenser to be released into the air. When the furnace temperature is above 300°C, the operator closes valve 1 and opens valve 2. This allows the clean combustible gas at the top of the condenser to flow through the flame arrester (4) into the burner in the hot air boiler (5) and provide heat energy, which is then used for various purposes such as drying and/or hot water/hot air heating etc
The red-brown tar solution condensed from the mixed exhaust gas during the wood material pyrolysis is called the wood vinegar. The wood vinegar takes 1-2 months to settle and separate, creating in 2 layers. The upper layer is the clear wood vinegar and the lower layer is the tar. The wood vinegar has a special smoky smell