DTU researcher combine pyrolysis with hydrogen-catalyst reaction to produce biofuels

March 29, 2018 |

In Denmark, researchers at DTU have combined the pyrolysis method and the catalyst reaction with hydrogen in a step called catalytic hydropyrolysis.

It works by feeding a reactor with solid biomass, while the catalyst is in constant motion. Hydrogen is fed in to the base of the reactor, partially lifting the biomass so it can move around. This allows the most reactive molecules in the bio-oil to react with hydrogen as soon as they form.

This prevents the molecules from reaching a state in which they could form coke, and so avoids deactivating the catalyst and removes around 95 per cent of the oxygen in the bio-oil.

This leaves the less reactive molecules (about five per cent), which can be removed by sending the oil through a traditional reactor, containing a catalyst, which is kept fixed.

The traditional reactor resembles those used to remove sulphur from petroleum in a process usually used in oil refineries to avoid sulphur in gasoline and diesel, thereby reducing sulphurous car emissions.

The reaction between hydrogen and biomass produces heat, so there is no need for additional energy during the process.

The product of catalytic hydro-pyrolysis are oil and water, which as we all know, do not like to mix and therefore separate automatically. This is important as it saves on energy-heavy distillation, which is normally used to separate alcohol from water.

This process creates light gases and less coke waste. The lighter gases include methane, ethane, and propane, and significant amounts of carbon monoxide and CO2. The latter two can be further reacted with hydrogen to create methane, which together with other light hydrocarbons can be used as biogas, meaning even less waste from the original biomass.

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Category: Research

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