New Torrefaction Process Reduces Transportation Costs for Biomass

Waste from olive oil pro­duc­tion is treated at a pilot plant in Spain that uses a unique tor­refac­tion process to reduce trans­porta­tion costs for bio­mass and pro­duces green chem­i­cals as a byprod­uct.

The new tor­refac­tion process, devel­oped through the EU-funded SteamBio project, results in tor­refied bio­mass that is lighter in weight and has improved com­bus­tion prop­er­ties.

Researchers from the Fraunhofer Institute for Interfacial Engineering and Biotechnology (IGB) in Stuttgart, Germany; together with ten project part­ners from four European coun­tries devel­oped the new tor­refac­tion process.

Fraunhofer IGB Group Manager Heat and Sorption Systems Antoine Dalibard told Olive Oil Times: ​“The obtained bio­mass is a high calorific mate­r­ial that can be used as bio­fuel, can be ground eas­ily for trans­port opti­miza­tion and can be stored in humid con­di­tions as it is hydropho­bic.

“It is really inter­est­ing,” he said in ref­er­ence to the process, ​‘because it allows to treat waste and make dou­ble use of it by simul­ta­ne­ous pro­duc­tion of bio­fu­els and green chem­i­cals.”

Up to now, these chem­i­cals have been obtained from nat­ural gas or crude oil. On Fraunhofer IGB’s web­site, Dalibard said: ​“In the case of many bio­mass mate­ri­als the plat­form chem­i­cals gen­er­ate so much profit that they finance the entire tor­refac­tion process.”

The SteamBio project was under­taken to address chal­lenges with bio­mass qual­ity, sta­bil­ity, stor­age and energy den­sity to ful­fill European Environmental Policy objec­tives to make bio­mass —which is cheap and abun­dant — more suit­able for wide­spread indus­trial use.

The new tor­refac­tion process was ini­tially devel­oped to adapt wood chips; which are heavy to trans­port, chal­leng­ing to store and sus­cep­ti­ble to rot; more suit­able for trans­porta­tion and stor­age.

In January this year, a pilot facil­ity of the new tor­refac­tion cham­ber was moved to Spain where types of bio­mass tor­refied are waste from olive oil pro­duc­tion; as well as pine, oak and beech wood, and vine­yard prun­ings.

Torrefaction is not a new tech­nique, but the new tor­refac­tion process is unique in that mois­ture con­tained in the bio­mass and vaporous prod­ucts result­ing from tor­refac­tion are retained in the tor­refac­tion cham­ber and become the process medium.

Oxygen is absent in the tor­refac­tion cham­ber, which results in higher qual­ity bio­mass and elim­i­nates the risk of explo­sion. Temperatures rang­ing between 390 and 482 degrees Fahrenheit dry out the bio­mass and cause organic com­pounds with low boil­ing points to become volatile.

During the process hemi­cel­lu­lose, which together with cel­lu­lose and lignin are the three main com­po­nents of bio­mass, is elim­i­nated.

Cellulose and lignin remain in a solid state, and hemi­cel­lu­lose changes into gas. Condensers are used to cap­ture the gas, cool it down and recover it as a liq­uid.

“The con­den­sate — liq­uid — is used for green chem­i­cals,” Dalibard said in ref­er­ence to the vapor­ized hemi­cel­lu­lose that is recov­ered.

The removal of the hemi­cel­lu­lose sig­nif­i­cantly reduces the weight of the tor­refied bio­mass, improves its calorific value and ren­ders it suit­able to grind into a highly reac­tive pow­der.

Biomass pow­der has a large sur­face area and pos­sesses more reac­tiv­ity than larger chunks. In energy appli­ca­tions, it can be mixed with coal dust and fed into fir­ing sys­tems of coal-fired power plants. It is also pos­si­ble to replace coal with tor­refied bio­mass while keep­ing the same com­bus­tion sys­tem.

Earlier this month researchers from Fraunhofer IGB show­cased a model pilot facil­ity of the new tor­refac­tion cham­ber at the ACHEMA 2018 trade fair in Frankfurt am Main, Germany.

“There was a great inter­est in the tech­nol­ogy demon­strated within the SteamBio project,” Dalibard told Olive Oil Times.

“The same tech­nol­ogy can be used to treat other waste mate­r­ial such as solid manure from ani­mal hus­bandry or solid diges­tate,” he said.

• Fraunhofer IGB


• SteamBio