Paper details

Title:

Gasification of Microalgae in Supercritical Water: Experimental Results from the Gasification of the Algal Species Scenedesmus Obliquus Cultivated in the Biq-House in Hamburg

Author(s):

Elsayed, S., Boukis, N., Kerner, M., Hindersin, S., Patzelt, D.

Document(s):

Abstract:

In this work, the hyd drothermal gasification of microalgae, Scenedesmus obliquu us, under supercritical water conditions was studied. The gasification experiments were conducted at a laboratory u unit in KIT. The algal biomass used was cultivated by Stra ategic Science Consult (SSC) GmbH in Hamburg using a no ovel configuration of a flat­plate photobioreactor (BIQ­Houuse) which utilizes sunlight for the growth of microalgae e. The ultimate target being researched is the integration b between the algal biomass production and hydrothermal gas sification. This can be realized by increasing the energetic efficiencies of the two processes and by using byproducts f from the hydrothermal gasification as a feed input to algal cultivation. For this purpose, the algal biomass was gasifie ed in a tubular reactor under a temperature of 600­650 °C and a pressure of 28 MPa. The biomass concentration (Dryy matter, DM) ranged from 2.5 to 5 % and a catalyst consissting of potassium carbonate (K2CO3) with a [K+] concentra ation of 1500 ppm was applied. The mean residence time at these conditions was 3­3.5 minutes and the product consiste ed mainly of (H2, CO2 and CH4) with small amounts of lighter hydrocarbons. Our experimental results show hig hgcarbon gasification efficiencies (> 90%). A continuous operation up to 50 hours has been achieved. The compositi ion of the gas mixture at steady state operation was measu ured to be (Vol. %; 46% H2, 19% CH4, 29% CO2, 4.5% C C2H6), having a lower heating value (LHV) of ~ 18.5 MJ/K Kg DM. In addition, the experiments for algal cultivation we ere conducted by SSC GmbH using the byproducts (residu ual water and nutrients) of hydrothermal gasification and tthe results provide an indication that the integration betweeen the two processes might be possible.

Keywords:

algae, biomass, cultivation, energy, gasification, microalgae

Topic:

Biomass Conversion Technologies for Heating, Cooling and Electricity

Subtopic:

Gasification for power, CHP and polygeneration

Event:

22nd European Biomass Conference and Exhibition

Session:

2AV.1.17

Pages:

573 - 578

ISBN:

978-88-89407-52-3

Paper DOI:

10.5071/22ndEUBCE2014-2AV.1.17

Price:

FREE