engleski

Utilizing the sewage sludge as a zero emissions energy source for production of hydrogen

Sewage sludge (SS) from wastewater treatment plants (WWTP) is a burning issue in Croatia. The amount of produced SS is constantly increasing and a suitable solution for its proper disposal must be found. The European Commission's new Action Plan for a Circular Economy calls for additional measures to achieve a carbon neutral, environmentally sustainable, non-toxic, and fully circular economy by 2050, including stricter recycling rules and binding targets for the use and consumption of materials by 2030. Gasification is an alternative method of converting SS into green energy that is in line with the principles of the circular economy. One of several advantages of this method over other thermal methods of SS treatment is the possibility of producing hydrogen. The experimental study was carried out in a pilot plant with a rotating gasification reactor. For the study, SS samples were supplied from the Zagreb WWTP, where mechanical-biological wastewater treatment processes are used. SS was anaerobically stabilized and mechanically dewatered. SS samples were dried at 105° C for 24 hours and the moisture content of SS was ~ 4 %. The sludge accumulations due to drying was crushed using a coarse grinder. The obtained SS samples were analyzed and subjected to gasification of 100 kg/h SS at a temperature of 1100°C. After a few minutes, the production of syngas starts. The syngas is treated with cyclones and scrubbers and the treated gas samples are analyzed using a MRU VARIOluxx syngas analyzer. The analysis showed that the syngas obtained consists of 35.19% H₂, 28.03 % CO, 17.7 % N₂, 8.71 % CO₂, 7.217 % CH₄, 3.16 % O₂, 7 ppm H₂S. The net calorific value of the syngas was 11.4 MJ/kg (9.9 MJ/m³), and the gross calorific value was 12.5 MJ/kg (10.9 MJ/m³). The syngas produced was burned in a flare and burned with a pale blue flame. In order to prevent the depletion of conventional energy sources, new solutions that enable the production of renewable energy are recommended. Therefore, future research will focus on the possibilities of using syngas and separating hydrogen from the syngas mixture.

Sewage sludge, Gasification, Syngas, Hydrogen, Circular econom

nije evidentirano