Effects of temperature, pH and O2 on the removal of hydrogen sulfide from biogas by external biological desulfurization in a full scale fixed-bed trickling bioreactor (FBTB)

Publikations-Art

Zeitschriftenbeitrag (peer-reviewed)

Autoren

Nägele, H.-J.; Lindner, J.; Merkle, W.; Lemmer, A.; Jungbluth, T. und Bogenrieder, C.

Erscheinungsjahr

2013

Veröffentlicht in

International Journal of Agricultural and Biological Engineering

Band/Volume

6/1

ISBN / ISSN / eISSN

19346344

DOI

10.3965/j.ijabe.20130601.007

Seite (von - bis)

69-81

Schlagworte

Entschwefelung

Hydrogen sulfide (H₂S) is a critical component of biogas formed under anaerobic conditions by sulfur and sulfate reducing bacteria from animal manure and renewable energy crops. H₂S causes high corrosion in equipment, has a negative environmental impact, inhibits the biogas formation process and is furthermore odorous and toxic. Although several methods for internal and external desulfurizationfound their way into practice and had been explored at laboratory scale, no data were available on the performance of such methods in full scale practice, especially for an external fixed-bed tricklingbioreactor (FBTB). The effects of temperature, pH and air ratio on H₂S removal efficiency (RE) were studied. The study was conducted at a research biogas plant with a given output of 96 m³ biogas per hour, and an H₂S concentration ranging between 500 ppm and 600 ppm (1 ppm=1 cm³/m³) on average. The FBTB column has been designed to hold a packing volume of 2.21 m³ at a gas retention time of 84 seconds being loaded at an average of 32.88 g H₂S/(m^3·h). The highest H₂S RE of 98% was found at temperatures between 30°C and 40°C. A major decline in RE to 21%-45% was observed attemperatures from 5°C to 25°C. The results clearly showed a temperature optimum range for sulfate reducing bacteria. The results reveal that RE is little affected by different pH values and air ratios. During the experimental period, the practical suitability of the FBTB system could be proved while avoiding the disadvantages of internal biological desulfurization methods.