Removal of H2S in biogas from concentrated latex industry with iron(III)chelate in packed column

• Main Authors: Rattana Saelee, Juntima Chungsiriporn, Janya Intamanee, Charun Bunyakan
• Format: Article
• Language: English
• Published: Prince of Songkla University 2009-07-01
• Series: Songklanakarin Journal of Science and Technology (SJST)
• Subjects: H₂S; Fe(III)EDTA; biogas; concentrated latex; packed column
• Online Access: http://www.rdoapp.psu.ac.th/html/sjst/journal/31-2/0125-3395-31-2-195-203.pdf

This work concerns hydrogen sulfide (H2S) removal from biogas produced from wastewater of concentrated latexrubber industry (CLRI). H2S content in the biogas of CLRI is significantly high (i.e., up to 0.77 mol/m3 or 26,000 ppm) dueto the use of H2SO4 during rubber coagulation process. Attempts to treat biogas with high H2S have not been found in literaturereviews. In this work, a chemical oxidation using an iron-chelated solution catalyzed by Fe(III)EDTA is selected forthe treatment of such high H2S concentrations. Experiments were performed using an industry-size packed column withdiameter and packed height of 0.5 and 0.8 m, respectively. The biogas flow rate and H2S concentration were in the range of5.16x10-3 - 5.61x10-3 m3/s and 0.35-0.77 mol/m3, respectively. Experimental results indicated that Fe(III)EDTA solution waseffective at removing H2S from biogas with a maximum removal efficiency of 97%. Suitable operating conditions, includingFe(III)EDTA concentration, flow of Fe(III)EDTA and air flow rate were determined. In addition, no side-reaction of Fe(III) EDTA with methane was found. Thus, chemical oxidation using an iron-chelated solution catalyzed by Fe(III)EDTA is a promising technology for H2S removal from biogas produced from CLRI or other industries. Finally, a mathematical model of the absorption and the reaction between H2S and Fe(III)EDTA in a packed column is proposed and verified against the experimental data. The results confirm the potential use of the model to design packed column for H2S removal from biogas using absorption coupled with oxidation by Fe(III)EDTA.