COAL BIOBENEFICIATION BY IRON- AND SULFUROXIDIZING MIXOTROPHIC BACTERIA IN COLUMN REACTORS FOR REDUCING ASH AND SULFUR CONTENT OF COAL

• Main Author: Bakhtiar, Arsyad
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/56382
• Institution: Institut Teknologi Bandung

Biobeneficiation coal is one method of beneficiation of coal by using bacteria. This method is relatively cheaper and more environmentally friendly than other method. Research on coal Biobeneficiation continues to be done to reduce impurities in coal is coal ash and sulfur. High ash content in coal can cause the contents of fly ash and bottom ash high after combustion. Meanwhile, high sulfur content (inorganic and organic sulfur) will produce gas SO2,cause acid rain, and corrosion on plant equipment. Biobeneficiation with biooxidation method using iron-oxidizing bacteria and sulfur mixotroph is done because it is more resistant to pH and capable to use organic matter content. The challenge ahead in this process is the use of the process on a larger scale. This research will be conducted on a coal biobeneficiation column reactor with a height of 30 cm and a diameter of 5 cm. Medium of bacteria is SKC8-broth (acid mine drainage, tempeh wastewater, and molasses). Variable experiment a combination of particle size, the addition of molasses, the concentration of bacteria, and processing time were studied in the research. Proximate analysis, total sulfur, forms of sulfur, and calorific value of coal shall refer to ASTM standard D3174 (ash), ASTM D3175 (volatile matter), ASTM D3177 (total sulfur), ASTM D2492 (form of sulfur), and ASTM D2015 (calorific value). Meanwhile, mineral, surface morphology, elements, and chemical bond coals before and after each process is analyzed by XRD (XRay Diffraction), SEM-EDX (Scanning Electron Microscope-Energy Dispersive X-Ray), and FTIR (Fourier Transform InfraRed). The result of biobeneficiation experiments using Pseudomonas plecoglossicida strain SKCSH-9 in the column reactor produce percent reduction of ash and sulfur highest total respectively 54.53%-db and 41%-db (particle size -8+14 #, adding molasses 20 grams/liter, the concentration of bacteria of 20% (v/v), and incubation time of 10 days). XRD analysis of the solid biobeneficiation result is peak intensity changes in the mineral quartz, pyrite, gypsum, manganosite, and Molybdite. SEM-EDX analysis of the solid biobeneficiation result is coal surface structure changes into a rough, porous, agglomerate, and change elements of C, O, and S coal. FTIR analysis of the solid biobeneficiation result indicate a change in the intensity at wave number 3408 cm-1 (O-H streching), 2.920 cm-1 (Aliphatic C-H stretching), 1.612 cm-1 (Aromatic C=C), 1442 cm-1 (S=O sulfate), 1166 cm-1(pyrite), 1118 cm-1 (clay minerals), 813 cm-1 (Aliphatic thiol C-S stretching) dan 450 cm-1 (S-S). Biobeneficiation coal in column reactor with an iron-oxidizing bacteria and sulfur mixotrof (Pseudomonas strains plecoglossicida SKCSH-9) is showed positive results to be able to reduce ash and sulfur contents. This may indicate that the coal biobeneficiation process can be considered to be further investigated with a larger scale.