STUDY OF ORGANIC SULFUR DESULFURIZATION OF COAL BY BIOFLOTATION METHOD FOLLOWING PRE-CONDITIONING PROCESS USING IRON AND SULFUR OXIDIZING BACTERIA

• Main Author: IDRIS (NIM : 12512042), ISKANDAR
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/22635
• Institution: Institut Teknologi Bandung

One of the problems of using coal as fuel in the industrial world is the sulfur gas emissions. Sulfur gas emissions can lead to acid rain that is bad for the environment. In addition, sulfur gas emissions can also aggravate the corrosion rate of the component and cause respiratory distress. Sulfur in coal can be classified into three types, namely pyritic sulfur, sulphate sulfur, and organic sulfur. Pyritic sulfur and sulfate sulfur can generally be removed physically. Organic sulfur is more difficult to remove than pyritic sulfur and sulfate sulfur because it binds covalently with coal bodies into complex structures. Organic sulfur is generally removed chemically and biologically. In this research, pre-conditioning (biooxidation) process was studied on the influence of medium type and bioflotation process on the influence of bacterial type and pH, bacterial concentration, and conditioning time. <br /> <br /> <br /> A series of experimental activities begins with coal sample preparation followed by proximate analysis, total sulfur and form of sulfur analysis, HGI value, calorific value, Fourier Transform Infra Red (FTIR) spectrum, and Scanning Electron Microscopy (SEM) - Energy Dispersive X-Ray Spectroscopy (EDS). Pre-conditioning (biooxidation) experiments were conducted on variations of medium. The medium that gives the best sulfur reduction results will be used as a medium for bioflotation experiments. The bacteria used consisted of two species, namely Citrobacter youngae strain SKC-4 and Pseudoclavibacter aromaticivorans strain SKC/XLWT. Flotation experiments were performed on a series of variables. The first series of flotation experiments were conducted to compare the two types of bacteria. The best pH of each bacteria is also sought by varying the pH at values of 3, 5, 7, 9, and 11. The type of bacteria and pH that gives the best sulfur reduction results is used in further variation experiments. Variations in bacterial concentration (v/v) were performed at values of 3%, 5%, 7%, and 10%, while the variation of conditioning time was performed at values of 15 minutes, 30 minutes, 45 minutes, 1 hour, 2 hours, 3 hours, and 6 hours. All the best flotation variables obtained will be used for subsequent experiments of pre-conditioning combined with bioflotation. Coal that has passed the pre-conditioning (biooxidation) stage with the best medium will be used as bioflotation process feed. The last experiment is the second stage flotation for each best variable bioflotation concentrate and pre-conditioning combined with bioflotation concentrate. <br /> <br /> <br /> The result of pre-conditioning experiment shows that the best medium for both bacteria is LB modification which is then used as bioflotation medium. The best bioflotation result was obtained using Citrobacter youngae strain SKC-4, pH 9, bacterial concentration 5% v/v and conditioning time for 3 hours. The best results were achieved in pre-conditioning (biooxidation) combined with twostage bioflotation treatment. Percentage of decreased sulfur content was 78,74% for total sulfur, 98,86% for pyritic sulfur, 97,33% for sulfate sulfur and 43,95% for organic sulfur with consecutive sulfur content 0,54%, 0,01 %, 0.02%, and 0.51%.