STUDY OF CATALYTIC BEHAVIOUR OF NATRIUM COMPOUNDS COAL & BIOMASS GASIFICATION PROCESS USING CO2 : REVIEW

• Main Author: Izzul Islam AS, Muh
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/70143
• Institution: Institut Teknologi Bandung

Gasification is the process of converting coal and biomass using gasification agents in the form of air, O2, steam or CO2, into syngas that can be utilized in many sectors. Gasification using CO2 can add options to the use of greenhouse gases. However, when compared to using other gasification agents, gasification with CO2 tends to be more endothermic and slower, thus requiring a catalyst so that the process can take place more quickly.. Alkaline and alkaline earth metals (AAEM) compounds have been widely studied because apart from being effective, AAEM compounds are also naturally found in coal and biomass. In this literature study, the catalytic behavior of sodium (Na), potassium (K), calcium (Ca), and magnesium (Mg) during gasification using CO2 was compared and determined which AAEM was most effective in the temperature range 700-1400ºC through a thermogravimetric analyzer. (TGA). As a result, Na showed the best performance from the catalytic side and its resistance to deactivation, which was then further analyzed to optimize its use. This literature used in this study are sourced from various journals, books, and proceedings related to gasification using CO2 in the presence of AAEM. Subsquently with the analysis the effect of dose, type of compound, and gasification temperature on was carried out. The results of the literature study show that to increase the rate of gasification, the method of adding AAEM using wet impregnation is more effective than dry mixing, and AAEM in the liquid phase is more effective than when it is in the solid phase. In the temperature range of 700-1400ºC, AAEM in the form of Na, K, Ca, and Mg has the potential to increase the gasification rate with the highest Na. However, of the four AAEMs, K, Ca, and Mg can be deactivated during gasification. K can form sintered layers, Ca is deactivated at high temperatures, and Mg has low effectiveness. Based on these facts, Na can be an effective catalyst candidate. To optimize the use of Na, an analysis of the addition dose, type of compound and gasification temperature was carried out. The optimal dose for adding Na is 3-5 wt% (to the dry weight of coal), depending on the type of sample and method of adding Na. Then, among the types of Na compounds: sodium hydroxide (NaOH), sodium sulfate (Na2SO4), and sodium chloride (NaCl), the compounds NaOH and Na2SO4 are proven to be effective in increasing the rate of gasification, while NaCl is not recommended because it can cause pitting corrosion in the gasification reactor material. In addition, the optimal temperature for effective performance of Na is in the temperature range of 850-1200ºC. This is because in this temperature range Na2CO3 is already in its liquid phase and melting of the mullite can be prevented.