The basic composition and thermal characteristics of Mongolian coal samples are determined: specifically, two coal samples from the Tavantolgoi and Nariins

Initial coal was purified in heavy liquid with a density 1.3 cm³ of ZnCl₂ solution and purified coal was carbonized and the initial coal samples of each deposits were purified by pyrolysis. Thus, the yield of pyrolysis hard residue in the enriched sample was slightly higher than in the hard residue of initial coal. Therefore, pyrolysis hard residue of purified coal (carbonized sample) was activated at 800°C for 2 hours by preheated water steam. Activated carbons (ACs) and non-activated and non-carbonized coal from Baganuur, Ereen and Nariin Sukhait deposits were technically analyzed and their iodine number, BET surface area, pore volume and adsorption of methylene blue (MB) were determined. When these results were compared, these indicators increased 5-17 times in the Baganuur activated carbon (BN-AC), Ereen activated carbon (E-AC) and Nariin Sukhait activated carbon (NS-AC) as compared to inactivated coal.

Activated carbon consumption is continuously increasing because of their application in such important areas as waste and drinkable water treatment, atmospheric pollution control, hazardous gas separation, cleaning of solvents, etc. Every year, Mongolia imports 700-800 tons of activated carbons for 700-900 USD per ton. We have selected 3 different types of coal, including a high ranking bituminous coal from Tavantolgoi deposit, stone sub-bituminous coal from Shariin Gol mine and brown lignite coal from Baganuur deposit and they were each enriched with heavy liquid, such as zinkum chlorade solution and processed by semicoking (carbonization) method to produce the main raw material for coal-derived active carbon. Using these carbonized coals, we have obtained coal-derived activeted carbon by activation with preheated water steam for 120 minutes. The most important technical properties of initial coal samples and activated carbons and their microporous properties, such as iodine number in percentage, methylene blue adsorption mg/g and surface area (BET)-m2/g were determined and characterized. The determined iodine number of activated carbon of purified and carbonized coals increased by 5-17 times and methylene blue adsorptions also increased from 4 to 10 times as compared to pyrolysis hard residue of initial coal samples without purification and activation. Basing on this, we are proposing a thecnological scheme for the production of coal-derived activated carbon.

Mongolia possesses substantial coal resources (173 billion tons), which include high-rank bituminous coals, subbituminous coals, and brown coals. Based on these coal types, a manufacturer of activated carbon can be developed using comparatively simple technology. The consumption of activated carbon is continuously increasing due to its use in waste and drinking water treatments, atmospheric pollution control, gas mixture separation, and solvent recovery. Currently, Mongolia imports 700–800 tons of activated carbon annually at a price of 700–900 USD per ton. For this study, we have selected several high-rank coals from Mongolia, including Tavan Tolgoi IV and Nariin Sukhait (both bituminous coking coals from Southern Mongolia), as well as the Saikhan-Ovoo deposit (a high-rank stone coal from Northern Mongolia). The selected coals were enriched with a zinc chloride solution and subjected to semicoking (carbonization) to produce the primary raw material for activated carbon production. Activated carbon was obtained from the carbonized coal by activation with preheated water steam within 120 minutes. The main technical characteristics of the initial coal samples and activated carbons, along with their microporous properties such as iodine number, methylene blue adsorption, and surface area (BET), have been determined. Additionally, a technological scheme for activated carbon production from high-rank coal has been proposed.

The main purpose of this study is to investigate the thermal stability and the mechanism of thermal decomposition of Mogoin gol coal, the possibility of liquefaction by pyrolysis and thermolysis, and the possibility of enriching by heavy liquids to reduce the mineral content of coal and improve its quality. Under this purpose, the Mogoin gol coal was characterized by proximate and ultimate analysis, thermogravimetry, and investigated its thermal decomposition (thermolysis and pyrolysis). Thermogravimetric analysis was performed using Japanese HITACHI TG/DTA7300 instrument and pyrolysis investigation was carried out at different heating temperatures 200–700 °C with constant heating rate 20 °C/min for 80 min. On the basis of proximate and elemental analysis results, it has been indicated that the Mogoin gol coal is high-rank coking coal. The pyrolysis of Mogoin gol coal was studied by SNOL furnace at different heating temperatures and obtained from pyrolysis products such as hard residue, tar, pyrolytic water, and gas. From pyrolysis, the yield of pyrolysis tar (6.28 %) was highest at 700 °C. The experiment of thermal decomposition (thermolysis) was carried out in air closed autoclave at 350–450 °C and using hydrogen donor solvent (tetraline) with different mass ratios of coal and solvent (1:1.75; 1:1.5). In the thermolysis experiment, the yield of liquid product is highest with the coal-solvent ratio of 1: 1.5 at 450 °C.

The main purpose of this study is to investigate the thermal stability and the mechanism of thermal decomposition of Mogoin gol coal, the possibility of liquefaction by pyrolysis and thermolysis, and the possibility of enriching by heavy liquids to reduce the mineral content of coal and improve its quality. Under this purpose, The Mogoin gol coal was characterized by proximate and ultimate analysis, thermogravimetry, and investigated its thermal decomposition (thermolysis and pyrolysis). Thermogravimetric analysis was performed using Japanese HITACHI TG/DTA7300 instrument and pyrolysis investigation was carried out at different heating temperatures 200–700 °C with constant heating rate 20 °C/min for 80 min. On the basis of proximate and elemental analysis results, it has been indicated that the Mogoin gol coal is high-rank coking coal. The pyrolysis of Mogoin gol coal was studied by SNOL furnace at different heating temperatures and obtained from pyrolysis products such as hard residue, tar, pyrolytic water, and gas. From pyrolysis, the yield of pyrolysis tar (6.28%) was highest at 700 °C. The experiment of thermal decomposition (thermolysis) was carried out in air closed autoclave at 350–450 °C and using hydrogen donor solvent (tetraline) with different mass ratios of coal and solvent (1:1.75; 1:1.5). In the thermolysis experiment, the yield of liquid product is highest with the coal: solvent ratio of 1:1.5 at 450 °C.