Thermodynamic analysis of coal gasification based multigeneration entegrated energy systems

Energy is one of the most important issues in many applications all around the world. The world's energy need depending on developing technology and population is increasing day by day. The rapid increase in the energy demand and decrease in the fossil fuel resources have forced people to look for alternative energy production methods in recent years. Coal is the most abundant and one of the oldest fossil fuel resources in the world. Energy is usually produced by burning coal. Instead of directly burning the coal, it can be converted into the main chemical components through the gasification method. Gasification is a thermochemistry transformation process generating gas from coal. In the other words, solid fuel is converted to gas fuel. The aim of the gasification of the coal is to decrease harmful emissions occurring when the coal is burned and to increase the fuel's energy density. The syngas obtained by gasification of coal is directly burned in the boiler or used to produce various chemicals. In this study, coal gasification based multi-generation systems are investigated. Six different coal types such as Tuncbilek, Soma, Elbistan, Can, Beypazarı, Yatagan, are used. Electricity, hydrogen and synthetic fuel are produced in the first system. In the second system, only hydrogen is produced. Lastly, only electricity is produced in the third system. Energy and exergy analysis were applied separately to the systems and compared among each other. Tuncbilek coal showed the best performance amongst other coals in the systems. The energy and exergy efficiencies of the first system were found 53% and 46%, respectively. In the second system, the energy efficiency ranged from 40% to 52%, while the exergy efficiency ranged from 36% to 48%. The energy and exergy efficiencies of the third system were found 49% to 45%, respectively.