## 1 Introduction
They observed that the integration of biomass with a steam power plant was achieved by combining the hot exhaust gases together with the biomass in the main combustion chamber of the plant, and showed that the efficiency of the energy conversion was much higher than that from incinerating Combustible Derived from Residues (CDR), and thus, wet biomass with high moisture content can be disposed of in a gasifier [15]. [PERSON] et al. developed an innovative study using a fluidized bed dryer with superheated steam and its integration into a gasification-combined cycle system power generation [16]. [PERSON] et al. evaluated the effects of various testing conditions on a top-lit forced-up-draft semi-gasifier cooking stove [17]. The investigation showed that using forced secondary air and more fuel tended to improve both thermal and gas emission performances. The ending points did not have significant effects on thermal efficiency and the carbon dioxide emission factor but did affect particulate matter emission. A relatively lower chamber height demonstrated a better performance on thermal metrics [17]. [PERSON] et al. analyzed the experimental and numerical analysis of a biomass steam power plant with a maximum power of 2.3 MW, a maximum pressure of 48 bar and a turbine inlet temperature of approximately 430 \({}^{\circ}\)C [18]. The analysis of the biomass power plant pointed out some critical issues could be summarized in three points: low plant efficiency due to the small size, biomass supply range and continuous variation of the operating point. Biomass residues are still being used in heating applications and power generation [19; 20]. Biomass fuels have numerous environmental advantages over fossil fuels [21], including the fact that the amount of CO\({}_{2}\) emitted during the burning process is 90% less than that during the burning process of fossil fuels [22]. Cork, pine and olive pomace contain minimal amounts of sulfur and heavy metals, and they are not a hazard to acid rain pollution [23]. The higher heating values (HHVs) of these residues are between 17 to 20 MJ/kg. Increasing moisture content of these residues decreases their HHVs. For large-scale combustors, such as fluidized bed combustors, the maximum acceptable moisture content of the residues is approximately 45%. The higher and significantly fluctuating moisture content in wood causes unstable combustion, and higher CO and volatile organic compound emissions [24]. In gasification process, if the wood has high moisture content, the concentration of tar is higher and the heating value of the generated gases decreases. The biomass residues are widely used for power generation [25], while the study of the effect of moisture content on overall energy efficiency is limited [26]. Normally, raw biomass has 60% to 70% moisture content. Therefore, high moisture content reduces the efficiency of the solid fuel for direct combustion and produces tar in pyrolysis and gasification [27]. The integration of a drying process into a power station fuel system was investigated by other authors [28]. They used waste heat from a process industry plant as a heat source for drying. [PERSON] et al. analyzed the environmental compatibility of a biomass plant with production of both electricity and heat in a small town in Piedmont (Italy) [29]. The pine chips with 60% moisture content were dried to be provided as the input fuel for a subsequent power plant. An aim of thermal drying is to reduce moisture content of the residues. In the drying process, the heat is transferred from hot fluid (gas) to the residues, and the mass transfer is processed from the residues to the hot gas simultaneously [30]. Many factors can be considered, such as the product nature, its different characteristics, the magnitude of the processes of heat and mass transfer, and finally, the periods and duration of the drying process [31]. The drying process can be divided into three periods: In the first one, the temperature of the wet product to be dried rises.