## 1 Introduction  
The increase in global energy depletion and the massive utilization of fossil fuels have led to an alarming increase in CO\({}_{2}\) emissions into the environment and to potential energy supply issues. World energy-related CO\({}_{2}\) emissions will increase from 30.2 billion metric tons in 2008 to 43.2 billion metric tons in 2035 [1]. The greenhouse gases (GHG) emissions from fossil fuels have a dominant impact on the atmospheric CO\({}_{2}\) concentrations, leading to global temperature and sea level rise [2]. With the rapidly increasing global energy demand and the growing concerns about the environmental challenges, renewable and sustainable energy (e.g., solar, wind, and biomass) have been considered as key resources to solve the coming energy crisis. Among all the possible alternatives, biofuels have been regarded as the most promising substitute to fossil fuels. Indeed, bioresources (such as biomass, biochar, and pyrolysis oil) are an attractive feedstock to produce fuels because their utilization emits less greenhouse gases (GHG) if we consider that the newly grown biomass absorbs CO\({}_{2}\) emissions [3]. However, the bioresources only account for a small proportion of energy consumption. Gasification is the most common thermochemical process to convert bioresources into a gaseous fuel in a high temperature, partially oxidized atmosphere [4]. The syngas produced by gasification can be burned directly or used as fuel for turbines. It is also one of the key building blocks to produce fuels for transportation and chemicals. For example, the current usage of synthesis gas is for the production of ammonia (50%) and hydrogen (25%). The rest is dedicated to the production of methanol, Fischer-Tropsch (FT) products, and other purposes [5]. Gasification is a process dedicated to the production of syngas, mainly composed of gases such as H\({}_{2}\), CO, CO\({}_{2}\), and CH\({}_{4}\). However, syngas contains impurities, including char, tars, high molecular weight hydrocarbons, sulfur, or CO\({}_{2}\); but also trace contaminants (e.g., ammonia, metals, halides, etc.) [6]. All these impurities must be removed before the downstream operations. In addition to this purification step, the syngas composition must also be modified to meet the requirements of methanol synthesis, especially the content of H\({}_{2}\), CO, and CO\({}_{2}\). The most frequently applied technology for syngas cleaning up and CO\({}_{2}\) removal is the absorption process by means of chemical solvents, such as alkanolamines and Monoethanolamine (MEA) [7]. However, those processes are expensive and a large scale is needed to be cost-effective [8]. Nowadays, Rectisol is a better method for its removal, given that more than 98% of CO\({}_{2}\) and sulfur in the gas can be removed [9]. Rectisol uses methanol as CO\({}_{2}\) solvent since it is much more effective than water, especially at low temperatures. The solubility of CO\({}_{2}\) in methanol is about four times of water at room temperature and more than eight times higher than of water at temperatures below 0 \({}^{\circ}\)C [10; 11]. Therefore, methanol has been industrially used in the Rectisol process as a physical absorber of CO\({}_{2}\)[12]. Nowadays, methanol is gaining more attention as a possible future fuel that can be consumed in fuel cells and engines [13; 14]. Methanol is of interest for large-scale transportation applications because it has a significant positive environmental impact over fossil fuels, particularly when used in fuel-cell vehicles [15]. The technology to produce methanol from biomass is similar to that used to produce methanol from coal [16]. The process flow chart is mainly composed of commercially established technologies such as gasification, syngas cleaning and conditioning, and methanol synthesis.