## 1 Introduction  
Biomass is one of the most commonly used forms of renewable energy around the world. It is a C-based organic material that primarily comes from plants such as crops and wood and also from byproducts such as agricultural waste. Biomass absorbs carbon dioxide from the atmosphere during growth in the process of photosynthesis and emits the same amount of carbon dioxide into the atmosphere during combustion. The utilization of biomass energy provides a number of benefits compared to fossil fuels, especially those related to environmental aspects, since biomass is a renewable and CO\({}_{2}\)-neutral fuel [1]. Replacing fossil fuels with sustainably-produced biomass has the potential to significantly reduce SO\({}_{x}\) and NO\({}_{x}\) emissions, which are acid rain precursors, because most biomass fuels have low levels of sulphur and nitrogen content [2]. Pyrolysis is a thermal decomposition process of organic materials that occurs through the application of intense heat in the absence of oxygen, leading to the production of biogas, bio-oil, and biochar. Thermochemical conversion of lignocellulosic biomass into bio-oil through fast pyrolysis process is considered one of the promising routes to replace conventional fossil oil [3]. Fast pyrolysis bio-oil (FPBO) is produced through rapid heating of organic material to temperatures of 500-600 \({}^{\circ}\)C to achieve decomposition in the absence of oxygen [4]. FPBO is a black-brownish organic liquid obtained by the condensation of gaseous pyrolysis products during the fast pyrolysis of biomass. It can be used as a fuel directly or can be upgraded to form a higher-energy-density liquid for transportation, heating, and power generation [5; 6; 7; 8]. Currently, FPBOs are being developed as potential substitutes for conventional fossil fuel to generate heat and power in diesel engines, gas turbines, and boilers, as well as in power generation and industrial processes [9]. Much attention has been paid to the use of biodiesel in diesel engines [10; 11; 12; 13; 14]. However, relatively few studies have been carried out on the performance and pollutant emissions of diesel engines [15] or industrial applications [16] using bio-oil as fuel. In particular, research on liquid biofuels for use in furnaces or boilers is quite rare [17]. [PERSON] et al. [18] performed a computational fluid dynamics (CFD) analysis on the combustion behavior of a bio-oil derived from macroalgae (Saccharina japonica) in a commercial 100 MW\({}_{\text{e}}\) generation plant. The thermal efficiency of the bio-oil (86.0%) was found to be quite similar to that of heavy fuel oil (HFO) (87.1%), suggesting that the HFO could be fully replaced by the bio-oil. [PERSON] et al. [19] investigated the combustion performance of a residential-scale hot water boiler fueled with a blend with 20% soy bean methyl ester (SOME) in No. 2 fuel oil. It was concluded that the NO\({}_{x}\) emissions were quite similar, and an approximately 20% reduction in SO\({}_{2}\) emissions was observed when compared to the use of the pure No. 2 fuel. [PERSON] et al. [9] explored the combustion characteristics of fast pyrolysis bio-oil produced from rice husak in a 43.5 kW\({}_{\text{th}}\)-capacity (thermal power) combustion chamber. They reported that the CO concentration decreased with the equivalence ratio (the ratio of the fed air to the required air for complete combustion), that the NO\({}_{x}\) concentration slightly increased with the equivalence ratio, and that the SO\({}_{x}\) concentration was very low (smaller than 30 ppm). [PERSON] et al. [20] investigated the combustion characteristics of heating fuel oil and cottonseed oil in a modified burner. They found that the CO, O\({}_{2}\), CO\({}_{2}\), NO\({}_{x}\), SO\({}_{2}\), and PAHs (polycyclic aromatic hydrocarbons) emissions were similar for these two fuels under optimized atomization and granulometry conditions. [PERSON] et al.