## 1 Introduction  
Renewable energy sources are of increased interest due to the high global demand for energy, unstable prices for fossil fuels, and significant climate change [1, 2]. The consumption of fossil fuels has dramatically changed the balance of the carbon cycle and exacerbated pollution. The availability of sustainable and carbon-neutral biofuels will largely solve the identified problems. One of the promising renewable energy sources is biomass, which can be used to produce biofuels and valuable chemicals [3]. Compared to coal or fuel oil, biomass-to-energy technologies are more environmentally friendly in terms of emissions of harmful substances (e.g., soot, nitrogen oxides, sulfur, and carbon). In terms of availability, cost, and specifics of reproduction, biomass can be considered a renewable raw material [4]. Agricultural waste such as straw, sawdust, coffee, and rice husks are biomass varieties of fairly high calorific value. More than 3 billion tons of such waste can be produced annually in the world [5]. In thermochemical or biochemical processing, biomass can be converted directly into heat and electricity, or into co-products such as biochar, bio-oil, and biogas [6, 7]. These products can be used as fuel or for the synthesis of new materials. For example, pyrolysis gas can be burned or converted to liquid fuel via Fischer-Tropsch synthesis [8]. Pyrolysis is a fairly simple and proven technology with a wide range of applications. In traditional pyrolysis, the biomass particle absorbs heat through the surface through conduction, convection, and radiation. During microwave pyrolysis, energy is transferred directly to the core of the particle, forming a temperature gradient in the volume of the particle without physical contact between the raw material and the heat source. Such a heating mechanism releases volatile substances that diffuse from the core to the outer surface, from the high-temperature region to the low-temperature region, significantly affecting the characteristics of the raw material conversion products [9]. Microwave pyrolysis is a promising approach in terms of increasing the yield and quality of the final liquid biofuel. Bio-oil contains many valuable compounds and can be used not only as a liquid fuel, but also as a resource for the extraction of chemicals [10]. Microwave pyrolysis is of increasing interest due to its low thermal inertia, uniform and volumetric heating, and high conversion rate, which together can increase productivity and energy efficiency [11]. The choice of the operating mode of microwave reactors is an important task both in the design of equipment and directly in the operation of a process plant. Microwave heating does not require the sample to come into contact with any surface to transfer energy. When a sample is irradiated with microwaves, heating is realized due to the rotation of the dipole and the ionic conductivity of polar molecules and/or ions of the sample [12]. The sample is heated in volume due to the direct and uniform penetration of microwaves into the deep layers, thereby forming a temperature gradient. In the case of pyrolysis based on contact heat transfer, it is difficult to achieve the same high heating rates [13]. Uneven heating during traditional pyrolysis can lead to overheating of the sample surface and overcooling of the active zone [14]. However, microwave pyrolysis does not have much flexibility in the choice of feedstock and is only suitable for polar materials and substances. The yield of pyrolysis products significantly depends on the physicochemical properties of the biomass and the process parameters [15]. The pyrolysis temperature is one of the main factors influencing the properties of the final products and their yield. [PERSON] et al. [13] studied the characteristics of coffee husk pyrolysis under two heating modes. An increase in temperature increased the yield of biogas and reduced its calorific value. The effect of temperature on biogas yield was more significant with microwave heating than with conventional pyrolysis.