**2. Compositional of lignocellulosic biomass**

In particular, lignocellulosic biomass, mainly composed of lignin, cellulose, and hemicellulose, has become an essential topic because lignocellulosic biomass does not compete with food and feed. There are several technologies for the conversion of lignocellulosic biomass into energy and chemicals [13]. As illustrated in **Figure 1**, the three main components are unevenly distributed in the cell wall as the skeleton, the connecting material, and the hard solid, respectively. Cellulose macromolecules regularly assemble to form tough microfibers that serve as the skeletal material of the cell wall, and the inner space is packed with hemicellulose linking materials and amorphous lignin [15]. Cellulose is linked to hemicellulose and lignin molecules

*The Biomass Waste Pyrolysis for Biopesticide Application DOI: http://dx.doi.org/10.5772/intechopen.100223*


**Table 1.**

*The compositional variation lignocellulosic biomass from CS, CNS, and CPH.*

mainly through hydrogen bonds, whereas the relationship between hemicellulose and lignin includes hydrogen and covalent bonds [16]. Carbohydrates and lignin are tightly bound in lignin-carbohydrate complexes, resulting in residual carbohydrates or lignin fragments in the extracted lignin or hemicellulose samples.

Lignocellulosic materials are mainly composed of cellulose (35–50%), hemicellulose (15–35%), and lignin (10–35%) [4]. The concentrations of the components mentioned vary with different plant species (as shown in **Table 1**). In addition to the three main components, a small fraction of extractives and inorganic ash are also present in the biomass as non-structural components, not cell walls or cell layers. Wood biomass contains significantly higher amounts of the three main components (»90%), while agricultural and herbaceous biomass contains more extractives and ash.

## **3. Optimization of parameter pyrolysis biomass**

Thermal decomposition of organic matter in the absence of oxygen has been widely developed as a promising platform for producing fuels, preservatives, pesticides, and chemicals from various types of biomass. Pyrolysis produces charcoal, liquid, and gas products, which is highly dependent on the reaction conditions. Fast pyrolysis of biomass at a rapid heating rate and a short residence time of hot steam (<1 s) produces bio-oil with a yield of up to 75% of weight [12, 13].

Pyrolysis is a technology that converts lignocellulosic biomass into gaseous, liquid, and solid products by using heat under an inert atmosphere. Depending on the heating rate and residence time of the pyrolysis stream in the reactor, pyrolysis can be broadly classified into slow and fast pyrolysis. Slow pyrolysis involves thermal cracking of lignocellulosic biomass at low heating rates to produce a high-yield solid product known as biochar (or charcoal). In fast pyrolysis, high yields of liquid (bio-oil) products are obtained because the short residence time of the pyrolysis vapor in the reactor suppresses the secondary reaction, promoting the formation of gas and biochar [8, 20]. The reaction temperature for the pyrolysis of lignocellulosic biomass usually ranges from 500 to 800°C [21]. The physical properties characterization of the pyrolysis results of CS, CNS, and CPH biomass at temperatures of 400–600°C can be seen in **Table 2**.

During pyrolysis, biomass undergoes primary and secondary reactions involving heat and mass transfer mechanisms. The immediate response consists of decomposing lignocellulosic biomass, which leads to the formation of introductory and intermediate products. This intermediate species undergoes secondary cracking. The pathways for the first category include dehydration and charring reactions, while the second is decomposition and evaporation of intermediates. The pyrolysis products obtained in these competitive reactions are susceptible to operational variations and types of biomass [21]. Parameters play a significant role to determine the composition and properties of the pyrolysis products. Since biomass consists of cellulose, hemicellulose, and lignin, the degree of thermal fragmentation of


### **Table 2.**

*The operational parameters, physical characteristics, and yield (%) of the pyrolysis results of CS, CNS, and CPH biomass.*

these components depends on the operating parameters [23]. **Table 2** shows the distribution of products obtained from various biomass and pyrolysis temperatures, indicating considerable flexibility that can change process conditions. During pyrolysis, many factors affect product properties such as type of biomass, residence time, age percentage of moisture in feed biomass, temperature, pressure conditions (atmosphere, vacuum), particle size, and heating rate of biomass so that pyrolysis efficiency also affects product composition. Optimization of reaction conditions can increase the yield of pyrolysis products to any of the three pyrolysis fuels such as pyrolysis oil, gas, or solid charcoal [20]. This parameter has a significant influence on the composition of the pyrolysis product.
