# Spouted-Bed Gasification of Flame Retardant Textiles as a Potential Non-Conventional Biomass
## 1 Introduction  
Renewable energy from thermal valorization plays a key part in today's energy outlook and there is not a biomass replaceable to cotton. Thousands of tons of biomass residues produced from cotton industry with a thermal energy potential from combustion were estimated around 4000 TJ annually [1]. With immense attention to cotton crops waste utilization, cotton products with synthetic functionalities like technical textiles are ignored in perspective of the thermal valorization panorama. In 2017, \(\copy\)181 billion turnover and \(\copy\)4.9 billion of investment were seen in the European textile and clothing industry and exports of technical textiles outside EU had increased 39%, while imports reached to 32.6% more [2, 3]. Flame retardant textiles are among technical textiles, used to withstand indoor safety regulations, consumption of which is also increased recently in the textile industry [4, 5, 6]. Flame retardants incorporated to textiles can be organic or inorganic in nature [7, 8], eventually make their way to landfills and incinerators. In the waste hierarchy, landfill being least preferable [9] and due to leachate of flame retardant chemicals [10], incineration is used commonly. Incineration constitutes a vast repository for toxic chemicals along with manmade or natural fibers, posing environmental emissions [11, 12]. Even in developed countries, combustion of domestic waste in barrels, open pile, household heating stoves, primitive incinerators or fireplaces is carried on, significantly [13]. A part from the environmental concerns raised related to flame retardants from last three decades, originated from the potential release of toxin polybrominated dioxins, during the incineration of polybrominated diphenyls and diphenyl ethers [14, 15], sustainable waste treatment of flame retardants is yet a challenge. Concerns over emissions of dioxin and similar persistent organic contaminants from the incineration of municipal solid waste (MSW) have been shown in various studies [16, 17]. On the other hand, MSW combustion from other thermal valorization technologies, especially flame retardants is rather limited to date [12, 18]. Thermal valorization technology like gasification is considered a more favorable method compared to incineration, as it converts material (biomass/organic mostly) to multipurpose fuel gas, known as the syngas [10, 19]. The produced syngas is taken as synthesis reactant or a mere fuel for industrial use [19, 20]. Considering thermal valorization techniques for flame retardant cotton textiles, lower energy yield in incineration is obvious, due to incomplete combustion from chemical substrate applied on textile [6, 21]. Moreover, from the combustion of flame retardant materials, the main thrust in incineration is given to the generation of carbon dioxide and monoxides, and other components. In previous study, an increase in heat release rate was realized by the degradation of flame retardant chemical on textiles using advanced oxidation process [6, 22]. As in gasification, the quality of syngas is highly dependent on the content and properties of the material gasified, design and operative conditions and the gasifier itself [19]. Optimal gasification conditions and design have been studied previously for flame retardant textiles [10], it will be however interesting to see the content and properties of the syngas produced from such textiles. For flame retardant textile waste treatment, incineration is practiced as the state of art technology. It is rare to find in literature on gasification acted as alternate disposal treatment of flame retardant textiles. Spouted bed reactors have demonstrated advantages in terms of medium gas consumption, pressure drop and the possibility to operate with coarse particles, compare to an equivalent bubbling bed unit [10, 19].