Wool textile waste is composed mainly of protein that can be hydrolyzed to generate amino acids. For the purpose of recycling, wool waste is subjected to pressurized hot water treatment to convert the protein to water-soluble protein, followed by hydrolysis of the water-soluble protein using cation exchange resins as catalysts. However, the wool proteins often undergo excessive decomposition during the pressurized hot water treatment. The present study examined methods for suppressing the excessive decomposition and optimizing conditions for hydrolysis of the water-soluble proteins. The results indicate that the excessive decomposition can be suppressed by shortening the retention time using a semi-flow reactor. In addition, a high ion-exchange capacity and an increase in the resin density in the reaction vessel effectively promoted hydrolysis.
Using a laser exhaust gas analyzer installed at an incinerator outlet, the authors measured O2, H2O, and CO2 concentrations in exhaust gases. The amounts of oxidation reactions of C and H in the waste and the H2O evaporation amount were calculated from the measurement results. The amount of heat generated by the waste combustion was calculated. Furthermore, the heating value of the waste was calculated. The generated calorific value showed good agreement with the estimate based on the heat balance around the incinerator, indicating high estimation accuracy. Moreover, comparison with the analysis result showing a lower measured heating value of waste, revealing large error in conventional heating value estimation. Furthermore, because the measured heat generated by exhaust gas components can be predicted in advance of the boiler evaporation amount, combustion can be stabilized when applied to combustion control. Benefits such as increased electrical generation were confirmed from reduced fluctuation of boiler evaporation.