The utilization of rice straw (Oryza Sativa L.) as a green catalyst in the enhanced production of hydrogen via the thermochemical conversion process of shrimp farm sludge

Abstract

The catalytic mechanism of rice straw, Oryza Sativa L., on the carbonation of shrimp farm sludges via the gasification process was investigated in this work. Rice straw possessed 75% of its weight is silicon dioxide (SiO2) which can be utilized as an effective catalyst whereas the tar decomposition and gas production during the thermochemical process can be enhanced. In that manner, the influence of working temperature (oC), the ratio (%wt) on the amount of rice straw used in the shrimp farm sludges, and the moisture content (%) in the prepared samples are taken into account to determine the role of rice straw catalytic. Gasification processes were carried out in 60 min in a stainless steel reactor, with a feeding rate of 0.5 kg/h and an air-pumped flow rate of 2 L/min. All experiments were performed under different conditions of working temperatures (600, 700, 800, and 900 °C), sample composition (0, 20, 40, and 60 %wt of rice straw added), and moisture content of the feedstock (20, 40, 60, 80, and 90%). It is essential to confirm that the change in sample moisture content and the working temperature are also significant to the production of hydrogen throughout the process. As the moisture content increase from 20 to 40%, the hydrogen yield is proportionally increased by 5–10%. On the aspect of working temperature influence, the hydrogen composition increased from 11% at 600 °C to 27% at 900 °C for the RS sample, from 13% at 600 °C to 29% at 900 °C for the RS20, from 17% at 600 °C to 35% at 900 °C for the RS40 sample, and from 19% at 600 °C to 43% at 900 °C for the RS60 sample. The findings in this work confirm the rice straw catalyst's role in enhancing hydrogen production via the gasification process. Furthermore, this work provides guidance information for simple but effective processes that can not only deal with the sludge waste management issue but also create a waste-to-energy route suitable for medium and small-scale aquaculture businesses.