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The current work is based on the simulation modeling of steam gasification of palm kernel shell (PKS) with CO2 capture through sorbent (CaO) using Aspen plus. The simulation model is developed using a Gibbs free energy minimization method. The objective of this work is to investigate the effect of key parameters like temperature, steam/biomass ratio, and CaO/biomass ratio on syngas yield. The system performance was also evaluated through carbon conversion efficiency, cold gas efficiency and gasification efficiency, lower and higher heating values by varying the gasification temperature, steam/biomass ratio, and CaO/biomass ratio. The H2 concentration increased from 65 to 79.32 vol % with the increase of temperature from 650 to 700 °C. The CO2 content was reduced from 20 to 5.32 vol % by increase in CaO/biomass ratio from 0.5 to 1.42. The maximum hydrogen content predicted is 79.32 vol %, and the minimum CO2 content is 5.42 vol % found at operating parameters including a temperature of 700 °C, steam/biomass ratio of 1.5, and CaO/biomass ratio of 1.42. In addition the simulation model predicted results were compared with experimental data obtained from the experimental set up used in the simulation.

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In this study, biodegradable slow-release fertilizer (SRF) hydrogels were synthesized from hydroxyl propyl methyl cellulose (HPMC), polyvinyl alcohol (PVA), glycerol and urea (SRF1) and HPMC, PVA, glycerol, urea and blended paper (SRF2). The fertilizer hydrogels were characterized by SEM, XRD and FTIR. The swelling capacity of the hydrogels in both distilled and tap water as well as their water retention capacity in sandy soil were evaluated. The hydrogels had good swelling capacity with maximum swelling ratio of 17.2 g/g and 15.6 g/g for SRF1 and SRF2 in distilled, and 14.4 g/g and 15.2 g/g in tap water, respectively. The water retention capacity of the hydrogels in sandy soil exhibited higher water retention when compared with soil without the (SRFs). The soil with the hydrogels was found to have higher water retention than the soil without the hydrogels. The slow-release profile of the hydrogels was also evaluated. The result suggested that the prepared fertilizer hydrogels has a good controlled release capacity. The blended paper component in SRF2 was observed to aid effective release of urea, with about 87.01% release in soil at 44 days compared to the pure urea which was about 97% release within 4 days. The addition of blended paper as a second layer matrix was found to help improve the release properties of the fertilizer. The swelling kinetic of the hydrogel followed Schott’s second order model. The release kinetics of urea in water was best described by Kormeye Peppas, suggesting urea release to be by diffusion via the pores and channels of the SRF, which can be controlled by changing the swelling of the SRF. However, the release mechanism in soil is best described by first order kinetic model, suggesting that the release rate in soil is depended on concentration and probably on diffusion rate via the pores and channels of the SRF.