High Surface Area Activated Carbon From Waste Biomass.

The present work relates to efforts made towards developing a high surface area, activated carbon from rubber wood sawdust by a two-stage activation process with phosphoric acid as the activating agent

Computer Simulation of Catalytic Oxidation of Gaseous Ammonia in Bubbling Fluidized Bed

Catalytic conversion of ammonia in bubbling fluidized bed has been simulated using three different hydrodynamic models: (a) Kunii and Levenspiel model, (b) Simple two-phase model, and (c) Dynamic two-phase model. The basic differences between the models lie in the assumptions and mass transfer correlations used to describe the hydrodynamics of the fluidized bed. This study compares the predictions of the performance of a fluidized bed reactor by different models, comparing with experimental data of ammonia oxidation using metal oxide catalysts. The predictions from all the models compared well with the experimental data within acceptable levels of error. The variations among the models were found to be insignificant. However, simulation of the model to assess the effect of different hydrodynamic parameters, including gas velocity, bed diameter and particle size, and bed density on conversion showed significant variation among the models

Waste walnut shell valorization to iron loaded biochar and its application to arsenic removal

Iron loaded biochar (ILB) was prepared from waste walnut shell by microwave pyrolysis and its application for arsenic removal was attempted. The ILB was characterized using X-ray diffraction, scanning electron microscopy and BET Surface area analyzer. The adsorption isotherm of As (V) in ILB covering a temperature range of 25 to 45 °C, as well as the kinetics of adsorption at 25 °C were experimentally generated. The adsorption isotherms were modeled using Langmuir and Freundlich isotherm models, while the kinetics of adsorption was modeled using the pseudo-first-order, pseudo-second-order kinetic models, and intra particle diffusion model. The ILB had a surface area of 418 m2 /g with iron present in the form of hematite (Fe2O3) and magnetite (Fe3O4). The arsenic adsorption isotherm matches well with Langmuir isotherm model with a monolayer adsorption capacity of 1.91 mg/g at 25 °C. The adsorption capacity of As (V) well compares with other porous adsorbents widely reported in literature, supporting its application as a cost effective adsorbent

Gasification conversion and char reactivity of rubber seed shell and high density polyethylene mixtures using steam Co-Gasification process

Due to the recent surge of global energy demand and the fear of climate change, an extensive attention from worldwide in seeking for cleaner alternative means of renewable energy and this has been a topic of interest widely. With the abundance supply of biomass and plastic waste generated annually and finding an effective method in utilizing these wastes, leads to a notion of using these wastes in the co-gasification process. Although there are studies on co-gasification of biomass and waste mixtures, limited studies focused on the understanding of the char reactivity and gasification conversion of this mixture. Hence, an experimental study on steam co-gasification of rubber seed shell and high density polyethylene mixtures in argon atmosphere is carried out using thermogravimetric (TGA) approach under non-isothermal condition. This work presents the surface physical morphology of rubber seed shell (RSS), high density polyethylene (HDPE), and its mixtures. Furthermore, the char conversion and char reactivity of RSS, HDPE, and their mixtures at different proportions are investigated in both pyrolysis and gasification process. The argon gas is supplied at a flowrate of 100 mL min-1and the steam is generated from superheater at 383 K whilst injected at flowrate of 3000 µL h-1into the TGA system

Performance Prediction of Waste Polyethylene Gasification Using CO2 in a Bubbling Fluidized Bed: A Modelling Study

Gasification of carbonaceous materials using CO2 from flue gases is an effective and economic means of waste recycling and environmental CO2 mitigation system. The paper presents investigation on conversion of plastics, such as (poly) ethylene, into valuable gaseous products, primarily Syngas or synthesis gas using CO2 as a gasifying agent instead of conventional steam. Typically, gasification is carried out in a fluidized bed reactor followed by sequential separation of syngas from tar and other undesired gaseous products. In this research work, the effect of operating conditions of the fluidized bed reactor on carbon conversion and H 2/CO mole ratio was examined. For this purpose, a process model of CO2 gasification of waste plastics using fluidized bed reactor was developed in ASPEN PLUS®. Sensitivity analysis concluded that parameters like CO2 – feed ratio, residence time, and gasification temperature serve to control the yield and quality of syngas. This work is licensed under a Creative Commons Attribution 4.0 International License

Effect of Different Cooling Modes on Crystal Size Distribution in a Batch Cooling Crystallizer for DL-Malic Acid

The effects of various cooling modes such as natural cooling mode, linear cooling mode, and controlled cooling modes type A and B in a batch cooling crystallizer on crystal size distribution (CSD) as well as the mean crystal size have been studied for DL-malic acid. The natural cooling mode was found to yield crystals in the range of 250 to 1000 mm, whereas the linear cooling mode was found to yield larger crystals, in the range of 800 to 1600 lm. The mean crystal size was found to increase in the order of natural cooling mode, controlled cooling mode A, controlled cooling mode B, and linear cooling mode. Since linear cooling mode was found to yield larger mean crystal size, the effect of operating parameters such as the seed concentration and agitation rates on CSD was assessed using the linear cooling mode. The increase in seed concentration from 0.5 to 1% resulted in a larger mean crystal size; while an increase from 1 to 2% reduced the mean crystal size. An agitator rate of 90 rpm was found to yield larger mean crystal size than agitation rates of 60 and 120 rpm