Takwa Kraiem

Bio: Takwa Kraiem is an academic researcher from Tunis University. The author has contributed to research in topics: Pyrolysis & Syngas. The author has an hindex of 4, co-authored 5 publications receiving 208 citations.

Production and characterization of bio-oil from the pyrolysis of waste frying oil.

Abstract: In this present work, the disposal of waste frying oil was explored. The experiment tests were performed under nitrogen (N2) atmosphere at 5 °C/min heating rate from the ambient temperature to 500 °C. In these operating conditions, the obtained pyrolitic liquid fraction was 76 wt% formed by 63.87 wt% of crude bio-oil and 12.13 wt% of aqueous fraction. The chemical characterization using FTIR, GC, and GC/MS has revealed that the bio-oil is a complex chemical mixture of linear saturated, unsaturated, and cyclic hydrocarbons and oxygenated compounds such as carboxylic acids, ketones, aldehydes, and alcohols. Moreover, the produced bio-oil can be considered as promising fuel with high calorific value (∼39 MJ/kg). However, the higher acidity (∼125 mg KOH/g sample) and viscosity (9.53 cSt at 40 °C) limit currently its direct use in engines. Therefore, although several promising results, further investigations are requested to improve the bio-oil quality in order to find an environmentally friendly issue to waste frying oil.

Hydrogen-rich syngas production from pyrolysis and gasification of palmitic fibers

Abstract: Pyrolysis and gasification are two attractive processes for converting pre-dried palmitic fibers (PF) into valuable gaseous products with high effectiveness and little environmental impact. The gasification and pyrolysis of pre-dried PF were conducted independently, using two different laboratory-scale fixed-bed reactors. The key properties of produced biofuels — and mainly of gaseous ones — obtained from both thermochemical processes have been investigated. The raw material characterization reveals that the pre-dried PF are suitable feedstock for thermochemical conversion and mainly for syngas production. The reactor temperature distribution was between 600 and 1000°C for gasification process and between 400 and 600°C for pyrolysis. Gasification and pyrolysis of pre-dried PF produce high-quality combustible gases (syngas), formed mainly of CO, H 2 , CO 2 , N 2 , CH 4 and C n H m , that can be used either as a fuel to produce heat and power or as an intermediate in the production of liquid fuels and chemicals. However, the syngas specifications requested for most of these applications require important upgrading operations that enhance considerably the energy efficiency.

Characterization of syngas and bio-char: Co-products from pyrolysis of waste fish fats

Abstract: Waste fish fats from Tunisian fish industry were pyrolyzed under nitrogen in a laboratory scale fixed-bed reactor. The pyrolysis was performed with a heating rate of 5°C/min from the ambient up to a final temperature of 500°C. In these conditions the main product is bio-oil (55 wt.%) while the co-products are syngas (44 wt.%) and bio-char (1 wt.%). The objective of this work is to characterize syngas and bio-char, to improve this technology in environmental and economic terms. The bio-char is characterized using elemental analysis (CHNS), moisture content, Fourier Transform Infrared spectroscopy (FTIR) and X-ray diffraction (XRD) analyses furthermore the syngas composition is determined during the pyrolysis reaction. From the obtained results, we can conclude that the characterization of the pyrolysis by-products indicate that: (i) The syngas contains CH, CO 2 , CO and H 2 S; (ii) The bio-char characterization by elemental analyses indicates a high oxygen content and a moderate carbon content; these properties are confirmed by a high proportion of oxygenated functions and a modest aliphaticity (FTIR analyses).

Progress in waste oil to sustainable energy, with emphasis on pyrolysis techniques

Abstract: The authors acknowledges the financial support by Ministry of Science, Technology, and Innovation Malaysia (MOSTI), Ministry of Higher Education Malaysia (MOHE), and Universiti Malaysia Terengganu for the conduct of the research under the E-Science fund (UMT/RMC/SF/13/52072(5), Vot no.: 52072), the Fundamental Research Grant Scheme (Project no.: FRGS/1/2013/TK05/UMT/02/2, Vot no.: 59296), and the Research Acculturation Grant Scheme (Project no.: RAGS/2012/UMT/TK07/3, Vot no.: 57085).

Recent trends of biodiesel production from animal fat wastes and associated production techniques

Abstract: Non-edible feedstocks such as animal fat wastes (AFWs) have recently increased in popularity as alternatives to vegetable oils in the production of biodiesel. They are low cost, mitigate environmental damage and increase the quality of the resultant biodiesel fuel (low NOx emissions, high Cetane number and oxidative stability). Therefore, AFWs are an excellent feedstock for biodiesel production. Here we provide a comprehensive review trends and techniques in biodiesel production from AFWs. A critical overview of homogeneous and heterogeneous (one- or two-step) catalytic transesterification of AFWs is presented. Similarly, enzyme-catalyzed transesterification and the application of supercritical fluids conversion techniques in the production of biodiesel from AFWs are thoroughly assessed. Finally, cutting edge advances in assisted transesterification processes for biodiesel production are critically reviewed.

Food waste to biochars through pyrolysis: A review

Abstract: Waste generated from anthropogenic activities contributes toward stresses on our natural systems through impacts associated with both production and disposal. Sustainable waste management necessitates that industries shift from the current linear model to a circular based economy, utilizing wastes as raw materials for the production of new products, eg. fuels and chemicals. Biomass and associated waste materials can be converted into value-added products using thermochemical processes. The pyrolysis process is a convenient thermochemical method, whereby biomass is efficiently converted into biofuels, biochars and BBQ briquettes; and further processing yields additional value added products, such as activated carbons, carbon black and printing ink. This paper reviews current development work and evaluates potential opportunities for food waste pyrolysis focusing on the conversion of food waste to biochar products. Overall, it was found that the constituents of the food waste together with the process conditions play a major role in the yield and composition of the produced chars. Moreover, more research work needs to be conducted on food waste to biochar and on mixed food blends in particular.

A comprehensive review of low cost biodiesel production from waste chicken fat

Abstract: This paper discusses about the importance of animal fats for power generation particularly from waste chicken fat, advantages of using chicken fat for biodiesel production, different ways of oil extraction from chicken fat and various biodiesel production techniques. A detailed review has been done on the use of novel heterogeneous catalysts for transesterification process such as metal based catalysts and organic catalysts. The factors influencing transesterification parameters like molar ratio, catalyst weight percentage, reaction time and temperature has been collected from several research articles were presented in detail. In addition, the transesterification reaction is studied at different co solvents employed to increase the methyl ester conversion. Also, analyses of relative optimization techniques implementing for transesterification process parameters have been discussed thoroughly. The physico-chemical properties of chicken fat methyl ester such as kinematic viscosity, density, pour, cloud, flash and cold filter plugging point, calorific value and fatty acid compositions of chicken fat methyl ester were compared with different animal fat methyl esters. The study reveals that biodiesel produced from waste chicken fat would be a suitable replacement of edible vegetable oils due to its low cost, ease of availability and the properties of chicken fat methyl ester were within the limits of ASTM D 6751 biodiesel standards. Furthermore, the research work has to be carried out for the improvement of cycles of catalyst reusability, biodiesel purity and cost-effectiveness of biodiesel production process in future.