Hydrothermal processing is an important thermochemical conversion process that is used to convert biomass into valuable products or biofuel. The process is usually performed in water at 250–374 °C under pressures of 4–22 MPa. The biomass is degraded into small components in water. Based on the target products, i.e., bio-oil, bio-gas or bio-carbon, the process conditions (temperature, pressure and time) are chosen. There has been significant effort in evaluating various biomass resources for hydrothermal processing because the process is suitable for any type of biomass including the co-utilization of biomass with waste materials. Additionally, because most biomass resources have high moisture contents, the most efficient way to process them is through hydrothermal processing. To understand hydrothermal biomass processing and the degradation pathway of biomass, it is necessary to understand the properties of water under hydrothermal conditions (i.e., subcritical and supercritical). In this respect, the physicochemical properties of water under subcritical and supercritical conditions and the interactions of water with biomass are discussed in the present paper. This review focuses on the hydrothermal processing of biomass and identifies the characteristics of various types of hydrothermal processing products. Additionally, this review provides an overview of the available biomass, the use of biomass as an energy source and related conversion technologies.

A review of hydrothermal biomass processing

Effect of pyrolysis temperature, heating rate, and residence time on rapeseed stem derived biochar

This paper reviews the global status of waste to energy (WTE) technologies as a mean for renewable energy production and municipal solid waste (MSW) disposal method. A case study of the Kingdom of Saudi Arabia (KSA) under this concept was developed. The WTE opportunities in the KSA is undertaken in the context of two scenarios: (1) incineration and (2) refuse derived fuel (RDF) along with biomethanation from 2012 to 2035. Biomethanation technology can proved to be the most suitable WTE technology for KSA due to (a) availability of high food waste volume (37% of total MSW) that can be used as a feedstock, (b) higher efficiency (25–30%) and (c) lowest annual capital ($0.1–0.14/ton) and operational cost. However, the need for large space for continuous operation might increase operational cost. The RDF has an advantage over incineration due to (a) less annual capital ($7.5–11.3/ton) and (b) operational cost ($0.3–0.55/ton), but the high labor skills requirements will most probably be a limitation, if appropriate training and related infrastructure are not scheduled to be included as a prerequisite. The incineration technology also proves to be an efficient solution with a relatively higher efficiency (25%) and lower operational cost ($1.5–2.5/ton). However, the need for treatment of air and waterborne pollutants and ash within the incineration facility can be the limiting factors for the development of this technology in KSA. In 2012, the power generation potential for KSA was estimated at 671 MW and 319.4 MW from incineration and RDF with biomethanation scenarios respectively, which was forecasted to reach upto 1447 MW and 699.76 MW for both scenarios respectively by 2035. Therefore, WTE technologies, could make a substantial contribution to the renewable energy production in KSA as well as alleviating the cost of landfilling and its associated environmental impacts. However, the decision to select between the two scenarios requires further in-depth financial, technical and environmental analysis using life cycle assessment (LCA) tool.

Waste to energy potential: A case study of Saudi Arabia

The potential of the Malaysian oil palm biomass as a renewable energy source

Modeling of lignocellulosic biomass pyrolysis processes can be used to determine their key operating and design parameters. This requires significant amount of information about pyrolysis kinetic parameters, in particular the activation energy. Thermogravimetric analysis (TGA) is the most commonly used tool to obtain experimental kinetic data, and isoconversional kinetic analysis is the most effective way for processing TGA data to calculate effective activation energies for lignocellulosic biomass pyrolysis. This paper reviews the overall procedure of processing TGA data for isoconversional kinetic analysis of lignocellulosic biomass pyrolysis by using the Friedman isoconversional method. This includes the removal of “error” data points and dehydration stage from original TGA data, transformation of TGA data to conversion data, differentiation of conversion data and smoothing of derivative conversion data, interpolation of conversion and derivative conversion data, isoconversional calculations, and reconstruction of kinetic process. The detailed isoconversional kinetic analysis of TGA data obtained from the pyrolysis of corn stalk at five heating rates were presented. The results have shown that the effective activation energies of corn stalk pyrolysis vary from 148 to 473 kJ mol−1 when the conversion ranges from 0.05 to 0.85.

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Processing thermogravimetric analysis data for isoconversional kinetic analysis of lignocellulosic biomass pyrolysis: Case study of corn stalk

Experimental evaluation of using various renewable energy sources for heating a greenhouse

Isı borulu güneş enerjili termosifon düzlemsel kollektörün performansı

This study determined the heat, flow, and electrical power values of and automotive thermoelectric generation system integrated in the exhaust system of an internal combustion gasoline engine. The combustion analyses of the engine integrated with and without automotive thermoelectric generation were carried out. The 20 thermoelectric modules were placed on the rectangular structure which was made of the aluminum 6061 material. The thermoelectric modules were electrically connected to each other in series. The gasoline engine was operated at full load at 1250, 1750, and 2250 rpm, and the electrical energy generated by the automotive thermoelectric generation system was calculated. At the same time, the heat and flow analyses of the automotive thermoelectric generation system were performed using the ANSYS FLUENT commercial software.

/pdf/analysis-of-an-automotive-thermoelectric-generator-on-a-760g1ab47v.pdf

Analysis of an automotive thermoelectric generator on a gasoline engine

Bu calismada, benzinli bir motor uzerinde birtakim duzenlemeler yapilarak biyoetanol gaz halinde ikincil yakit olarak kullanildi. Farkli oranlarda ikincil yakit olarak kullanilan biyoetanolun motorun performans degerleri, yakit tuketimi ve emisyon degisimleri arastirildi.  Yakitin silindir icerisine gaz haliyle gonderilmesi sayesinde sivi yakitin olusturdugu bazi olumsuzluklara cozum bulunmaya calisildi. Deneylerde kullanilan motor 1000, 1250, 1500, 1750, 2000 ve 2250 dak -1 devirlerde tam yukte (tam gazda) calistirilarak motor performans, emisyon ve yanma karakteristikleri incelendi. Elde edilen sonuclara gore emisyon salinimlarinda iyilesmelerin oldugu gozlemlendi ve farkli calisma sartlari altinda silindir ici maksimum basinclari ve isi salinim miktarlari Febris yanma analiz programi yardimi ile hesaplandi

/pdf/benzinli-bir-motorda-isitilmis-biyoetanolun-ikincil-yakit-4wsl6fe1ne.pdf

Tahsin Yüksel

Papers

Experimental evaluation of using various renewable energy sources for heating a greenhouse

Isı borulu güneş enerjili termosifon düzlemsel kollektörün performansı

Analysis of an automotive thermoelectric generator on a gasoline engine

Benzinli Bir Motorda Isıtılmış Biyoetanolün İkincil Yakıt Olarak Kullanımının İncelenmesi

Elaziğ i̇li̇ i̇çi̇n çeşi̇tli̇ yeni̇lenebi̇li̇r enerji̇ kaynaklarinin deneysel olarak değerlendi̇ri̇lmesi̇