scholarly journals Gasification of Densified Biomass (DB) and Municipal Solid Wastes (MSW) Using HTA/SG Technology

Processes ◽  
2021 ◽  
Vol 9 (12) ◽  
pp. 2178
Author(s):  
Jan A. Stasiek ◽  
Jacek Baranski ◽  
Marcin Jewartowski ◽  
Jan Wajs

The necessity of economical and rational use of natural energy sources caused a rapid development of research on the possibilities of using non-conventional energy resources. Taking the above into account, a new technological process of thermochemical conversion of biomass and communal waste, commonly known as High Temperature Air/Steam Gasification (HTA/SG) and Multi-Staged Enthalpy Extraction Technology (HTAG-MEET), was developed. In relation to traditional techniques of gasification or combustion of hydrocarbon fuels, the presented concept is characterized by higher thermal efficiency of the process, low emission of harmful compounds of carbon, sulfur, nitrogen, dioxins, furans and heavy metals. The use of a high-temperature gasification factor causes an increased thermochemical decomposition of solid fuels, biomass and municipal waste into gaseous fuel (syngas), also with increased hydrogen content and Lower Calorific Value (LCV). In this study, the possibility of using a batch type reactor (countercurrent gasifier) was analyzed for gasification of biomass and municipal waste in terms of energy recovery and environmental protection. The proposed research topic was aimed at examining the possibility of using the thermal utilization of biomass and municipal waste through their high-temperature decomposition in the presence of air, a mixture of air and steam. The main goals of the research were achieved during the implementation of several parallel stages of the schedule, which included, primarily: (a) study of the possibility of using thermal utilization of biomass and municipal waste through their high-temperature gasification in the presence of air or a mixture of air and steam and, secondary (b) analytical and numerical modeling of high-temperature gasification of biomass and municipal waste with the use of ANSYS CFD Fluent 6.3 software. Selected results of the experimental and numerical studies are properly presented. The higher temperature gasification concept shows the capability of this technology for maximizing the gaseous product yield in an up-draft fixed bed gasifier. It was also observed that at a high temperature, steam addition contributed to the thermal conversion of biofuels to gas with higher production of hydrogen.

Author(s):  
Frédéric Paviet ◽  
Olivier Bals ◽  
Gérard Antonini

Gasification is an attractive technology for waste thermal treatment. The successful design and modelling of a gasifier requires reliable kinetic data. The purpose of this work is to study the steam gasification kinetics of chars produced by municipal wastes pyrolysis. The municipal solid wastes (MSW) are modelled as a mixture of four organic constituents: paper, wood, plastics, and vegetables. The various char samples are obtained by pyrolysis of each waste constituent, in a fixed bed reactor at 1000°C, in order to minimize their volatile content and thus, to eliminate any subsequent devolatilization of the carbonaceous residues. These chars are used as raw materials in steam gasification experiments. The gasification studies are performed on each char separately, in a tubular kiln at various temperatures (900°C, 950°C and 1000°C) and various vapour pressures (0.2 bar, 0.5 bar and 0.7 bar). The gases produced are analysed by gas chromatography in order to determine the gasification kinetics. The kinetics parameters, with respect to H2O, together with the influence of the char's physical properties are experimentally determined. A kinetic expression for the gasification reaction, based on the random pore model is deduced. It is shown that the char resulting from the pyrolysis of MSW constituents, essentially paper, wood and vegetables have the same gasification kinetics. On the contrary, the plastic char steam gasification kinetic appears to be significantly slower.


2008 ◽  
Vol 49 (1-2) ◽  
pp. 59-67 ◽  
Author(s):  
T. Valliyappan ◽  
D. Ferdous ◽  
N. N. Bakhshi ◽  
A. K. Dalai

2013 ◽  
Vol 830 ◽  
pp. 477-480 ◽  
Author(s):  
Wei Qing Zeng ◽  
Ling Jun Zhu ◽  
Qi Wang

Steam gasification of biochar from fast pyrolysis of biomass was conducted in a fixed bed reactor. The experiments were carried out at temperature of 700, 750, 800 °C with steam flow rate of 0.1 g/min and reaction time of 3 h. The gas products mainly included H2, CO, CO2and some hydrocarbons with low carbon number. The results showed that the conversion of biochar at 700, 750, 800 °C was 68, 78, 96 wt%, respectively, and high gasification temperature favored the production of hydrogen-rich gases. The hydrogen yield increased with temperature rising and reached the maximum of 35.70 mol/kg with a hydrogen concentration of 74 V% at 800 °C.


Author(s):  
Romain Demarthon ◽  
Frédéric Marias ◽  
Alice Fourcault ◽  
Jean Paul Robert-Arnouil

One way of biomass and/or waste recycling is its thermochemical conversion into combustible gas. Mainly composed of CO,H2 and CH4, the gas may also contain varying amounts of impurities (dust, polluting products, tar or soot). Specifically, there is a tar problem: their high condensation temperature is incompatible with an industrial utilization. They can cause rapid fouling, corrosion and abrasion into turbines or engines. Proposed by EUROPLASMA, the CHO-Power process aims to generate electricity from a mixture of municipal waste and biomass using a fixed bed gasifier with conventional gas treatment. Its specificity consists of an unit called Turboplasma. This stage allows to reach very high temperature in order to obtain temperature around 1600K, and so to degrade all tars present, even heavier. Indeed, EUROPLASMA built a gasification pilot unit based on fluidized bed technology, (called KIWI) to qualify the synthesis gas produced. TURBOPLASMA pilot scale will be installed there. The objective of this work is the design of this high temperature stage thanks to numerical modeling. Reaction scheme used previously [4] to modelize tar degradation in the Turboplasma of CHO-Power, has been improved: a discrete phase modeling has been added providing a better view of the TURBOPLASMA internal behavior. Indeed, char particles from syngas can significantly change the reactor performance. This study shows that char particles react primarily with the H2O and CO2. Char gasification takes place in areas of high velocity and temperature gradient. Increased understanding of aerodynamics inside the reactor allows a better estimate of the overall performance of the reactor. Performance evaluation of the reactor is based on a set of parameters such as levels of heat loss, velocity gradient, mixing quality, residence time.


2013 ◽  
Vol 316-317 ◽  
pp. 105-108
Author(s):  
Wu Xing Sun ◽  
Yan Zhou ◽  
Qi Wang ◽  
Shu Rong Wang

Steam gasification of biochar from catalytic pyrolysis of biomass was studied in a fixed bed reactor at atmospheric pressure. The experiments were carried out at bed temperature of 700, 750, 800 °C at steam flow rate of 0.1 g/min with reaction time of 3h. The gases produced included mainly H2, CO, CO2 and some small molecular hydrocarbons. The results showed that high gasification temperature was favorable for the production of hydrogen-rich gases. The maximum concentration of hydrogen exceeded 85% at 800 °C and the total gas yield increased with temperature rising. Meanwhile, the conversion efficiency of biochar at 700, 750, 800 °C was 48%, 60%, 72% respectively.


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