|
Academic Knowledge Archives of Gunma Institutes >
群馬大学(Gunma University) >
50 工学研究科 >
学位論文 >
Please use this identifier to cite or link to this item:
http://hdl.handle.net/10087/5146
|
Title: | CATALYTIC DECOMPOSITION OF BIOMASS TARS WITH NICKEL CATALYSTS |
Other Titles: | ニッケル触媒を用いたバイオマスタールの接触分解 |
Authors: | Le Duc Dung レ ジウク ジウン |
Keywords: | Catalyst Tar Fluidized Bed Gasification Biomass gasification |
Issue Date: | Mar-2010 |
Abstract: | Tar is a viscous black liquid derived from pyrolysis of organic matter
and a complex mixture of hydrocarbons. The presence of tar in the
product gas may cause blockage and corrosion of equipments and be
responsible for fouling or reducing overall efficiency of processes. By far,
tar removal is the most problematic during biomass gasification. Hence,
a successful implementation of gasification technology for gas engines,
gas turbines or fuel cells based power projects depend much on the
effective and efficient removal or conversion of tar from the product gas.
Beside that, the catalytic steam reforming tar is one of the most
promising methods to suppress the problems. The biomass product gas is
usually low calorific value; therefore, an enhancement of the product gas
quality is other important target. We propose a research topic that to
utilise nickel–loaded brown coal char as a new catalyst for decomposing
tar from biomass gasification in a fluidized bed gasifier. The method is
promising to get benefits from the use of low rank coal char as a catalyst
support material, a high catalyst activity of nickel and an enhancement
of product gas quality. In this study, yallourn brown coal has been
selected to prepare the catalyst support. The coal that is a low rank with
high moisture content, a low heat value and high oxygen content is hard
to use for generating energy. However, it has a lot of outstanding features
such as less ash and sulfur content, and with abundant of
oxygen–containing functional groups such as carboxyl and phenol groups
which are available for ion–exchange with metals. In this study, the
nickel–loaded brown coal char (Ni/BCC) was prepared by an
ion–exchange method, dried at 380 K in nitrogen for 24 h, and then
pyrolysed at 923 K in nitrogen for 90 min. The works have been carried
out is the use of the Ni/BCC catalyst to decompose tar in pyrolysis and
steam gasification processes. The experiments were performed on a
two–stage fixed–bed reactor and a laboratory–scale fluidized–bed gasifier
under mild conditions (temperatures, steam, space velocities, operation
time). Inside of the gasifier was constructed by two beds, the primary one
is a fluidized bed with sand, and the second one is a catalyst bed. The
Ni/BCC catalyst has shown high catalytic activity and stable activity and
given the high quality of the product gas. In the presence of steam,
approximately 90% of biomass tar was decomposed and useful gas
components (CH4, CO, and H2) yields were higher than those of a
conventional Ni/Al2O3 catalyst. The Ni/BCC catalyst was characterized
and exhibited a good dispersion of nickel particles, ultra–fine Ni less than
15 nm and a large surface area (Approximately 350 m2/g). Moreover, at
the end of its life span, the catalyst can be easily disposed by gasifying or
burning the coal char, during which the energy value of the char support
can be recovered. Further, the agglomerated nickel residues can be also
used as functional materials for powder metallurgy and battery
development. The general results suggest that the Ni/BCC catalyst offers
a potential to be used as a high activity catalyst for steam reforming of
tar in biomass gasification. |
Description: | 学位記番号:工博甲398 |
URI: | http://hdl.handle.net/10087/5146 |
Academic Degrees and number: | 12301甲第398号 |
Degree-granting date: | 2010-03-24 |
Degree name: | 博士(工学) |
Degree-granting institutions: | 群馬大学 |
Appears in Collections: | 学位論文
|
Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.
|