Journal of Analytical and Applied Pyrolysis 89 (2010) 265–270
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Journal of Analytical and Applied Pyrolysis
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Brown
Marcela
Brown Coal Res
a r t i c l
Article history:
Received 8 Ap
Accepted 17 S
Available onlin
Keywords:
Pyrolysis of co
Coal tar
Tar hydrotreat
Hydrotreatme
Catalyst
labora
n coa
press
drotre
sente
orth
the f
d the
used
1. Introdu
Through
deprived at
and 900 ◦C
is the most important one. At high activation temperatures and
employing proper activation medium, materials with extensive
system of pores can be prepared from the semi-coke, which mate-
rials can be used in the area of environmental protection as
adsorbents [1,5,21,29–32]. Utilisation of such carbon-based mate-
rials in this
of various t
separation
[3,28,33,36
considerabl
cal properti
of the pores
pyrolysis al
and pyroge
can serve a
arrive at m
hydrogenat
employing
Within t
of Physical–
ing and Use
∗ Correspon
E-mail ad
andel@vuhu.c
ian R
isati
sis) [
roce
mixtu
are suitable for further industrial use; in particular in the area of
propulsion fuels and their derivates. The envisaged outcome of the
research of the properties of brown-coal-based mass consists in
enhancement of knowledge on the brown coal tar, its qualitative
properties in relation to the typeof the rawmaterial used, acquiring
0165-2370/$ –
doi:10.1016/j.
area varies very much: from treatment/purification
ypes of wastewater streams, purification of flue gas,
of permanent gases or capture of carbon dioxide
–39]. The manner of use of these adsorbents depends
y on the properties of these materials, whilst the criti-
es are the specific surface area, distribution and shapes
and the bulk weight [36]. Besides gas, the brown coal
so generates liquid products; namely brown coal tar
netic water [31]. The brown coal tar is a product that
s appropriate raw material for ensuing processing to
uch more noble products, such as motor fuels and oil
es, which are currently produced mainly from crude oil
multiple technological processes.
he MSM 4456918101 research project titled “Research
Chemical Properties of Materials Associated with Min-
of Coal and their Environmental Effects in the North
ding author. Tel.: +420 476208704; fax: +420 476208702.
dresses: safarova@vuhu.cz (M. Sˇafárˇová), kusy@vuhu.cz (J. Kusy´),
z (L. Andeˇl).
information on prospective technological procedures and process
condition needed for its splitting, including knowledge on the qual-
ity of the products and the options of their hydrotreatment relying
on the use of modern catalysts [26,40].
2. Coal hydrotreatment
Hydrotreatment processes belong to the group of processes of
direct liquefying of coal mass; i.e. the processes by which coal are
converted to liquid products. During these processes hydrogen is
applied on the coal mass; either directly, in gaseous phase, or via so
called H-donor solvent. In simplified terms the liquefying process
can be described by the following equation:
C + 0.8H2 = (CH1.6)n
The hydrogen applied on the coal mass partly reduces sulphur and
nitrogen contained in the coal, whereby the process also enables
their easier removal from the fuel. At the same time ash content is
also removed. The objective of the coal liquefying processes is pro-
duction of fuel oil, diesel and naphtha from coal (which products
have predominantly been produced from crude oil). On industrial
see front matter © 2010 Elsevier B.V. All rights reserved.
jaap.2010.09.002
coal tar hydrotreatment
Sˇafárˇová, Jaroslav Kusy´, Lukásˇ Andeˇl ∗
earch Institute, j.s.c., Budovatelu˚ 2830, 43437 Most, Czech Republic
e i n f o
ril 2010
eptember 2010
e 25 September 2010
al
ment
nt reactor
a b s t r a c t
The paper dealswith the outcomes of
inwhich tarwas a by-product of brow
tor at 300 ◦C and at varied operational
coal tar samples earmarked for the hy
of brown coal, in which samples repre
be found in individual districts of the N
parameters were determined both of
(gaseous, water and organic phases an
on the operational hydrogen pressure
ction
pyrolysis of solid carbon-based materials at air-
mosphere and at temperatures ranging between 600
multiple products are generated, of which semi-coke
Bohem
on util
pyroly
such p
noble
m/locate / jaap
tory experiments concerning brown coal tar hydrotreatment,
l pyrolysis. The experimentswere carried out in pressure reac-
ures of hydrogenused as hydrotreatmentmedium. The brown
atment tests had been prepared through pyrolysis of samples
d, in terms of qualitative parameters, the brown coal types to
Bohemian Coal Basin. During the experiments the qualitative
eed material (brown coal tar) and of the products generated
hydrotreatment residue). The yields of these products as per
during the hydrotreatment process were also determined.
© 2010 Elsevier B.V. All rights reserved.
egion”, in recent years research has also been focused
on of brown coal tar (liquid product of coal material
34]. On the basis of multiple experiments carried out,
dures have been employed that enable to generate a
re of hydrocarbons from the tar, which hydrocarbons
266 M. Sˇafárˇová et al. / Journal of Analytical and Applied Pyrolysis 89 (2010) 265–270
Nomenclature
Symbols and abbreviations
TSKd
WSKd
GSKd
SKd
scale, the te
ticular befo
multiple fa
technology
in Leuna (Be
tion of Czec
coal was als
operated un
In the se
of motor fu
nologies, as
crude oil su
and its risin
developed
in a pilot sc
prognoses s
crude oil in
As far as
priate coal
(brown coa
groups (vitr
and genera
completely
compositio
fying techn
The follo
direct lique
• Pyrolysis:
ture exce
evaporate
of liquid
process g
hydrogen
are used,
liquefying
process (G
• Hydro-py
870 ◦C) in
are used
pyrolysis
COED (US
• Hydrotrea
ature of a
20MPa) i
is employ
of this pro
• Solvent ex
much as 4
environm
whilst no
given as a
• Extraction
toluene o
from the
tures and pressures that are higher than the critical temperature
and the critical pressure of the relevant solvent are. The NCB
(Great Britain) process is an example of this technology [4].
the
sitio
arbo
cal tr
arbo
oces
the
her
hydr
prod
e de
,14]
ted i
, nam
ond
and
rproc
l or
erim
obje
, the
he py
Bohe
ts, in
ying
exp
ssibi
s con
ratio
qual
rude
bro
ut in
, inle
f cob
ercia
% of C
e is A
m i
teria
chos
raw
tical
nera
epar
reatm
the h
coal
hich
tar content (converted to dry condition)
pyrogenetic water content (converted to dry condi-
tion)
gas content (converted to dry condition)
semi-coke content (converted to dry condition)
chnologies of liquefying of coal had been used in par-
re and during the World War II in Germany, where
cilities of the kind had been operated [2,26]. The first
of direct liquefying had been made operational in 1927
rgius Process – IG Farben). During the German occupa-
hoslovakia an industrial complex for liquefying brown
o built in the Záluzˇí u Litvínova village, which had been
til the mid-1960s.
cond half of the 20th century the process of production
els from crude oil was gradually replacing these tech-
crude oil was a cheaper feed material. Due to multiple
pply crises, decreasing amounts of available crude oil
gprices, the technologiesof coal liquefyingare currently
intensively. Multiple facilities of the kind are operated
ale particularly in Europe and the USA. Moreover, the
uggest that coalwill be one of the fuels thatwill replace
future [2,12,35].
the liquefyingprocesses are concerned, themost appro-
is such coal that contains high amount of hydrogen
l and lignite) and high amounts of reactive maceral
inite and exinite). Hard coal is more difficult to liquefy
tes lower yields of liquid products, whilst anthracite is
unsuitable for the liquefying process. The yields and the
n of liquid products depend mainly on the used lique-
ology, type of coal and selected reaction conditions.
wing procedures are the basic types of the processes of
fying of coal:
In air-deprived atmosphere coal is heated to tempera-
eding 500 ◦C, whereby volatile flammable material is
d, which, after cooling down, emerges as a mixture
and gaseous products. Of all the other processes this
enerates the lowest yields of liquid products and no
is supplied from an external source and no catalysts
nor is increased pressure applied. This is not a typical
process as coke is themainproduct. The Lurgi–Ruhrgas
ermany) may serve as an example [20,25].
rolysis: Coal is heated to high temperature (as much as
the gaseous hydrogen environment,whilst no catalysts
or increased pressure applied. In comparison with the
process the yields of liquid products are higher [41]. The
A) processmay serve as an example of this process [13].
tment liquefying: Coal paste is heated to the temper-
s much as 450 ◦C at increased pressure (as much as
n the environment of gaseous hydrogen and a catalyst
ed. The H-Coal (USA) process may serve as an example
cess [15,16].
traction: The coal paste is heated to temperature as
All
compo
hydroc
nologi
hydroc
tant pr
out by
alyst, w
As the
liquid
mixtur
too [11
separa
ranges
corresp
range)
furthe
therma
3. Exp
The
ditions
from t
North
produc
emplo
The
the po
carbon
at gene
whose
from c
The
ried o
300 ◦C
ence o
(comm
1.5wt.
balanc
and 8m
the ma
it was
in the
the cri
test-ge
3.1. Pr
hydrot
For
brown
unit, w
50 ◦C at increased pressure (as much as 15MPa) in the
ent of H-donor solvent (hydrogen transfer medium),
catalysts are used. The EXXON (USA) process can be
n example [22].
in above-critical conditions: Ordinary solvents, such as
r water, are used for separation of liquid hydrocarbons
coal mass. The extraction takes place at such tempera-
that brown
For the pur
coal tar, sa
coal in the
from theNo
Coal Basin (
Mine Nástu
above processes generate liquid products of various
ns, whilst these products are very rich mixtures of
ns. These mixtures must be subjected to further tech-
eatment, which will enable splitting these mixtures to
n cuts as per the boiling point ranges. The most impor-
ses include hydrotreatment splitting, which is carried
addition of hydrogen in the presence of a suitable cat-
eby the C:H ratio changes in the hydrocarbon mixture.
ogen content grows in the hydrotreatment-generated
uct, the molecular weight of the components of the
creases and, hence, the boiling points of the products
. Afterwards, the emerged liquid product is distillation-
nto individual distillation cuts as per the boiling point
ely to naphtha cut (boiling pointwithin 200 ◦C), the cut
ing todiesel (virgindiesel) (the200–360 ◦Cboilingpoint
the cut with boiling point above 400 ◦C, which could be
essedemployingother splittingprocesses (visbreaking,
catalytic cracking).
ental
ctiveof theexperimentswas toapply, in laboratory con-
procedure of hydrotreatment splitting of tar originating
rolysis of brown coal mined in individual mines of the
mian Brown Coal Basin and to check the quality of the
particular in terms of prospective further processing
other technologies.
eriments carried out were focussed on verification of
lity of hydrotreatment splitting of polynuclear hydro-
tained in brown coal tars employing modern catalysts
nofhydrocarboncutswithboilingpointswithin400 ◦C,
ity is close to the quality of naphtha anddiesel produced
oil.
wn coal tar hydrotreatment experiments were car-
hydrotreatment pressure reactor at temperature of
t hydrogen pressure of 0.1–3MPa and in the pres-
alt–molybdenum-based catalyst deposited on alumina
l code: BASF 0852). Composition of Co–Mo catalyst is
oO, 11wt.% of MoO3 and 5wt.% of TiO2 (the rest to the
l2O3 as a carrier), the particle size is 3mm in diameter
n length. This catalyst is suitable for hydrotreatment of
ls with the content of organic sulphur compounds, so
en due to the relatively high amount of total sulphur
material (0.24wt.%) [40]. During these experiments all
qualitative parameters of both input raw materials and
ted products were determined.
ation of blended samples of brown coal tar for the
ent tests
ydrotreatment tests a blended sample was prepared of
tar by pyrolysis of brown coal in a laboratory pyrolysis
is provided with a retort of volume of some 2.5 L, so
coal batch of weight of some 1000g can be processed.
pose of preparation of the blended sample of brown
mples had been taken of all routinely mined types of
Czech Republic. They included samples of brown coal
rth Bohemian BrownCoal Basin and the Sokolov Brown
frommines titled as follows: Centrum, CˇSA,Mine Bílina,
p Tusˇimice and Mine Jirˇí).
M. Sˇafárˇová et al. / Journal of Analytical and Applied Pyrolysis 89 (2010) 265–270 267
Table 1
The results of determination of the yields of tar, water, gas and coke residue at low
temperature distillation of brown coal samples.
Sample code TSKd (%) SKd (%) WSKd (%) GSKd (%)
Mine Centrum 16.54 63.44 9.21 10.81
Mine CˇSA 19.27 63.45 8.07 9.21
Mine Bílina 14.62 65.89 8.57 10.92
Mine DNT 7.01 68.79 9.77 14.43
Mine Jirˇí 18.12 64.51 8.29 9.08
The brown coal batch of weight of 1000g was put into the retort
of the laboratory pyrolysis unit and was subjected to pyrolysis
(the temperature reached 650 ◦C). The yields of the products were
determined by laboratory carbonisation tests [6], whose results
are given in Table 1. By pyrolysis of individual batches of brown
coal from different mines partial samples of brown coal tar were
obtained, from which blended sample of overall volume of some
1000ml was prepared by homogenisation. This blended sample of
thebrowncoal tarwas the feedmaterial for theensuinghydrotreat-
ment tests. Before execution of the tar hydrotreatment splitting
experiments themselves, the basic analyses of the tar had been car-
ried out, which had included determination of kinematic viscosity
at 40 ◦C [7], specific gravity [8], flash point as per Pensky Martens
[9], sulphur content [10], water content (distillation method with
xylene) as well as identification of organic substances employ-
ing gas chromatography (GC) +detection by flame-ionisation mass
detector (FID/MS).
The results of the determination of the basic qualitative param-
eters of the blended samples of the brown coal tar are given in
Table 2
The results of determination of qualitative parameters of blended sample of tar.
Parameter
Specific gravity (kgm−3) 953.56
Flashpoint in closed cup (◦C) 0.5
Water content – distillation (xylene) (%) 2.86
Sulphur content (%) 0.24
Carbon content (%) 78.83
Hydrogen content (%) 9.90
Nitrogen content (%) 0.51
Table 2. Employing the GC FIT/MS methodology more than 500
species of organic substances was discovered, of which phenols,
toluene, benzene and its derivates and xylene formed the best part.
The blended sample of brown coal tar prepared by the above
procedure was used for ensuing hydrotreatment tests. In terms of
qualitative parameters this sample is an average sample of tar pre-
pared by pyrolysis of brown coal originating from the districts of
the North Bohemian Coal Basin.
3.2. Hydrotreatment tests
The hydrotreatment tests were carried out in hydrotreatment
reactormade by PARR company,model 4520,whichwas controlled
by a control unit (model 4843), as can be seen in Fig. 1. The reac-
tor is provided with pressure vessel of 1000ml volume, to which
a basket with catalyst is installed as well as a stirrer (see Fig. 2).
The maximum operating pressure and temperature of the reactor
are 13MPa and 350 ◦C, respectively, with the option to introduce
Fig. 1. The PARR hydrotreatment reactor, model 4520,
and the control unit.
268 M. Sˇafárˇová et al. / Journal of Analytical and Applied Pyrolysis 89 (2010) 265–270
Fig. 2. Catalyst-accommodating basket, stirrer and catalyst BASF 0852.
hydrogen gas up to the pressure of 4MPa. The design of the reac-
tor is such that it can be purged with inert gas (nitrogen) and it is
also possible to introduce into it liquid organic phase—up to the
maximum operational pressure of 10MPa. The equipment is pro-
vided with water-cooled condensation loop to enable separation of
the liquid phase generated by the hydrotreatment processes in the
reactor. Cobalt–molybdenum hydrotreatment catalyst on alumina
carrier was chosen for testing the hydrotreatment processes—due
to its capability to hydrotreat sulphur compounds present in the
brown coal tar to sulphane as per the following reactions [17]:
RSH + H2 ⇔
The hydrotr
perature of
(correspond
respectively
ment in the
Each hy
pressure in
gas was int
ment, wher
were collec
were separ
[18] for the
raphy (GC)
compositio
Fig. 3. The catalyst and the hydrotreatment products generated at the operating
pressure of 5Mpa.
arated organic phase was deprived of dust impurities employing
filtration through glass wool and the residual water was removed
using water-free sodium sulphate.
The operational conditions were identical for all the executed
hydrotreatment tests and what was only changed was the oper-
ating pressure (5, 6.5 and 8MPa). With all the tests carried out,
the weight of the emerged products was recorded; i.e. water and
organic phases and hydrotreatment residue so that the hydrotreat-
est y
tativ
ssure
vesse
prod
was
. On
ered
weig
r pres
hyd
show
each
tar h
drot
occu
was
Graph 1.
RH + H2SandR2S + 2H2 ⇔ 2RH + H2S
eatment testswere carried out at the basic reactor tem-
300 ◦C and operating pressures of 5, 6.5 and 8MPa
ing to inlet hydrogen pressure of 0.1, 1 and 3MPa,
). Some 150ml of blended tar was used for hydrotreat-
reactor for each test.
drotreatment test was discontinued after the steady
the reactor had lasted 1h and the reaction-generated
roduced via capillary tube to the condensation equip-
e it was cooled down. The condensed liquid products
ted and water and organic phases of these products
ated. During the tests the gaseous phase was sampled
purpose of ensuing analysis employing gas chromatog-
and thermal-conductivity detector (TCD) so that the
n of the emerging gas might be determined. The sep-
ment t
quanti
tor pre
of the
of this
basket
iments
discov
which
reacto
ing the
tar are
For
by the
and hy
nents
phase
Simulated distillation curve of the liquid organic phase generated during hydrotreatmen
ieldsmight be determined. Therewere difficulties about
e transfer of the hydrotreatment residue from the reac-
vessel as, due to its high density, it stuck onto thewalls
l and on the catalyst surface, which caused some losses
uct. That is why the weight of the catalyst-containing
determinedbefore the experiments and after the exper-
the basis of this weight differential the amount was
of the hydrotreatment residue stuck on the catalyst, by
ht the weight of the product taken directly from the
sure vesselwas increased. The products generated dur-
rotreatment tests of the blended samples of brown coal
n in Fig. 3.
test analyseswerecarriedoutof theproductsgenerated
ydrotreatment; i.e. liquid organic phase, reaction water
reatment residue. Identification of individual compo-
rring in the reaction water and in the liquid organic
carried out employing the GC-FID/MS method. At the
t of brown coal tar at different hydrogen operational pressures.
M. Sˇafárˇová et al. / Journal of Analytical and Applied Pyrolysis 89 (2010) 265–270 269
Graph2. Yield sures o
catalyst (Notes
same time,
mined for
method.
4. The resu
For evalu
of brown co
generated a
operating p
determined
the graph t
distillation
The ana
tained some
by weight o
of sulphur a
the tests ca
in the hydr
rising opera
content in t
pressure of
content in t
with its con
Employi
organic spe
during the
their deriva
naphthalen
tar, concent
eral factors
tar hydrotre
of xylene an
parison wit
in the orga
Phenol met
in both the
the tar, the
alkyl deriva
double.
Employi
identified in
nols and the
in particula
com
rotr
show
d8%
the
cha
e di
reatm
8M
l pre
s. Th
f liq
f the
clus
yrol
air-f
– be
tar is
and
e the
oduc
mix
le te
we
s of individual components generatedduringbrowncoal tar hydrotreatment at pres
: OF – liquid organic phase; HZ – hydrotreatment residue).
distillation curve of the liquid orga