ISSN 0361-5219, Solid Fuel Chemistry, 2017, Vol. 51, No. 4, pp. 214–215. © Allerton Press, Inc., 2017.
Original Russian Text © K.O. Krysanova, O.N. Krysanov, A.Yu. Krylova, V.M. Zaitchenko, 2017, published in Khimiya Tverdogo Topliva, 2017, No. 4, pp. 22–23.
Hydrothermal Carbonization of Peat
K. O. Krysanova
*, O. N. Krysanov
**, A. Yu. Krylova
and V. M. Zaitchenko
Joint Institute for High Temperatures, Russian Academy of Sciences (JIHT RAS), Moscow, Russia
OOO Al’ternativnye Tekhnologii, Moscow, Russia
Received January 10, 2017
Abstract—The influence of peat hydrothermal carbonization at 180 and 220°C for 8–10 h on the thermal
characteristics of the resulting biochar was studied. It was found that hydrothermal carbonization reduced the
yield of volatiles to about 50% and increased the calorific value (to 7200 or 7600 kcal/kg for the lower or
higher calorific value, respectively); that is, it afforded biochar whose characteristics approached those of fos-
sil brown coal or black coal in terms of caloricity.
In recent years, attention was focused on the pro-
cessing different forms of biomass. Plant biomass
attracts special attention because it can be considered
as the renewable raw material for a number of energy
generation and chemical processes. The production of
biochar is a line of its processing. Biochar is a product
synthesized artificially by the thermal processing of
biomass, primarily, different wastes (plant residues or
human and animal waste products). Although this
term seems doubtful from the point of view of etymol-
ogy because coal itself is of biological origin, the name
biocoal or biochar has been widely used in the litera-
A hydrothermal carbonization (HTC) or cold car-
bonization process is a currently available method for
the production of biochar from biomass; this process
takes place at ~200°C and a saturated vapor pressure at
this temperature in the presence of water and in the
absence of air . The HTC technology has an
important advantage: the process is exothermic. The
heat released can be used for drying the coal obtained
or for electric energy generation. The distribution of
HTC products depends on the type of utilized raw
materials and the reaction conditions (temperature,
residence time, ash content, etc.) .
We studied the influence of hydrothermal carbon-
ization on the high-moor peat of the Borovskoe
deposit in Novgorod oblast.
An SDTQ600 thermal analyzer, which makes it
possible to carry out synchronous thermal analysis,
including thermogravimetric and differential thermo-
gravimetric analyses and differential scanning calo-
rimetry, was used for determining the moisture, ash,
and volatile contents.
The calorific value of the materials was determined
based on the elemental analysis, which was carried out
on a Vario MICRO Cube elemental analyzer intended
for the simultaneous determination of the elements C,
H, N, and S in the samples.
The hydrothermal carbonization of peat was per-
formed in a steel batch apparatus at 180 and 200°C for
The table gives the thermophysical characteristics
of the high-moor peat and the biochar obtained by the
hydrothermal carbonization of this material.
The initial high-moor peat was characterized a
34% moisture content and a relatively low ash content
(9.3%). The elemental composition of the peat was the
following (wt %): nitrogen, 1.42; carbon, 52.09;
hydrogen, 5.72; sulfur, 0.15; and oxygen, 31.
The hydrothermal carbonization process led to the
production of biochar, which differed from the source
material in the moisture content lower by an order of
magnitude (3.5%); this can be explained by the hydro-
phobic ability of the material obtained. Furthermore,
because of the dissolution of a portion of the initial
mineral compounds in hot water, the ash content of
the biochar (3.9%) was smaller than that of the initial
peat by a factor of almost 3.
The yield of volatile substances is an important
thermophysical characteristic of solid fuel. This char-
acteristic determines not only the area of application