INTERNATIONAL YOUTH SCIENCE FORUM “LITTERIS ET ARTIBUS”, 24–26 NOVEMBER 2016, LVIV, UKRAINE
201
Analysis of Coke Gas Properties
at Operation of its Metering Systems
Viktor Dzhyhyrei, Fedir Matiko
Department of Automation of Heat and Chemical Processes,
Lviv Polytechnic National University, UKRAINE, Lviv,
S. Bandery street, 12, E-mail: dv-@ukr.net
Abstract – The generalization and analysis of coke oven gas
composition using the data of literary sources and coke
enterprises are carried out in the paper. The range of pressure
and temperature of coke gas during transportation is defined.
The physical properties of coke gas (density, compressibility
factor, adiabatic index, dynamic viscosity) that are the part of
the equation of gas flowrate by method of variable differential
pressure are in vestigated in the defined range of pressure and
temperature. 25 gas mixtures with different composition were
synthesized in order to make the analysis o f dependency of
physical properties versus pressure, temperature and
composition of the mixtures. According to the results of the
research the recommendations for the development of
simplified methods for calculating the physical p roperties of
coke oven gas are made.
Key words – mixture, coke gas, physical properties, density,
compressibility factor, adiabatic index, dynamic viscosity.
I. Introduction
Coke oven gas is the result of coal carbonization and
contains a lot of combustible components. Since the coke
oven gas is a valuable energy resource and is used in
various manufacturing processes it is necessary to meter
its flowrate. In order to calculate the flow and volume of
coke oven gas it is necessary to know its physical
parameters (density at operating conditions, compressi-
bility factor, adiabatic index, dynamic viscosity).
However, the measuring process the instruments for
measuring the properties of coke oven gas are expensive.
Therefore physical parameters are calculated using the
measured values of temperature, pressure and component
composition of coke oven gas. Complex methods of
calculating the properties of coke oven gas that require full
information about its composition could not always be
realized in algorithms of calculators of flowrate. Hence we
have the problem of the development of simplified methods
for calculating the physical properties of coke oven gas.
II. Analysis of coke oven gas properties
According to the analysis of literary sources such as [1,
2] and based on laboratory data of coke enterprises we
analyzed the composition of coke oven gas. The range of
content of each component of coke oven gas (see. table 1)
was defined based on the results of this analysis.
Methods for calculating the properties of moderately
compressed gas mixture of variable composition [3] are
applied to calculate the physical properties of coke oven
gas (density , compressibility factor z, adiabatic index ,
coefficient of dynamic viscosity ). These substances
such as methane, ethane, propane, normal- and isobutane,
normal- and isopentane, hexane, nitrogen, carbon dioxide,
hydrogen, oxygen, argon, carbon monoxide, ethylene,
helium-4, hydrogen sulfide and ammonia imitate
components coke oven gas in various combinations.
Number of components of the mixture (N) can vary in the
range of 1 N 18. TABLE 1
COMPOSITION OF COKE OVEN GAS
The components
content
Mol%.
Data source
Limits of
components content
JSK «AMK»
JSK «YKKHZ»
PC «Zaporizhstal»
Literary sources
H2
55-62
54.2-
56.7
56.1-
56.8
42-61.2
42-62
CH4
23-26
23.2-
24.5
25.5-
26.9
10-32
10-32
CmHn
2,5-3
6.6-6.8
2-2.4
2.2-2.5
2-6.8
O2
0-1
0.7-1.3
1-1.3
0.1-1
0-1.3
CO
6-8,5
4-6.2
6.2-7.2
5-10
4-10
CO2
2-4
2.3-3.5
2.3-2.5
1.7-5
1.7-5
N2
2-5
3-6.1
4.3-5.2
1-13
1-13
The method has the limited range of the absolute
temperature 200 T 400 K and pressure
0.1 p 1 MPa. The density of the mixture (T, p)
should not exceed half of pseudo critical density pc.
This methodology is based on theoretically grounded
virial equation of state for calculating the density,
compressibility factor and adiabatic index. For the
calculation of dynamic viscosity in the state of rarefied
gas are used the classic expression of molecular-kinetic
theory. To calculate the viscosity at the working pressure
used decomposition on degrees of density, the similar
virial equation.
We formed 25 gas mixtures with different composition
for analyzing coke oven gas properties. The content of
each component must be within the values that presented
in Table 1. The sum of all the individual components of
the mixture equals 100 %. The mixtures are formed so
that to cover the whole range of the molar proportion of
each component.
The values of density, compressibility factor, adiabatic
index and dynamic viscosity coefficient for synthesized
mixtures at standard conditions (РS = 0.101325 МPа,
ТS = 293.15 К) are calculated using the methodology for
calculating of properties of moderately compressed gas
mixture [3]. Minimum, maximum and average values for
each parameter of physical properties of coke gas are
defined. The deviation from the average value is also
calculated by formulas 1 and 2.
δmin = [(ρmin – ρmid) / ρmid] · 100 %; (1)
δmax = [(ρmax – ρmid) / ρmid] · 100 %, (2)
where ρmin, ρmax, ρmid are the minimum, the maximum and
the average value of density of coke oven gas, calculated
according to the methodology [3].
The relative deviation from the average value for
compressibility factor, adiabatic index and dynamic
