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Separation of coal gasification tar residue by solvent extracting
Accepted Manuscript Separation of coal gasification tar residue by solvent extracting Yan-xia Niu, Xiong-lei Wang, Jun Shen, Qing-tao Sheng, Gang Liu, Chang Li, Yu-gao Wang PII: DOI: Reference:
S1383-5866(17)30715-3 http://dx.doi.org/10.1016/j.seppur.2017.07.002 SEPPUR 13859
To appear in:
Separation and Purification Technology
Received Date: Revised Date: Accepted Date:
25 March 2017 30 June 2017 1 July 2017
Please cite this article as: Y-x. Niu, X-l. Wang, J. Shen, Q-t. Sheng, G. Liu, C. Li, Y-g. Wang, Separation of coal gasification tar residue by solvent extracting, Separation and Purification Technology (2017), doi: http://dx.doi.org/ 10.1016/j.seppur.2017.07.002
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Separation of coal gasification tar residue by solvent extracting Yan-xia Niu* *, Xiong-lei Wang, Jun Shen*, Qing-tao Sheng, Gang Liu, Chang Li,Yu-gao Wang College of Chemistry and Chemical Engineering, Taiyuan University of Technology, Shanxi 030024, China
Abstract: Coal gasification tar residue (CGTR) is a kind of industrial solid waste produced in the coal utilization process. It demands being correctly disposed due to the toxicity with some carcinogenic aromatic compounds. High heat value of CGTR indicates that it can be a useful energy resource. In this work, 22 solvents with different properties were used to extract CGTR and the Hansen solubility parameter theory was applied to relate with the experimental results. The basic thermo-physical properties of the extracting solvents were analyzed based on the physical property estimation from Aspen plus software. It was supposed that the solvent systems like toluene, n-butyl acetate and n-butyl acetate + dimethyl carbonate could be promising extracting solvents for the effective separation of CGTR in practice. Keywords: Coal gasification tar residue; Hansen solubility parameter; Extraction; Physical property estimation; Aspen plus
1 Introduction In china, though the percentage in total energy consumption decreases gradually, coal is the most abundant energy source and will still keep an irreplaceable position before 2050. Some data
[1-2]
have shown that coal can produce 0.05 %～0.07 % coal
tar residue (CTR) in general, and 0.19 %～0.21 % CTR when the technology of smokeless loading coal with high-pressure ammonia water are used during the coking process. Also, there are 3 %～4 % CTR produced from the semi-coke process
[3]
.
According to national bureau of statistics of China, the total output of coal reached to 3.87 billion tons in 2014, occupying 66.0 % in all energy consumption. This indicated that a large number of CTR had been generated during the process of coal utilization. Especially many new coal conversion technologies, such as coal-to-methane, coal-to-gasoline, coal-to-methanol, coal-to-olefin, etc, were developed rapidly. In these technologies, coal gasification was usually the first step. Coal gasification tar *
Corresponding author:Yan-xia Niu(Y. X. Niu), [email protected];Jun Shen(J. Shen), [email protected]. 1
residue (CGTR) is a solid by-product originated from coal gasification processes, especially in fix-bed coal gasification. As is reported in our previous researches [4-6], the CGTR consisted of high-boiling organic compounds, the unconverted pulverized coal and other solid particles entrained in the coal pyrolysis gases. Apart from toxic character which had been proven by our work, CGTR owns a high caloric value, over 8000 kcal/kg, with high fixed carbons and organic compositions [5]. Therefore, CGTR was also a potent energy resource if being treated reasonably before using. Based on our previous results, the promising treatment way of CGTR was to separate CGTR into residue and tar using an appropriate solvent, and then utilize them further economically and environmentally benign. Hansen solubility parameter was a useful tool in explaining solvents extracting solute from complex system. Abolfazl
[7]
studied the extraction of soy proteins using
Hansen solubility parameter theory. Mohamad
[8]
carried out the study on extracting
resveratrol from cell culture based on this tool. Consequently, the theory can be used for predicting and finding a proper solvent for the extraction process. Aspen plus[9] was a popular software having been used widely in chemical industry to model a stable chemical process, where some basic properties parameters were provided in order to carry out property estimation. As a consequence, this paper aims at separating CGTR by several solvents using extraction way and the tools of Hansen solubility parameter and Aspen plus were also applied to explain the extraction performances and predict the properities of extraction systems. 2. Materials and methods 2.1. Materials Coal gasification tar residues (CGTR) were obtained from a Lurgi gasifier in coal-to-methane process in Inner Mongolia, China and some basic data were shown in Table 1. 22 solvents, cyclohexane, n-heptane, petroleum ether, n-hexane, ethanol, isopropanol, n-butyl alcohol,
acetonitrile, methylene
dimethyl
formamide,
dichloride,
pyridine,
methanol,
ethyl acetate,
methyl acetate,
acetone,
dioxane, furfural, tetrahydrofuran, butyl acetate, dimethyl carbonate, toluene and 2
benzene, AR grade, with a purity high than 99.9% were purchased from Tianjin Kermel Chemical Reagent Company, and used directly without further purification. 2.2. Experiment method Extraction experiment of CGTR was performed by using soxhlet apparatus. 3-10g CGTR sample was loaded in a cylinder made of filter paper and 150mL extraction solvent was put into the flask. The extraction was stopped as the reflux solvent was near to itself color, and the extraction ratio was calculated after the residual sample and cylindrical filter paper are dried to constant weight at room temperature. The calculation equation of extraction ratio (Y) was given as follows: Y=
m1 ×100 − M ad m
Where m is the initial mass of CGTR (g), and m1 is the lost mass of sample (g), Mad is the mass percent of water in CGTR (%), shown in Table 1. 3 Results and discussion 3.1 Soxhlet extraction result analysis In the same condition, different solvents had different selectivity and extraction effects for CGTR in general. The extraction experiment results were shown in Fig. 1. About 22 solvents were used in this experiment, including alkanes, alcohol, esters, ethers, benzene, amide, acetone, furfural and other heteroatom compounds like acetonitrile, methylene dichloride, pyridine, etc. According to reference
[10]
, organic
solvents could be divided into four types, namely N type, A type, B type and AB type, based on whether containing X-H bond with electron receiver or B atom with electron donor, where A and B were respectively the atoms with bigger electronegativity and smaller radius, such as O, N, F et al. For N type solvent, called as inert solvent, it had neither X-H bond nor B atom in molecular structure and could not form hydrogen bond with other molecular. A type solvent had only X-H bond and could form hydrogen bond with B type solvent which was the solvent with electron donor capacity. AB type represented the solvent having the ability of electron receiver and donor simultaneously. Therefore, these selected 22 solvents were classified and shown 3
in Table 2, in which some other basic information were also included [11]. It was clear from Fig.1 that the extraction ratio increased as the solvent order ranked from up to down. The solvent order in Table 2 was the same as that in Fig.1. The solvent with superior extraction ratio was only related to its type rather than other properties like dipole emoment and permittivity. In other words, the solvents assigned as B type and N type with benzene ring structure were inclined to higher extraction ratio for CGTR within the investigated solvents, guiding us a proper direction to select extraction solvent. Except from the extraction ratio, the extraction rate was also a critical factor to the extraction effect. In order to better illustrate it, the related data from Fig.1 were given in Table 3, where a similar conclusion could be deduced, namely, the solvent with B type and aromatic structure have more quick extraction rate than AB type and N type without aromatic structure. This could be attributed to intermolecular hydrogen bond in AB type solvent, which was stronger interaction than that between solvent molecule and extracted molecule and was not destroyed easily during the extraction process. On the basis of our previous researches [4,5], there were almost the same extracted components using ethyl acetate and toluene, which were the representative of B type and N type solvent, respectively. The results were shown in Table 4. It was seen that the extracted substances were mainly polycyclic aromatic hydrocarbons (PAHs), only little amount of heterocyclic aromatic compounds ， such as dibenzofuran, 3-methyl-phenol and 4,6-dichloropyrimidine, et al. These PAHs were all N type organics. Therefore, the good extraction ability of benzene and toluene resulted from the same structure type as the extracted PAHs, and the extraction result could be explained by the similarity-intermiscibility theory. In contrast, the ethyl acetate appeared also a good extraction ability, meaning that CGTR could be well dealt with B type solvent. For the reason of which having high extraction capacity could be caused by the stronger van der waals forces between extraction solvent and extracted molecule than that between the solvent molecules. 4
3.2 Solubility analysis As aforementioned results, the solvents with B type and N type containing aromatic ring structure had better extraction ability than that of AB type for CGTR. To explore further the reason of some solvent possessing good extraction ability, the solubility theories were used in this section. Hansen solubility parameters, including intermolecular dispersion forces (δd), intermolecular polar interactions (δp) and intermolecular hydrogen boding (δh), were indeed an expanded theory for Hildebrand solubility parameter (δ) which was based on the square root of cohesive energy density of the substance. A solvent having the same or very close value of δ with a solute would possess the great ability of dissolving solute [8]. Solubility parameter distance (R) was another meaningful parameter to evaluate the strength of a solute dissolved by a specific solvent. And the smaller the R value was, the higher the dissolving capability of solvent. As far as the relation among these parameters, the corresponding equations were depicted as follows: 2
2
δ = δ d + δ p + δh
2
(1)
R 2 = 4(δ d 2 − δ d1 ) 2 + (δ p 2 − δ p1 ) 2 + (δ h2 − δ h1 ) 2
(2)
In addition, partition coefficient was also critical to estimate the ability of a solvent dissolving another solute, and its value could be calculated using the following formula. VmD V S1 [(δ S1 − δ D )2 − (δ S 2 − δ D )2 ] + ln mS 2 RT Vm
ln k S 2 S1 =
(3)
Where ln kS 2 S1 is partition coefficient; Vm , T, R represent the molar volume, Kelvin temperature and gas constant, respectively. And S1, S2 and D denote solvent one, solvent two, and the extracted solute, respectively. All these mentioned parameters above were obtained from the published handbook
[12]
, other than some lacking data like petroleum ether, fluoranthene,
phenanthrene (seen in Table 4) etc. The relevant calculation results were shown in Table 5 and Table 6. 5
As is illustrated in Table 5, the two δ values, 20.2 and 20.1, of naphthalene and 9H-fluorene were almost equal and very close to that of 1-methyl-naphthalene being 21.1, indicating that the three PAHs from CGTR sample were difficult to be separated. Based on the mentioned knowledge, if the solvent had the same or very close δ value to the dissolved solute as well as small R value, it could emerge better dissolving behavior to the special solute. In Table 5, those solvents, like acetone, methylene dichloride, 1,4-dioxane, pyridine, tetrahydrofuran, had very good performance to dissolve the three solutes, such as naphthalene, 9H-fluorene, 1-methyl-naphthalene, owing to their similar δ value. This was consistent with the result of Fig.1. However, those solvents with the δ value being around 18.5, such as benzene, dimethyl carbonate, and toluene had superior dissolving capability, resulting potentially from the smaller R values for the three solutes. By contrast, even thought ethyl acetate and methyl acetate had near δ value with benzene, their dissolving behaviors were inferior to benzene, which was maybe attributed to their larger R value. These results implied us the solubility parameter distance R being more important factor than Hildebrand solubility parameter δ, and proved indeed the solubility theory being rather useful tool to estimate the extraction process of a solvent to a special solute, which could substitute for the time-consuming and expensive experiment. Table 6 offered the information of partition coefficients of naphthalene, 9H-fluorene and 1-methyl-naphthalene, which were the extracted substances in the CGTR sample, extracted by benzene or other different solvents. These calculated data originating from the equation (3), where the S1 was benzene and S2 was other solvent. Undoubtedly, D was the extracted solute, namely, naphthalene, 9H-fluorene and 1-methyl-naphthalene here. According to literature
[9]
, positive values of partition
coefficient meant that the concentration of the extracted solute in other solvent was higher than in benzene; inversely, negative values indicated higher concentration in benzene. And the higher the negative value, the higher the concentration of the extracted solute in benzene compared to other solvents. As described in Table 6, many values of lnk were near to zero, meaning these corresponding solvents like dimethyl carbonate, ethyl acetate, methyl acetate, pyridine, had similar dissolving 6
capability compared with benzene. Nevertheless, those solvents like ethanol, n-heptane, n-hexane and methanol displayed larger differences in the performance of dissolving the same solute, attributing to their higher negative values in contrast to benzene. These results were in complete agreement with that in Fig.1. All these deduced results from the theoretical calculation of solubility parameters were coincident with the experimental results, which revealed the solubility theory was a promising guidance tool to predict the dissolving behaviour of a proper solvent extracting a processable solute.
3.3 Solvent properties analysis The properties of solvent are necessary factors to be considered when used as extracting solvent. Therefore, the density, viscosity and vapor pressure of some solvents with superior dissolving performance were discussed at the temperature range from 25 °C to 100 °C in this section. Their corresponding data were obtained from Aspen plus software as well as the published literatures [11,13-22]. Since there was water in CGTR sample, water was also considered here. All these results were shown in Fig.2 ~ Fig.4, where the lines denoted the data from Aspen plus with the calculation model of UNIQUAC method and the scatters represented the data from these literatures. From these figures, it could be found clearly that the data from software could overlap greatly with those from literatures, which means that Aspen plus was a very useful tool to obtain some basic information for the pure material, saving much time to search the fundamental data from the related literatures. Furthermore, it was also displayed from Fig.2 that the density of Furfural was the highest in these studied solvents; dimethyl carbonate is in the second, while other solvents were less than water. Fig.3 showed the relationship between solvents’ viscosity and temperature. The viscosity of furfural kept still the highest, while others were lower than water. Generally, the lower the viscosity of material was, the quicker its mass transfer was. As for the extracting system, the lower viscosity meant the larger dissolving rate. Fig.4 plotted the variation of solvents’ vapor pressure with temperature. All curves of vapor pressure of solvents studied grew with the increase of temperature at 7
different extent. Specifically, the curve of methyl acetate varied at the fastest way, presenting methyl acetate was very sensitive to temperature, even if smaller change in temperature brought large change to vapor pressure. Therefore, methyl acetate was not a suitable solvent to extract CGTR because of its high volatility, which would bring a large number of mass losses. Within 80 °C, ethyl acetate and benzene possessed similar vapor pressures and both of them were over dimethyl carbonate’s. Butyl acetate and furfural had lower vapor pressure than toluene in the studied temperature range, indicating more safety when they being used in the extracting process. Apart from these elementary solvent characters, their boiling points or azeotropic points of several solvents mixture are also necessary to design a processable extraction technology. Thereby, it was analyzed and the involved information was given in Table 7 and Table 8. Similarly, these data were obtained from Aspen Plus software and the literature [11]. In Table 7, the data from software was in line with that from the literatures, meaning the information from Aspen plus was reasonable. The azeotropic points of the mixture systems were also calculated by Aspen plus and shown in Table 8. Results showed these systems forming azeotrope with water, indicating that the water contained in CGTR sample could be taken out together during the extracting process. Moreover, the calculation results of binary system were also well in accordance with the literature [11] only other than the system of n-Butyl acetate + H2O. As for the two ternary systems, their azeotropic points were under 100 °C, which seemed to be good nature for reducing energy expenditure during running process. However, the ternary system with furfural contained over 50 percent water (mass basis), which could give rise to inferior extracting effect. Likewise, the binary system of furfural with H2O was also inadvisable for its high amount of H2O. In addition, those binary systems like methyl acetate, benzene, and ethyl acetate could not be good candidates, because their azeotropic points were low, which would bring about the solvent loss during extracting process. Consequently, the solvent systems such as toluene, n-butyl acetate, and n-butyl acetate + dimethyl carbonate would be suitable extracting system for CGTR. Furthermore, these three systems were all 8
immiscible with H2O, indicating they could be recycled easily. 4 Conclusions Coal gasification tar residue (CGTR) was investigated using extracting method. Combining the extraction experiment with the theory analysis, it was proposed that Hansen solubility parameters was a very useful theory to predict and explain the extraction process and Aspen plus was also a convenient tool to search some fundamental thermo-physical data, not only the density, viscosity, vapor pressure for pure substance but also the zeotropic points for mixture system. Based on these researches, the solvents with B type and N type with aromatic ring structure displayed superior extracting performance for CGTR. These experimental results were in agreement with the analysis of solubility parameters. Finally, it was supposed that the solvent systems like toluene, n-butyl acetate, and n-butyl acetate + dimethyl carbonate could be promising extracting solvents for the separation of CGTR. Acknowledgements This work is supported by National Natural Science Foundation of China (Grant No. 21606161), NSFC-Shanxi joint fund of coal-based low carbon (Grant No. U1610223), and Shanxi Scientific and Technological Plan, China (Grant No. 20150313014-4). References [1] Xie Quanan,Xue Liping. Safety and environmental protection on coal chemical engineering, Chemical Industry Press, Beijing, China. 1st, edn, 2005. [2]Xie Quanan, Wang jieping, Fen Xinglei, Li Liansun. Disposal and utilization progress of coking production wastes. Chemical Industry and Engineering
Progress 1 (2011) 424-427. [3] Cheng Xuan. The experimental research of formed coke preparation using low rank pulverized coal and tar slag. Xi'an University of Architecture and Technology, 2013. [4] Wang, Xionglei, Niu, Yanxia, Liu, Gang, Shen, Jun. Research progress of coal tar residue treatment technology. Chemical industry and engineering progress 34 (2015) 2016-2022. 9
[5] Xiong-lei Wang, Jun Shen, Yan-xia Niu, et al. Solvent extracting coal gasification tar residue and the extracts characterization. Journal of Cleaner Production 133 (2016) 965-970. [6] Jun Shen, Xiong-lei Wang, Yan-xia Niu et al. Combustion properties and toxicity analysis of coal gasification tar residue. Journal of Cleaner Production 139 (2016) 567-575. [7] Abolfazl Aghanouri, Gang Sun. Hansen solubility parameters as a useful tool in searching for solvents for soy proteins. RSC Advances 5 (2015) 1890-1892. [8] Mohamad Houssam Al balkhi, Mohammad Amin Mohammad, Léo-Paul Tisserant, Michèle Boitel-Conti. Development of a liquid-liquid extraction method of resveratrol from cell culture media using solubility parameters. Separation and
Purification Technology 2016 (170) 138-145. [9] Lan-yi Song. Chemical Engineering Process Simulation using Aspen Plus. Chemical Industry Press, 1st, edn, 2015. [10]Xu Guangxian, Wang Wenqing, Wu Jinguang et al. Extraction chemistry Principle , Shanghai scientific and technical publishers, Shanghai, China, 1 st, edn, 1984. [11] Chen, Nenglin. Solvents Handbook, Chemical Industry Press, Beijing, China, 4 nd, edn, 2007. [12] C. Hansen, Hansen Solubility Parameters: A User's Handbook, CRC Press, Boca Raton, Fla, 2nd, edn, 2007. [13] F. J. Vieira dos Santos, C. A. Nieto de Castro. Viscosity of toluene and benzene under high pressure. International Journal of Thermophysics 18 (1997) 369-377. [14] Laura Lomba, Beatriz Giner, Isabel Bandrés, et al. Physicochemical properties of green solvents derived from biomass. Green Chemistry 13 (2011) 2062-2070. [15] Jiang Zhiqing. Physical chemistry experiment instruction. Xiamen university press, Xiamen,China, 1st, edn, 2014. [16] Xia Yuyu, Chemical Experiment Handbook. Chemical Industry Press, Beijing, China, 2nd, edn, 2008. [17] Mehrdad Moosavi, Ahmad Motahari, Amir Vahid, et al. Densities, Viscosities, 10
and Refractive Indices of Dimethyl Carbonate + 1-Hexanol/1-Octanol Binary Mixtures at Different Temperatures[J]. Journal of Chemical Engineering Data 61 (2016) 1981-1991. [18] Jiang Biyuan, Zhang Jianhou. Determination and correlation of vapor pressures of Dimethyl carbonate and 2,3-Dichloropropene. Journal of Tianjin university 3(1987) 54-62. [19] M. V. Rathnam, Reema T. Sayed, Kavita R. Bhanushali, M. S. S. Kumar. Density and viscosity of binary mixtures of n-butyl acetate with ketones at (298.15, 303.15, 308.15, and 313.15) K. Journal of Chemical Engineering Data 57 (2012) 1721-1727. [20] K. SARAVANAKUMAR, R. BASKARAN, AND T. R. KUBENDRAN, Densities, Viscosities, Refractive Indices and Sound Speeds of Acetophenone with Methylacetate at Different Temperatures. CODEN ECJHAO E-Journal of
Chemistry 9 (2012) 1711-1720. [21] Li Xi, Hu ShanZhou. Physical Chemistry Experiment. Wuhan University of Technology Press, Wuhan, China, 2010. [22] Naushad Anwar, Riyazuddeen, Shama Yasmeen. Volumetric, compressibility and
viscosity
studies
of
binary
mixtures
of
[EMIM][NTf2]
with
ethylacetate/methanol at (298.15–323.15) K. Journal of Molecular Liquids 224 (2016) 189-200.
11
0
5
10
E x tra tio n tim e /h 20 25
15
30
C yc lohe xa ne n-H epta ne P etroleum ethe r n-H e xa ne E thano l Is op ro pano l A c e tonitrile D im eth ylform a m ide M ethano l E th yl ac etate n-B u tyl alc oho l M ethy le ne dic h loride P y ridine M eth yl ac e tate A c etone 1,4-D io x ane F urfu ra l T etrah ydrofuran B utyl ac etate D im eth yl c arbon ate T o lu ene B en z ene
35
40
E x tration tim e E x tration ra tio
0
5
10
15
20 25 E x tration ratio/%
30
Fig.1 Extraction results of GCTR by different solvents
12
35
40
115 0 110 0
D en s ity/k g · m
-3
105 0 100 0 95 0 90 0 85 0 80 0 0
20
40
60
80
100
o
T e m pe ra ture / C
Fig.2 Densities of the selected solvents at the temperature range from 0°C to 100°C Line: the deduced data by Aspen Plus software, Scatter: the published literature data.▼ Furfural, ★ Dimethyl Carbonate, ●H2O, △ Methyl acetate, ○ Ethyl acetate, □ Butyl acetate, ■Benzene, ▲ Toluene.
13
2 .4
V is c os ity /m p a · s
2 .0
1 .6
1 .2
0 .8
0 .4
0 .0 0
20
40
60
80
100
o
T e m pe ra ture / C
Fig.3 Viscosities of the selected solvents at the temperature range from 0°C to 100°C Line: the deduced data by Aspen Plus software, Scatter: the published literature data.▼ Furfural, ●H 2O, □ Butyl acetate, ■Benzene, ★ Dimethyl Carbonate, ▲ Toluene, ○ Ethyl acetate, △ Methyl acetate
14
40 0 35 0
V ap o r P res s u re /k p a
30 0 25 0 20 0 15 0 10 0 50 0 0
20
40
60
80
100
o
T e m pe ra ture / C
Fig.4 Vapor Pressures of the selected solvents at the temperature range from 0°C to 100°C Line: the deduced data by Aspen Plus software, Scatter: the published literature data. △ Methyl acetate, ○ Ethyl acetate, ■Benzene, ★ Dimethyl Carbonate, ●H2O, ▲ Toluene, □ Butyl acetate, ▼ Furfural.
15
Tables
Table 1 Properties of coal gasification tar residues (CGTR) Heat value(cal·g-1)
Ultimate analysis (wt %) Mad
Aad
Vad
FCad
Sad
TId
QId
Qgr.daf
16.30
4.30
36.86
42.54
0.31
48.12
52.09
8927
16
Table 2 Solvent type and some basic data
Solvent
Structure
Boiling point
Permittivity
(°C)
Dipole emoment
Type
-30
(10 C· m)
Cyclohexane
80.70
2.052
-
N
n-Heptane
98.50
1.924
0.0
N
30-60
-
-
N
68.95
1.890
0.27
N
78.30
25.7
5.60
AB
Petroleum ether
-
n-Hexane Ethanol
HO
Isopropanol
OH
82.45
18.3
5.6
AB
Acetonitrile
N
81.60
37.5
11.47
B
N
153.00
36.71
12.88
AB
OH
64.70
31.2
5.55
AB
77.20
6.02
6.27
B
117.25
17.1
5.6
AB
40.00
9.1
3.8
A
115.30
12.3
7.44
B
58.00
6.68
5.37
B
56.00
1.0235
8.97
B
101.30
2.209
1.5
B
161.80
38
12.1
B
66.00
7.58
5.70
B
126.00
5.01
6.14
B
90.00
2.6
-
B
Toluene
110.60
2.24
1.23
N
Benzene
80.00
2.283
0
N
Dimethyl formamide
O
Methanol
O
Ethyl acetate n-Butyl alcohol Methylene dichloride
O
HO
Cl
N
Pyridine
O
Methyl acetate
O
O
Acetone
O
1,4-Dioxane
Furfural
O
O
O
O
Tetrahydrofuran
Butyl acetate
Dimethyl carbonate
Cl
O
O
O O
O
17
Table 3 Extraction rate and solvent type Solvent
AER*
Type
Solvent
AER*
Type
n-Heptane
1.34
N
Ethanol
5.51
AB
Methanol
2.48
AB
Tetrahydrofuran
6.11
B
Isopropanol
2.76
AB
Acetone
6.87
B
1-Butanol
3.01
AB
Ethyl acetate
7.69
B
n-Hexane
3.12
N
Furfural
8.31
B
Cyclohexane
3.19
N
Methyl acetate
8.55
B
Petroleum ether
3.3
N
Butyl acetate
8.8
B
Dimethyl formamide
3.74
AB
Benzene
9.1
N
1,4-Dioxane
4.17
B
Dimethyl carbonate
9.22
B
Toluene
4.37
N
Methylene dichloride
12.3
A
Pyridine
5.49
B
Acetonitrile
15.44
B
*AER represents Average extraction rate(%/h) and its value is obtained by extraction ratio divided by extraction time from Fig.1.
18
Table 4 Extraction results using Toluene and Ethyl Acetate from GCTR (chemical composition analysis) Relative content Extracted compound
(%)
Structure
Type
Toluene
Ethyl Acetate
Naphthalene
25.45
30.92
N
Fluoranthene
10.50
13.01
N
Phenanthrene
9.75
10.64
N
Pyrene
8.20
9.63
N
9H-Fluorene
6.66
8.32
N
Acenaphthene
5.61
7.09
N
1-Methyl-naphthalene
4.22
5.16
N
Indane
4.20
4.46
N
Dibenzofuran
2.46
2.47
B
2-Methyl-naphthalene
2.01
2.36
N
Anthracene
2.17
2.32
N
O
4,6-dichloropyrimidine
N
N
Cl
3.32
Cl
3-Methyl-phenol
3.61 HO
--
AB
--
15.46
19
AB
Table 5 Solubility parameter and solubility distance for the investigated system δd
δp
δh
δ
Vm
(MPa0.5)
(MPa0.5)
(MPa0.5)
(MPa0.5 )
(cm3/mol)
15.5
10.4
7.0
19.9
Acetonitrile
15.3
18.0
6.1
Benzene
18.4
0.0
2.0
1-Butanol
16.0
5.7
15.8
Substance Acetone
R1a
R2 b
R3c
74.0
11.2
13.6
14.2
24.4
52.6
17.8
19.3
20.3
18.5
89.4
4.7
3.6
5.2
23.2
91.5
12.4
16.7
15.2
n-Butyl Acetate
15.8
3.7
6.3
17.4
132.5
7.0
9.8
10.2
Cyclohexane
16.8
0.0
0.2
16.8
108.7
7.7
6.8
8.9
Methylene dichloride
18.2
6.3
6.1
20.2
63.9
4.8
7.3
7.4
Dimethyl carbonate
15.5
3.9
9.7
18.7
84.2
8.6
12.2
11.8
Dimethyl formamide
17.4
13.7
11.3
24.9
77.0
13.4
16.2
15.8
1,4-Dioxane
19.0
1.8
7.4
20.5
85.7
1.6
6.0
4.3
Ethanol
15.8
8.8
19.4
26.5
58.5
16.6
20.8
19.3
Ethyl acetate
15.8
5.3
7.2
18.2
98.5
7.7
10.7
10.9
Furfural
18.6
14.9
5.1
24.4
83.2
13.0
13.9
14.7
n-Heptane
15.3
0.0
0.0
15.3
147.4
10.0
9.7
11.6
n-Hexane
14.9
0.0
0.0
14.9
131.6
10.6
10.5
12.4
2-Propanol
15.8
6.1
16.4
23.6
76.8
13.2
17.5
16.0
Methanol
15.1
12.3
22.3
29.6
40.7
21.0
25.2
23.7
Methyl acetate
15.5
7.2
7.6
18.7
79.7
9.2
12.1
12.4
19.0
8.8
5.9
21.8
80.9
6.8
8.5
8.7
Pyridine Petroleum ether
d
-
-
-
-
-
-
-
-
Tetrahydrofuran
16.8
5.7
8.0
19.5
81.7
6.4
9.8
9.6
Toluene
18.0
1.4
2.0
18.2
106.8
4.6
4.0
5.9
Naphthalene
19.2
2.0
5.9
20.2
111.5
9H-Fluorene
20.0
1.7
1.7
20.1
138.2
1-Methyl-naphthalene
20.6
0.8
4.7
21.1
138.8
Notes：Naphthalene, 9H-Fluorene and 1-Methyl-naphthalene are the solutes which are extracted from GCTR while others are solvents. a
R1 indicates the R value between the substance and Naphtanlene.
b
R2 indicates the R value between the substance and 9H-Fluorene.
c
R3 indicates the R value between the substance and 1-Methyl-naphthalene.
d
Parameter δ values of petroleum ether cannot be found.
20
Table 6 Partition coefficient of Naphthalene, 9H-Fluorene, 1-Methyl-naphthalene, from benzene to other different solvents Solvent
Ln k (Naphthalene)
Ln k (9H-Fluorene)
Ln k (1-Methyl-naphthalene)
Acetone
0.31
0.33
0.11
Acetonitrile
-0.13
-0.36
-0.76
Benzene
0.00
0.00
0.00
1-Butanol
-0.30
-0.42
0.16
n-Butyl Acetate
-0.61
-0.65
0.01
Cyclohexane
-0.58
-0.66
-0.46
Methylene Dichloride
0.47
0.48
-0.00
Dimethyl Carbonate
0.09
0.09
-0.00
Dimethyl Formamide
-0.70
-0.97
-0.56
1,4-Dioxane
0.17
0.18
0.31
Ethanol
-1.24
-1.73
-1.70
Ethyl Acetate
-0.16
-0.16
-0.01
Furfural
-0.58
-0.80
-0.29
n-Heptane
-1.45
-1.64
-1.00
n-Hexane
-1.52
-1.75
-1.39
2-Propanol
-0.23
-0.38
-0.12
Methanol
-3.06
-4.11
-4.46
Methyl Acetate
0.14
0.15
-0.06
Pyridine
0.12
0.09
0.25
Petroleum ether
-
-
-
Tetrahydrofuran
0.20
0.21
0.14
Toluene
-0.23
-0.24
0.07
21
Table 7 Boiling points of the different pure solvents at 101.325 KPa Component
Temperature*/°C
Temperature#/°C
Water
100.02
100
Benzene
80.13
80.00
Toluene
110.68
110.60
Methyl Acetate
57.05
58.00
Ethyl Acetate
77.20
77.20
n- Butyl Acetate
126.01
126.00
Dimethyl Carbonate
90.22
90.00
Furfural
161.35
161.80
Note： * data from Aspen Plus, while # from literature[11]
22
Table 8 Boiling points and composition of several azeotropes No. 1
2
3
4
5
6
7
8
Homogeneous
Mole* Basis
Mass* Basis
Temperature*/°C
Mass# Basis
56.64
0.0350
H2O
0.0898
0.0234
Methyl Acetate
0.9102
0.9766
H2O
0.2990
0.0896
Benzene
0.7010
0.9104
H2O
0.3659
0.1055
Ethyl Acetate
0.6341
0.8945
H2O
0.5596
0.1990
Toluene
0.4404
0.8010
H2O
0.8622
0.5398
Furfural
0.1378
0.4602
H2O
0.7326
0.2982
n- Butyl acetate
0.2674
0.7018
H2O
0.4396
0.1327
n- Butyl acetate
0.0484
0.0943
Dimethyl Carbonate
0.512
0.773
H2O
0.8516
0.5208
Furfural
0.1242
0.4052
Dimethyl Carbonate
0.0242
0.074
0.965 69.35
70.19
84.53
96.23
84.64
92.05
96.25
#
Note： *data from Aspen Plus, while from literature [11]
23
0.0883 0.9117 0.0847 0.9153 0.1350 0.8650 0.6500 0.3500 0.2870 0.7130
Temperature#/°C 56.5
69.25
70.38
84.1
97.9
90.2
Highlights： ： 1）Coal gasification tar residue (CGTR), an industrial solid waste from coal utilization process, was researched using solvent extracting way. 2）Hansen solubility parameter theory was used to explained and relate with the extracting experimental results. 3）Aspen plus software was applied to estimate the properties of solvents as extracting agents. 4）The possible extraction systems were predicted to be put them into practice based on the above concluded knowledges.
24
S1383-5866(17)30715-3 http://dx.doi.org/10.1016/j.seppur.2017.07.002 SEPPUR 13859
To appear in:
Separation and Purification Technology
Received Date: Revised Date: Accepted Date:
25 March 2017 30 June 2017 1 July 2017
Please cite this article as: Y-x. Niu, X-l. Wang, J. Shen, Q-t. Sheng, G. Liu, C. Li, Y-g. Wang, Separation of coal gasification tar residue by solvent extracting, Separation and Purification Technology (2017), doi: http://dx.doi.org/ 10.1016/j.seppur.2017.07.002
This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Separation of coal gasification tar residue by solvent extracting Yan-xia Niu* *, Xiong-lei Wang, Jun Shen*, Qing-tao Sheng, Gang Liu, Chang Li,Yu-gao Wang College of Chemistry and Chemical Engineering, Taiyuan University of Technology, Shanxi 030024, China
Abstract: Coal gasification tar residue (CGTR) is a kind of industrial solid waste produced in the coal utilization process. It demands being correctly disposed due to the toxicity with some carcinogenic aromatic compounds. High heat value of CGTR indicates that it can be a useful energy resource. In this work, 22 solvents with different properties were used to extract CGTR and the Hansen solubility parameter theory was applied to relate with the experimental results. The basic thermo-physical properties of the extracting solvents were analyzed based on the physical property estimation from Aspen plus software. It was supposed that the solvent systems like toluene, n-butyl acetate and n-butyl acetate + dimethyl carbonate could be promising extracting solvents for the effective separation of CGTR in practice. Keywords: Coal gasification tar residue; Hansen solubility parameter; Extraction; Physical property estimation; Aspen plus
1 Introduction In china, though the percentage in total energy consumption decreases gradually, coal is the most abundant energy source and will still keep an irreplaceable position before 2050. Some data
[1-2]
have shown that coal can produce 0.05 %～0.07 % coal
tar residue (CTR) in general, and 0.19 %～0.21 % CTR when the technology of smokeless loading coal with high-pressure ammonia water are used during the coking process. Also, there are 3 %～4 % CTR produced from the semi-coke process
[3]
.
According to national bureau of statistics of China, the total output of coal reached to 3.87 billion tons in 2014, occupying 66.0 % in all energy consumption. This indicated that a large number of CTR had been generated during the process of coal utilization. Especially many new coal conversion technologies, such as coal-to-methane, coal-to-gasoline, coal-to-methanol, coal-to-olefin, etc, were developed rapidly. In these technologies, coal gasification was usually the first step. Coal gasification tar *
Corresponding author:Yan-xia Niu(Y. X. Niu), [email protected];Jun Shen(J. Shen), [email protected]. 1
residue (CGTR) is a solid by-product originated from coal gasification processes, especially in fix-bed coal gasification. As is reported in our previous researches [4-6], the CGTR consisted of high-boiling organic compounds, the unconverted pulverized coal and other solid particles entrained in the coal pyrolysis gases. Apart from toxic character which had been proven by our work, CGTR owns a high caloric value, over 8000 kcal/kg, with high fixed carbons and organic compositions [5]. Therefore, CGTR was also a potent energy resource if being treated reasonably before using. Based on our previous results, the promising treatment way of CGTR was to separate CGTR into residue and tar using an appropriate solvent, and then utilize them further economically and environmentally benign. Hansen solubility parameter was a useful tool in explaining solvents extracting solute from complex system. Abolfazl
[7]
studied the extraction of soy proteins using
Hansen solubility parameter theory. Mohamad
[8]
carried out the study on extracting
resveratrol from cell culture based on this tool. Consequently, the theory can be used for predicting and finding a proper solvent for the extraction process. Aspen plus[9] was a popular software having been used widely in chemical industry to model a stable chemical process, where some basic properties parameters were provided in order to carry out property estimation. As a consequence, this paper aims at separating CGTR by several solvents using extraction way and the tools of Hansen solubility parameter and Aspen plus were also applied to explain the extraction performances and predict the properities of extraction systems. 2. Materials and methods 2.1. Materials Coal gasification tar residues (CGTR) were obtained from a Lurgi gasifier in coal-to-methane process in Inner Mongolia, China and some basic data were shown in Table 1. 22 solvents, cyclohexane, n-heptane, petroleum ether, n-hexane, ethanol, isopropanol, n-butyl alcohol,
acetonitrile, methylene
dimethyl
formamide,
dichloride,
pyridine,
methanol,
ethyl acetate,
methyl acetate,
acetone,
dioxane, furfural, tetrahydrofuran, butyl acetate, dimethyl carbonate, toluene and 2
benzene, AR grade, with a purity high than 99.9% were purchased from Tianjin Kermel Chemical Reagent Company, and used directly without further purification. 2.2. Experiment method Extraction experiment of CGTR was performed by using soxhlet apparatus. 3-10g CGTR sample was loaded in a cylinder made of filter paper and 150mL extraction solvent was put into the flask. The extraction was stopped as the reflux solvent was near to itself color, and the extraction ratio was calculated after the residual sample and cylindrical filter paper are dried to constant weight at room temperature. The calculation equation of extraction ratio (Y) was given as follows: Y=
m1 ×100 − M ad m
Where m is the initial mass of CGTR (g), and m1 is the lost mass of sample (g), Mad is the mass percent of water in CGTR (%), shown in Table 1. 3 Results and discussion 3.1 Soxhlet extraction result analysis In the same condition, different solvents had different selectivity and extraction effects for CGTR in general. The extraction experiment results were shown in Fig. 1. About 22 solvents were used in this experiment, including alkanes, alcohol, esters, ethers, benzene, amide, acetone, furfural and other heteroatom compounds like acetonitrile, methylene dichloride, pyridine, etc. According to reference
[10]
, organic
solvents could be divided into four types, namely N type, A type, B type and AB type, based on whether containing X-H bond with electron receiver or B atom with electron donor, where A and B were respectively the atoms with bigger electronegativity and smaller radius, such as O, N, F et al. For N type solvent, called as inert solvent, it had neither X-H bond nor B atom in molecular structure and could not form hydrogen bond with other molecular. A type solvent had only X-H bond and could form hydrogen bond with B type solvent which was the solvent with electron donor capacity. AB type represented the solvent having the ability of electron receiver and donor simultaneously. Therefore, these selected 22 solvents were classified and shown 3
in Table 2, in which some other basic information were also included [11]. It was clear from Fig.1 that the extraction ratio increased as the solvent order ranked from up to down. The solvent order in Table 2 was the same as that in Fig.1. The solvent with superior extraction ratio was only related to its type rather than other properties like dipole emoment and permittivity. In other words, the solvents assigned as B type and N type with benzene ring structure were inclined to higher extraction ratio for CGTR within the investigated solvents, guiding us a proper direction to select extraction solvent. Except from the extraction ratio, the extraction rate was also a critical factor to the extraction effect. In order to better illustrate it, the related data from Fig.1 were given in Table 3, where a similar conclusion could be deduced, namely, the solvent with B type and aromatic structure have more quick extraction rate than AB type and N type without aromatic structure. This could be attributed to intermolecular hydrogen bond in AB type solvent, which was stronger interaction than that between solvent molecule and extracted molecule and was not destroyed easily during the extraction process. On the basis of our previous researches [4,5], there were almost the same extracted components using ethyl acetate and toluene, which were the representative of B type and N type solvent, respectively. The results were shown in Table 4. It was seen that the extracted substances were mainly polycyclic aromatic hydrocarbons (PAHs), only little amount of heterocyclic aromatic compounds ， such as dibenzofuran, 3-methyl-phenol and 4,6-dichloropyrimidine, et al. These PAHs were all N type organics. Therefore, the good extraction ability of benzene and toluene resulted from the same structure type as the extracted PAHs, and the extraction result could be explained by the similarity-intermiscibility theory. In contrast, the ethyl acetate appeared also a good extraction ability, meaning that CGTR could be well dealt with B type solvent. For the reason of which having high extraction capacity could be caused by the stronger van der waals forces between extraction solvent and extracted molecule than that between the solvent molecules. 4
3.2 Solubility analysis As aforementioned results, the solvents with B type and N type containing aromatic ring structure had better extraction ability than that of AB type for CGTR. To explore further the reason of some solvent possessing good extraction ability, the solubility theories were used in this section. Hansen solubility parameters, including intermolecular dispersion forces (δd), intermolecular polar interactions (δp) and intermolecular hydrogen boding (δh), were indeed an expanded theory for Hildebrand solubility parameter (δ) which was based on the square root of cohesive energy density of the substance. A solvent having the same or very close value of δ with a solute would possess the great ability of dissolving solute [8]. Solubility parameter distance (R) was another meaningful parameter to evaluate the strength of a solute dissolved by a specific solvent. And the smaller the R value was, the higher the dissolving capability of solvent. As far as the relation among these parameters, the corresponding equations were depicted as follows: 2
2
δ = δ d + δ p + δh
2
(1)
R 2 = 4(δ d 2 − δ d1 ) 2 + (δ p 2 − δ p1 ) 2 + (δ h2 − δ h1 ) 2
(2)
In addition, partition coefficient was also critical to estimate the ability of a solvent dissolving another solute, and its value could be calculated using the following formula. VmD V S1 [(δ S1 − δ D )2 − (δ S 2 − δ D )2 ] + ln mS 2 RT Vm
ln k S 2 S1 =
(3)
Where ln kS 2 S1 is partition coefficient; Vm , T, R represent the molar volume, Kelvin temperature and gas constant, respectively. And S1, S2 and D denote solvent one, solvent two, and the extracted solute, respectively. All these mentioned parameters above were obtained from the published handbook
[12]
, other than some lacking data like petroleum ether, fluoranthene,
phenanthrene (seen in Table 4) etc. The relevant calculation results were shown in Table 5 and Table 6. 5
As is illustrated in Table 5, the two δ values, 20.2 and 20.1, of naphthalene and 9H-fluorene were almost equal and very close to that of 1-methyl-naphthalene being 21.1, indicating that the three PAHs from CGTR sample were difficult to be separated. Based on the mentioned knowledge, if the solvent had the same or very close δ value to the dissolved solute as well as small R value, it could emerge better dissolving behavior to the special solute. In Table 5, those solvents, like acetone, methylene dichloride, 1,4-dioxane, pyridine, tetrahydrofuran, had very good performance to dissolve the three solutes, such as naphthalene, 9H-fluorene, 1-methyl-naphthalene, owing to their similar δ value. This was consistent with the result of Fig.1. However, those solvents with the δ value being around 18.5, such as benzene, dimethyl carbonate, and toluene had superior dissolving capability, resulting potentially from the smaller R values for the three solutes. By contrast, even thought ethyl acetate and methyl acetate had near δ value with benzene, their dissolving behaviors were inferior to benzene, which was maybe attributed to their larger R value. These results implied us the solubility parameter distance R being more important factor than Hildebrand solubility parameter δ, and proved indeed the solubility theory being rather useful tool to estimate the extraction process of a solvent to a special solute, which could substitute for the time-consuming and expensive experiment. Table 6 offered the information of partition coefficients of naphthalene, 9H-fluorene and 1-methyl-naphthalene, which were the extracted substances in the CGTR sample, extracted by benzene or other different solvents. These calculated data originating from the equation (3), where the S1 was benzene and S2 was other solvent. Undoubtedly, D was the extracted solute, namely, naphthalene, 9H-fluorene and 1-methyl-naphthalene here. According to literature
[9]
, positive values of partition
coefficient meant that the concentration of the extracted solute in other solvent was higher than in benzene; inversely, negative values indicated higher concentration in benzene. And the higher the negative value, the higher the concentration of the extracted solute in benzene compared to other solvents. As described in Table 6, many values of lnk were near to zero, meaning these corresponding solvents like dimethyl carbonate, ethyl acetate, methyl acetate, pyridine, had similar dissolving 6
capability compared with benzene. Nevertheless, those solvents like ethanol, n-heptane, n-hexane and methanol displayed larger differences in the performance of dissolving the same solute, attributing to their higher negative values in contrast to benzene. These results were in complete agreement with that in Fig.1. All these deduced results from the theoretical calculation of solubility parameters were coincident with the experimental results, which revealed the solubility theory was a promising guidance tool to predict the dissolving behaviour of a proper solvent extracting a processable solute.
3.3 Solvent properties analysis The properties of solvent are necessary factors to be considered when used as extracting solvent. Therefore, the density, viscosity and vapor pressure of some solvents with superior dissolving performance were discussed at the temperature range from 25 °C to 100 °C in this section. Their corresponding data were obtained from Aspen plus software as well as the published literatures [11,13-22]. Since there was water in CGTR sample, water was also considered here. All these results were shown in Fig.2 ~ Fig.4, where the lines denoted the data from Aspen plus with the calculation model of UNIQUAC method and the scatters represented the data from these literatures. From these figures, it could be found clearly that the data from software could overlap greatly with those from literatures, which means that Aspen plus was a very useful tool to obtain some basic information for the pure material, saving much time to search the fundamental data from the related literatures. Furthermore, it was also displayed from Fig.2 that the density of Furfural was the highest in these studied solvents; dimethyl carbonate is in the second, while other solvents were less than water. Fig.3 showed the relationship between solvents’ viscosity and temperature. The viscosity of furfural kept still the highest, while others were lower than water. Generally, the lower the viscosity of material was, the quicker its mass transfer was. As for the extracting system, the lower viscosity meant the larger dissolving rate. Fig.4 plotted the variation of solvents’ vapor pressure with temperature. All curves of vapor pressure of solvents studied grew with the increase of temperature at 7
different extent. Specifically, the curve of methyl acetate varied at the fastest way, presenting methyl acetate was very sensitive to temperature, even if smaller change in temperature brought large change to vapor pressure. Therefore, methyl acetate was not a suitable solvent to extract CGTR because of its high volatility, which would bring a large number of mass losses. Within 80 °C, ethyl acetate and benzene possessed similar vapor pressures and both of them were over dimethyl carbonate’s. Butyl acetate and furfural had lower vapor pressure than toluene in the studied temperature range, indicating more safety when they being used in the extracting process. Apart from these elementary solvent characters, their boiling points or azeotropic points of several solvents mixture are also necessary to design a processable extraction technology. Thereby, it was analyzed and the involved information was given in Table 7 and Table 8. Similarly, these data were obtained from Aspen Plus software and the literature [11]. In Table 7, the data from software was in line with that from the literatures, meaning the information from Aspen plus was reasonable. The azeotropic points of the mixture systems were also calculated by Aspen plus and shown in Table 8. Results showed these systems forming azeotrope with water, indicating that the water contained in CGTR sample could be taken out together during the extracting process. Moreover, the calculation results of binary system were also well in accordance with the literature [11] only other than the system of n-Butyl acetate + H2O. As for the two ternary systems, their azeotropic points were under 100 °C, which seemed to be good nature for reducing energy expenditure during running process. However, the ternary system with furfural contained over 50 percent water (mass basis), which could give rise to inferior extracting effect. Likewise, the binary system of furfural with H2O was also inadvisable for its high amount of H2O. In addition, those binary systems like methyl acetate, benzene, and ethyl acetate could not be good candidates, because their azeotropic points were low, which would bring about the solvent loss during extracting process. Consequently, the solvent systems such as toluene, n-butyl acetate, and n-butyl acetate + dimethyl carbonate would be suitable extracting system for CGTR. Furthermore, these three systems were all 8
immiscible with H2O, indicating they could be recycled easily. 4 Conclusions Coal gasification tar residue (CGTR) was investigated using extracting method. Combining the extraction experiment with the theory analysis, it was proposed that Hansen solubility parameters was a very useful theory to predict and explain the extraction process and Aspen plus was also a convenient tool to search some fundamental thermo-physical data, not only the density, viscosity, vapor pressure for pure substance but also the zeotropic points for mixture system. Based on these researches, the solvents with B type and N type with aromatic ring structure displayed superior extracting performance for CGTR. These experimental results were in agreement with the analysis of solubility parameters. Finally, it was supposed that the solvent systems like toluene, n-butyl acetate, and n-butyl acetate + dimethyl carbonate could be promising extracting solvents for the separation of CGTR. Acknowledgements This work is supported by National Natural Science Foundation of China (Grant No. 21606161), NSFC-Shanxi joint fund of coal-based low carbon (Grant No. U1610223), and Shanxi Scientific and Technological Plan, China (Grant No. 20150313014-4). References [1] Xie Quanan,Xue Liping. Safety and environmental protection on coal chemical engineering, Chemical Industry Press, Beijing, China. 1st, edn, 2005. [2]Xie Quanan, Wang jieping, Fen Xinglei, Li Liansun. Disposal and utilization progress of coking production wastes. Chemical Industry and Engineering
Progress 1 (2011) 424-427. [3] Cheng Xuan. The experimental research of formed coke preparation using low rank pulverized coal and tar slag. Xi'an University of Architecture and Technology, 2013. [4] Wang, Xionglei, Niu, Yanxia, Liu, Gang, Shen, Jun. Research progress of coal tar residue treatment technology. Chemical industry and engineering progress 34 (2015) 2016-2022. 9
[5] Xiong-lei Wang, Jun Shen, Yan-xia Niu, et al. Solvent extracting coal gasification tar residue and the extracts characterization. Journal of Cleaner Production 133 (2016) 965-970. [6] Jun Shen, Xiong-lei Wang, Yan-xia Niu et al. Combustion properties and toxicity analysis of coal gasification tar residue. Journal of Cleaner Production 139 (2016) 567-575. [7] Abolfazl Aghanouri, Gang Sun. Hansen solubility parameters as a useful tool in searching for solvents for soy proteins. RSC Advances 5 (2015) 1890-1892. [8] Mohamad Houssam Al balkhi, Mohammad Amin Mohammad, Léo-Paul Tisserant, Michèle Boitel-Conti. Development of a liquid-liquid extraction method of resveratrol from cell culture media using solubility parameters. Separation and
Purification Technology 2016 (170) 138-145. [9] Lan-yi Song. Chemical Engineering Process Simulation using Aspen Plus. Chemical Industry Press, 1st, edn, 2015. [10]Xu Guangxian, Wang Wenqing, Wu Jinguang et al. Extraction chemistry Principle , Shanghai scientific and technical publishers, Shanghai, China, 1 st, edn, 1984. [11] Chen, Nenglin. Solvents Handbook, Chemical Industry Press, Beijing, China, 4 nd, edn, 2007. [12] C. Hansen, Hansen Solubility Parameters: A User's Handbook, CRC Press, Boca Raton, Fla, 2nd, edn, 2007. [13] F. J. Vieira dos Santos, C. A. Nieto de Castro. Viscosity of toluene and benzene under high pressure. International Journal of Thermophysics 18 (1997) 369-377. [14] Laura Lomba, Beatriz Giner, Isabel Bandrés, et al. Physicochemical properties of green solvents derived from biomass. Green Chemistry 13 (2011) 2062-2070. [15] Jiang Zhiqing. Physical chemistry experiment instruction. Xiamen university press, Xiamen,China, 1st, edn, 2014. [16] Xia Yuyu, Chemical Experiment Handbook. Chemical Industry Press, Beijing, China, 2nd, edn, 2008. [17] Mehrdad Moosavi, Ahmad Motahari, Amir Vahid, et al. Densities, Viscosities, 10
and Refractive Indices of Dimethyl Carbonate + 1-Hexanol/1-Octanol Binary Mixtures at Different Temperatures[J]. Journal of Chemical Engineering Data 61 (2016) 1981-1991. [18] Jiang Biyuan, Zhang Jianhou. Determination and correlation of vapor pressures of Dimethyl carbonate and 2,3-Dichloropropene. Journal of Tianjin university 3(1987) 54-62. [19] M. V. Rathnam, Reema T. Sayed, Kavita R. Bhanushali, M. S. S. Kumar. Density and viscosity of binary mixtures of n-butyl acetate with ketones at (298.15, 303.15, 308.15, and 313.15) K. Journal of Chemical Engineering Data 57 (2012) 1721-1727. [20] K. SARAVANAKUMAR, R. BASKARAN, AND T. R. KUBENDRAN, Densities, Viscosities, Refractive Indices and Sound Speeds of Acetophenone with Methylacetate at Different Temperatures. CODEN ECJHAO E-Journal of
Chemistry 9 (2012) 1711-1720. [21] Li Xi, Hu ShanZhou. Physical Chemistry Experiment. Wuhan University of Technology Press, Wuhan, China, 2010. [22] Naushad Anwar, Riyazuddeen, Shama Yasmeen. Volumetric, compressibility and
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studies
of
binary
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[EMIM][NTf2]
with
ethylacetate/methanol at (298.15–323.15) K. Journal of Molecular Liquids 224 (2016) 189-200.
11
0
5
10
E x tra tio n tim e /h 20 25
15
30
C yc lohe xa ne n-H epta ne P etroleum ethe r n-H e xa ne E thano l Is op ro pano l A c e tonitrile D im eth ylform a m ide M ethano l E th yl ac etate n-B u tyl alc oho l M ethy le ne dic h loride P y ridine M eth yl ac e tate A c etone 1,4-D io x ane F urfu ra l T etrah ydrofuran B utyl ac etate D im eth yl c arbon ate T o lu ene B en z ene
35
40
E x tration tim e E x tration ra tio
0
5
10
15
20 25 E x tration ratio/%
30
Fig.1 Extraction results of GCTR by different solvents
12
35
40
115 0 110 0
D en s ity/k g · m
-3
105 0 100 0 95 0 90 0 85 0 80 0 0
20
40
60
80
100
o
T e m pe ra ture / C
Fig.2 Densities of the selected solvents at the temperature range from 0°C to 100°C Line: the deduced data by Aspen Plus software, Scatter: the published literature data.▼ Furfural, ★ Dimethyl Carbonate, ●H2O, △ Methyl acetate, ○ Ethyl acetate, □ Butyl acetate, ■Benzene, ▲ Toluene.
13
2 .4
V is c os ity /m p a · s
2 .0
1 .6
1 .2
0 .8
0 .4
0 .0 0
20
40
60
80
100
o
T e m pe ra ture / C
Fig.3 Viscosities of the selected solvents at the temperature range from 0°C to 100°C Line: the deduced data by Aspen Plus software, Scatter: the published literature data.▼ Furfural, ●H 2O, □ Butyl acetate, ■Benzene, ★ Dimethyl Carbonate, ▲ Toluene, ○ Ethyl acetate, △ Methyl acetate
14
40 0 35 0
V ap o r P res s u re /k p a
30 0 25 0 20 0 15 0 10 0 50 0 0
20
40
60
80
100
o
T e m pe ra ture / C
Fig.4 Vapor Pressures of the selected solvents at the temperature range from 0°C to 100°C Line: the deduced data by Aspen Plus software, Scatter: the published literature data. △ Methyl acetate, ○ Ethyl acetate, ■Benzene, ★ Dimethyl Carbonate, ●H2O, ▲ Toluene, □ Butyl acetate, ▼ Furfural.
15
Tables
Table 1 Properties of coal gasification tar residues (CGTR) Heat value(cal·g-1)
Ultimate analysis (wt %) Mad
Aad
Vad
FCad
Sad
TId
QId
Qgr.daf
16.30
4.30
36.86
42.54
0.31
48.12
52.09
8927
16
Table 2 Solvent type and some basic data
Solvent
Structure
Boiling point
Permittivity
(°C)
Dipole emoment
Type
-30
(10 C· m)
Cyclohexane
80.70
2.052
-
N
n-Heptane
98.50
1.924
0.0
N
30-60
-
-
N
68.95
1.890
0.27
N
78.30
25.7
5.60
AB
Petroleum ether
-
n-Hexane Ethanol
HO
Isopropanol
OH
82.45
18.3
5.6
AB
Acetonitrile
N
81.60
37.5
11.47
B
N
153.00
36.71
12.88
AB
OH
64.70
31.2
5.55
AB
77.20
6.02
6.27
B
117.25
17.1
5.6
AB
40.00
9.1
3.8
A
115.30
12.3
7.44
B
58.00
6.68
5.37
B
56.00
1.0235
8.97
B
101.30
2.209
1.5
B
161.80
38
12.1
B
66.00
7.58
5.70
B
126.00
5.01
6.14
B
90.00
2.6
-
B
Toluene
110.60
2.24
1.23
N
Benzene
80.00
2.283
0
N
Dimethyl formamide
O
Methanol
O
Ethyl acetate n-Butyl alcohol Methylene dichloride
O
HO
Cl
N
Pyridine
O
Methyl acetate
O
O
Acetone
O
1,4-Dioxane
Furfural
O
O
O
O
Tetrahydrofuran
Butyl acetate
Dimethyl carbonate
Cl
O
O
O O
O
17
Table 3 Extraction rate and solvent type Solvent
AER*
Type
Solvent
AER*
Type
n-Heptane
1.34
N
Ethanol
5.51
AB
Methanol
2.48
AB
Tetrahydrofuran
6.11
B
Isopropanol
2.76
AB
Acetone
6.87
B
1-Butanol
3.01
AB
Ethyl acetate
7.69
B
n-Hexane
3.12
N
Furfural
8.31
B
Cyclohexane
3.19
N
Methyl acetate
8.55
B
Petroleum ether
3.3
N
Butyl acetate
8.8
B
Dimethyl formamide
3.74
AB
Benzene
9.1
N
1,4-Dioxane
4.17
B
Dimethyl carbonate
9.22
B
Toluene
4.37
N
Methylene dichloride
12.3
A
Pyridine
5.49
B
Acetonitrile
15.44
B
*AER represents Average extraction rate(%/h) and its value is obtained by extraction ratio divided by extraction time from Fig.1.
18
Table 4 Extraction results using Toluene and Ethyl Acetate from GCTR (chemical composition analysis) Relative content Extracted compound
(%)
Structure
Type
Toluene
Ethyl Acetate
Naphthalene
25.45
30.92
N
Fluoranthene
10.50
13.01
N
Phenanthrene
9.75
10.64
N
Pyrene
8.20
9.63
N
9H-Fluorene
6.66
8.32
N
Acenaphthene
5.61
7.09
N
1-Methyl-naphthalene
4.22
5.16
N
Indane
4.20
4.46
N
Dibenzofuran
2.46
2.47
B
2-Methyl-naphthalene
2.01
2.36
N
Anthracene
2.17
2.32
N
O
4,6-dichloropyrimidine
N
N
Cl
3.32
Cl
3-Methyl-phenol
3.61 HO
--
AB
--
15.46
19
AB
Table 5 Solubility parameter and solubility distance for the investigated system δd
δp
δh
δ
Vm
(MPa0.5)
(MPa0.5)
(MPa0.5)
(MPa0.5 )
(cm3/mol)
15.5
10.4
7.0
19.9
Acetonitrile
15.3
18.0
6.1
Benzene
18.4
0.0
2.0
1-Butanol
16.0
5.7
15.8
Substance Acetone
R1a
R2 b
R3c
74.0
11.2
13.6
14.2
24.4
52.6
17.8
19.3
20.3
18.5
89.4
4.7
3.6
5.2
23.2
91.5
12.4
16.7
15.2
n-Butyl Acetate
15.8
3.7
6.3
17.4
132.5
7.0
9.8
10.2
Cyclohexane
16.8
0.0
0.2
16.8
108.7
7.7
6.8
8.9
Methylene dichloride
18.2
6.3
6.1
20.2
63.9
4.8
7.3
7.4
Dimethyl carbonate
15.5
3.9
9.7
18.7
84.2
8.6
12.2
11.8
Dimethyl formamide
17.4
13.7
11.3
24.9
77.0
13.4
16.2
15.8
1,4-Dioxane
19.0
1.8
7.4
20.5
85.7
1.6
6.0
4.3
Ethanol
15.8
8.8
19.4
26.5
58.5
16.6
20.8
19.3
Ethyl acetate
15.8
5.3
7.2
18.2
98.5
7.7
10.7
10.9
Furfural
18.6
14.9
5.1
24.4
83.2
13.0
13.9
14.7
n-Heptane
15.3
0.0
0.0
15.3
147.4
10.0
9.7
11.6
n-Hexane
14.9
0.0
0.0
14.9
131.6
10.6
10.5
12.4
2-Propanol
15.8
6.1
16.4
23.6
76.8
13.2
17.5
16.0
Methanol
15.1
12.3
22.3
29.6
40.7
21.0
25.2
23.7
Methyl acetate
15.5
7.2
7.6
18.7
79.7
9.2
12.1
12.4
19.0
8.8
5.9
21.8
80.9
6.8
8.5
8.7
Pyridine Petroleum ether
d
-
-
-
-
-
-
-
-
Tetrahydrofuran
16.8
5.7
8.0
19.5
81.7
6.4
9.8
9.6
Toluene
18.0
1.4
2.0
18.2
106.8
4.6
4.0
5.9
Naphthalene
19.2
2.0
5.9
20.2
111.5
9H-Fluorene
20.0
1.7
1.7
20.1
138.2
1-Methyl-naphthalene
20.6
0.8
4.7
21.1
138.8
Notes：Naphthalene, 9H-Fluorene and 1-Methyl-naphthalene are the solutes which are extracted from GCTR while others are solvents. a
R1 indicates the R value between the substance and Naphtanlene.
b
R2 indicates the R value between the substance and 9H-Fluorene.
c
R3 indicates the R value between the substance and 1-Methyl-naphthalene.
d
Parameter δ values of petroleum ether cannot be found.
20
Table 6 Partition coefficient of Naphthalene, 9H-Fluorene, 1-Methyl-naphthalene, from benzene to other different solvents Solvent
Ln k (Naphthalene)
Ln k (9H-Fluorene)
Ln k (1-Methyl-naphthalene)
Acetone
0.31
0.33
0.11
Acetonitrile
-0.13
-0.36
-0.76
Benzene
0.00
0.00
0.00
1-Butanol
-0.30
-0.42
0.16
n-Butyl Acetate
-0.61
-0.65
0.01
Cyclohexane
-0.58
-0.66
-0.46
Methylene Dichloride
0.47
0.48
-0.00
Dimethyl Carbonate
0.09
0.09
-0.00
Dimethyl Formamide
-0.70
-0.97
-0.56
1,4-Dioxane
0.17
0.18
0.31
Ethanol
-1.24
-1.73
-1.70
Ethyl Acetate
-0.16
-0.16
-0.01
Furfural
-0.58
-0.80
-0.29
n-Heptane
-1.45
-1.64
-1.00
n-Hexane
-1.52
-1.75
-1.39
2-Propanol
-0.23
-0.38
-0.12
Methanol
-3.06
-4.11
-4.46
Methyl Acetate
0.14
0.15
-0.06
Pyridine
0.12
0.09
0.25
Petroleum ether
-
-
-
Tetrahydrofuran
0.20
0.21
0.14
Toluene
-0.23
-0.24
0.07
21
Table 7 Boiling points of the different pure solvents at 101.325 KPa Component
Temperature*/°C
Temperature#/°C
Water
100.02
100
Benzene
80.13
80.00
Toluene
110.68
110.60
Methyl Acetate
57.05
58.00
Ethyl Acetate
77.20
77.20
n- Butyl Acetate
126.01
126.00
Dimethyl Carbonate
90.22
90.00
Furfural
161.35
161.80
Note： * data from Aspen Plus, while # from literature[11]
22
Table 8 Boiling points and composition of several azeotropes No. 1
2
3
4
5
6
7
8
Homogeneous
Mole* Basis
Mass* Basis
Temperature*/°C
Mass# Basis
56.64
0.0350
H2O
0.0898
0.0234
Methyl Acetate
0.9102
0.9766
H2O
0.2990
0.0896
Benzene
0.7010
0.9104
H2O
0.3659
0.1055
Ethyl Acetate
0.6341
0.8945
H2O
0.5596
0.1990
Toluene
0.4404
0.8010
H2O
0.8622
0.5398
Furfural
0.1378
0.4602
H2O
0.7326
0.2982
n- Butyl acetate
0.2674
0.7018
H2O
0.4396
0.1327
n- Butyl acetate
0.0484
0.0943
Dimethyl Carbonate
0.512
0.773
H2O
0.8516
0.5208
Furfural
0.1242
0.4052
Dimethyl Carbonate
0.0242
0.074
0.965 69.35
70.19
84.53
96.23
84.64
92.05
96.25
#
Note： *data from Aspen Plus, while from literature [11]
23
0.0883 0.9117 0.0847 0.9153 0.1350 0.8650 0.6500 0.3500 0.2870 0.7130
Temperature#/°C 56.5
69.25
70.38
84.1
97.9
90.2
Highlights： ： 1）Coal gasification tar residue (CGTR), an industrial solid waste from coal utilization process, was researched using solvent extracting way. 2）Hansen solubility parameter theory was used to explained and relate with the extracting experimental results. 3）Aspen plus software was applied to estimate the properties of solvents as extracting agents. 4）The possible extraction systems were predicted to be put them into practice based on the above concluded knowledges.
24