RECYCLING COKE-CHEMICAL TAR IN THE PRESENCE OF
MO-CONTAINING CATALYST
Zh. Kairbekova, N. Smagulovaa , A Sabitova a, А Байсенгирова a.
a
Scientific research institute of new chemical technologies and materials,
Almaty, Kazakhstan
a
Al-Farabi Kazakh National University, Almaty, Kazakhstan
Corresponding e-mail: [email protected]
Introduction
The ever increasing demand for light products, are less polluting, high-quality chemical products leads
to further development of the processes of deep processing of hydrocarbon raw materials of high-oil (bp. 360520С and 520С above) and coal (coking resin) origin. Stricter requirements for the quality of the resulting
products leads to significant changes in the technological schemes and the development of new recycling
processes of these raw materials [1].
Experimental
Experiments were carried out on the installation developed by us shown in Figure 1 at a pressure of 5
MPa, and the argon working temperature 350-450 °C. At this temperature the reactor was maintained for 1020 minutes. The main part of the installation of the reactor type are metal "duck" (1) stainless steel X18H10T
volume of 0.25 dm3. Thermal-heating "duck" (1) carried heater (3) AC. amperage regulated transformer (5)
and an ammeter (4). Temperature control in the inner part of the reactor was performed with a thermocouple
Chromel-Copel (6), the registration unit - KSP-4 range tape which sizing water boiling temperature (100 °C),
tin melting (232 °C), lead (327 °C) and zinc (427 °C). To create pressure employed during hydrogenation of
technical argon cylinder pressure change in the system model fixed gauge (9). Coke mixture tar and catalyst
paste-heated to 70-80 °C, was charged to the reactor which was purged three times with argon under a pressure
of 0.4-0.5 MPa, and the system was checked for leaks, and included a heating device and KSP-4. Upon
reaching 150 °C before entering the mode (400 - 420 °C) comprised a mixing device.
At fixed pressure gauge gains by increasing the temperature, release of gases and volatile in the process
of coal liquefaction. After exposure in a heating experiment was turned off and the reactor cooled to 30 ° C 35 ° C. By the pressure difference (Р-Рinit) determined the amount of generated gas which via a fine adjustment
valve collected in calibrated gasometer filled with brine.
8
7
5
4
16
9
10
12
15
14
3
1
2
11
6
13
1 reactor; 2 - a glass insert; 3 - heater; 4 - ammeter; 5 - Voltage Regulator; 6 - thermocouple (Chromel - Copel); 7 - Relay; 8 KSP-4; 9 - Gauge model; 10 - the fine adjustment valve; 11 - tank with inert gas or hydrogen; 12 - gasometer; 13 - agitator; 14 - a
sealing device; 15 - the plug; 16 - sealing bolts.
Figure 1. - Installation of the high-pressure hydrogenation of coke-chemical pitch in a batch mode.
Results and discussion
The sulfur content of the tar is 0 to 35 wt. %. Therefore, to increase the sulfur content in the resin
composition as an additive sulfiding elemental sulfur used as raw materials in the hydrogenation of high sulfur
sulphidation agent role performed sulfur organic components. When liquefaction of coal with sulfur content
below 0.5 % requires additional administration sulfiding agents. In the process, as sulphidation agent used
elemental sulfur. In the process of heating the emulsion and feedstock containing sulfiding agent in an
atmosphere of hydrogen and hydrogen sulfide recovered starting compounds and to form a sulfided
catalytically active phase - metal sulfide. It should be noted that, unlike traditional heterogeneous catalysts
using slurried catalysten practically no deposition of coke on their surface and metal compounds, which lead
to rapid deactivation of [ 2].
The dispersion medium contains a resin and asphaltene molecules that stabilize the resulting emulsion.
As noted, for the formation of MoS2 (NH4) 6Mo7O24 ∙ 4H2O requires sulfiding agent under hydrogenation
conditions capable of forming hydrogen sulfide. In the hydrogenation of raw materials with a high content of
sulfur role sulphidation agent perform sulfur organic components of coal tar. The resulting emulsion is
hydrotreated by high pressure batch operation at temperatures of 300-450 ° C and an initial hydrogen pressure
of 5 MPa. During hydrotreating resins studied the effect of additives on the yield of liquid products (table 1).
Temperat
ure,
°С
Without catalyst
350
400
450
0,025 by weight.
% + S 0,03 %
350
400
450
350
400
450
350
400
450
0,05 by weight %
+ S 0,06. %
0,12 by weight %
+ S 0,09 %
Yield of liquid products by
weight, %
∑L.P
till 180
180-250 250-320
°С
°С
°С
5,25
11,45
13,2
29,9
7,80
15,30
24,0
46,6
10,3
7,60
12,9
46,6
Impact of amount of catalyst, by weight. %
1,75
22,8
52,32
76,8
1,32
15,2
42,0
58,5
1,22
11,5
38,8
46,2
4,25
6,45
23,3
34,6
14,7
18,7
31,7
65,5
10,3
7,60
13,7
31,6
4,25
6,45
23,2
33,9
9,30
14,05
34,6
58,0
5,29
7,13
12,60
25,02
Losses by
weight%
Catalyst
Yield of
gas+Н2О
(byweightt
)Slime
мас.
%%
weight
Table 1. Results of the tar in the presence of hydrogenation catalyst emulsified Mo (400 ° C, 5 MPa,% S, high-pressure flow).
36,00
36,8
36,00
16,2
9,1
19,3
17,9
7,5
13,9
8,2
22,8
29,4
34,7
10,8
37,0
40,0
22,1
45,0
9,2
14,5
15,7
14,5
18,7
17,3
17,8
10,60
18,94
5,8
4,2
8,7
16,2
6,1
13,0
8,3
9,30
11,04
As shown in Table 1, increasing the amount of catalyst to feedstock of 0.05 wt. % To 0.12 wt. % sulfur
and 0.06 wt. % To 0.09 wt. % Yield of liquid products on the catalyst compared with the yield of liquid
products without catalyst reduced at all temperatures studied. According to the research, it was found that the
amount of catalyst 0 025 wt. %, The optimum amount of sulfur 0.03 wt. %. In their presence, the total liquid
yield was 76.8 wt. % At 350 ° C, 58.5 wt. % At 400 ° C and 38.8 wt. % At 450 ° C.
Results to determine the conditions effective for increasing the yield of motor fuels tar hydrogenation
was carried out in the temperature range 350-450 ° C in the presence of a Mo-containing catalyst and of
elemental sulfur. As a result of the study shows that in comparison with the gasoline fraction obtained in the
absence of a catalyst composition of the gasoline fraction obtained using catalyst content of iso-paraffins
increased from 10.14 to 49.4% and a paraffin content decreased from 55.40 to 8.22 wt. % Aromatics has
increased from 17.2 to 27.60% The results of analysis of the hydrocarbon group can be concluded that with
the hydrogenation of coal tar in the presence of suspended catalyst and the sulfur components available motor
fuel with a high content of iso-paraffins.
Conclusions
Thus, we researched and optimized process of hydtrotreating of coke-chemical pitch resin under low
pressure hydrogen in the presence of elemental sulfur and developed the original catalyst systems. According
to the research, it was found that the optimum amount of catalyst 0 025 wt. % Sulfur and 0.03 wt. %. In their
presence, the total liquid yield was 76.8 wt. % At 350 ° C, 58.5 wt. % At 400 ° C and 38.8 wt. % At 450 ° C.
References
1.
1. A.A. Krichko, B.K. Nefedov, M.V. Landau. Hydrogenation of coal liquefaction products using НВС catalyst, J. Solid
fuel chemistry. 2(1990) 66-69.
2.
A.A. Krichko, A.S. Mololetnev, S.N. Khadjiev. Deep processing of coal and heavy oil residues, J. Russian Chemical
journal. 5(1994) 100-104.