ПРЕВРАЩЕНИЕ ГАЗОВОГО БЕНЗИНА НА СУЛЬФАТИРОВАННЫХ (ВОЛЬФРАМАТИРОВАННЫХ) ДИОКСИД ЦИРКОНИЯ-ЦЕОЛИТНЫХ КОМПОЗИТНЫХ СИСТЕМАХ

Алиева Айнура Анвер кызы1, Кязимова Лала Галиб кызы2
1Азербайджанский государственный университет нефти и промышленности, доктор философии по химическим наукам, доцент
2Азербайджанский государственный университет нефти и промышленности, магистрант

Аннотация
Производство бензина, отвечающего современным экологическим требованиям, является одним из основных направлений нефтеперерабатывающей промышленности. Качество и ассортимент выпускаемых автомобильных бензинов определяются структурой автопарка, техническими возможностями нефтяной отрасли, а также экологическими требованиями. Введение строгих правил приводит к увеличению спроса на экологически чистое топливо. Состав бензина значительно регулируется с помощью процесса изомеризации алканов С56. Целью данной работы было изучение конверсии природного бензина на композиционных каталитических системах, содержащих вольфрамированный или сульфатированный диоксид циркония (ZrO2), цеолит (MOR).

Ключевые слова: алканы С5-С6, диоксидциркониевый катализатор, изомеризация, природный бензин, температура


CONVERSION OF NATURAL GASOLINE OVER SULFATED (TUNGSTATED) ZIRCONIA-ZEOLITE COMPOSITE SYSTEMS

Aliyeva Aynura Anver qizi1, Kazimova Lale Qalib qizi2
1Azerbaijan State Oil and Industry University, Doctor of Philosophy in Chemical Sciences, associate professor
2Azerbaijan State Oil and Industry University, master student

Abstract
The production of gasoline that meets modern environmental requirements is one of the main directions of the petroleum refining industry. The quality and range of produced motor gasoline are determined by the structure of the vehicle fleet, the technical capabilities of the oil industry, as well as environmental requirements. Imposing stringent regulations leads to the increasing of demand for eco-friendly fuels. The composition of gasoline has been regulated greatly using isomerization process of C5-C6 alkanes. This study aimed to investigate the conversion of natural gasoline on composite catalytic systems containing tungstated or sulfated zirconium dioxide (ZrO2), zeolite (MOR).

Keywords: C5-C6 alkanes, isomerization, natural gasoline, temperature, zirconium dioxide catalyst


Рубрика: 02.00.00 ХИМИЧЕСКИЕ НАУКИ

Библиографическая ссылка на статью:
Алиева А.А.к., Кязимова Л.Г.к. Conversion of natural gasoline over sulfated (tungstated) zirconia-zeolite composite systems // Современные научные исследования и инновации. 2023. № 7 [Электронный ресурс]. URL: https://web.snauka.ru/issues/2023/07/100485 (дата обращения: 19.07.2024).

Introduction

Modern stringent environmental requirements for gasolines suggest the limitations of aromatic hydrocarbons by maintaining their high anti-knock characteristics [1-3]. One of the solutions of this problem is a conversion of straight run gasolines or natural gasoline from high-temperature dehydrocyclization to low-temperature isomerization process [1, 4-6].

The isomerization process of C5-C6 alkanes plays an important role in the production of modern gasolines with a low content of aromatic hydrocarbons [7-9]. The isomerization process has very high technical and economic indicators compared to other processes that increase the octane number of fuel [3-5, 10].

Isomerate is practically indispensable in the production of motor fuels that meet the latest environmental requirements. Straight-run gasoline or natural gasoline containing C5-C6 paraffin hydrocarbons are the main feedstocks for production of environmentally friendly high-octane gasoline components [6, 11-14]. Conversion of straight-run gasoline or natural gasoline on composite catalytic systems containing tungstated or sulfated zirconium dioxide (ZrO2), zeolite (MOR, HZSM-5) can lead to the production of eco-friendly high-octane gasolines with limited content of aromatics [1, 15].

Experimental Part

The main objects of study were anion-modified composite catalysts containing H-zeolite, such as mordenite and anion-modified sulfated zirconium dioxide or anion-modified tungstated zirconium dioxide. Zeolites modification was carried out by decationization and dealumination, ion-impregnation of various metals such as nickel or cobalt [12]. Zeolite catalysts were promoted using metal ions of salts obtained from nickel (NiNO3), cobalt (CoSO4∙7H2O) and zirconium ZrO(NO3)2∙2H2O, tungsten (NH4)6H2W12O40  as a source of active components.

The content of SO42- and WO42- ions was controlled using solutions with a given content of ions, and their content in the obtained samples was controlled by elemental analysis (Agilent Technologies 7700 Series ICP-MS). The amount of SO3 and WO3 on ZrO2 in the final samples was 6.1 and 11.8%, respectively.

Comparative analysis of reactants and reaction products was carried out directly at the inlet and outlet of the reactor (on-line mode) and analyzed using the Perkin-Elmer Autosystem XL gas chromatograph.

Results and Discussion

Sulfated (tungstated) composite catalytic systems containing zirconium dioxide (ZrO2), zeolite (MOR, HZSM-5) and cobalt, nickel can involve natural gasoline in isomerization process with an increasing of C5-C6 paraffin hydrocarbons resources [1, 16]. The composition of natural gasoline considerably affects the efficiency of the process.

Natural gasoline is a mixture consisting mainly of C5-C7 alkanes. Such hydrocarbon composition is quite acceptable for isomerization process of natural gasoline to increase the concentration of iso-C5-C6 high octane components.

The composition of natural gasoline: gaseous alkanes C4-(5.4%), iso-C5 (25.5%), n-C5 (19.3%), iso-C6 (18.2 %), n-C6 (8.6%), C7+ - 22.7%. The conversion of natural gasoline was carried out at atmospheric pressure, in the temperature range of 150-2000C. Natural gasoline conversion over Со/HMOR/WO2-4 ZrO2 catalyst is presented in table 1.

Table 1. Natural gasoline conversion over Со/HMOR/WO2-4 ZrO2 catalyst: LHSV=2,5 h-1; τ=30 min

Temperature, 0C

Composition of natural gasoline, %

C4-

iso-C5

n-C5

iso-C6

n-C6

C7+

5.4

25.5

19.3

18,2

8.6

22.7

150

2.9

32,1

22

25.6

4.3

14.5

180

1.3

34.3

38.7

23.2

3.5

12.19

200

1.1

26.0

18.5

20.8

2.1

20,5

Conversion of natural gasoline on composite catalyst which combines the properties of anion-modified zirconia and H-zeolite, leads to significant changes in the distribution of hydrocarbons. Moreover, the most important of these changes are consumption of C7+ alkanes (C7+ conversion); reduction of C4- alkanes and accumulation of C5-C6 alkanes, including high-octane iso-pentane and dimethylbutanes.

C4- consumption is observed in the temperature range of 150-2000C. However, the consumption of C7+ occurs in the range of 150-1800C. Moreover in this temperature range the amount of isostructural C5-C6 alkanes increases.

Table shows 2 the results of natural gasoline conversion on Ni/HMOR/SO2-4 ZrO2 catalyst. Conversion of the natural gasoline on Ni/HMOR/SO2-4 ZrO2 allows increasing of isostructural C5-C6 alkanes and normal C6 components and decreasing of С4-, С6 and С7 components. The increase in the content of these hydrocarbons is a consequence of a similar decrease in other hydrocarbons, especially C7+. Ni/HMOR/SO2-4 ZrO2 can convert natural gasoline and straight-run gasoline components and considerably increase the iso-C5, n-C5 and iso-C6 components which are high octane resources.

Table 2. Natural gasoline conversion over Ni/HMOR/SO2-4 ZrO2 catalyst LHSV= 2 h-1; τ=30 min; υH2 =30 ml/min

Temperature, 0C

Composition of natural gasoline, %

С4-

iso-C5

n-С5

iso-C6

n-С6

С7+

5.4

25.5

19.3

18.2

8.6

22.7

150

2,9

33

22

26,4

4,2

2,8

180

1,8

33,4

21

29,8

3,4

1,6

200

1,3

40

22

21,2

3,3

2,5

 

Table 3. Influence of temperature on natural gasoline conversion over Ni/HMOR/SO2-4 ZrO2 catalyst LHSV= 2 h-1; τ=30 min; υH2 =30 ml/min

Temperature,

ºС

∑iso-С5 -iso-C6,%

∑n-С5-n-C6, %

Conversion ∑С7+%

RON

43.7

27.9

18.3

63

150

57.5

25.6

39.8

82

180

60,9

23,4

41,1

85

200

61,7

24,5

44,8

78

220

46,7

29,5

22,0

67

Table shows 3 influences of temperature on natural gasoline conversion on Ni/HMOR/SO2-4 ZrO2 catalyst. Conversion of the natural gasoline on Ni/HMOR/SO24 ZrO2 enables to isomerize C5 and C6 alkane hydrocarbons and to involve heptane in the process. Natural gasoline undergoes significant enrichment with high octane components due to extremely low octane heptane components.

Table 3 shows that in one pass over the sulfated based composite catalytic system the research octane number of gasoline increases by 15-22 points. So, reformate compounding with the resulting mixture can be the best method for production of high-octane gasolines.

The possibility of using the H-zeolite/SO2-4 ZrO2 and H-zeolite /WO2-4 ZrO2 catalytic systems for the conversion of components of natural gasoline between the temperature range 150-200ºС enable to increase the concentration of isostructural C5-C6 hydrocarbons and involve C7+ alkanes in the catalytic conversion process. Furthermore, the involvement of C7+ hydrocarbons in the catalytic processoccurs without the formation of C1-C3 alkanes.

Conclusion

The results of this research showed that C4- gaseous alkanes are consumed in the conversion process of natural gasoline by forming high molecular weight of hydrocarbons. Moreover, the conversion of natural gasoline over sulfated (tungstated) composite catalytic systems containing zirconium dioxide (ZrO2), zeolite (MOR, HZSM-5) and cobalt, nickel can open perspective opportunity for conversion of natural gasoline and straight run gasoline from high-temperature dehydrocyclization to low-temperature isomerization process.


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