STEAM CRACKING METHOD UTILIZING ELECTRICITY FOR PROVIDING ENERGY

Abstract

The present invention provides a method of steam cracking using electricity to supply energy. This method is to provide energy for steam cracking reaction of a cracking raw material by electromagnetic induction with electricity; the cracking raw material comprises one or more of naphtha, cycloalkane and cycloolefin; wherein the cycloalkane is a C4-C8 cycloalkane, and the cycloolefin is a C4-C8 cycloolefin. The present invention utilizes electricity to provide energy for the steam cracking reaction through an electromagnetic coil, which is a new use of electricity and solve the current problem of excess electricity. Moreover, utilizing the electromagnetic coil to provide power can make the heat distribution in the furnace tube of the cracking furnace more uniform, and it is easier to control the reaction temperature and the progress of the reaction.

Claims

1. A method of steam cracking using electricity to supply energy, comprising supplying energy for a steam cracking reaction of a cracking raw material with electricity by electromagnetic induction, wherein the cracking raw material comprises one or more of naphtha, cycloalkane and cycloolefin, and wherein the cycloalkane is a C4-C8 cycloalkane, and the cycloolefin is a C4-C8 cycloolefin.

2. The method according to claim 1, wherein supplying energy is carried out by heating a steam cracking reaction tube by means of an induction coil, and supplying the cracking raw material with heat from the reaction tube.

3. The method according to claim 2, wherein the induction coil is wrapped around the outside of the steam cracking reaction tube.

4. The method according to claim 2, wherein the frequency of the current inputted into the induction coil is a medium frequency or a high frequency, wherein the high frequency is 5-20 KHz, and wherein the medium frequency is 50-3,000 Hz.

5. The method according to claim 2, wherein the frequency of the current inputted into the induction coil is regulated by a power supply and a capacitor.

6. The method according to claim 5, wherein the induction coil is connected to the power supply to form a circuit, and the power supply is connected in parallel with the capacitor.

7. The method according to claim 5, wherein the power of the power supply is 100-1,000 KW.

8. The method according to claim 2, wherein the induction coil is one or more of a ferrite coil, an iron core coil, a hollow coil, and a copper core coil.

9. The method according to claim 1, wherein the cycloalkane is cyclohexane, and the cycloolefin is cyclohexene.

10. The method according to claim 1, wherein the cracking raw material is a cracking raw material containing cyclohexene and/or cyclohexane.

11. The method according to claim 10, wherein the total content of cyclohexene and cyclohexane in the cracking raw material is 80% or more.

12. The method according to claim 11, wherein the total content of cyclohexene and cyclohexane in the cracking raw material is 100%.

13. The method according to claim 10, wherein the weight ratio of cyclohexane to cyclohexene is from 2:8 to 8:2.

14. The method according to claim 1, wherein the reaction temperature of the steam cracking reaction is 500-1,200 C.

15. The method according to claim 1, wherein the water-oil ratio for the steam cracking reaction is 0.3-0.7.

16. The method according to claim 1, wherein the residence time of the steam cracking reaction is 0.1-1 s.

17. The method according to claim 2, wherein the steam cracking reaction tube has an inner diameter of 50-250 mm.

18. The method according to claim 2, wherein the steam cracking reaction tube is made of a metal or alloy.

19. The method according to claim 18, wherein the metal or alloy is a metal or alloy capable of withstanding a temperature of 1,000 C.

20. The method according to claim 18, wherein the metal or alloy is selected from 316L stainless steel, 304S stainless steel, HK40 high-temperature furnace tube material, HP40 high-temperature furnace tube material, HP Micro Alloy micro-alloy steel or Manaurite XTM material for a steam cracking furnace.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0026] FIG. 1 shows a schematic circuit diagram of the power supply, electromagnetic coil, and capacitor of the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0027] In order to have a clearer understanding of the technical features, objectives and beneficial effects of the present invention, the following detailed description of the technical solutions of the present invention is given, but it is not to be understood as limiting the implementable scope of the present invention.

Example 1

[0028] The example provides a method of steam cracking powered by electricity, which is carried out using the device shown in FIG. 1. The device includes a power supply (300 KW medium-frequency power supply), a capacitor (matching with the medium-frequency power supply), an induction coil (copper-core coil, 30 cm in length, wrapped around the outside of the reaction tube) and a steam cracking reaction tube (316L stainless steel, 30 cm in length, 1.7 cm in inner diameter), wherein the induction coil is connected to the power supply to form a circuit, and the power supply is connected in parallel with the capacitor. The power supply is used to adjust the electricity to a current of appropriate frequency, which is then input into the capacitor, through which the induction coil is powered. Electromagnetic induction generated between the steam cracking reaction tube and the energized induction coil starts generating heat, which heats up the steam cracking raw material inside the reaction tube in order to allow the steam cracking reaction to take place.

[0029] In this example, cyclohexene, cyclohexane, a mixture of cyclohexene and cyclohexane, and industrial cyclohexane samples are used as cracking raw materials for the steam cracking reaction, respectively, wherein the industrial cyclohexane samples comprise naphtha sample produced as a by-product of coal-to-liquid production and reformed raffinate oil samples. The physical parameters of them are shown in Tables 1 and 2, respectively. The reaction conditions and reaction results are shown in Table 3.

TABLE-US-00001 TABLE 1 Physical parameters of naphtha samples produced as a by-product of coal-to-liquid production Initial Final distillation distillation Total Density point 10% 50% 90% point distillation kg/m.sup.3 C. C. C. C. C. ml 760-790 78 90 101 119 150 98

TABLE-US-00002 TABLE 2 Physical parameters of reformed raffinate oil samples Initial Final distillation distillation Total Density point 10% 50% 90% point distillation kg/m.sup.3 C. C. C. C. C. ml 678.5 67 69 74 85 99 98 678.3 66 70 74 83 106 99

[0030] The data in Table 2 are the results of the tests under two different experiments.

TABLE-US-00003 TABLE 3 Reaction conditions Water- Reaction Residence Cracking raw oil Voltage Current Power Frequency temperature time Sampling materials ratio V A KW KHz C. s time Cyclohexene 0.5 72.89 9.49 1.12 13.3 800 0.4 1 h (analytically pure) 0.5 74.23 9.54 1.09 13.4 0.4 1.5 h Cyclohexane: 0.5 77.00 9.72 1.12 13.0 750 0.4 1 h cyclohexene 0.5 77.00 9.72 1.12 13.2 0.4 1.5 h (mass ratio 3:7) 0.5 77.00 9.72 1.2 13.1 800 0.4 3 h 0.5 77.00 9.72 1.2 13.2 0.4 3.5 h 0.5 77.00 9.89 1.24 13.0 850 0.4 5 h 0.5 75.62 9.72 1.2 13.2 0.4 5.5 h Cyclohexane: 0.5 72.89 9.49 1.09 13.4 750 0.4 1.5 h cyclohexene 0.5 72.89 9.49 1.2 13.5 0.4 2 h (mass ratio 5:5) 0.5 74.23 9.72 1.12 13.2 800 0.4 3.5 h 0.5 74.23 9.72 1.09 13.3 0.4 4 h Cyclohexane: 0.5 77.00 9.66 1.27 13.2 750 0.4 1 h cyclohexene 0.5 77.00 9.66 1.16 13.1 0.4 1.5 h (mass ratio 7:3) 0.5 78.39 9.95 1.12 13.1 800 0.4 2.5 h 0.5 78.39 9.95 1.12 13.0 0.4 3 h 0.5 77.00 9.83 1.2 13.3 850 0.4 4 h 0.5 77.00 9.83 1.27 13.4 0.4 4.5 h Cyclohexane 0.5 63.24 8.05 0.8 13.4 800 0.4 1 h (analytically pure) 0.5 63.24 8.05 0.8 13.3 0.4 1.5 h Huidong 0.4 75.62 9.66 1.01 13.1 800 0.7 2 h Cyclohexane 0.4 75.62 9.72 1.01 13.3 0.7 3 h 0.4 77.00 9.89 101 13.1 850 0.7 1 h 40 mi 0.4 27.49 1.84 0.71 13.2 0.7 2 h Yatong 0.4 77.00 9.77 1.27 13.1 800 0.7 1 h Cyclohexane 0.4 77.00 9.77 1.16 13.2 0.7 1.5 h (reformed 0.4 77.00 9.89 1.2 13.4 850 0.7 2.5 h raffinate oil) 0.4 77.00 9.95 1.2 13.3 0.7 3 h Products Cracking raw Total materials Methane Ethane Ethylene Propane Propylene Butene trienes Cyclohexene 3.4974 1.4469 47.2171 0.1012 3.1516 39.4092 89.7779 (analytically pure) 3.5458 1.3643 49.7403 0.0454 3.0688 36.2263 89.0354 Cyclohexane: 3.1279 1.9498 42.489 0.0453 3.9374 39.3554 85.7818 cyclohexene 3.3194 2.127 38.9112 0.0937 3.9615 37.3018 80.1745 (mass ratio 3:7) 3.0191 1.524 38.5642 0.0503 3.75 38.7742 81.0884 3.9027 1.8915 41.0005 0.057 4.0237 34.1912 79.2154 4.4708 2.0958 38.7481 0.0512 3.4374 32.6918 74.8773 5.0244 2.0881 39.5009 0.0567 3.5109 31.2597 74.2715 Cyclohexane: 3.5636 2.2053 38.5089 0.0603 5.0733 37.4382 81.0224 cyclohexene 3.2405 2.047 34.1241 0.0564 4.6804 36.91 75.7145 (mass ratio 5:5) 5.1709 2.5124 37.8757 0.0711 4.8495 28.691 21.4162 5.0284 2.3579 34.062 0.0643 4.2468 22.9179 61.2267 Cyclohexane: 9.046 6.4634 36.6466 0.2396 10.7173 22.5383 69.9022 cyclohexene 8.7891 6.3974 35.7076 0.2365 10.7589 21.7985 68.265 (mass ratio 7:3) 4.6004 3.0648 32.8679 0.0666 5.2291 23.0243 61.1213 4.7071 3.5438 35.3197 0.1005 6.7098 24.1722 66.2017 6.4373 3.5144 40.671 0.0755 5.4114 20.7051 66.7875 6.8628 3.3383 41.3017 0.0732 5.1064 19.4559 65.864 Cyclohexane 4.4699 4.3835 34.4622 0.0797 9.9466 27.1383 71.5471 (analytically pure) 4.0814 4.0981 32.0438 0.0809 9.2811 27.2341 68.559 Huidong 16.9915 5.9973 24.9578 0.7405 20.3573 13.2808 58.5959 Cyclohexane 21.4102 7.2942 29.5447 0.8218 20.1825 8.6577 58.3849 25.1457 4.8292 40.4643 0.253 10.2572 11.2306 61.9521 25.1152 4.2494 39.7559 0.2788 12.0778 11.1931 63.0268 Yatong 25.1589 5.0748 32.0324 0.6008 14.5279 3.5826 50.1429 Cyclohexane 26.7583 5.437 35.1806 0.4871 12.2206 3.2053 50.6065 (reformed 31.8051 4.0287 42.8874 0.2183 6.6009 3.1222 52.6105 raffinate oil) 32.7209 3.7536 43.5557 0.1649 5.5012 2.9457 52.0026

[0031] CN103588608A discloses a method for the preparation of butadiene by steam cracking using cyclohexene and naphtha as raw materials, and in the case where pure cyclohexene is used as the cracking raw material, the yield of butadiene only reaches 13.51%. As can be seen from Table 3, by using electromagnetic induction to apply electrical energy to the steam cracking of cyclohexane and cyclohexene, the yield of 1,3-butadiene can reach more than 19%, and the total yield of triene can reach more than 60%, which are significantly higher than that of the conventional steam cracking process.

TABLE-US-00004 TABLE 4 Parameter upper limits under industrial electricity conditions Power Voltage Current Frequency 200 KW 3-phase 380 V 305 A 5-20 KHz 300 KW 3-phase 380 V 455 A 5-20 KHz 500 KW 3-phase 380 V 760 A 5-20 KHz 200 KW 3-phase 220 V 530 A 5-20 KHz 300 KW 3-phase 220 V 790 A 5-20 KHz 500 KW 3-phase 220 V 1320 A 5-20 KHz

[0032] The voltage, current and power given in Table 3 are parameters under experimental conditions. In industrial applications, the size of the reaction tube, and the like, will be larger, and the degree of reaction and experimental conditions will be different. Industrial electricity is generally 220V three-phase or 380V three-phase, and the current and power can be adjusted according to the actual situation (Table 4 shows the upper limit of the parameters under industrial electricity conditions). This difference in parameters will not bring substantial difference to the products.