STEEL SMELTING METHOD

Abstract

The present invention provides an iron and steel smelting method, wherein separating the product of the catalytic dehydrogenation reaction on propane to obtain a mixed gas containing hydrogen, methane, and ethane; and mixing the mixed gas with water and/or CO.sub.2 as a catalytic conversion raw material, and producing synthesis gas by means of a catalytic conversion reaction, the synthesis gas being used for iron smelting, and electricity being used to provide energy for the catalytic conversion reaction. The method catalytic dehydrogenation of propane is combined with steam cracking, and unconverted propane is prepared into methane, ethane, etc. by means of steam cracking; synthesis gas is further obtained by means of reforming and component adjustment, and the synthesis gas is a good raw material for direct reduction of iron.

Claims

1. A steel smelting method, comprising the steps of: subjecting propane to a catalytic dehydrogenation reaction, wherein electricity is used to provide power for the catalytic dehydrogenation reaction; separating the products of the catalytic dehydrogenation reaction to give a mixed gas containing hydrogen, methane, and ethane, as well as ethylene and propylene; mixing the mixed gas containing hydrogen, methane, and ethane with water and/or CO.sub.2, and then using the mixture as a catalytic conversion feedstock to produce a syngas for iron smelting by a catalytic conversion reaction, wherein electricity is used to provide power for the catalytic conversion reaction.

2. The method according to claim 1, wherein the catalytic dehydrogenation reaction is carried out in a reaction tube; and a front section of the reaction tube is filled with a catalytic dehydrogenation catalyst, to allow propane to undergo the catalytic dehydrogenation reaction; a rear section of the reaction tube is not filled with a catalyst, to allow propane to undergo a steam cracking reaction.

3. The method according to claim 1, wherein the power is provided by heating the reaction tube by means of an induction coil, and the heat is supplied from the reaction tube to the reaction materials inside the reaction tube.

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

5. The method according to claim 3, 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 the medium frequency is 50-3,000 Hz.

6. The method according to claim 3, wherein the frequency of the current inputted into the induction coil is regulated by a power supply and a capacitor.

7. The method according to claim 6, 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.

8. The method according to claim 6, wherein the power of the power supply is 100-1,000 KW.

9. The method according to claim 3, wherein the induction coil is one or a combination of two or more selected from ferrite coils, iron core coils, hollow coils, and copper core coils.

10. The method according to claim 1, wherein the raw material for the catalytic dehydrogenation reaction is propane or a mixed gas of propane and hydrogen and the volume ratio of propane to hydrogen is from 1:1 to 5:1.

11. The method according to claim 1, wherein the catalyst for the catalytic dehydrogenation reaction is a platinum-based catalyst or a chromium-based catalyst.

12. The method according to claim 11, wherein the catalyst for the catalytic dehydrogenation reaction is a PtSnK/Al.sub.2O.sub.3 catalyst or a CrK dehydrogenation catalyst.

13. The method according to claim 1, wherein the reaction temperature of the catalytic dehydrogenation reaction is 500-1,000? C.

14. The method according to claim 2, wherein the reaction temperature of the steam cracking reaction is 500-1,000? C.; the water-to-oil ratio for the steam cracking reaction is 0.3-0.7; and the residence time of the steam cracking reaction is 0.1-1.0 s.

15. The method according to claim 14, wherein the water-to-oil ratio for the steam cracking reaction is 0.4-0.5.

16. The method according to claim 1, wherein the method further comprises a step of adjusting the composition of the syngas to a volume percentage content of CO+H.sub.2 of >90%, and a volume ratio of H.sub.2/CO of 1.5-2.5.

17. The method according to claim 1, wherein: a catalyst of the catalytic conversion reaction has an active component of nickel and a carrier which is one or a combination of two or more selected from alumina, magnesium oxide and magnesium-aluminum spinel, and the content of the active component is 5-20% based on the total mass of the catalyst; and the reaction conditions of the catalytic conversion reaction are: a pressure of 0.1-1.0 MPa, a reaction temperature of 500-1,100? C., a space velocity of 500-4,000 h.sup.?1, and a volume ratio of water and/or CO.sub.2 to CH.sub.4 of 1.2-1.5/1.

18. The method according to claim 2, wherein the material for the reaction tube is a metal or alloy.

19. 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-alloyed steel or Manaurite XTM material for steam cracking furnace.

20. The method according to claim 18, wherein the reaction tube has an inner diameter of 50-250 mm.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0037] FIG. 1 is a schematic circuit diagram of the power supply, electromagnetic coil, and capacitor of the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0038] 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

[0039] This example provides a steel smelting method comprising the following steps: [0040] the catalyst is filled into a reaction tube, and activated with hydrogen or nitrogen; [0041] the raw materials containing propane are introduced into the reaction tube for a catalytic dehydrogenation reaction; [0042] the products of the catalytic dehydrogenation reaction are separated to give a mixed gas containing hydrogen, methane and ethane, as well as ethylene and propylene in which the ethylene and propylene are output as products; [0043] the mixed gas containing hydrogen, methane and ethane is subjected to the catalytic conversion: the mixed gas is allowed to enter the catalytic conversion reactor tube, and then reacts with the input CO.sub.2 in the catalytic conversion reactor tube to convert hydrocarbons such as methane, ethane, and CO.sub.2 into CO and H.sub.2; [0044] the composition of the catalytically converted gas product is adjusted to the extent that the volume percentage content of CO+H.sub.2 is >90% and the volume ratio of H.sub.2/CO is 1.5-2.5 (preferably 1.7-1.9), and then it is fed into a gas-based shaft furnace for the production of sponge iron; [0045] in the gas-based shaft furnace, iron ore oxide pellets are added from the top of the shaft furnace and move from top to bottom, the syngas enters the furnace from the perimeter pipe of the reduction section at the bottom of the shaft furnace and flows from bottom to top, wherein the syngas undergoes a reduction reaction with the oxide pellets to obtain sponge iron and top gas, with the main reaction: 3H.sub.2+Fe.sub.2O.sub.3=2Fe+3H.sub.2O. There is no carbon dioxide emission during the above process.

[0046] The above top gas can be subjected to a washing and cooling treatment, a compression treatment and a desulfurization and decarburization treatment at one time, so as to obtain an unreacted reducing gas.

[0047] In the above reaction, electricity is used to provide power for the catalytic dehydrogenation reaction and catalytic conversion reaction through electromagnetic induction, 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), a catalytic dehydrogenation reaction tubes (316L stainless steel, 30 cm in length, 1.7 cm in inner diameter) and a catalytic conversion 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 reaction tube and the energized induction coil starts generating heat, which heats up the raw materials inside the reaction tube in order to allow the catalytic dehydrogenation and catalytic conversion reactions to take place. In the reaction tube, the raw materials enter from the upper end of the reaction tube and the products leave from the lower end of the reaction tube.

[0048] The composition of the propane feedstock used in the example is shown in Table 1.

TABLE-US-00001 TABLE 1 Composition of the propane feedstock feedstock vapor iso- n- trans- n- iso- cis- phase methane ethane ethylene propane cyclopropane propylene butane butane butene butene butene butene propane 0.227 0.0595 0.0058 97.4485 0.0221 1.4684 0.3638 0.1569 0.0867 0.0889 0.0187 0.0537

[0049] The reaction conditions and results are shown in Table 2, in which the catalyst is a Cr-based catalyst commonly used for propane dehydrogenation; the start position for catalyst filling is defined as the position between the top position of the catalyst filled in the reaction tube and the horizontal position of the inductor coil inlet; in the reaction tube, the part of the reaction tube where the induction coil is wrapped around the outside of the reaction tube is filled with catalyst, starting from the catalyst filling position and going downward; and in addition to methane, ethane, ethylene, propane, propylene, another component mainly remaining in the product is hydrogen.

[0050] The voltage, current and power given in Table 2 are parameters under experimental conditions. In industrial applications, the reaction tube would have a larger size, or the like, and the degree of reaction will be different from the experimental conditions. 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 3 shows the upper limit of the parameters under industrial electricity conditions). This difference in parameters does not make a substantial difference to the products.

TABLE-US-00002 TABLE 2 position tem- for start vol- cur- pow- fre- per- propane propyl- propyl- filling activiza- tage rent er quence ature propyl- conver- ene ene No. catalyst tion V A KW KHz ? C. methane ethane ethylene propane ene sion slectivity yield 1 2.5 cm nitrogen 32 7.9 0.3 11.4 600 2.5512 0.4036 2.8312 73.5719 19.746 24.41% 76.64% 18.71% below the purge 31 7.8 0.3 11.2 650 2.3897 0.4118 2.9089 73.6246 19.779 40.53% 36.09% 14.63% horizontal at 300? C. 45 10.2 0.5 10.7 700 25.1288 8.8634 19.7498 24.4026 20.7268 74.96% 26.36% 19.76% position for 0.5 h, of the at 590? C. induction for 0.5 h, coil inlet with space velocity of 300 h.sup.?1 2 2.5 cm nitrogen 38 7.8 0.3 11.3 600 8.0757 0.3611 1.8621 83.9201 5.2798 13.88% 28.17% 3.91% below the purge 52 11.2 0.8 12.8 650 12.97 1.3052 9.2328 64.0451 11.9417 34.28% 31.35% 10.75% horizontal at 600? C. 62 12.9 1 12.7 700 28.6929 3.8921 22.3345 31.8928 12.6049 67.27% 16.99% 11.43% position for 0.5 h, 65 13.6 1.2 12.6 800 69.4705 4.2447 22.5429 2.5492 1.0991 97.38% ?0.39% ?0.38% of the with space induction velocity coil inlet of 300 h.sup.?1 3 the nitrogen 42 9.4 0.6 13.6 550 6.1046 1.1912 10.0097 66.373 14.9502 31.89% 43.38% 13.83% horizontal purge 43 9.5 0.6 13.8 600 15.904 3.6231 23.9943 31.9869 22.7686 67.18% 32.54% 21.86% position at 300? C. 51 10.4 0.8 13.6 650 34.0685 7.3404 38.5291 6.8664 10.9231 92.95% 10.44% 9.70% of the for 1 h, induction at 550? C. coil inlet for 1 h, with space velocity of 300 h.sup.?1 4 the hydrogen 32 8 0.3 11.8 550 8.6396 2.1064 12.6161 58.8797 16.5837 39.58% 39.19% 15.51% horizontal purge at 35 8.5 0.4 12.3 600 31.4723 7.9834 37.15 9.6902 11.894 90.06% 11.88% 10.70% position 350? C. 36 8.6 0.4 12.4 650 54.5859 8.7136 31.664 2.8599 1.9471 97.07% 0.51% 0.49% of the for 2 h, induction with flow coil inlet rate of 32 ml/min

Example 2

[0051] This example provides a steel smelting method in which the catalytic dehydrogenation reaction and the steam cracking reaction of propane are integrated into a single reaction tube, and is the same as Example 1 except for the following steps:

[0052] In the reaction tube, catalyst filling begins at a point corresponding to 2.5 cm below the horizontal position of the induction coil inlet; the catalyst is filled until it corresponds to the general length of the induction coil outside the reaction tube, and the remaining portion is not filled with catalyst; [0053] nitrogen is used for activation, with a purge of 0.5 h at 650? C. and a space velocity of 300 h.sup.?1; [0054] the raw materials containing propane and water are introduced into the reaction tube for the catalytic dehydrogenation reaction; [0055] the product of the catalytic dehydrogenation reaction undergoes the steam cracking reaction in the lower half of the reaction tube, with the water-oil ratio controlled at 0.4 and a residence time of 0.3 s; [0056] the products of the catalytic dehydrogenation reaction and the steam cracking reaction are separated to give a mixed gas containing hydrogen, methane and ethane, as well as ethylene and propylene, in which the ethylene and propylene are output as products.

[0057] Electricity is used to provide power for the steam cracking reaction through electromagnetic coil, with the same equipment, operation and parameters as in Example 1. The reaction conditions and the products are shown in Table 4.

[0058] Based on the above, it can be seen that the catalytic dehydrogenation of propane in combination with the production of sponge iron can develop new applications for the by-products of the catalytic dehydrogenation of propane, while providing new applications for electricity.

TABLE-US-00003 TABLE 3 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

TABLE-US-00004 TABLE 4 fre- temper- propane propane propylene voltage current power quency ature methane ethane ethylene propane propylene conversion selectivity yield V A KW KHz ? C. % % % % % % % % 50 10.8 0.8 13.3 650 4.3021 0.1161 0.7072 91.3066 2.877 6.30 22.93 1.45 70 14 1.3 13.5 700 7.8717 0.4396 4.4786 78.4061 8.1223 19.54 34.94 6.83 78 15.4 1.5 13.4 800 30.8997 4.4536 20.8537 32.5722 10.7535 66.57 14.31 9.53 78 15.3 1.5 13.3 850 63.2978 7.8189 24.6991 2.3788 1.715 97.56 0.26 0.25