PROCESS OF ALKALINE CATALYTIC CRACKING OF INFERIOR HEAVY OIL WITH DOUBLE REACTION TUBES IN MILLISECONDS AND GASEOUS COUPLING

Abstract

The invention provides a process of alkaline catalytic cracking of inferior heavy oil with double reaction tubes in milliseconds and gaseous coupling, the process comprising: a high-efficiency atomizing nozzle sprays the preheated heavy oil into an upper portion of a downflow reaction tube, the produced oil mist mixes with a high temperature regenerated alkaline catalyst flowing downward from a dual-regulation return feeder, so as to heat, vaporize and crack the oil mist, the obtained stream containing a cracked oil and gas and an alkali catalyst to be generated flows rapidly and downward to the bottom of the downflow reaction tube to carry out a gas-solid separation; then the cracked oil and gas obtained from the gas-solid separation enters a fractionation column to be separated, the oil slurry obtained by separating the cracked oil and gas returns to mix with the heavy oil for recyclable use, while the other products separated from the cracked oil and gas are output as intermediate products; the alkali catalyst to be generated obtained from the gas-solid separation is subject to steam stripping and enters into a lower portion of a riser gasification reactor and carries out a catalytic gasification reaction with an oxidant and water vapor at a reaction temperature of 750 C. to 1,000 C., the subsequently generated material stream containing synthesis gas and regenerated alkaline catalyst flows rapidly and upward to a top of the riser gasification reactor to carry out a gas-solid separation; the high-temperature regenerated alkaline catalyst obtained from the gas-solid separation flows into the dual-regulation return feeder, wherein a portion of the high-temperature regenerated alkaline catalyst flows into the downflow reaction tube to continue to crack the heavy oil, the remaining portion of the high-temperature regenerated alkaline catalyst returns to the riser gasification reactor so as to continue the regeneration gasification; the synthesis gas obtained from the gas-solid separation is subject to a heat exchange and then output as a product.

Claims

1. A process of alkaline catalytic cracking of inferior heavy oil with double reaction tubes in milliseconds and gaseous coupling, wherein the process comprising: 1) a high-efficiency atomizing nozzle sprays the inferior heavy oil preheated to 180 C.-350 C. from a feed inlet of a downflow reaction tube into an upper portion of the downflow reaction tube, the produced oil mist mixes with a high temperature regenerated alkaline catalyst having a temperature ranging from 700 C.-950 C. flowing downward from a dual-regulation return feeder in milliseconds, so as to heat, vaporize and crack the oil mist, the cracking reaction temperature is within a range of 530 C.-850 C.; a stream containing a cracked oil and gas and a coked alkali catalyst to be generated is obtained, this stream flows rapidly and downward to a rapid gas-solid separator at the bottom of the downflow reaction tube to carry out a gas-solid separation to obtain the cracked oil and gas and the coked alkali catalyst to be generated respectively; 2A) the cracked oil and gas enters a fractionation column to be chilled and separated, thereby obtain a column bottom oil slurry and other products including gasoline, diesel oil, liquefied gas and cracked dry gas, respectively; the column bottom oil slurry returns to mix with the heavy oil for recyclable use, and the other products including gasoline, diesel oil, liquefied gas and cracked dry gas are output as intermediate products; 2B) the coked alkali catalyst to be generated is subject to steam stripping and then passes through a flow controller and enters into a lower portion of a riser gasification reactor to mix with an oxidant and water vapor to carry out a catalytic gasification regeneration reaction at a reaction temperature of 750 C. to 1,000 C., thereby generating a material stream containing synthesis gas and regenerated alkaline catalyst, this material stream flows rapidly and upward to a gas-solid separator on the top of the riser gasification reactor to carry out a gas-solid separation to obtain a high-temperature regenerated alkaline catalyst and a synthesis gas, respectively; 3A) the high-temperature regenerated alkaline catalyst flows into the dual-regulation return feeder such that a portion of the high-temperature regenerated alkaline catalyst with a catalyst/oil ratio of 3-12 flows into a top of the downflow reaction tube, thereby participating in the circulation and cracking of the heavy oil in the downflow reaction tube, and the remaining portion of the high-temperature regenerated alkaline catalyst passes through a recycle tube and returns to a lower portion of the riser gasification reactor so as to continue participation in the gasification regeneration reaction; 3B) the synthesis gas is subject to a heat exchange and then output as a product.

2. The process of alkaline catalytic cracking of inferior heavy oil with double reaction tubes in milliseconds and gaseous coupling according to claim 1 wherein the oxidant is one of oxygen, air, and oxygen-enriched air.

3. The process of alkaline catalytic cracking of inferior heavy oil with double reaction tubes in milliseconds and gaseous coupling according to claim 1, wherein the alkaline catalyst is one of calcium aluminate porous microsphere, magnesium aluminum spinel porous microsphere, calcium silicate porous microsphere, magnesium silicate porous microsphere, a porous carrier loaded with alkali metal or/and alkaline-earth metal or a mixture thereof, the particle size ranges from 5 m to 300 m.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0028] FIG. 1 is a schematic diagram of a technological process in the present invention.

DESCRIPTION OF THE REFERENCE SIGNS

[0029] 1. gas-solid separator;

[0030] 2. dual-regulation return feeder;

[0031] 3. high-efficiency atomizing nozzle;

[0032] 4. downflow reaction tube:

[0033] 5. rapid gas-solid separator;

[0034] 6. cracked gas outlet;

[0035] 7. flow controller;

[0036] 8. steam inlet;

[0037] 9. oxidant inlet;

[0038] 10. riser gasification reactor;

[0039] 11. heat exchanger;

[0040] 12. synthesis gas outlet;

[0041] 13. recycle tube;

[0042] 14. fractionation column.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0043] Each of the following examples illustrates the process of the present invention by referring to FIG. 1.

[0044] The flow diagram shown in FIG. 1 comprises the following steps:

[0045] 1) a high-efficiency atomizing nozzle 3 sprays the inferior heavy oil preheated to 180 C.-350 C. from a feed inlet of a downflow reaction tube 4 into an upper portion of the downflow reaction tube 4, the produced oil mist mixes with a regenerated alkaline catalyst having a temperature ranging from 700 C.-950 C. flowing downward from a dual-regulation return feeder 2 in milliseconds, so as to heat, vaporize and crack the oil mist, the cracking reaction temperature is within a range of 530 C.-850 C.; a stream containing a cracked oil and gas and a coked alkali catalyst to be generated is obtained, this stream flows rapidly and downward to a rapid gas-solid separator 5 at the bottom of the downflow reaction tube 4 to carry out a gas-solid separation to obtain the cracked oil and gas and the coked alkali catalyst to be generated respectively;

[0046] 2A) the cracked oil and gas derived from step 1) passes through a cracked gas outlet 6 and enters a fractionation column 14 to be chilled and separated, thereby obtain a column bottom oil slurry and other products such as gasoline, diesel oil, liquefied gas and cracked dry gas, respectively; the column bottom oil slurry returns to mix with the heavy oil for recyclable use, and the other products, i.e. gasoline, diesel oil, liquefied gas and cracked dry gas, are output as intermediate products;

[0047] 2B) the coked alkali catalyst to be generated derived from step 1) is subject to steam stripping and then passes through a flow controller 7 and enters into a lower portion of a riser gasification reactor 10 to mix with an oxidant introduced through an oxidant inlet 9 and water vapor introduced through a steam inlet 8 to carry out a gasification reaction at a reaction temperature of 750 C. to 1,000 C., thereby generating a material stream containing synthesis gas and regenerated alkaline catalyst, this material stream flows rapidly and upward to a gas-solid separator 1 on the top of the riser gasification reactor 10 to carry out a gas-solid separation to obtain a high-temperature regenerated alkaline catalyst and a synthesis gas, respectively;

[0048] 3A) the high-temperature regenerated alkaline catalyst derived from step 2B) flows into the dual-regulation return feeder 2 such that a portion of the high-temperature regenerated alkaline catalyst with a catalyst/oil ratio of 3-12 flows into a top of the downflow reaction tube 4, thereby participating in the circulation and cracking of the heavy oil in the downflow reaction tube, and the remaining portion of the high-temperature regenerated alkaline catalyst passes through a recycle tube 13 and returns to a lower portion of the riser gasification reactor 10 so as to continue participation in the gasification regeneration reaction;

[0049] 3B) the synthesis gas derived from step 2B) is subject to a heat exchange with a heat exchanger 11 and then output as a product through a synthesis gas outlet 12.

[0050] The key property parameters of the inferior heavy oil processed in the following examples and comparative examples are shown in Table 1:

TABLE-US-00001 TABLE 1 Density (kg/m.sup.3, 20 C.) 1,038 Viscosity (mm .Math. s.sup.1, 100 C.) 520 Residual carbon content (wt %) 20 Carbon content (wt %) 85.8 Hydrogen content (wt %) 6.9

[0051] The yield of olefins refers to the total yield of three olefins (i.e., ethylene, propylene and butene) derived from cracked dry gas.

[0052] The yield of light oil refers to the total yield of liquefied gas, gasoline and diesel oil.

[0053] The yield of hydrogen gas: the yield of hydrogen in the synthesis gas produced by per ton of heavy oil during the gasification regeneration process in the technological process.

EXAMPLE 1

[0054] The alkaline catalyst used in the example is a calcium silicate porous microsphere having a particle size ranging from 15-150 m.

[0055] The technological process is as follows:

[0056] 1) a high-efficiency atomizing nozzle 3 sprays the inferior heavy oil preheated to 200 C. from a feed inlet of a downflow reaction tube 4 into an upper portion of the downflow reaction tube 4, the produced oil mist mixes with a regenerated alkaline catalyst having a temperature of 800 C. flowing downward from a dual-regulation return feeder 2 in milliseconds, so as to heat, vaporize and crack the oil mist, the cracking reaction temperature is 580 C.; a stream containing a cracked oil and gas and a coked alkali catalyst to be generated flows rapidly and downward to a rapid gas-solid separator 5 at the bottom of the downflow reaction tube 4 to carry out a gas-solid separation;

[0057] 2A) the cracked oil and gas derived from step 1) passes through a cracked gas outlet 6 and enters a fractionation column 14 to be chilled and separated, the obtained column bottom oil slurry returns to mix with the heavy oil for recyclable use, and the other products, i.e. gasoline, diesel oil, liquefied gas and cracked dry gas, are output as intermediate products;

[0058] 2B) the coked alkali catalyst to be generated derived from step 1) is subject to steam stripping and then passes through a flow controller 7 and enters into a lower portion of a riser gasification reactor 10 to mix with an oxidant introduced through an oxidant inlet 9 and water vapor introduced through a steam inlet 8 to carry out a gasification reaction at a reaction temperature of 870 C., thereby generating a material stream containing synthesis gas and regenerated alkaline catalyst, this material stream flows rapidly and upward to a gas-solid separator 1 on the top of the riser gasification reactor 10 to carry out a gas-solid separation;

[0059] 3A) the high-temperature regenerated alkaline catalyst derived from step 2B) flows into the dual-regulation return feeder 2 such that a portion of the high-temperature regenerated alkaline catalyst with a catalyst/oil ratio of 6 flows into a top of the downflow reaction tube 4, thereby participating in the circulation and cracking of the heavy oil in the downflow reaction tube, and the remaining portion of the high-temperature regenerated alkaline catalyst passes through a recycle tube 13 and returns to a lower portion of the riser gasification reactor 10 so as to continue participation in the gasification regeneration reaction;

[0060] 3B) the synthesis gas derived from step 2B) is subject to a heat exchange with a heat exchanger 11 and then output as a product through a synthesis gas outlet 12.

[0061] The result shows that the yield of olefins is 30%, the yield of light oil is 87%, and the yield of hydrogen gas is 250 Nm.sup.3.

[0062] During the operation of the apparatus, if the gasification regeneration temperature is lowered from 870 C. to 800 C., while the catalyst/oil ratio during the cracking of heavy oil is increased from 6 to 7.9, and the cycle ratio of the high-temperature regenerated alkaline catalyst in the riser gasification reactor is hiked, the yields of the obtained olefins and light oil are almost unchanged, and the yield of hydrogen gas is increased to 280 Nm.sup.3 in this case;

[0063] During the operation of the apparatus, if the catalyst/oil ratio during the cracking of heavy oil is raised from 6 to 6.8, the cracking temperature is increased from 580 C. to 610 C., and the gasification regeneration operating conditions may be kept substantially unchanged. In this case, the yield of olefins and the yield of light oil increase by 0.5 percentage point respectively, while the yield of hydrogen gas is basically unchanged.

[0064] As can be seen from the above Example 1 that the process of the present invention may adopt various control means according to the required yields of olefins and light oil and the desirable yield of hydrogen gas, and it is convenient to perform a flexible adjustment and control.

EXAMPLE 2

[0065] The process of alkaline catalytic cracking of inferior heavy oil with double reaction tubes in milliseconds and gaseous coupling is performed in accordance with Example 1, except that the gas entering the oxidant inlet 9 is changed from the oxygen to the oxygen-enriched air having an oxygen content of 35 volume %.

[0066] The result shows that the yield of olefins is 30%, the yield of light oil is 87%, and the yield of hydrogen gas is 220 Nm.sup.3.

EXAMPLE 3

[0067] The process of alkaline catalytic cracking of inferior heavy oil with double reaction tubes in milliseconds and gaseous coupling is performed in accordance with Example 1, except that the gas entering the oxidant inlet 9 is changed from the oxygen to the air.

[0068] The result shows that the yield of olefins is 30%, the yield of light oil is 87%, and the yield of hydrogen gas is 190 Nm.sup.3.

COMPARATIVE EXAMPLE 1

[0069] The process of alkaline catalytic cracking of inferior heavy oil with double reaction tubes in milliseconds and gaseous coupling is performed in accordance with Example 1, except that the catalyst used in the comparative example is acidic alumina microspheres having a particle size range of 15-150 m.

[0070] The result shows that the yield of olefins is 20%, the yield of light oil is 73%, and the yield of hydrogen gas is 450 Nm.sup.3.

COMPARATIVE EXAMPLE 2

[0071] The alkaline catalyst used in this comparative example is a calcium silicate porous microsphere having a particle size range of 15-150 m.

[0072] 1) a high-efficiency atomizing nozzle sprays the inferior heavy oil preheated to 200 C. from a feed inlet of a downflow reaction tube into an upper portion of the downflow reaction tube, the produced oil mist mixes with a regenerated alkaline catalyst having a temperature of 800 C. flowing downward from a return feeder in milliseconds, so as to heat, vaporize and crack the oil mist, the cracking reaction temperature is 580 C.; a stream containing a cracked oil and gas and a coked alkali catalyst to be generated flows rapidly and downward to a rapid gas-solid separator at the bottom of the downflow reaction tube to carry out a gas-solid separation;

[0073] 2A) the cracked oil and gas derived from step 1) passes through a cracked gas outlet and enters a fractionation column to be chilled and separated, the obtained column bottom oil slurry returns and mixes with the heavy oil for recyclable use, and the other products, i.e. gasoline, diesel oil, liquefied gas and cracked dry gas, are output as intermediate products;

[0074] 2B) the coked alkali catalyst to be generated derived from step 1) is subject to steam stripping and then passes through a flow controller and enters into a lower portion of a riser gasification reactor to mix with an oxidant introduced through an oxidant inlet and water vapor introduced through a steam inlet to carry out a gasification reaction at a reaction temperature of 870 C., the generated material stream containing synthesis gas and regenerated alkaline catalyst flows rapidly and upward to a gas-solid separator on the top of the riser gasification reactor to carry out a gas-solid separation;

[0075] 3A) all the high-temperature regenerated alkaline catalyst derived from step 2B) passes through the return feeder to flow into a top of the downflow reaction tube, thereby participating in the circulation and cracking of the heavy oil;

[0076] 3B) the synthesis gas derived from step 2B) is subject to a heat exchange with a heat exchanger 11 and then output as a product through a synthesis gas outlet 12.

[0077] The result shows that the yield of olefins is 30%, the yield of light oil is 87%, and the yield of hydrogen gas is 250 Nm.sup.3.

[0078] With respect to a given raw material heavy oil in the comparative example, in order to ensure the above-mentioned yields of the olefins, light oil and hydrogen gas, the reaction temperatures and the recycle ratio of catalyst in each part must be strictly maintained during the operation of the apparatus following an establishment of the balance between the catalytic cracking reaction and the catalyst regeneration reaction, otherwise it will easily lead to unstable operation of the apparatus, or even cause a temperature runaway phenomenon. For example, in order to increase the yield of olefins, the cracking temperature may be raised to 610 C., the ratio of water vapor/oxidant must be adjusted to lower the yield of hydrogen gas, thus it is required to re-adjust the operating conditions of the entire apparatus.

[0079] Therefore, the process in the comparative example has extremely high requirements on the manipulation and control, and the apparatus has poor manipulation flexibility, thus the yields of hydrogen gas, olefins and light oil cannot be effectively adjusted and controlled.

[0080] As can be seen from a comparison between Example 1 and Comparative Example 2, Example 1 has preferable manipulation flexibility, and the catalystloil ratio and the cracking temperature during the cracking process of heavy oil are not completely confined by the gasification regeneration temperature, and it can also achieve higher target product yields and increase production efficiency.