CN114836239B - Device and method for recovering heat of pyrolysis gas and removing heavy components - Google Patents
Device and method for recovering heat of pyrolysis gas and removing heavy components Download PDFInfo
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- CN114836239B CN114836239B CN202110143235.6A CN202110143235A CN114836239B CN 114836239 B CN114836239 B CN 114836239B CN 202110143235 A CN202110143235 A CN 202110143235A CN 114836239 B CN114836239 B CN 114836239B
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- 238000000197 pyrolysis Methods 0.000 title claims abstract description 170
- 238000000034 method Methods 0.000 title claims abstract description 49
- 239000002994 raw material Substances 0.000 claims abstract description 254
- 238000011084 recovery Methods 0.000 claims abstract description 227
- 239000007788 liquid Substances 0.000 claims abstract description 150
- 239000003921 oil Substances 0.000 claims abstract description 144
- 238000010791 quenching Methods 0.000 claims abstract description 139
- 230000000171 quenching effect Effects 0.000 claims abstract description 131
- 239000012071 phase Substances 0.000 claims abstract description 38
- 239000002245 particle Substances 0.000 claims abstract description 30
- 239000007791 liquid phase Substances 0.000 claims abstract description 24
- 239000000295 fuel oil Substances 0.000 claims abstract description 19
- 238000001816 cooling Methods 0.000 claims abstract description 12
- 239000007787 solid Substances 0.000 claims abstract description 12
- 239000000463 material Substances 0.000 claims abstract description 6
- 238000005336 cracking Methods 0.000 claims description 108
- 239000000571 coke Substances 0.000 claims description 43
- 238000004140 cleaning Methods 0.000 claims description 24
- 238000005192 partition Methods 0.000 claims description 22
- 238000005194 fractionation Methods 0.000 claims description 15
- 238000005235 decoking Methods 0.000 claims description 13
- 238000000926 separation method Methods 0.000 claims description 9
- 238000001704 evaporation Methods 0.000 claims description 7
- 230000008020 evaporation Effects 0.000 claims description 7
- ATUOYWHBWRKTHZ-UHFFFAOYSA-N Propane Chemical compound CCC ATUOYWHBWRKTHZ-UHFFFAOYSA-N 0.000 claims description 6
- 238000000605 extraction Methods 0.000 claims description 6
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 5
- 239000007790 solid phase Substances 0.000 claims description 5
- 230000001174 ascending effect Effects 0.000 claims description 4
- OTMSDBZUPAUEDD-UHFFFAOYSA-N Ethane Chemical compound CC OTMSDBZUPAUEDD-UHFFFAOYSA-N 0.000 claims description 3
- 239000002283 diesel fuel Substances 0.000 claims description 3
- 238000002156 mixing Methods 0.000 claims description 3
- JTJMJGYZQZDUJJ-UHFFFAOYSA-N phencyclidine Chemical class C1CCCCN1C1(C=2C=CC=CC=2)CCCCC1 JTJMJGYZQZDUJJ-UHFFFAOYSA-N 0.000 claims description 3
- 239000001294 propane Substances 0.000 claims description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 3
- 239000004215 Carbon black (E152) Substances 0.000 claims description 2
- 239000001273 butane Substances 0.000 claims description 2
- 125000004432 carbon atom Chemical group C* 0.000 claims description 2
- 239000008236 heating water Substances 0.000 claims description 2
- 229930195733 hydrocarbon Natural products 0.000 claims description 2
- 150000002430 hydrocarbons Chemical class 0.000 claims description 2
- IJDNQMDRQITEOD-UHFFFAOYSA-N n-butane Chemical compound CCCC IJDNQMDRQITEOD-UHFFFAOYSA-N 0.000 claims description 2
- OFBQJSOFQDEBGM-UHFFFAOYSA-N n-pentane Natural products CCCCC OFBQJSOFQDEBGM-UHFFFAOYSA-N 0.000 claims description 2
- 238000012856 packing Methods 0.000 claims description 2
- 238000012546 transfer Methods 0.000 claims description 2
- 239000007789 gas Substances 0.000 abstract description 336
- VGGSQFUCUMXWEO-UHFFFAOYSA-N Ethene Chemical compound C=C VGGSQFUCUMXWEO-UHFFFAOYSA-N 0.000 abstract description 20
- 239000005977 Ethylene Substances 0.000 abstract description 20
- 238000005265 energy consumption Methods 0.000 abstract description 9
- 239000002918 waste heat Substances 0.000 abstract description 6
- 238000004134 energy conservation Methods 0.000 abstract description 4
- 230000007774 longterm Effects 0.000 abstract description 2
- 230000000052 comparative effect Effects 0.000 description 6
- 238000010992 reflux Methods 0.000 description 5
- 238000010586 diagram Methods 0.000 description 4
- 238000004891 communication Methods 0.000 description 3
- 239000007858 starting material Substances 0.000 description 3
- 238000004939 coking Methods 0.000 description 2
- 238000009833 condensation Methods 0.000 description 2
- 230000005494 condensation Effects 0.000 description 2
- 238000010790 dilution Methods 0.000 description 2
- 239000012895 dilution Substances 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 239000006227 byproduct Substances 0.000 description 1
- 239000013256 coordination polymer Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005984 hydrogenation reaction Methods 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000006116 polymerization reaction Methods 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- 239000013589 supplement Substances 0.000 description 1
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Classifications
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- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
- C10G55/00—Treatment of hydrocarbon oils, in the absence of hydrogen, by at least one refining process and at least one cracking process
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C4/00—Preparation of hydrocarbons from hydrocarbons containing a larger number of carbon atoms
- C07C4/02—Preparation of hydrocarbons from hydrocarbons containing a larger number of carbon atoms by cracking a single hydrocarbon or a mixture of individually defined hydrocarbons or a normally gaseous hydrocarbon fraction
- C07C4/04—Thermal processes
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
- C10G5/00—Recovery of liquid hydrocarbon mixtures from gases, e.g. natural gas
- C10G5/06—Recovery of liquid hydrocarbon mixtures from gases, e.g. natural gas by cooling or compressing
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
- C10G7/00—Distillation of hydrocarbon oils
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
- C10G7/00—Distillation of hydrocarbon oils
- C10G7/12—Controlling or regulating
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
- C10G9/00—Thermal non-catalytic cracking, in the absence of hydrogen, of hydrocarbon oils
- C10G9/002—Cooling of cracked gases
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- Chemical & Material Sciences (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Organic Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Production Of Liquid Hydrocarbon Mixture For Refining Petroleum (AREA)
Abstract
The invention belongs to the technical field of ethylene industry, and relates to a device and a method for recovering heat of pyrolysis gas and removing heavy components. Liquid raw material pyrolysis gas is mixed with a quenching material after heat recovery and cooled, and then enters the lower part of a fractionating tower to separate gas, liquid and solid particles, wherein liquid phase heavy component fuel oil carrying solid is sent out from a tower kettle, and gas phase enters the upper part of the fractionating tower; the gas raw material pyrolysis gas is sent to the upper part of a fractionating tower after heat recovery, is mixed with the pyrolysis gas from the lower part of the fractionating tower for further cooling, and partial components are condensed into liquid-phase quenching oil; the quenching oil is pumped out by a pump, is divided into two parts after heat recovery, one part returns to the upper part of the fractionating tower, and the other part is used as a quenching medium and is mixed with the liquid raw material pyrolysis gas after heat recovery. The method for recovering heat of the pyrolysis gas and removing heavy components remarkably improves the recovery rate of waste heat of the pyrolysis gas, can effectively control the viscosity of the quenching oil within a proper range, and has important significance for realizing long-term stable operation of an ethylene device and energy conservation and consumption reduction.
Description
Technical Field
The invention belongs to the technical field of ethylene industry, and particularly relates to a pyrolysis gas heat recovery and heavy component removal device and a pyrolysis gas heat recovery and heavy component removal method.
Background
The cracking raw materials of the ethylene device comprise naphtha, diesel oil, hydrogenation tail oil, ethane, propane, LPG and other petrochemical raw materials, the energy consumption of the cracking process accounts for 50-60% of the whole device, and the recovery of the high-temperature waste heat of the cracking gas has great significance for energy conservation and consumption reduction of the ethylene device.
The temperature of the bottom of the fractionating tower is increased, so that the amount of dilution steam generated by the quenching oil is increased, and the consumption of medium-pressure steam is reduced. But meanwhile, the viscosity of the quenching oil is continuously increased due to the increase of the content of heavy components in the quenching oil, so that the running state of the quenching oil heat exchange equipment is deteriorated, the generation amount of the dilution steam of the quenching oil is seriously insufficient, the supplement amount of the medium-pressure steam is increased, and the stable operation of an ethylene device and energy conservation and consumption reduction are finally influenced. It is therefore necessary to remove the heavies from the cracked gas and quench oil.
In the traditional process, pyrolysis gas is firstly recycled by a waste heat boiler to obtain high-grade heat energy and generate a byproduct of ultrahigh pressure steam, and the temperature of the liquid raw material pyrolysis gas is generally 400-480 ℃. After ultrahigh pressure steam is generated on part of gas raw material pyrolysis gas, the temperature is generally 350-380 ℃, then quenching oil is injected to reduce the temperature of the pyrolysis gas to 200-250 ℃, and the pyrolysis gas is sent into a fractionating tower. The other part of the gas raw material pyrolysis gas is maintained at a higher temperature, generally 420-520 ℃, after passing through the waste heat boiler, in order to ensure that the gas raw material pyrolysis gas has enough heat to gasify the intermediate components in the injected quenching oil and then returns to the fractionating tower along with the pyrolysis gas, and the non-gasified liquid phase heavy components are discharged, so as to maintain the viscosity of the quenching oil within a reasonable range.
As the temperature of the pyrolysis gas of the two gas raw materials is higher after passing through the quenching boiler, the heat recovery of the traditional process is insufficient. On the other hand, only part of quenching oil and the gas raw material pyrolysis gas can be mixed to remove heavy components, so that the viscosity control effect of the quenching oil is general.
Therefore, it is highly desirable to develop a better method for recovering heat and removing heavy components from the cracked gas.
Disclosure of Invention
In order to solve the problems of incomplete high-temperature pyrolysis gas heat recovery technology, insufficient control of the viscosity of quenching oil and the like in the prior art, the invention develops a method and a device for recovering heat and removing heavy components in quenching oil.
In order to achieve the above object, a first aspect of the present invention provides a device for recovering heat of a cracked gas and removing heavy components, the device comprising a liquid raw material cracked gas heat recovery unit, a gas raw material cracked gas heat recovery unit and a heavy component removal unit;
the liquid raw material pyrolysis gas heat recovery unit comprises a liquid raw material pyrolysis gas heat recovery facility; the liquid raw material cracking gas heat recovery facility is connected with a discharge port of the liquid raw material cracking furnace;
the gas raw material pyrolysis gas heat recovery unit comprises a first gas raw material pyrolysis gas heat recovery facility and a second gas raw material pyrolysis gas heat recovery facility; the first heat recovery facility of the gas raw material cracking gas is connected with a discharge hole of the gas raw material cracking furnace;
the heavy component removing unit comprises a fractionating tower, wherein the fractionating tower is divided into an upper part and a lower part which are communicated with each other in a gas phase through a partition plate, and the upper part and the lower part are respectively a lower part A section and an upper part B section; the fractionating tower is provided with a top gas phase discharge pipeline and a bottom liquid solid phase discharge pipeline;
a discharge pipeline of the liquid raw material pyrolysis gas heat recovery facility is connected with the lower section A of the fractionating tower; a discharge pipeline of the second heat recovery facility of the gas raw material pyrolysis gas is connected with the fractionating tower;
the bottom of the upper section B of the fractionating tower is provided with a quenching oil discharge pipeline, the quenching oil discharge pipeline is divided into two branches after being sequentially connected with a quenching oil pump and a quenching oil heat recovery facility, one branch is connected with the upper section B of the fractionating tower, and the other branch is connected with a discharge pipeline of a liquid raw material pyrolysis gas heat recovery facility or connected with the lower section A of the fractionating tower.
The second aspect of the invention provides a method for recovering heat of cracked gas and removing heavy components, which comprises the following steps:
liquid raw material cracking gas from a liquid raw material cracking furnace enters a liquid raw material cracking gas heat recovery facility to be cooled to a temperature T1, so that the liquid raw material cracking gas after heat recovery is obtained, and then enters a lower section A of a fractionating tower which is divided into an upper section and a lower section by a partition plate; before or after the liquid raw material pyrolysis gas enters the fractionating tower, the liquid raw material pyrolysis gas after heat recovery is mixed with quenching oil to be further cooled to T2;
in the section A at the lower part of the fractionating tower, the gas of the mixed material is separated from the liquid and the solid particles after the liquid raw material pyrolysis gas after heat recovery contacts the quenching oil, the separated liquid phase heavy component fuel oil with the solid particles is sent out from the tower kettle, and the separated gas phase passes through the partition plate and enters the section B at the upper part of the fractionating tower for further cooling;
the gas raw material cracking gas from the gas raw material cracking furnace enters a first heat recovery facility of the gas raw material cracking gas to be cooled to a temperature T3, then enters a second heat recovery facility of the gas raw material cracking gas to be further cooled to a temperature T4, and the gas raw material cracking gas after the second heat recovery is sent to a fractionating tower;
and (3) further cooling the gas phase obtained by separation from the lower section A of the fractionating tower and the gas raw material cracking gas subjected to secondary heat recovery in the upper section B of the fractionating tower, and condensing part of components into liquid-phase quenching oil, wherein the quenching oil from the bottom of the section B of the fractionating tower is pumped out by a quenching oil pump and subjected to heat recovery by a quenching oil heat recovery facility, one part of the quenching oil subjected to heat recovery returns to the upper section B of the fractionating tower, the other part of the quenching oil is used as quenching oil to be mixed with the liquid raw material cracking gas subjected to heat recovery, and the uncondensed components are discharged as the gas phase at the top of the fractionating tower.
The device and the method for recovering heat of the pyrolysis gas and removing heavy components remarkably improve the recovery rate of waste heat of the pyrolysis gas, can effectively control the viscosity of the quenching oil within a proper range, can reduce the number of equipment, and have important significance for realizing long-term stable operation of an ethylene device and energy conservation and consumption reduction.
Additional features and advantages of the invention will be set forth in the detailed description which follows.
Drawings
The above and other objects, features and advantages of the present invention will become more apparent by describing in more detail exemplary embodiments thereof with reference to the attached drawings, in which like reference numerals generally represent like parts throughout.
Fig. 1 is a process flow diagram of a method for recovering heat from cracked gas and removing heavy components according to an embodiment of the present invention.
Fig. 2 is a process flow diagram of another embodiment of the pyrolysis gas heat recovery and heavy component removal method provided by the invention.
Fig. 3 is a process flow diagram of another embodiment of the pyrolysis gas heat recovery and heavy component removal method provided by the invention.
FIG. 4 is a schematic diagram of a fractionation column used in the present invention.
Description of the reference numerals
P-1: a gaseous feed; p-2: quenching oil; p-4: cracking gas of a gas raw material; p-5: cracking gas of the gas raw material after primary heat recovery; p-9: cracking gas of liquid raw materials; p-10: a liquid feedstock; p-11: the gas raw material cracking gas after the second heat recovery; p-12: liquid raw material cracking gas after heat recovery; p-13: liquid phase heavy fraction fuel oil; p-14: the sent liquid phase heavy component fuel oil; p-15: cracking gas of liquid raw material after mixing with quenching oil; p-16: quenching oil after pressure boosting; p-17: recovering the heat of the quenching oil; p-18: the quenching oil returns to the section B of the fractionating tower; p-19: fractionating tower top gas phase; p-20: refluxing the top of the fractionating tower; p-23: quench oil from the bottom of section B of the fractionation column; p-25: and (4) steam.
E-1: a first heat recovery facility for the gas feedstock pyrolysis gas; e-2: a second heat recovery facility for the gas raw material pyrolysis gas; e-3: a liquid raw material pyrolysis gas heat recovery facility; e-6: a liquid phase heavy component fuel oil pump; e-7: a quench oil pump; e-8: a quench oil heat recovery facility; e-9: a gaseous feedstock cracking furnace; e-10: a liquid feedstock cracking furnace; e-11: a fractionating tower.
1. A flash evaporation section; 2. a fractionation section; 3. a cyclone separator; 4. a riser pipe; 6. a discharge pipeline of a second heat recovery facility E-2 for gas raw material pyrolysis gas; 7. a discharge pipeline of a liquid raw material pyrolysis gas heat recovery facility; 8. a quenching oil extraction port; 9. a gas lift pipe; 10. collecting liquid; 11. a fuel oil withdrawal line; 12. a char particle discharge pipe; 13. a quench oil discharge line; 14. an external char particle discharge line; 15. a first vortex breaker; 16. a second vortex breaker; 18. a coke cleaning tank; 19. a steam feed line.
Detailed Description
Preferred embodiments of the present invention will be described in more detail below. While the following describes preferred embodiments of the present invention, it should be understood that the present invention may be embodied in various forms and should not be limited by the embodiments set forth herein.
The invention provides a device for recovering heat of pyrolysis gas and removing heavy components, which comprises a liquid raw material pyrolysis gas heat recovery unit, a gas raw material pyrolysis gas heat recovery unit and a heavy component removing unit;
the liquid raw material pyrolysis gas heat recovery unit comprises a liquid raw material pyrolysis gas heat recovery facility E-3; the liquid raw material pyrolysis gas heat recovery facility E-3 is connected with a discharge hole of the liquid raw material pyrolysis furnace E-10;
the gas raw material pyrolysis gas heat recovery unit comprises a first gas raw material pyrolysis gas heat recovery facility E-1 and a second gas raw material pyrolysis gas heat recovery facility E-2; the first heat recovery facility E-1 of the gas raw material cracking gas is connected with a discharge hole of a gas raw material cracking furnace E-9;
the heavy component removing unit comprises a fractionating tower E-11, wherein the fractionating tower E-11 is divided into an upper part and a lower part which are communicated in a gas phase through a partition plate, and the upper part and the lower part are respectively a lower part A section and an upper part B section; the fractionating tower E-11 is provided with a top gas phase discharge pipeline and a bottom liquid-solid phase discharge pipeline;
a discharge pipeline of the liquid raw material pyrolysis gas heat recovery facility E-3 is connected with the lower section A of the fractionating tower E-11; a discharge pipeline of the second heat recovery facility E-2 for the gas raw material pyrolysis gas is connected with the fractionating tower E-11;
the bottom of the upper section B of the fractionating tower E-11 is provided with a quenching oil discharge pipeline, the quenching oil discharge pipeline is sequentially connected with a quenching oil pump E-7 and a quenching oil heat recovery facility E-8 and then divided into two branches, one branch is connected with the upper section B of the fractionating tower E-11, and the other branch is connected with a discharge pipeline of a liquid raw material pyrolysis gas heat recovery facility E-3 (as shown in figures 1 and 2) or connected with the lower section A of the fractionating tower E-11 (as shown in figure 3).
The apparatus according to the present invention, wherein the lower part of the lower section a of the fractionation column E-11 may be further provided with a vapor feed line.
According to the invention, the lower section A of the fractionating tower E-11 can be provided with no internals or with internals, and the internals are preferably at least one of a distributor, a grid, a wire mesh and a nozzle.
According to the invention, preferably, the bottom of the lower section A of the fractionating tower E-11 is provided with a liquid collecting bag, and the bottom of the liquid collecting bag is communicated with a fuel oil extraction pipeline.
According to the present invention, preferably, the upper section B of the fractionation column E-11 is provided with internals, preferably trays, packing or a combination thereof.
According to the invention, the upper section B of the fractionating tower E-11 can be divided into 2-4 small sections, usually into 3 sections, i.e. the upper section B of the fractionating tower E-11 is divided into a quenching oil section, a tray oil section and a rectifying section from bottom to top.
According to the invention, the bottom partition plate structure of the upper section B of the fractionating tower E-11 can adopt a seal head or a liquid collecting tank.
According to the invention, preferably, the partition is provided with a plurality of openings respectively connected with a plurality of gas risers for gas phase communication between the lower section a and the upper section B. According to the invention, the riser is used for gas communication between the upper section B and the lower section a, and is therefore preferably arranged in the upper section B of the fractionation column E-11 at an outlet end level above the high quench oil level.
According to the invention, the bottom of the liquid collecting bag and the bottom of the upper section B of the fractionating tower E-11 are preferably respectively provided with a vortex breaker.
According to a preferred embodiment of the present invention, the quenching oil discharge line is connected to a quenching oil pump E-7 and a quenching oil heat recovery facility E-8 and then divided into two branches, one branch is connected to the upper section B of the fractionating tower E-11, and the other branch is connected to the top of the section A of the fractionating tower E-11; and a discharge pipeline of the liquid raw material pyrolysis gas heat recovery facility E-3 is connected with the bottom of the section A of the fractionating tower E-11. So as to realize the countercurrent contact of the liquid raw material pyrolysis gas P-12 after heat recovery and the quenching oil P-2.
According to the invention, the discharge pipeline of the second heat recovery facility E-2 for the gas raw material pyrolysis gas can be connected to the section A of the fractionating tower E-11 and also can be connected to the section B of the fractionating tower E-11.
According to the invention, a coke cleaning facility can be arranged according to the requirement.
When the discharge pipeline of the second heat recovery facility E-2 for the gas raw material pyrolysis gas is connected to the section B of the fractionating tower E-11 (as shown in fig. 2), the decoking facility may be disposed on the pipeline connecting the second heat recovery facility E-2 for the gas raw material pyrolysis gas and the fractionating tower E-11.
When the discharge pipeline of the second heat recovery facility E-2 for the gas raw material pyrolysis gas is connected to the section B of the fractionating tower E-11 (as shown in figure 1), the decoking facility can be arranged in the section A at the lower part of the fractionating tower, and the discharge pipeline of the second heat recovery facility E-2 for the gas raw material pyrolysis gas is communicated with the decoking facility through a pyrolysis gas inner extension pipe; the top of the coke cleaning facility is provided with an ascending pipe which is upwards inserted into the upper section B to reach a position above the high liquid level of the quenching oil; the bottom of the coke cleaning facility is provided with a coke particle discharge pipe which extends downwards to the bottom of the tower and is communicated with an external coke particle discharge pipeline (as shown in figure 4). By adopting the device, heavy components and coke particles in the quenching oil are obviously reduced, a quenching oil system does not need to be arranged to meet the separation requirement, the equipment investment and the occupied area are obviously reduced, the operation period of the filter is prolonged to some extent, and the maintenance cost is reduced. The self-polymerization tendency of the quenching oil is reduced, the temperature is increased, the heat of the quenching oil section of the fractionating tower is increased, and the medium-pressure steam consumption of the device is reduced.
According to the invention, the pyrolysis gas inner extension pipe is preferably connected with the coke cleaning facility tangentially.
The decoking facility is preferably at least one of a decoking tank, a single cyclone, and a combination of cyclones. When a combination of cyclones is used, the combination can be placed in a decoking tank.
The invention also provides a method for recovering heat of the pyrolysis gas and removing heavy components, which can adopt the device for recovering heat of the pyrolysis gas and removing the heavy components and comprises the following steps:
liquid raw material cracking gas P-9 from a liquid raw material cracking furnace E-10 enters a liquid raw material cracking gas heat recovery facility E-3 to be cooled to the temperature T1 to obtain liquid raw material cracking gas P-12 after heat recovery, and then enters a section A at the lower part of a fractionating tower E-11 which is divided into an upper part and a lower part by a partition plate; before or after the liquid raw material is fed into a fractionating tower E-11, mixing the liquid raw material pyrolysis gas P-12 subjected to heat recovery with quenching oil P-2, and further cooling to T2;
in the section A at the lower part of the fractionating tower E-11, the gas of the mixed material is separated from liquid and solid particles after the liquid raw material pyrolysis gas P-12 after heat recovery contacts with the quenching oil, the separated liquid phase heavy component fuel oil P-13 carrying the solid particles is sent out from the tower kettle, and the separated gas phase passes through the partition plate and enters the section B at the upper part of the fractionating tower E-11 for further cooling;
the gas raw material cracking gas P-4 from the gas raw material cracking furnace E-9 enters a first heat recovery facility E-1 of the gas raw material cracking gas to be cooled to a temperature T3, then enters a second heat recovery facility E-2 of the gas raw material cracking gas to be further cooled to the temperature T4, and the gas raw material cracking gas P-11 after the second heat recovery is sent to a fractionating tower E-11;
and further cooling the gas phase separated from the section A at the lower part of the fractionating tower E-11 and the gas raw material pyrolysis gas P-11 subjected to the second heat recovery at the section B at the upper part of the fractionating tower E-11, and condensing part of components into liquid-phase quenching oil, wherein the quenching oil P-23 from the bottom of the section B of the fractionating tower is pumped by a quenching oil pump E-7 and subjected to heat recovery by a quenching oil heat recovery facility E-8, one part of the quenching oil P-17 subjected to heat recovery returns to the section B at the upper part of the fractionating tower, the other part of the quenching oil P-2 is mixed with the liquid raw material pyrolysis gas P-12 subjected to heat recovery, and the uncondensed components are discharged as the gas phase P-19 at the top of the fractionating tower E-11.
In the pyrolysis gas waste heat recovery and heavy component removal technology provided by the invention, the pyrolysis raw material has both liquid raw material and gas raw material; wherein,
the liquid raw material cracking gas P-9 is obtained by cracking a liquid raw material P-10 in a liquid raw material cracking furnace E-10, wherein the liquid raw material P-10 is selected from one or more of light hydrocarbon with five or more carbon atoms, naphtha, diesel oil and hydrogenated tail oil;
the gas raw material cracking gas P-4 is obtained by cracking a gas raw material P-1 through a gas raw material cracking furnace E-9, wherein the gas raw material P-1 is one or more selected from ethane, propane, butane, refinery dry gas and LPG.
According to the method, the temperature T1 is controlled to be not lower than the dew point, and a certain margin is provided generally, so that the heat is recovered to the maximum extent on the premise of avoiding heavy component condensation and coking; the T1 value varies depending on the starting materials and is generally in the range from 300 to 500 ℃.
According to the method, the temperature T2 is controlled within a certain range, so that the aim of removing heavy components in the section A of the fractionating tower E-11 to the maximum extent is ensured; the T2 value varies depending on the starting materials and is generally in the range from 200 to 350 ℃ and preferably from 250 to 280 ℃.
According to the method of the invention, a certain heat transfer temperature difference exists between the control temperature T3 and the heat taking medium, and the T3 range is generally 200-400 ℃.
According to the method, the temperature T4 is controlled to be not lower than the dew point, and a certain margin is provided generally, so that the maximum heat recovery is realized on the premise of avoiding heavy component condensation and coking; the T4 value varies depending on the starting materials, and the T4 range is generally from 160 to 240 ℃.
According to the present invention, preferably, the first heat recovery means for the gas raw material pyrolysis gas E-1 and the heat recovery means for the liquid raw material pyrolysis gas E-3 perform heat recovery by generating steam at a pressure of 3.5 to 13.0MPaG, preferably 10.0 to 12.0MPaG.
According to the present invention, it is preferable that the second heat recovery facility E-2 for the cracked gas of the gaseous raw material recovers heat by generating steam, heating water or other medium, and more preferably, heating boiler feed water for the first heat recovery facility E-1 for the cracked gas of the gaseous raw material to generate high-grade steam more.
According to the method, the first heat recovery facility E-1 of the gas raw material pyrolysis gas, the second heat recovery facility E-2 of the gas raw material pyrolysis gas and the heat recovery facility E-3 of the liquid raw material pyrolysis gas can be respectively and independently one-stage or multi-stage serial heat recovery facilities or multi-stage parallel heat recovery facilities.
According to the invention, the gas raw material cracking gas P-11 after the second heat recovery can directly enter the upper section B of the fractionating tower E-11, or can enter the lower section A of the fractionating tower E-11 firstly and then enter the upper section B of the fractionating tower E-11 through the partition plate.
According to a preferred embodiment of the invention, the liquid raw material cracking gas P-12 after heat recovery enters the bottom of the section A of the fractionating tower E-11, and the quenching oil P-2 enters the top of the section A of the fractionating tower E-11; in the section A of the fractionating tower E-11, the liquid raw material pyrolysis gas P-12 after heat recovery is in countercurrent contact with the quenching oil P-2, so that the liquid raw material pyrolysis gas P-12 after heat recovery is further cooled to T2 and then enters the bottom of the section B of the fractionating tower E-11.
According to the present invention, the lower part of the section A of the fractionation column E-11 may or may not be introduced with steam P-25 as a stripping medium, and the pressure level of the introduced steam is preferably 1.2 to 13.0MPaG, more preferably 3.5 to 10.0MPaG.
According to the invention, the pipeline for the gas raw material cracked gas P-11 after the second heat recovery to enter the fractionating tower E-11 can be provided with no coke cleaning facility or a coke cleaning facility.
According to a preferred embodiment of the invention, a decoking facility is arranged in the lower section A of the fractionating tower, and a discharge pipeline of the second heat recovery facility E-2 of the gas raw material pyrolysis gas is communicated with the decoking facility through a pyrolysis gas internal extension pipe;
the liquid raw material pyrolysis gas P-12 after heat recovery enters a lower section A of a fractionating tower E-11, a mixed material after countercurrent contact with the quenching oil (P-2) is subjected to flash evaporation gas-liquid separation, the obtained gas phase enters an upper section B, and the obtained coke particles and liquid phase heavy components are accumulated at the bottom of the lower section A and then discharged;
and the gas raw material cracking gas P-11 after the secondary heat recovery enters a coke cleaning facility through a cracking gas inner extension pipe to remove coke particles and coke powder contained in the gas raw material cracking gas, the gas phase separated by the coke cleaning facility enters the upper section B, and the coke particles and the coke powder are discharged from the bottom of the coke cleaning facility.
The top of the fractionation column E-11 is typically provided with reflux in accordance with the process of the present invention.
The invention is further explained by the following embodiments in combination with the drawings. It should be understood that the detailed description and specific examples, while indicating the present invention, are given by way of illustration and explanation only, not limitation.
In the following examples and comparative examples, the compositions of the gaseous raw materials and the liquid raw materials are shown in table 1.
TABLE 1
Example 1
Example 1 an apparatus and process for pyrolysis gas heat recovery and heavies removal as shown in figure 1 was employed.
The device comprises a liquid raw material pyrolysis gas heat recovery unit, a gas raw material pyrolysis gas heat recovery unit and a heavy component removal unit.
The liquid raw material pyrolysis gas heat recovery unit comprises a liquid raw material pyrolysis gas heat recovery facility E-3; the liquid raw material pyrolysis gas heat recovery facility E-3 is connected with a discharge hole of the liquid raw material pyrolysis furnace E-10, and a feed hole of the liquid raw material pyrolysis furnace E-10 is connected with a liquid raw material pipeline.
The gas raw material pyrolysis gas heat recovery unit comprises a first gas raw material pyrolysis gas heat recovery facility E-1 and a second gas raw material pyrolysis gas heat recovery facility E-2; the first heat recovery facility E-1 of the gas raw material cracking gas is connected with a discharge hole of a gas raw material cracking furnace E-9, and a feed hole of the gas raw material cracking furnace E-9 is connected with a gas raw material pipeline.
The heavy component removal unit comprises a fractionating tower E-11, the specific structure of the fractionating tower E-11 is shown in figure 4, and the fractionating tower E-11 comprises a shell, a partition plate arranged in the shell, a top gas phase discharge pipeline and a bottom liquid-solid phase discharge pipeline; the separator separates the inner part of the shell into an upper part and a lower part which are communicated with each other in a gas phase, namely a lower part A section (namely a flash evaporation section 1) and an upper part B section (namely a fractionation section 2), a coke cleaner is arranged in the flash evaporation section 1, and the coke cleaner adopts a coke cleaning tank 18 internally provided with a plurality of cyclone separators 3. Three openings on the side wall of the flash evaporation section 1 are respectively communicated with a discharge pipeline 6 of a second heat recovery facility E-2 of the gas raw material pyrolysis gas, a discharge pipeline 7 of a heat recovery facility of the liquid raw material pyrolysis gas and a steam feed pipeline 19. The bottom of the flash evaporation section 1 is provided with a liquid collection bag 10, the bottom of the liquid collection bag 10 is provided with a second vortex breaker 16, and the bottom opening of the liquid collection bag 10 is communicated with a fuel oil extraction pipeline 11. The coke cleaning tank 18 is communicated with a discharge pipeline 6 of a second heat recovery facility of the gas raw material pyrolysis gas through a pyrolysis gas inner extension pipe (not shown), an ascending pipe 4 at the top of the coke cleaning tank 18 is inserted into the fractionating section 2 until the liquid level of the quenching oil is higher than the high liquid level, and a coke particle discharge pipe 12 at the bottom of the coke cleaning tank 18 extends downwards until a bottom end socket of the tower is communicated with an external coke particle discharge pipeline 14. The separation plate is provided with a plurality of openings which are respectively connected with a plurality of gas risers 9, the gas risers 9 are arranged in the fractionating section 2, the outlet end of the gas risers is higher than the high liquid level of the quenching oil, the fractionating section 2 is divided into a quenching oil section, a coil oil section and a rectifying section from bottom to top, a tower plate internal part is arranged, the bottom of the fractionating section is in a seal head type, a quenching oil extraction port 8 is communicated with a quenching oil discharge pipeline 13, and a first vortex breaker 15 is arranged at the bottom.
And a quenching oil discharge pipeline arranged at the bottom of the upper section B of the fractionating tower E-11 is sequentially connected with a quenching oil pump E-7 and a quenching oil heat recovery facility E-8 and then divided into two branches, one branch is connected with the upper section B of the fractionating tower E-11, and the other branch is connected with a discharge pipeline of a liquid raw material pyrolysis gas heat recovery facility E-3.
The method for recovering heat of the pyrolysis gas and removing heavy components by adopting the device comprises the following steps:
the liquid raw material P-10 is cracked by a liquid raw material cracking furnace E-10 to obtain liquid raw material cracking gas P-9, the liquid raw material cracking gas P-9 enters a liquid raw material cracking gas heat recovery facility E-3 to be cooled to 410 ℃ to obtain liquid raw material cracking gas P-12 after heat recovery, and then the liquid raw material cracking gas P-12 is mixed with quenching oil P-2 to be further cooled to 280 ℃ and then enters a section A at the lower part of a fractionating tower E-11.
In the section A at the lower part of the fractionating tower E-11, gas in liquid raw material pyrolysis gas P-15 mixed with quenching oil is separated from liquid and solid particles, liquid-phase heavy component fuel oil P-13 which is obtained by separation and carries solid particles is sent out from a liquid-phase heavy component fuel oil pump E-6 at the bottom of the tower through a fuel oil extraction pipeline 11 at the bottom of a liquid collection bag 10 to be used as sent liquid-phase heavy component fuel oil P-14, and gas phase obtained by separation passes through the partition plate to enter the section B at the upper part of the fractionating tower E-11 for further cooling.
The gas raw material P-1 is cracked by a gas raw material cracking furnace E-9 to obtain gas raw material cracking gas P-4, the gas raw material cracking gas P-4 enters a first heat recovery facility E-1 of the gas raw material cracking gas and is cooled to 350 ℃, then enters a second heat recovery facility E-2 of the gas raw material cracking gas and is further cooled to 210 ℃, the gas raw material cracking gas P-11 after the second heat recovery is sent to a section A at the lower part of a fractionating tower E-11 and enters a cyclone separator 3 in a coke cleaning tank 18 through a cracking gas inner extension pipe to remove a small amount of coke particles/coke powder contained in the cracking gas, the gas phase separated by the cyclone separator 3 enters a fractionating section 2 through an ascending pipe 4 for fractionation, and a small amount of coke particles at the bottom of the coke cleaning tank 18 are discharged through a coke particle discharge pipe 12 and an external coke particle discharge pipe 14.
The gas phase separated from the lower section A of the fractionating tower E-11 and the gas phase separated from the gas raw material pyrolysis gas P-11 after the second heat recovery are further cooled in the upper section B of the fractionating tower E-11, and part of the components are condensed into liquid-phase quenching oil, wherein the quenching oil P-23 from the bottom of the section B of the fractionating tower is pumped out by a quenching oil pump E-7 and subjected to heat recovery by a quenching oil heat recovery facility E-8, one part of the quenching oil P-17 after the heat recovery is returned to the upper section B of the fractionating tower as the quenching oil P-18 returned to the section B of the fractionating tower, the other part of the quenching oil P-2 is mixed with the liquid raw material pyrolysis gas P-12 after the heat recovery and then enters the lower section A of the fractionating tower E-11, and the uncondensed components are discharged as the top gas phase P-19 of the fractionating tower E-11. The top of the fractionating tower is provided with a fractionating tower top reflux P-20.
The first heat recovery facility E-1 of the gas raw material pyrolysis gas and the heat recovery facility E-3 of the liquid raw material pyrolysis gas perform heat recovery by generating steam, and the pressure of the generated steam is 11.5MPaG.
The second heat recovery facility E-2 for the gas raw material pyrolysis gas performs heat recovery by heating boiler feed water for the first heat recovery facility E-1 for the gas raw material pyrolysis gas.
The first heat recovery facility E-1 of the gas raw material pyrolysis gas, the second heat recovery facility E-2 of the gas raw material pyrolysis gas and the heat recovery facility E-3 of the liquid raw material pyrolysis gas are multistage heat recovery facilities which are connected in series.
The lower part of section A of the fractionation column E-11 is fed with steam P-25 as a stripping medium, the pressure level of the fed steam being preferably 1.6MPaG.
Example 2
Example 2 an apparatus and process for pyrolysis gas heat recovery and heavies removal as shown in figure 3 was employed.
The device comprises a liquid raw material pyrolysis gas heat recovery unit, a gas raw material pyrolysis gas heat recovery unit and a heavy component removal unit.
The liquid raw material pyrolysis gas heat recovery unit comprises a liquid raw material pyrolysis gas heat recovery facility E-3; the liquid raw material pyrolysis gas heat recovery facility E-3 is connected with a discharge hole of the liquid raw material pyrolysis furnace E-10, and a feed hole of the liquid raw material pyrolysis furnace E-10 is connected with a liquid raw material pipeline.
The gas raw material pyrolysis gas heat recovery unit comprises a first gas raw material pyrolysis gas heat recovery facility E-1 and a second gas raw material pyrolysis gas heat recovery facility E-2; the first heat recovery facility E-1 of the gas raw material cracking gas is connected with a discharge hole of the gas raw material cracking furnace E-9, and a feed hole of the gas raw material cracking furnace E-9 is connected with a gas raw material pipeline.
The heavy component removing unit comprises a fractionating tower E-11, wherein the fractionating tower E-11 is divided into an upper part and a lower part through a partition plate, and the upper part and the lower part are respectively a lower part A section and an upper part B section; the partition board is provided with a plurality of openings which are respectively connected with a plurality of riser pipes for gas phase communication between the lower section A and the upper section B, the partition board is arranged in the upper section B of the fractionating tower E-11, and the height of the outlet end of the partition board reaches above the high liquid level of the quenching oil; the fractionating tower E-11 is provided with a top gas phase discharge line and a bottom liquid-solid phase discharge line.
A discharge pipeline of the liquid raw material pyrolysis gas heat recovery facility E-3 is connected with the bottom of the lower section A of the fractionating tower E-11; and a discharge pipeline of the second heat recovery facility E-2 for the gas raw material pyrolysis gas is connected with the upper section B of the fractionating tower E-11.
The bottom of the upper section B of the fractionating tower E-11 is provided with a quenching oil discharge pipeline, the quenching oil discharge pipeline is divided into two branches after being sequentially connected with a quenching oil pump E-7 and a quenching oil heat recovery facility E-8, one branch is connected with the upper section B of the fractionating tower E-11, and the other branch is connected with the top of the lower section A of the fractionating tower E-11.
The lower part A section of the fractionating tower E-11 is provided with a distributor, and the lower part of the fractionating tower E-11 is provided with a steam feeding pipeline. The upper section B of the fractionating tower E-11 is provided with a tower plate internal part, the upper section B is divided into a quenching oil section, a tray oil section and a rectifying section from bottom to top, and the bottom structure of the upper section B is an end enclosure.
The method for recovering heat of the pyrolysis gas and removing heavy components by adopting the device comprises the following steps:
the liquid raw material P-10 is cracked by a liquid raw material cracking furnace E-10 to obtain liquid raw material cracking gas P-9, the liquid raw material cracking gas P-9 enters a liquid raw material cracking gas heat recovery facility E-3 to be cooled to 410 ℃, liquid raw material cracking gas P-12 after heat recovery is obtained, and then the liquid raw material cracking gas P-12 enters the bottom of a section A at the lower part of a fractionating tower E-11.
In the section A at the lower part of the fractionating tower E-11, the liquid raw material pyrolysis gas P-12 after heat recovery is in countercurrent contact with the quenching oil P-2 from the top of the section A at the lower part of the fractionating tower E-11, the temperature is further reduced to 280 ℃, then gas-liquid separation is carried out, the separated liquid phase heavy component fuel oil P-13 with solid particles is sent out from a liquid phase heavy component fuel oil pump E-6 at the tower bottom as the sent liquid phase heavy component fuel oil P-14, and the separated gas phase passes through the partition plate and enters the section B at the upper part of the fractionating tower E-11 for further temperature reduction.
And the gas raw material P-1 is cracked by a gas raw material cracking furnace E-9 to obtain a gas raw material cracking gas P-4, the gas raw material cracking gas P-4 enters a first heat recovery facility E-1 of the gas raw material cracking gas to be cooled to 350 ℃, then enters a second heat recovery facility E-2 of the gas raw material cracking gas to be further cooled to 210 ℃, and the gas raw material cracking gas P-11 subjected to secondary heat recovery is sent to the upper section B of a fractionating tower E-11.
And further cooling the gas phase separated from the section A at the lower part of the fractionating tower E-11 and the gas raw material pyrolysis gas P-11 subjected to the second heat recovery in the section B at the upper part of the fractionating tower E-11, and condensing part of components into liquid-phase quenching oil, wherein the quenching oil P-23 from the bottom of the section B of the fractionating tower is pumped by a quenching oil pump E-7 and subjected to heat recovery by a quenching oil heat recovery facility E-8, one part of the quenching oil P-17 subjected to heat recovery is returned to the section B at the upper part of the fractionating tower as the quenching oil P-18 returned to the section B of the fractionating tower, the other part of the quenching oil P-2 is fed to the top of the section A at the lower part of the fractionating tower E-11 as the quenching oil P-2, and the uncondensed components are discharged as the gas phase P-19 at the top of the fractionating tower E-11. The top of the fractionating tower is provided with a fractionating tower top reflux P-20.
The setting mode and the process conditions of a first heat recovery facility E-1 of the gas raw material pyrolysis gas, a second heat recovery facility E-2 of the gas raw material pyrolysis gas, a heat recovery facility E-3 of the liquid raw material pyrolysis gas and the steam P-25 introduced to the lower part of the section A of the fractionating tower E-11 are the same as those of the embodiment 1.
Comparative example 1
Comparative example 1 used a conventional procedure and the same cracking feedstock as in examples 1, 2.
One part of gas raw material pyrolysis gas from the pyrolysis furnace is cooled to 420 ℃ by a quenching boiler, then is mixed with quenching oil and is further cooled to 275 ℃, and then enters a stripping tower. The other part is cooled to 350 ℃ by a quenching boiler and is merged with the liquid raw material cracking gas.
And carrying out gas-liquid separation in the stripping tower, separating the tower bottom to obtain liquid-phase heavy component fuel oil carrying solid particles, and sending the gas phase at the top of the tower into the tower bottom of the fractionating tower for further cooling.
The liquid raw material cracking gas from the cracking furnace is cooled to 410 ℃ by a quenching boiler, is converged with the gas raw material cracking gas at 350 ℃, is mixed with quenching oil, is further cooled to 200 ℃, and then enters a fractionating tower.
Reflux is arranged at the top of the fractionating tower.
And further cooling the cooled liquid raw material cracking gas and the gas phase at the top of the stripping tower in a fractionating tower, and condensing part of components into liquid-phase quenching oil.
And after the quenching oil is pumped out by a pump and heat is recovered, one part of the quenching oil returns to the fractionating tower, and the other part of the quenching oil is used as a quenching medium and is mixed with the gas raw material cracked gas cooled to 420 ℃ and then returns to the fractionating tower.
The quench oil viscosity, cracked gas heat recovery and energy and operating cost data for examples 1 and 2 using the process of the present invention and comparative example 1 without the process of the present invention under the same cracked feedstock conditions are listed in table 2.
TABLE 2
| Item | Example 1 | Example 2 | Comparative example 1 |
| Temperature (. Degree.C.) of the bottom of the fractionating column | 195.3 | 195.1 | 195.0 |
| viscosity/(CP) of quenching oil | 0.676 | 0.679 | 7.061 |
| Superhigh pressure steam flow/(t/hr) | 544.3 | 544.1 | 524.1 |
| Specific ethylene energy consumption/(kg standard oil/t ethylene) | 504.5 | 504.7 | 520.0 |
| Annual operating costs/(ten thousand yuan/ten thousand ton ethylene) | Standard-24.8 | Standard-24.4 | Reference(s) |
As can be seen from the data in Table 2, under the same cracking raw material conditions as in examples 1 and 2, by using the method of comparative example 1, the amount of generated ultrahigh pressure steam and the viscosity of the quenching oil were 524.1t/hr and 7.061CP, respectively, and the energy consumption per ethylene was 520.0kg standard oil/t ethylene; the ultrahigh pressure steam generated in the embodiment 1 and the embodiment 2 adopting the method of the invention is 544.3t/hr and 544.1t/hr respectively, the viscosity of the quenching oil is 0.676CP and 0.679CP correspondingly, the unit ethylene energy consumption is 504.5 standard oil/t ethylene and 504.7 standard oil/t ethylene, and the operation cost can be saved by 24.8 ten thousand yuan/ten thousand ton ethylene and 24.5 ten thousand yuan/ten thousand ton ethylene respectively every year.
As can be seen from the comparison of the data, the traditional process is adopted, the generation amount of the ultrahigh pressure steam is small, and the viscosity of the quenching oil is high; by adopting the method, the ultrahigh pressure steam generation amount is high, the viscosity of the quenching oil is low, meanwhile, the unit ethylene energy consumption can be reduced by about 15kg standard oil/t ethylene, and the operation cost is saved by more than 24 ten thousand yuan/ten thousand tons of ethylene every year.
Having described embodiments of the present invention, the foregoing description is intended to be exemplary, not exhaustive, and not limited to the embodiments disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments.
Claims (23)
1. The device for recovering heat of the pyrolysis gas and removing the heavy components is characterized by comprising a liquid raw material pyrolysis gas heat recovery unit, a gas raw material pyrolysis gas heat recovery unit and a heavy component removing unit;
the liquid raw material pyrolysis gas heat recovery unit comprises a liquid raw material pyrolysis gas heat recovery facility (E-3); the liquid raw material pyrolysis gas heat recovery facility (E-3) is connected with a discharge hole of the liquid raw material pyrolysis furnace (E-10);
the gas raw material pyrolysis gas heat recovery unit comprises a first gas raw material pyrolysis gas heat recovery facility (E-1) and a second gas raw material pyrolysis gas heat recovery facility (E-2); the first heat recovery facility (E-1) of the gas raw material cracking gas is connected with a discharge hole of the gas raw material cracking furnace (E-9);
the heavy component removing unit comprises a fractionating tower (E-11), wherein the fractionating tower (E-11) is divided into an upper part and a lower part which are communicated in a gas phase through a partition plate, and the upper part and the lower part are respectively a lower part A section and an upper part B section; the fractionating tower (E-11) is provided with a top gas phase discharge pipeline and a bottom liquid solid phase discharge pipeline;
a discharge pipeline of the liquid raw material pyrolysis gas heat recovery facility (E-3) is connected with the lower section A of the fractionating tower (E-11); a discharge pipeline of the second heat recovery facility (E-2) for the gas raw material pyrolysis gas is connected with the fractionating tower (E-11);
and a quenching oil discharge pipeline is arranged at the bottom of the upper section B of the fractionating tower (E-11), the quenching oil discharge pipeline is sequentially connected with a quenching oil pump (E-7) and a quenching oil heat recovery facility (E-8) and then divided into two branches, one branch is connected with the upper section B of the fractionating tower (E-11), and the other branch is connected with a discharge pipeline of a liquid raw material pyrolysis gas heat recovery facility (E-3) or connected with the lower section A of the fractionating tower (E-11).
2. The pyrolysis gas heat recovery and heavy component removal device according to claim 1, wherein a steam feed line is arranged at the lower part of the section A of the fractionating tower (E-11);
the lower section A of the fractionating tower (E-11) is provided with or not provided with an internal part;
the bottom of the lower section A of the fractionating tower (E-11) is provided with a liquid collection bag, and the bottom of the liquid collection bag is communicated with a fuel oil extraction pipeline;
the upper B section of the fractionating tower (E-11) is provided with an internal part;
the upper section B of the fractionating tower (E-11) is divided into 2-4 small sections;
the bottom partition plate structure of the upper section B of the fractionating tower (E-11) adopts an end enclosure or a liquid collecting tank;
the partition board is provided with a plurality of openings which are respectively connected with a plurality of gas risers and used for communicating the gas phase of the lower section A with the gas phase of the upper section B.
3. The pyrolysis gas heat recovery and heavies removal apparatus of claim 2, wherein the internal components of the lower section a of the fractionation column (E-11) are at least one of a distributor, a grid, a wire mesh, and a nozzle.
4. The cracked gas heat recovery and heavies removal apparatus of claim 2, wherein the internals of the upper B section of the fractionation column (E-11) are trays, packing, or a combination thereof.
5. The pyrolysis gas heat recovery and heavy component removal device according to claim 2, wherein the upper section B of the fractionating tower (E-11) is divided into a quenching oil section, a coil oil section and a rectifying section from bottom to top.
6. The pyrolysis gas heat recovery and heavies removal apparatus of claim 2, wherein the riser is disposed in the upper B section of the fractionation tower (E-11) and has an outlet end at a height above the quench oil high level.
7. The pyrolysis gas heat recovery and heavy component removal device according to claim 2, wherein a vortex breaker is respectively arranged at the bottom of the liquid collecting bag and the bottom of the upper section B of the fractionating tower (E-11).
8. The pyrolysis gas heat recovery and heavy component removal device according to claim 1, wherein the quenching oil discharge pipeline is connected with a quenching oil pump (E-7) and a quenching oil heat recovery facility (E-8) and then divided into two branches, one branch is connected with the upper section B of the fractionating tower (E-11), and the other branch is connected with the top of the section A of the fractionating tower (E-11); and a discharge pipeline of the liquid raw material pyrolysis gas heat recovery facility (E-3) is connected with the bottom of the section A of the fractionating tower (E-11).
9. The pyrolysis gas heat recovery and heavy component removal device according to any one of claims 1 to 8, wherein a decoking facility is optionally arranged on a pipeline connecting the second gas raw material pyrolysis gas heat recovery facility (E-2) and the fractionating tower (E-11);
or,
a coke cleaning facility is arranged in the lower section A of the fractionating tower, and a discharge pipeline of the second heat recovery facility (E-2) of the gas raw material pyrolysis gas is communicated with the coke cleaning facility through a pyrolysis gas inner extension pipe; the top of the coke cleaning facility is provided with an ascending pipe which is upwards inserted into the upper section B to reach a position above the high liquid level of the quenching oil; the bottom of the coke cleaning facility is provided with a coke particle discharge pipe which extends downwards to the bottom of the tower and is communicated with an external coke particle discharge pipeline.
10. The device for recovering heat of pyrolysis gas and removing heavy components of claim 9, wherein the pyrolysis gas inner extension pipe is tangentially connected with the coke cleaning facility.
11. The cracked gas heat recovery and heavies removal apparatus of claim 9, wherein the decoking utility is at least one of a decoking tank, a single cyclone, and a combination of cyclones.
12. A method for recovering heat of pyrolysis gas and removing heavy components is characterized by comprising the following steps:
liquid raw material cracking gas (P-9) from a liquid raw material cracking furnace (E-10) enters a liquid raw material cracking gas heat recovery facility (E-3) to be cooled to the temperature T1 to obtain liquid raw material cracking gas (P-12) after heat recovery, and then enters a lower section A of a fractionating tower (E-11) which is divided into an upper part and a lower part by a partition plate; mixing the liquid raw material pyrolysis gas (P-12) after heat recovery with quenching oil (P-2) before or after entering a fractionating tower (E-11) to further reduce the temperature to T2;
in the section A at the lower part of the fractionating tower (E-11), the gas of the mixed material after the liquid raw material pyrolysis gas (P-12) after heat recovery contacts the quenching oil is separated from the liquid and solid particles, the separated liquid phase heavy component fuel oil (P-13) carrying the solid particles is sent out from the tower kettle, and the separated gas phase passes through the partition plate and enters the section B at the upper part of the fractionating tower (E-11) for further cooling;
gas raw material cracking gas (P-4) from a gas raw material cracking furnace (E-9) enters a first heat recovery facility (E-1) of the gas raw material cracking gas to be cooled to a temperature T3, then enters a second heat recovery facility (E-2) of the gas raw material cracking gas to be further cooled to the temperature T4, and the gas raw material cracking gas (P-11) after secondary heat recovery is sent to a fractionating tower (E-11);
further cooling the gas phase separated from the section A at the lower part of the fractionating tower (E-11) and the gas raw material pyrolysis gas (P-11) subjected to the second heat recovery at the section B at the upper part of the fractionating tower (E-11), and condensing part of components into liquid-phase quenching oil, wherein the quenching oil (P-23) from the bottom of the section B of the fractionating tower is pumped by a quenching oil pump (E-7) and subjected to heat recovery by a quenching oil heat recovery facility (E-8), one part of the quenching oil (P-17) subjected to heat recovery returns to the section B at the upper part of the fractionating tower, the other part of the quenching oil is used as quenching oil (P-2) to be mixed with the liquid raw material pyrolysis gas (P-12) subjected to heat recovery, and the uncondensed components are discharged as the gas phase (P-19) at the top of the fractionating tower (E-11);
controlling the temperature T1 to be not lower than the dew point temperature;
controlling the temperature T2 to be 200-350 ℃;
controlling the temperature T3 and the heat taking medium to have heat transfer temperature difference;
the control temperature T4 is not lower than the dew point temperature.
13. The process for cracked gas heat recovery and heavies removal of claim 12, wherein,
the cracking raw material comprises a liquid raw material and a gas raw material; wherein,
the liquid raw material cracking gas (P-9) is obtained by cracking a liquid raw material (P-10) in a liquid raw material cracking furnace (E-10), wherein the liquid raw material (P-10) is selected from one or more of light hydrocarbon with five or more carbon atoms, naphtha, diesel oil and hydrogenated tail oil;
the gas raw material cracking gas (P-4) is obtained by cracking a gas raw material (P-1) through a gas raw material cracking furnace (E-9), wherein the gas raw material (P-1) is one or more selected from ethane, propane, butane, refinery dry gas and LPG.
14. The process for cracked gas heat recovery and heavies removal of claim 12, wherein,
controlling the temperature T1 to be 300-500 ℃;
controlling the temperature T2 to be 250-280 ℃;
controlling the temperature T3 to be 200-400 ℃;
the temperature T4 is controlled in the range of 160-240 ℃.
15. The process for cracked gas heat recovery and heavies removal of claim 12, wherein,
the first heat recovery facility (E-1) of the gas raw material pyrolysis gas and the heat recovery facility (E-3) of the liquid raw material pyrolysis gas carry out heat recovery by generating steam, and the pressure of the generated steam is 3.5-13.0MPaG;
the second heat recovery facility (E-2) of the gas raw material pyrolysis gas recovers heat by generating steam, heating water or other media;
the first heat recovery facility (E-1) of the gas raw material cracking gas, the second heat recovery facility (E-2) of the gas raw material cracking gas and the heat recovery facility (E-3) of the liquid raw material cracking gas are respectively and independently one-stage or multi-stage series heat recovery facilities or multi-stage parallel heat recovery facilities.
16. The process for cracked gas heat recovery and heavies removal of claim 15, wherein the steam generation pressure is from 10.0 to 12.0MPaG.
17. The method for heat recovery and heavies removal of a cracked gas as claimed in claim 15, wherein the second means for heat recovery (E-2) of the cracked gas of the gaseous feedstock heats boiler feed water for the first means for heat recovery (E-1) of the cracked gas of the gaseous feedstock.
18. The method for heat recovery and heavy component removal of cracked gas as claimed in claim 12, wherein the gas raw material cracked gas (P-11) after the second heat recovery is directly introduced into the upper section B of the fractionating tower (E-11), or is introduced into the lower section a of the fractionating tower (E-11) and then introduced into the upper section B of the fractionating tower (E-11) through the partition.
19. The method for recovering pyrolysis gas heat and removing heavy components according to claim 12, wherein the liquid raw material pyrolysis gas (P-12) after heat recovery enters the bottom of the section a of the fractionating tower (E-11), and the quenching oil (P-2) enters the top of the section a of the fractionating tower (E-11); in the section A of the fractionating tower (E-11), the liquid raw material pyrolysis gas (P-12) after heat recovery is in countercurrent contact with the quenching oil (P-2), so that the liquid raw material pyrolysis gas (P-12) after heat recovery is further cooled to T2, and then enters the bottom of the section B of the fractionating tower (E-11).
20. The pyrolysis gas heat recovery and heavies removal process of claim 12, wherein steam (P-25) is introduced into the lower portion of section a of fractionation column (E-11) as a stripping medium.
21. The process for cracked gas heat recovery and heavies removal of claim 20, wherein the steam pressure rating is from 1.2 to 13.0MPaG.
22. The process for cracked gas heat recovery and heavies removal of claim 21, wherein the steam has a pressure rating of from 3.5 to 10.0MPaG.
23. The method for recovering heat and removing heavy components from cracked gas as claimed in any one of claims 12 to 22, wherein a decoking facility is arranged in the lower section a of the fractionating tower, and the discharge pipeline of the second heat recovery facility (E-2) for cracked gas of the gaseous raw material is communicated with the decoking facility through a cracked gas inner extension pipe;
the liquid raw material pyrolysis gas (P-12) after heat recovery enters a lower section A of a fractionating tower (E-11), the mixed material after countercurrent contact with the quenching oil (P-2) is subjected to flash evaporation gas-liquid separation, the obtained gas phase enters an upper section B, and the obtained coke particles and liquid phase heavy components are accumulated at the bottom of the lower section A and then discharged;
and the gas raw material cracked gas (P-11) subjected to the secondary heat recovery enters a coke cleaning facility through a cracked gas inner extension pipe to remove coke particles and coke powder contained in the gas raw material cracked gas, the gas phase separated by the coke cleaning facility enters a section B at the upper part of a fractionating tower (E-11), and the coke particles and the coke powder are discharged from the bottom of the coke cleaning facility.
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| CN202110143235.6A CN114836239B (en) | 2021-02-02 | 2021-02-02 | Device and method for recovering heat of pyrolysis gas and removing heavy components |
| PCT/CN2022/074232 WO2022166740A1 (en) | 2021-02-02 | 2022-01-27 | Cracked gas heat recovery apparatus and cracked gas heat recovery method |
| US18/263,888 US20240084203A1 (en) | 2021-02-02 | 2022-01-27 | Heat Recovery Apparatus for Cracked Gas and Heat Recovery Process for Cracked Gas |
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