CN107418614B - Online decoking method for hydrocarbon fuel tubular cracking furnace - Google Patents
Online decoking method for hydrocarbon fuel tubular cracking furnace Download PDFInfo
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- CN107418614B CN107418614B CN201710605465.3A CN201710605465A CN107418614B CN 107418614 B CN107418614 B CN 107418614B CN 201710605465 A CN201710605465 A CN 201710605465A CN 107418614 B CN107418614 B CN 107418614B
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- coke cleaning
- cracking furnace
- coke
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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
- C10G9/00—Thermal non-catalytic cracking, in the absence of hydrogen, of hydrocarbon oils
- C10G9/14—Thermal non-catalytic cracking, in the absence of hydrogen, of hydrocarbon oils in pipes or coils with or without auxiliary means, e.g. digesters, soaking drums, expansion means
- C10G9/16—Preventing or removing incrustation
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- Oil, Petroleum & Natural Gas (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Production Of Liquid Hydrocarbon Mixture For Refining Petroleum (AREA)
Abstract
The invention relates to an on-line decoking method for a hydrocarbon fuel tubular cracking furnace, which comprises the step of introducing H into the tubular cracking furnace which is coked in the tubular cracking furnace2O2The aqueous solution is decoked, and the temperature in the tubular cracking furnace is set to be 600-850 ℃. In the invention, the coke cleaning agent H is used after the fuel is cracked2O2The aqueous solution is directly introduced into the reaction tube for on-line coke cleaning, and other tube valves are not required to be arranged on the reaction tube. The invention adopts the hydrogen peroxide decoking technologyIn the operation, hydrogen peroxide is decomposed into steam and oxygen under the high-temperature condition, so that the on-line decoking of the tube furnace is carried out, and the use of the cracking furnace can be quickly recovered after decoking. The coke cleaning effect is evaluated through the pressure difference and the wall temperature of the reaction tube, the coke cleaning effect is obvious, and the reuse of the reaction tube can be ensured.
Description
Technical field
The invention belongs to the tubular heater attended operation fields in petrochemical industry, and in particular to a kind of hydrocarbon fuel
The online coke cleaning method of tube cracking furnace.
Background technique
Hydrocarbon fuel, especially Endothermic Hydrocarbon Fuel are the preferred fuels for realizing hypersonic vehicle, are not only had
Excellent combustibility, and can satisfy the cooling of hypersonic vehicle and require, each spacefaring nation fuel is had become at present
The emphasis and hot spot of research.Endothermic Hydrocarbon Fuel is in Pintsch process through non-catalytic and catalysis two ways in reactor
Wall forms burnt body.Non-catalytic coking refers to that the coking presoma in pyrolysis product is diffused into reactor surface, at high temperature through poly-
The reactions such as conjunction, cyclisation, annelation and deep dehydrogenation form coking.Catalytic coking refers to coking forerunner's sport active surface
Absorption is learned, dehydrogenation occurs under catalytic action, generates coking.This not only will affect the heat transfer efficiency of reactor, will cause simultaneously
Conversion zone pressure difference increases, and makes cracking in a kind of extreme unstable state.
Currently, in the device of simulation hypersonic vehicle fuel-pyrolysis, tool the most mature with pyrolysis in tubular furnace technology
There is the features such as structure is simple, heat-transfer capability is big, operating is stablized.But since tube furnace diameter is smaller, it is stranded to coke cleaning band is certain
It is difficult.The coke cleaning of tube cracking furnace is divided into offline coke cleaning and two kinds of online coke cleaning, the former needs will reaction after cracking reaction
Pipe, which unloads to be put into wood charcoal burning furnace, carries out coke cleaning, and the method is not only time-consuming and laborious, can also cause to reaction pipe outer wall a degree of
Damage, advantage is that the coke cleaning time is abundant, and coke cleaning is thorough.Online coke cleaning by by vapor and air according to a certain percentage with fuel
It is passed through after mixing in conversion zone boiler tube and carries out coke cleaning, principle is mixed with vapor and air under the high temperature conditions using coke
It closes object and carries out reaction generation COx(COxIncluding CO and CO2, CO can further be oxidized to CO2), achieve the purpose that except carbon.Advantage
It is that coke cleaning speed is fast, easy to operate, the disadvantage is that after introducing air in fuel, oxygen therein can react life with fuel molecule
At alkyl peroxide.Alkyl peroxide is unstable, is easy to generate free radical, is reacted by taking hydrogen and collateralization by force, final to turn
It turns to ketone or aldehyde is deposited on reaction tube and forms colloid.
101852557 B of patent CN provides a kind of decoking method of tubular heater of urea dewaxing device, by repeatedly
It is passed through the hot water and steam of certain temperature, the biuret coking that dissolved urea generates is rinsed and achievees the purpose that thorough coke cleaning.Patent
104353403 B of CN provide it is a kind of realize that thermal energy recycles the system that couple with continuous coke cleaning, the thermal energy of the system recycle and
The technique of continuous coke cleaning coupling is that the heat for losing thermal plasma torch and reactor wall surface is used to produce steam, and by steam
Continuous coke-removing procedure for reactor.The general character of both patents is to set hot-water line, steam pipe, cold water certainly on tube furnace
The coke cleanings pipeline such as pipe, gas-liquid separator makes this body structure of system become complicated and complex for operation step.
101872205 B of patent CN provide a kind of online rapid decoking process of ethylene industry pyrolysis furnace radiant section from
Flowing control method passes through carbon monoxide, the carbon dioxide and oxygen levels in on-line monitoring coke cleaning tail gas, adjust automatically water
Steam, air mass flow and coil outlet temperature.This method can accurately control coke cleaning amount, but maximum to air and vapor
The limitation of mass velocity ratio is stringent, and coke cleaning time needs 6.5 hours or more.Coke cleaning overlong time easily causes the waste of resource.
Summary of the invention
Present invention aims to overcome that the deficiency in background technique, a kind of saving raw material is provided, saves the time, while not being changed
Become the online coke cleaning method that tube cracking furnace itself constructs.
The present invention solves the above problems by the following technical programs:
A kind of online coke cleaning method of hydrocarbon fuel tube cracking furnace, the method includes the tubular types of coking into it to split
H is passed through in solution furnace2O2Aqueous solution carries out coke cleaning, and the temperature in the tube cracking furnace is set as 600~850 DEG C.
Wherein, the H2O2The mass percent concentration of aqueous solution is 15~30%.
Preferably, the coke cleaning time is 10~60min.
Preferably, the H2O2The volume space velocity of aqueous solution is 0.05 × 10-2s-1~1.06 × 10-2s-1, it is highly preferred that
The wherein H2O2The volume space velocity of aqueous solution is 0.80 × 10-2s-1。
Beneficial effects of the present invention:
1, easy to operate.The present invention uses online coke cleaning mode, on the basis of not changing original cracker structure, only
It need to be by H2O2Feed pump is directly connected to reaction tube inlet, simplifies coke cleaning step.
2, the coke cleaning time is short.The coke cleaning agent that the present invention uses is H2O2, utilize H under hot conditions2O2It decomposes and generates H2O and O2
Carry out coke cleaning.O2The heat released is reacted with C can be by H2O is utilized with reacting for C, balances the heat of system.Meanwhile phase
For air, O2Faster with the reaction rate of C, coke cleaning efficiency is improved.
3, coke cleaning efficiency is significant.The present invention is mainly decomposed into vapor and oxygen using hydrogen peroxide under the high temperature conditions,
And vapor and oxygen can be reacted with coke, to play the role of coke cleaning.As shown in following present invention embodiment, dioxygen
The volume space velocity of aqueous solution is 0.80 × 10-2s-1, coke cleaning rate is 93.7%.
Detailed description of the invention
Fig. 1 is pyrolysis in tubular furnace schematic device of the present invention.
Fig. 2 is that reaction tube wall temperature tests distributed point.
Fig. 3 monitors that reaction tube pressure difference changes when being using online coke cleaning method.
Fig. 4 monitors that reaction tube wall temperature changes when being using online coke cleaning method.
Fig. 5 is reaction tube coke content comparison diagram before and after coke cleaning.
Appended drawing reference meaning in Fig. 1 is as follows:
1 is raw material storage tank, and 2 be pump, and 3 be valve, and 4 be pressure sensor, and 5 be temperature sensor, and 6 be electric heating tube, and 7 are
Condenser, 8 be filter, and 9 be counterbalance valve, and 10 be gas-liquid separator.
Specific embodiment
Below by examples and drawings, the present invention is further explained, and purpose, which is only that, more fully understands the content of present invention.
Embodiment 1
1) cracking experiment
(1) by the good pipeline of sequential connection in Fig. 1, and the air-tightness of whole system is checked；
(2) start to supply hydrocarbon fuel in from 1 to 6, flow velocity 1g/s, adjust the pressure of reaction tube to 4MPa, temperature from
Room temperature is gradually increased to 750 DEG C, and cracks 30min at this temperature；
(3) specified time is reached, heating, pressure release are stopped.
2) the pipe pressure difference after cracking experiment and wall temperature measurement
(1) again into fuel, flow velocity 1g/s, pressure adjusting to 4MPa；
(2) after being heated to 600 DEG C, stablize 2min, write down pipe pressure difference P and wall temperature T at this time；
(3) stop experiment, pressure release, cooling.After being down to room temperature to temperature, with ethyl alcohol detergent line, then with being dried with nitrogen.
3)H2O2Coke cleaning
(1) pipeline is reequiped, changes the fuel in Fig. 11 into H2O2；
(2) after system average rate being heated to 750 DEG C, start logical H2O2Solution carries out coke cleaning, H2O2Concentration is 30wt%, H2O2
The volume space velocity of solution is 0.80 × 10-2s-1；
(3) after coke cleaning reaction carries out 30min, stop logical H2O2, cooling.It is cooled to room temperature to temperature, leads to ethyl alcohol detergent line
In water.
4) the pipe pressure difference after coke cleaning reaction and wall temperature measurement
(1) pipeline is reequiped, by the H in Fig. 112O2Change fuel into；
(2) after reaction tube is heated to 600 DEG C, stablizes 2min, write down pipe pressure difference P ' and wall temperature T ' at this time；
(3) stop experiment, pressure release, cooling.After being down to room temperature to temperature, with ethyl alcohol detergent line, then with being dried with nitrogen.
5) coke cleaning effect assessment
H is evaluated by pipe pressure difference and wall temperature2O2Coke cleaning effect.
(1) pipe pressure difference
Using reaction tube import and export between pressure differential deltap P=P-P ' coke cleaning effect is evaluated, as a result such as Fig. 3 institute
Show.It can be seen from the figure that reaction tube pressure difference maintains between 45~70KPa before coke cleaning, and pressure difference is near 30KPa after coke cleaning
Fluctuation, pressure difference are substantially reduced, and represent coke cleaning significant effect.
(2) wall temperature
Thermocouple is welded in reaction pipe outer wall at 6 in Fig. 1, for testing cracking, reacting pipe outer wall in coke-removing procedure
Temperature variation, the welding position of thermocouple is as shown in Fig. 2, totally 12 points.By coke cleaning front and back, by the wall temperature T and T ' at this 12 points
It compares, coke cleaning effect is evaluated, as a result as shown in Figure 4.It can be seen from the figure that after coke cleaning, from reaction tube inlet
It is decreased obviously to 80cm sections of wall temperature of pipe range, wall temperature decline illustrates the decline of the coke content on tube wall.But 80~95cm sections of wall temperature differences
Away from little.
(3) coke content
(hydrocarbon fuel flow velocity is 1g/s, the pressure of reaction tube to 4MPa, highest cracking temperature under identical cracking condition
750 DEG C, and cracking 30min is kept at this temperature), carry out the characterization of control group and experimental group coke content.Control group only into
Row cracking, but and unused H2O2Coke cleaning, experimental group utilize H after primary cracking2O2Coke cleaning is carried out by above-mentioned steps.Most
Afterwards, the characterization discovery of reaction tube coke content is carried out using method of making charcoal, the total coke content of experimental group is 2.0mg, the coke content of control group
For 31.6mg, coke cleaning rate reaches 93.7%.
Embodiment 2
It is only 30wt%H concentration therein substantially with embodiment 12O2Aqueous solution replaces with molar ratio
The water of 10.8:1 and the mixture of oxygen, the ratio exactly 30wt%H2O2Aqueous solution obtained water and oxygen after decomposing completely
The molar ratio of gas.The rate that is passed through for controlling the mixture makes it and is passed through 30wt%H2O2Aqueous solution decomposes the water and oxygen generated
The mole of gas is identical.And coke cleaning rate is calculated with same method, discovery coke cleaning rate only has 73.
As it can be seen that using H2O2Aqueous solution can not only coke cleaning, and than and H in decomposition product2O:O2Molar ratio same ratio
Water and oxygen mixture coke cleaning efficiency it is taller go out about 29% or so.This illustrates H2O2Aqueous solution coke cleaning is not to be only
The simple superposition of the coke cleaning effect of the mixture of the water and oxygen of same ratio, but effect is better than above-mentioned simple superposition.
Embodiment 3
Cracking process selects deionized water, is gasificated into water using hot conditions deionised water with embodiment 1, coke cleaning reagent
Steam is reacted with coke carries out coke cleaning.After system average rate is heated to 750 DEG C, start logical deionized water, volume space velocity 0.80
×10-2s-1.After coke cleaning reaction carries out 30min, stop logical deionized water, cooling.It is cooled to room temperature to temperature, leads to ethyl alcohol cleaning
Water in pipeline.Equally, reaction tube coke content is characterized using the method for making charcoal.Last coke content is as the result is shown
13.8mg, compared with the control group in embodiment 1, coke cleaning rate is 56.3%.
Thus it proves, under the conditions of identical cracking, coke cleaning, H2O2The coke cleaning efficiency of solution is higher than the coke cleaning efficiency of vapor, and
Significant effect.
Claims (1)
1. a kind of online coke cleaning method of hydrocarbon fuel tube cracking furnace, which is characterized in that the method includes having tied into it
H is passed through in burnt tube cracking furnace2O2Aqueous solution carries out coke cleaning, and the temperature in the tube cracking furnace is set as 750 DEG C；Institute
State H2O2The mass percent concentration of aqueous solution is 30%；The H2O2The volume space velocity of aqueous solution is 0.8 × 10-2s-1；When coke cleaning
Between be 30min.
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| CN201710605465.3A CN107418614B (en) | 2017-07-24 | 2017-07-24 | Online decoking method for hydrocarbon fuel tubular cracking furnace |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN110452732B (en) * | 2019-09-10 | 2020-08-14 | 天津大学 | Low-temperature coke cleaning method |
| CN113701172B (en) * | 2020-05-20 | 2024-03-12 | 中国石化工程建设有限公司 | Method for treating burnt gas of ethylene cracking furnace |
| CN113831930B (en) * | 2020-06-08 | 2023-04-07 | 中国石化工程建设有限公司 | Decoking device and decoking method for ethylene cracking furnace |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| US2882237A (en) * | 1956-05-29 | 1959-04-14 | Shell Dev | Method for oxidizing carbonaceous deposits |
| US4849025A (en) * | 1987-06-05 | 1989-07-18 | Resource Technology Associates | Decoking hydrocarbon reactors by wet oxidation |
| JPH06248310A (en) * | 1993-02-26 | 1994-09-06 | Sumitomo Metal Ind Ltd | Operation of blast furnace |
| CN101372630A (en) * | 2007-08-23 | 2009-02-25 | 中国石油化工股份有限公司 | On-line coke cleaning method for tube cracking furnace |
| CN101423453A (en) * | 2007-10-31 | 2009-05-06 | 中国石油化工股份有限公司 | Control method for accelerating on-line coke burning for industrial pyrolysis furnace |
| CN101872205B (en) * | 2009-04-27 | 2011-11-02 | 中国石油化工股份有限公司 | Automatic control method of online rapid decoking of cracking furnace |
| CN103254962A (en) * | 2013-04-27 | 2013-08-21 | 晟通科技集团有限公司 | Boiler coke restraining and removing agent |
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