CN109749769B - Two-pass furnace tube cracking furnace system and cracking method - Google Patents
Two-pass furnace tube cracking furnace system and cracking method Download PDFInfo
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Abstract
The invention relates to the field of cracking, in particular to a two-pass furnace tube cracking furnace system and a cracking method. The two-stroke furnace tube cracking furnace system comprises two-stroke cracking furnace tubes (4), a cracking raw material source (1), a first inlet and outlet switching valve (2), a second inlet and outlet switching valve (6) and a cracking product collecting device (7); wherein, the inlet of the first inlet and outlet switching valve is connected with a cracking raw material source, and the outlet of the first inlet and outlet switching valve is respectively connected with the inlet of the first-stroke cracking furnace tube (401) and the outlet of the second-stroke cracking furnace tube (402) in a freely switchable manner; the inlet of the second inlet and outlet switching valve is respectively connected with the inlet of the first stroke cracking furnace tube and the outlet of the second stroke cracking furnace tube in a freely switchable manner, and the outlet of the second inlet and outlet switching valve is connected with the cracking product collecting device; the inner diameter of the first-stage cracking furnace tube is not larger than that of the second-stage cracking furnace tube, and the difference is not larger than 14 mm. The invention can effectively prolong the operation period of the cracking furnace.
Description
Technical Field
The invention relates to the field of cracking, in particular to a two-pass furnace tube cracking furnace system and a cracking method.
Background
Ethylene is a basic feedstock for the petrochemical industry. Ethylene yield, production scale and technology mark a state of the petrochemical industry. The current process for producing ethylene is based on the tubular furnace petroleum hydrocarbon steam cracking technology, and statistically, about 99% of the ethylene and more than 50% of the propylene in the world are produced by the process.
The core equipment of the ethylene plant is a tubular cracking furnace, which consists of a convection section and a radiation section. The cracking feedstock and dilution steam are first heated in a convection section furnace tube, where the feedstock is vaporized and heated to an initial cracking temperature (i.e., "cross-over temperature"), and then passed into a radiant section furnace tube for cracking. In the radiant section of an industrial cracking furnace, a plurality of groups of furnace tubes with the same configuration are generally arranged. Cracking raw materials are introduced into the tube, heat generated by combustion of liquid fuel or gas fuel is used for heating the tube wall outside the tube, and the heat is transferred to reaction materials in the tube through heat transfer of the tube wall. Because the cracking reaction temperature is high (about 800-900 ℃ and the trend of high temperature development is in progress), the temperature of the tube wall must be higher so as to transfer heat into the tube. The heat transfer process in the furnace is mainly carried out by radiation.
Cracking is a well-known process in which petroleum hydrocarbons undergo carbon chain scission or dehydrogenation reactions at high temperatures to form olefins and other products. The cracking aims at producing ethylene and propylene mainly and by-producing olefin such as butylene and butadiene and products such as cracked gasoline, diesel oil, fuel oil and the like. The chemical reaction of petroleum hydrocarbon cracking is a strong endothermic reaction, and the petroleum hydrocarbon cracking reaction is divided into a primary reaction and a secondary reaction, generally speaking, the primary reaction is that hydrocarbon molecules are changed from large to small, namely paraffin is subjected to dehydrogenation and chain scission reaction, naphthene and aromatic hydrocarbon are subjected to dehydrogenation ring-opening reaction, and olefin products such as ethylene, propylene and the like are produced through the primary reaction; the secondary reaction is that hydrocarbon molecules are changed from small to large, namely olefin and alkyne are polymerized and dehydrogenated for condensation, and naphthene and arene are dehydrogenated for condensation and dehydrogenated for condensed cyclization, and the like, and coke is generated due to the reaction, which is particularly unfavorable for the normal operation of the cracking furnace, because the generated coke is attached to the inner wall of the cracking furnace tube, the heat conduction resistance is increased, and the resistance of a reaction system is also increased. Therefore, the cracking reaction is required to be finished by cooling after the primary reaction in the furnace tube is carried out and the secondary reaction is reduced as much as possible, so that the shorter retention time is required.
Because the radiant section transfers a large amount of heat in a short retention time, the temperature of the pipe wall is high and reaches 950-1100 ℃, and the secondary reaction near the pipe wall is serious due to the high temperature, so that coking is caused, the hydrocarbon partial pressure, the operation period and the like of the cracking furnace are influenced, and how to reduce the heat load of the radiant section is an important direction for slowing down coking and prolonging the operation period.
Obviously, how to avoid coking is the fundamental approach to solving the problem of periodic furnace shutdowns.
Patent CN103773421A has invented a two journey radiation section boiler tube for ethylene cracking furnace, this boiler tube adopts the return bend to connect between first journey boiler tube and second journey boiler tube, has eliminated the stress that produces under the radiation boiler tube high temperature, has prolonged the life of boiler tube, simultaneously, owing to adopt the return bend form, the intraductal reaction material flow fluctuation is less, does not flow the detention region, has reduced the dwell time of intraductal material, is favorable to hydrocarbon cracking reaction, has improved the yield of target product.
Patent CN101723784A discloses an ethylene cracking furnace, each radiant section tube of the furnace comprises a first pass tube and a second pass tube and a connecting piece for connecting the first pass tube and the second pass tube. Under high temperature, when the second tube expands downwards, the connecting piece and the first tube move regularly in the same direction, thereby avoiding the bending of the furnace tube. The cracking furnace has the advantages of long running period, mechanical performance and long service life.
As can be seen from the above, for a two-pass furnace tube cracking furnace, a special furnace tube structure or a special heat transfer enhancing element is generally adopted to realize the long-period operation of the cracking furnace. Although such a method can extend the operating period of the cracking furnace, there are limitations to the improvement of the operating period of the cracking furnace, and the advantages of such an extension are not sufficient for industrial production, so that a new method for extending the operating period of the cracking furnace is required.
Disclosure of Invention
The invention aims to overcome the problem that the operating period of a cracking furnace in the prior art is not long enough, and provides a two-pass furnace tube cracking furnace system and a cracking method. The two-pass furnace tube cracking furnace system and the cracking method can effectively prolong the operation period of the cracking furnace.
The inventor of the invention finds that after the normal cracking furnace operates for a period of time, the outlet part of the cracking furnace tube has high coking speed and large coke layer thickness due to high tube wall temperature, while the inlet part has low coking speed and small coke layer thickness due to low tube wall temperature. Therefore, the inventor of the invention thinks that the inlet and outlet switching system of the furnace tube is added in the cracking furnace, and after the switching of the switching system, the residual coking capacity of the original inlet part of the furnace tube is large, so that more coke can be contained, and the operation cycle of the cracking furnace is further prolonged.
In order to achieve the above object, the present invention provides a two-pass furnace tube cracking furnace system, wherein the two-pass furnace tube cracking furnace system comprises a two-pass cracking furnace tube, a cracking raw material source, a first inlet/outlet switching valve, a second inlet/outlet switching valve, and a cracking product collecting device; wherein the inlet of the first inlet and outlet switching valve is connected with the cracking raw material source, and the outlet of the first inlet and outlet switching valve is respectively connected with the inlet of the first-pass cracking furnace tube and the outlet of the second-pass cracking furnace tube of the two-pass cracking furnace tube in a freely switchable manner; the inlet of the second inlet and outlet switching valve is respectively connected with the inlet of the first stroke cracking furnace tube and the outlet of the second stroke cracking furnace tube of the two-stroke cracking furnace tube in a freely switchable manner, and the outlet of the second inlet and outlet switching valve is connected with the cracking product collecting device; the inner diameter of the first-pass cracking furnace tube is not larger than that of the second-pass cracking furnace tube, and the difference of the inner diameters of the tubes is not larger than 14 mm.
In another aspect, the present invention provides a cracking method, wherein the cracking method is performed in the two-pass furnace tube cracking furnace system of the present invention, and the cracking method comprises: in the process of cracking reaction, a first inlet and outlet switching valve and a second inlet and outlet switching valve of the two-stroke furnace tube cracking furnace system are switched simultaneously, so that the flow direction of materials in the two-stroke cracking furnace tubes is changed.
Additional features and advantages of the invention will be set forth in the detailed description which follows.
Drawings
FIG. 1 is a two pass furnace tube cracking furnace according to one embodiment of the present invention.
Description of the reference numerals
1 cracking a raw material source; 2 a first inlet/outlet switching valve; 3, a Venturi tube;
4 two-pass cracking furnace tube; 401 a first pass cracking furnace tube; 402 second pass cracking furnace tubes;
403, a connecting piece; 5, a pyrolysis product discharge pipeline; 6 a second inlet/outlet switching valve;
7 a pyrolysis product collecting device; 8, back flushing steam valve; 9. cracking raw material feeding pipeline
Detailed Description
The endpoints of the ranges and any values disclosed herein are not limited to the precise range or value, and such ranges or values should be understood to encompass values close to those ranges or values. For ranges of values, between the endpoints of each of the ranges and the individual points, and between the individual points may be combined with each other to give one or more new ranges of values, and these ranges of values should be considered as specifically disclosed herein.
In the present invention, the use of directional terms such as "upper" and "lower" generally means the upper and lower in reference to the drawings, and the use of connection terms generally means the connection in reference to the drawings, unless otherwise specified.
The invention provides a two-pass furnace tube cracking furnace system on one hand, as shown in fig. 1, wherein the two-pass furnace tube cracking furnace system comprises a two-pass cracking furnace tube 4, a cracking raw material source 1, a first inlet and outlet switching valve 2, a second inlet and outlet switching valve 6 and a cracking product collecting device 7; wherein the inlet of the first inlet/outlet switching valve 2 is connected to the cracking raw material source 1, and the outlet of the first inlet/outlet switching valve 2 is respectively connected to the inlet of the first pass cracking furnace tube 401 and the outlet of the second pass cracking furnace tube 402 of the two-pass cracking furnace tube 4 in a freely switchable manner; an inlet of the second inlet/outlet switching valve 6 is connected with an inlet of a first-stroke cracking furnace tube 401 and an outlet of a second-stroke cracking furnace tube 402 of the two-stroke cracking furnace tube 4 respectively in a freely switchable manner, and an outlet of the second inlet/outlet switching valve 6 is connected with the cracking product collecting device 7; the inner diameter of the first-pass cracking furnace tubes 401 is not greater than the inner diameter of the second-pass cracking furnace tubes 402, and the difference between the inner diameters of the tubes is not greater than 14 mm.
According to the two-pass furnace tube cracking furnace system of the present invention, the operation cycle of the cracking furnace tube can be effectively prolonged when the difference between the inner diameter of the first-pass cracking furnace tube 401 and the inner diameter of the second-pass cracking furnace tube 402 is not more than 14 mm. Preferably, the inner diameter of the tube of the first pass cracking furnace tube 401 is 5-10mm smaller than that of the second pass cracking furnace tube 402; more preferably, the tube inner diameter of the first pass cracking furnace tubes 401 is 6-8mm smaller than the tube inner diameter of the second pass cracking furnace tubes 402.
According to the two-pass furnace tube cracking furnace system, the two-pass cracking furnace tube 4 is a 1-1 type furnace tube, as shown in fig. 1.
According to the two-pass furnace tube cracking furnace system of the present invention, other characteristics and parameters of the two-pass cracking furnace tube 4 are not particularly limited, and may be selected according to the conventional two-pass cracking furnace tube in the art. For example, the first pass cracking furnace tubes 401 may have an outside tube diameter of 50-90mm (preferably 70-80mm), and a wall thickness of 5-8 mm; the tube outer diameter of the second pass cracking furnace tube 402 can be 55-110mm (preferably 75-85mm), and the tube wall thickness can be 6-8 mm; the total length of the two-pass cracking furnace tube 4 (excluding the connecting member) can be 18000-28000 mm; the connecting member 403 is not particularly limited, and may be a connecting member of a cracking furnace tube conventional in the art, for example, the connecting member 403 is an elbow connection. In the present invention, the tube inner diameter is tube outer diameter-tube wall thickness × 2.
According to the two-pass furnace tube cracking furnace system, the two-pass furnace tube cracking furnace system further comprises a venturi tube 3 arranged on a cracking raw material feeding pipeline 9, wherein the cracking raw material feeding pipeline 9 is a pipeline connecting the first inlet/outlet switching valve 2 and the inlet of the first-pass cracking furnace tube 401 with the outlet of the second-pass cracking furnace tube 402. The venturi tube 3 can evenly distribute the cracking raw materials, and is beneficial to keeping the cracking reaction conditions among all groups of furnace tubes consistent, thereby ensuring that the set optimal operation conditions of the cracking reaction can be controlled.
According to the two-pass furnace tube cracking furnace system of the present invention, the two-pass furnace tube cracking furnace system further comprises a back-flushing steam valve 8 respectively disposed on a cracking raw material feeding pipeline 9 and a cracking product discharging pipeline 5, as shown in fig. 1, wherein the cracking raw material feeding pipeline 9 is a pipeline connecting the first inlet/outlet switching valve 2 and the inlet of the first pass cracking furnace tube 401 and the outlet of the second pass cracking furnace tube 402, and the cracking product discharging pipeline 5 is a pipeline connecting the inlet of the first pass cracking furnace tube 401 and the outlet of the second pass cracking furnace tube 402 with the second inlet/outlet switching valve 6. Through setting up blowback steam valve 8 can sweep two journey boiler tube cracking furnace system with dilution steam, thereby aim at prevents that switching system from producing the jam that the coking leads to the system because remaining schizolysis raw materials when it is idle, is favorable to switching system's fast switch, dilutes the pollution that can not cause the cleavage product in steam leakage to the schizolysis boiler tube simultaneously.
In another aspect, the present invention provides a cracking method, wherein the cracking method is performed in the two-pass furnace tube cracking furnace system of the present invention, and the cracking method comprises: in the process of cracking reaction, the first inlet and outlet switching valve 2 and the second inlet and outlet switching valve 6 of the two-stroke furnace tube cracking furnace system are switched simultaneously, so that the flowing direction of the material in the two-stroke cracking furnace tube 4 is changed.
According to the lysis method of the present invention, preferably, the lysis method further comprises: the initial flow direction of the cracking feedstock was: flows from the first pass cracking furnace tubes 401 to the second pass cracking furnace tubes 402. That is, in the cracking method of the present invention, the flow direction from the first-pass cracking furnace tubes 401 to the second-pass cracking furnace tubes 402 is switched to the flow direction from the second-pass cracking furnace tubes 402 to the first-pass cracking furnace tubes 401. Such a flow pattern can effectively extend the operating cycle of the cracking furnace tubes.
According to the cracking method of the present invention, in a preferred case, the switching timing is: the handover is performed when either one of the following is satisfied,
when the cracking reaction is run to 70% -95% of the theoretical run cycle if no switching is performed,
when the temperature of the cracking reaction is 10-50 ℃ away from the temperature resistance limit of the material of the two-way cracking furnace tube 4.
In the cracking method of the present invention, the "theoretical operating cycle without switching" is clearly judged by those skilled in the art, and is generally described in the specification of the purchased two-pass furnace tube cracking furnace. Switching when the cracking reaction is operated to 70% -95% of the theoretical operating cycle if switching is not performed can effectively prolong the operating cycle of the cracking furnace tube, and preferably switching is performed when the cracking reaction is operated to 85% -90% of the theoretical operating cycle if switching is not performed.
In the cracking method of the present invention, the "temperature resistance limit of the material of the two-pass cracking furnace tube 4" is also a value that can be clearly judged by those skilled in the art, and is generally described in the specification of the purchased two-pass furnace tube cracking furnace. When the temperature of the cracking reaction is 10-50 ℃ away from the temperature resistance limit of the material of the two-pass cracking furnace tube 4, the switching can effectively prolong the operation period of the cracking furnace tube, and preferably, when the temperature of the cracking reaction is 15-30 ℃ away from the temperature resistance limit of the material of the two-pass cracking furnace tube 4, the switching is performed.
According to the lysis method of the present invention, preferably, the method further comprises: in the operation process of the two-stroke furnace tube cracking furnace system, the cracking raw material feeding pipeline 9 and/or the cracking product discharging pipeline 5 which are idle are/is purged by dilution steam through the back-flushing steam valve 8, so that the blockage of the system caused by coking generated by residual cracking raw materials when the switching system is idle can be prevented, the rapid switching of the switching system is facilitated, and meanwhile, the dilution steam is leaked into the cracking furnace tube to avoid the pollution of cracking products.
Other conditions and parameters of the cleavage reaction according to the cleavage process of the present invention are within the ordinary skill in the art.
By the cracking method, the operation period of the cracking furnace tube can be prolonged to be more than 130% of the theoretical operation period without switching, can be more than 150% of the theoretical operation period without switching in a preferable case, and can be more than 170% of the theoretical operation period without switching in a more preferable case.
The present invention will be described in detail below by way of examples.
Example 1
The cracking reaction is performed in the two-pass cracking furnace tube system shown in fig. 1, wherein the outer diameter of the first pass furnace tube of the two-pass cracking furnace tube 4 is 78mm, the outer diameter of the second pass furnace tube is 84mm, the tube wall thickness is 7mm, and the total tube length is 26245 mm. According to the description of the specification of the two-pass furnace tube cracking furnace, the theoretical operation period of the two-pass cracking furnace tube without switching is 62 days, and the temperature resistance limit of the material of the two-pass cracking furnace tube is 1115 ℃.
The cleavage reaction was carried out according to the following conditions: the batch charge was 16 tons/hour, the water-to-oil ratio was 0.5, the cross-over temperature (XOT) was 600 ℃ and the furnace exit temperature (COT) was 832 ℃. The ethylene yield was 29.90% by weight.
When the operation lasts for 55 days (88% of the theoretical operation cycle), the highest tube wall temperature is 1080 ℃, the first inlet-outlet switching valve 2 and the second inlet-outlet switching valve 6 are switched, the inlet and the outlet of the two-way cracking furnace tube 4 are switched, the charging amount after switching is 16 tons/hour, the water-oil ratio is 0.5, the crossing temperature (XOT) is 620 ℃, and the outlet temperature (COT) of the cracking furnace is 838 ℃. The ethylene yield is 29.90 wt%, the furnace is continuously operated for 60 days, the highest tube wall temperature of the furnace tube is 1100 ℃, and the furnace is stopped to be burnt. The cracking furnace was operated for a total of 115 days, which was 185% of the theoretical operating cycle.
Example 2
The procedure of example 1 was followed, except that different two-pass cracking furnace tubes were used, the first-pass tube outer diameter of the two-pass cracking furnace tube 4 was 72mm, the second-pass tube outer diameter was 79mm, the tube wall thicknesses were 7mm, and the total tube length was 26245 mm. According to the description of the specification of the two-pass furnace tube cracking furnace, the theoretical operation period of the two-pass cracking furnace tube without switching is 51 days, and the temperature resistance limit of the material of the two-pass cracking furnace tube is 1115 ℃.
The switchover is likewise carried out at 88% of the theoretical operating cycle (day 44). The final furnace was run for a total of 88 days, 173% of the theoretical run length.
Example 3
The procedure of example 1 was followed, except that different two-pass cracking furnace tubes were used, the first-pass tube outer diameter of the two-pass cracking furnace tube 4 was 74mm, the second-pass tube outer diameter was 82mm, the tube wall thicknesses were 7mm, and the total tube length was 26245 mm. According to the description of the specification of the two-pass furnace tube cracking furnace, the theoretical operation period of the two-pass cracking furnace tube without switching is 55 days, and the temperature resistance limit of the material of the two-pass cracking furnace tube is 1115 ℃.
The switchover is likewise carried out at 88% of the theoretical operating cycle (day 48). The final furnace was run for a total of 98 days, which was 179% of the theoretical run period.
Example 4
The procedure of example 1 was followed except that the timing of the switching was varied, specifically at 85% of the theoretical operating cycle (day 53).
The final cracking furnace was operated for a total of 112 days, which is 180% of the theoretical operating cycle.
Example 5
The procedure of example 1 was followed, except that the switching timing was different, specifically at 90% of the theoretical operating cycle (day 56).
The final furnace was run for a total of 116 days, 187% of the theoretical run period.
Example 6
The procedure of example 1 was followed, except that the switching timing was different, specifically at 70% of the theoretical operating cycle (day 43).
The final furnace was run for a total of 98 days, 158% of the theoretical run period.
Example 7
The procedure of example 1 was followed, except that the switching timing was different, specifically switching was performed at 95% of the theoretical operating cycle (day 59).
The final furnace was run for a total of 104 days, 167% of the theoretical run period.
Comparative example 1
The same two-pass cracking furnace tube as in example 1 was used to conduct the cracking reaction under the same conditions except that no switching was performed.
Finally, the cracking furnace runs for 62 days, and the theoretical operation period is met.
Comparative example 2
The procedure of example 1 was followed except that the two-pass cracking furnace tubes of the examples of patent application CN103773421A were used and no switching was performed during the cracking reaction.
The final furnace was run for 62 days.
Comparative example 3
The procedure of example 1 was followed except that the two-pass cracking furnace tubes of example 1 of patent application CN101723784A were used and no switching was performed during the cracking reaction.
The final furnace was run for 62 days.
As can be seen from the above examples and comparative examples, the single pass furnace tube cracking furnace system and cracking method according to the present invention can extend the operating cycle of the cracking furnace to over 150% of the theoretical operating cycle without switching, and more preferably to over 170% of the theoretical operating cycle without switching, which is much higher than that of comparative example 1 without switching (i.e., the practical verification of "the theoretical operating cycle without switching"). And the number of days of operation was much greater than comparative examples 2 and 3, which were conducted according to the two-pass coil cracking furnace and process of the prior art. Therefore, the one-way furnace tube cracking furnace system and the cracking method can effectively prolong the operation period of the cracking furnace.
The preferred embodiments of the present invention have been described above in detail, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, many simple modifications can be made to the technical solution of the invention, including combinations of various technical features in any other suitable way, and these simple modifications and combinations should also be regarded as the disclosure of the invention, and all fall within the scope of the invention.
Claims (10)
1. The two-stroke furnace tube cracking furnace system is characterized by comprising two-stroke cracking furnace tubes (4), a cracking raw material source (1), a first inlet and outlet switching valve (2), a second inlet and outlet switching valve (6) and a cracking product collecting device (7); wherein the inlet of the first inlet and outlet switching valve (2) is connected with the cracking raw material source (1), and the outlet of the first inlet and outlet switching valve (2) is respectively connected with the inlet of the first-pass cracking furnace tube (401) and the outlet of the second-pass cracking furnace tube (402) of the two-pass cracking furnace tube (4) in a freely switchable manner; an inlet of the second inlet and outlet switching valve (6) is respectively connected with an inlet of a first-stroke cracking furnace tube (401) and an outlet of a second-stroke cracking furnace tube (402) of the two-stroke cracking furnace tube (4) in a freely switchable manner, and an outlet of the second inlet and outlet switching valve (6) is connected with the cracking product collecting device (7); the inner diameter of the first-pass cracking furnace tube (401) is not larger than that of the second-pass cracking furnace tube (402), and the difference of the inner diameters of the tubes is not more than 14 mm.
2. The two pass furnace tube cracking furnace system of claim 1 wherein the first pass cracking furnace tubes (401) have a tube inner diameter that is 5-10mm smaller than the tube inner diameter of the second pass cracking furnace tubes (402).
3. The two pass furnace tube cracking furnace system of claim 2 wherein the first pass cracking furnace tubes (401) have a tube inner diameter 6-8mm smaller than the tube inner diameter of the second pass cracking furnace tubes (402).
4. The two-pass furnace tube cracking furnace system of claim 1, further comprising a venturi (3) disposed on a cracking feedstock feed conduit (9), wherein the cracking feedstock feed conduit (9) is a conduit connecting the first inlet/outlet switching valve (2) with an inlet of a first pass cracking furnace tube (401) and an outlet of a second pass cracking furnace tube (402).
5. The two-pass furnace tube cracking furnace system according to claim 1, further comprising a back-flushing steam valve (8) respectively disposed on the cracking raw material feeding pipeline (9) and the cracking product discharging pipeline (5), wherein the cracking raw material feeding pipeline (9) is a pipeline connecting the first inlet/outlet switching valve (2) and the inlet of the first-pass cracking furnace tube (401) and the outlet of the second-pass cracking furnace tube (402), and the cracking product discharging pipeline (5) is a pipeline connecting the inlet of the first-pass cracking furnace tube (401) and the outlet of the second-pass cracking furnace tube (402) and the second inlet/outlet switching valve (6).
6. A cracking process carried out in a two pass furnace tube cracking furnace system as claimed in any one of claims 1 to 5, the cracking process comprising: in the cracking reaction process, a first inlet and outlet switching valve (2) and a second inlet and outlet switching valve (6) of the two-stroke furnace tube cracking furnace system are switched simultaneously, so that the flowing direction of the materials in the two-stroke cracking furnace tubes (4) is changed.
7. The lysis method of claim 6, wherein the lysis method further comprises: the initial flow direction of the cracking feedstock was: flowing in a direction from the first pass cracking furnace tubes (401) to the second pass cracking furnace tubes (402).
8. A lysis method according to claim 6, wherein the switching is timed to: the handover is performed when either one of the following is satisfied,
when the cracking reaction is run to 70% -95% of the theoretical run cycle if no switching is performed,
when the temperature of the cracking reaction is 10-50 ℃ away from the temperature of the material of the two-way cracking furnace tube (4).
9. The cracking process of claim 8, wherein when the cracking reaction is run to 85-90% of the theoretical run cycle if switching is not performed.
10. The cracking method according to claim 8, wherein the cracking reaction is carried out to a temperature 15-30 ℃ away from the temperature resistance limit of the material of the two-pass cracking furnace tube (4).
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS62192657A (en) * | 1986-02-19 | 1987-08-24 | Shimadzu Corp | Thermal cracking device with standard sample introducing device |
| CN1766042A (en) * | 2004-10-29 | 2006-05-03 | 中国石油化工股份有限公司 | Cracking furnace of boiler tube with one-way reducing diameter |
| CN102292151A (en) * | 2009-01-26 | 2011-12-21 | 鲁玛斯科技公司 | Adiabatic reactor to produce olefins |
-
2017
- 2017-11-01 CN CN201711055162.5A patent/CN109749769B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS62192657A (en) * | 1986-02-19 | 1987-08-24 | Shimadzu Corp | Thermal cracking device with standard sample introducing device |
| CN1766042A (en) * | 2004-10-29 | 2006-05-03 | 中国石油化工股份有限公司 | Cracking furnace of boiler tube with one-way reducing diameter |
| CN102292151A (en) * | 2009-01-26 | 2011-12-21 | 鲁玛斯科技公司 | Adiabatic reactor to produce olefins |
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