DE1468183A1 - Process for the production of unsaturated hydrocarbons by pyrolysis - Google Patents

Description

H. April 1964

T I5O6 9/24

Pr.ExpL

The Lummue Company
New York, NT (USA)

Process for the production of unsaturated hydrocarbons by pyrolysis

The invention relates to an improved method for thermal cracking of a hydrocarbon feedstock and more particularly to an improved method for cracking a hydrocarbon seed material in a directly heated pyrolysis heater with the formation of ethylene and propylene.

In pyrolysis heaters as they are currently used for the production of ethylene and propylene, the hydrocarbon feed is diluted with a large amount of steam to facilitate cooling in the Reduce the pipes of the heater to a minimum. The temperature is used to produce ethylene and propylene the radiant section of the heater normally

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kept at a value between 982 ⁰ C - 1093 ° C \ this leads to a total heat utilization of the radiant heating section of about 50 ^. Accordingly, in order to get a reasonable total utilization of the heater, it is necessary to build a convection section in the heater to a part to absorb the residual heat.

For pyrolysis heaters with a convection section the hydrocarbon feed is normally passed through the convection section to maximize overall utilization of the heater before it goes into the ν

Radiant section of the heater is introduced. Since it is undesirable to preheat the hydrocarbon feedstock to a temperature above about 593 ⁰ C (1100 °?) Before the feedstock is introduced into the radiant section where Pyrolyseerhitzer a separate convection section is installed to a part of the heat given in another To absorb electricity, e.g. to generate low-pressure steam. In this way, the overall utilization of a Pyrolyseerhitzers, in a temperature range between 982 ⁰ C - 1093 ⁰ C works can be remarkably improved.

ϊη operation, dilution steam is normally added to the hydrocarbon feed,

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in order to minimize the formation of coca during the passage of the hydrocarbon seeds ^r /.material8 through the convection section as well as the radiant section of the heater. supplied by a separate steam generation system including a steam boiler

According to the invention, the hydrocarbon feed is used introduced into the convection section of a pyrolysis heater · water or water and steam also introduced into the convection section of the heater. Depending on the input material and the desired end product and other investment factors are the feedstock and water or water and Steam mixed in a specific part of the convection section of the heater. The preheated mixture is in initiated the radiation section of the heater where the pyrolysis of the hydrocarbon feed is carried out will.

The gaseous exiting stream, which is withdrawn from the heater, is cooled and sent to a vent where cracked gas, liquid hydrocarbons and water are separated from the pyrolysis gas stream will. The water withdrawn from the separation zone contains a significant amount of phenolic compounds,

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which are formed during the pyrolysis of the carbon feedstock material are phenolics Connections are so difficult to find and offer a seriously ** pollution problem if the water is not treated before ββ in a waste water outlet is delivered. #, -

The water withdrawn from Atr Trenneone becomes a particular embodiment of the invention The water is fed to the fuel heater and provides the water that is mixed with the hydrocarbon feed Pyrolyssgasgsmisohes has been withdrawn »eliminated. Furthermore, it results in a substantial reduction in the capacity of the facilities normally required to prepare treatment feed water to be fed into the boiler for the production of Dilution steam is introduced. It also results a substantial saving in the amount of steam used for dilution, as well as savings, those on the lesser of the larger facilities that are required for steam generation. The cracked gas is then sent to a fractionation system where ethylsn and other desired products be won.

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One feature of the invention is to provide a improved process for pyrolysis of "a hydrocarbon sows!" materials, with a greater thermal Utilization of the pyrolytic heater is achieved without that two separate convection units are required in the heater.

Another feature of the invention is

the creation of an improved process for pyro-

lyee. of a hydrocarbon feed, wherein a A significantly lower amount of dilution steam is required for the pyrolysis of the input material.

Yet another feature of the invention is to provide an improved process for pyrolysis of a hydrocarbon feed wherein tight% r% control of time-temperature drawdown; of the radiation section is achieved by varying the ratio of water to steam introduced into the hydrocarbon feed material in the convection section of the heater.

Yet another feature of the invention is to provide an improved process by pyrolysis of a hydrocarbon feedstock, where sioh there is no impairment of the steam weight,

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when the heater is operated at reduced capacity

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The invention is described in greater detail with reference to FIG the drawing described in more detail; the an aohematic Represents a flow diagram of a preferred embodiment.

As can be seen from the drawing "a coal feedstock is introduced into the line 10 into the pyrolysis heater" this is generally designated by 11, with a convection chamber 12 and a radiation room or a radiant heat zone 13 being present. The water in line H is introduced into the heater 11 and combined with the hydrocarbon feedstock in line 10} it is passed through the convection section or the convection zone 12 of the pyrolysis heater. The combined current that flows through the convection section 12 of the heater 11 is 1O93 ° O - preheated and maintained at a temperature takes place whereby pyrolysis of the Kohlenwasseifstoffeinsatzmaterials, usually 982 ⁰ O passed in the radiant heat zone of the heater 11.

Depending on the procedural circumstances, this can be Water with ^ em hydrocarbon feed in the Introduction to the convection section 12 of the heater 11 can be combined »or it can be added to the hydrocarbon insert material are introduced after the insertion

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eatzmaterlal duroh part of the convection 12 let the tarry 11 flow · On the other hand, can Steam and water in the Rrhitser 11 through the line 14 for association with the coal waeeeretoffelneatzmaterial are introduced in line 10. If one applies a combined stream of water and steam, that becomes Ratio of water bu steam ao regulated that the time-temperature ratio of the radiation suction or the Radiant heatBone 13 is checked.

The pyrolytic gas mixture from the heater 11 duroh the line 13 is withdrawn, a cooling system is generally designated 16, passed, wherein the pyrolysis gas mixture is cooled to such a temperature that further cracking of the etching material is stopped. Dae now cooled pyrolysis gas mixture is withdrawn from the cooling system 16 and duroh the line 17 to a separation system, generally designated 18, directed. In the separation system 18, the pyrolysis gas mixture is separated, whereby one receives cracked gas withdrawn from system 18 through line 19 and becomes a traction generator system (not shown) for the recovery of ethylene or other hydrocarbon products. A liquid one Hydrocarbon is withdrawn from separation system 18 through line 20 and introduced into a suitable disposal system (not shown). Water or condensate is removed from the separation system 18 through line 21 *

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peeled off and put in tin Waste Disposal Systems (not split clear) directed · ·

The water or condensate from the separation zone By the time the line 21 has been withdrawn, it is, however, preferably passed through the pump 22 and returned to the pyrolysis heater 11 through the line 14. To this In this way it is possible to eliminate the problem of disposal of sewage * which contains disadvantageous proportions of phenol and other phenolic compounds. phenol and phenolic compounds collect in the again circulated water flow eu such a concentration of "whereby the pure amount of phenol and phenolic-BOhe compounds" that nan finds in the heater, "d * h" is withdrawn together with the liquid hydrocarbons in line 20 " Return of the water to the pyrolysis heater a substantial reduction in the facilities for the pretreatment of water for the preparation of demineralized water Water for the production of dilution steam which is introduced into the pyrolysis heater with the hydrocarbon fuel feed.

BemäS the invention is the overall utilization of a Pyrolytic heater noticeably improved to about # 67 - $ 82 or 75? i - 850 for light hydrocarbon gas use- ■ material or for liquid vaphtha feedstock. One

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Increase of about $ 5 - lOji In comparison with the oeaant utilization of a pyrolytic heater using only γόη steam for dilution is achieved. Sine

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Such increased notch is obtained without constructive external guidance of the heater with two separate convection zones, furthermore one obtains an improved time-temperature ratio of the radiation absorption. or the Radiant heat zone of the heater by changing d «s Proportion of water stu steam. Steam generating devices, which are normally associated with pyrolysis heaters of the type described »are withheld by the invention ·

The operation of the Pyrolyeeerhitsers with reduced capacity does not affect the steam exhaustion of the system. Since the requirement of dilution steam in the substantially the same or may increase with reduced capacity further Wasner can be introduced into the heater, umd the reduced amount of steam generated during cooling of the Pyrolysegapgemisches "off \

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at the same time.

In a preferred embodiment of the invention were 4 * 767 kg (10,500 lbs.) Per hour of a 'light debutanisierten Naphthaetromes with Analyeenwerten gernä'3 Table I below and at a temperature of 21 ⁰ O and a pressure of 9.14 kg / cm (130 psig) overall

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with 2,383 kg (5,250 pounds) per hour «water te! a tfc temperature τοη 99 C and a pressure of 15 »5 kg / om (220 psig) are combined and one into convection plane 12 Naphthakraokerhitaers initiated. The radiant heat zone of the heater was at a temperature of 1010 0 held so as to carry out the pyrolysis of the feedstock in the first place with the formation of ethylene. A pyro-lyaegas mixture with analysis values in Table II below was withdrawn from the pyrolysis heater at a temperature of 760 ° 0 and passed through a waste heat boiler » to cool the mixture before introducing it into the separation system. The condensate that results from the gaseous-liquid Hydrocarbons separated into the separating stream were discharged at a rate of 4,761 kg (10,500 engl. Pounds) per hour to the pyrolytic heater back in Circulated.

Make-up water is periodically added to the pyrolytic heater} it has been treated for the time being to those Remove compounds that cause adverse buildup

would form the pipe surface of the pyrolysis heater.

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Table I Analysis of the feed material

'Weight ⁰ API 72.5 initial boiling point ⁰ C 41.7 50 * point ⁰ C 88.3 90 * point ⁰ C 124.4 End point ⁰ C 145.6 Paraffins wt .- ^ 76 Naphthenes and olefins 17th Aromats by weight 7th

Table II Wt .- ^ PyrοIys egasgemis eh 1.0 Anhydrous base 15.7 Comoonente 25.2 ^H 2 CH ₄ ^C s ^H 4

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O ₂ H ₆ 4.6

O ₃ H ₆ 21.6

O ₃ H ₈ '0.7

O ₄ S 22.8

Oe and heavier 8.4

100.0

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Claims (7)

T% 68183-13 patent claims 1) Process for the production of "unsaturated hydrocarbons by pyrolysis in a pyrolysis heater with a convection zone and a radiation zone and for increasing the thermal utilization of the heater, characterized in that the hydrocarbon feedstock and water are fed into the convection zone of the heater with preheating of the combined stream of hydrocarbon feedstock and Yanser initiates, passes the preheated combined stream through the radiant zone of the heater, which is maintained at a temperature sufficient to carry out the pyrolysis of the hydrocarbon feed, cools the pyrolysis gas mixture formed by pyrolysis of the hydrocarbon caffeine waste material, and separates valuable hydrocarbons from the pyrolysis gas unit. 2) In accordance with original 1, characterized in that steam y.uanunone with the hydrocarbon feedstock and “./c; scr” is introduced into the convection zone. 3) Method according to claim 2, characterized in that the ratio of water to steam to regulate the time ·· ': ompcratur-Ratniayeo of the radiation zone is varied · 909822/128 ^ BATH ORIGINAL 1468T83 4-) Method according to one of the preceding claims, characterized in that the Pyrolysegasgemiach before Cooling - is withdrawn from the radiation zone. 5) Method according to one of the preceding claims, characterized in that the cooled pyrolysis gas mixture da3 into a gas stream containing ethylene, a liquid hydrocarbon electricity and water are separated and the water separated in this way is brought into circulation again to the convection zone. 6) Method according to one of the preceding claims, characterized in that the radiation zone of the heater is kept at a temperature of 982 ⁰ O to 1093 ° C. » 7) Method according to one of claims 1 to 6, characterized characterized that ethylene and propylene are valuable Hydrocarbons wins. 909822/1283 BATH ORIGINAL