JPH08511039A - Pyrolysis of hydrocarbon feedstocks - Google Patents

Abstract

(57) [Summary] The hydrocarbon feed material is heated in the furnace (1), the feed material is supplied to the reaction chamber (15), and the flow from the reaction chamber (15) is changed to a light product stream and a heavy product stream. And a heavy product stream is fed to a vacuum distillation column (30) to separate the heavy product into a plurality of fractions. The heavy product flow is supplied to the heavy product flow through the flow control valve (36), and the vertical pipe having a length such that the fluid pressure at the end thereof suppresses vaporization at the bottom end ( 38) passing the heavy product stream upwards, and then flowing the heavy product stream through a transfer conduit (40) to a vacuum distillation column (30), the transfer conduit (40) comprising: The structure is such that the fluid pressure at the outlet of the column becomes equal to the fluid pressure at the vacuum distillation column (30). That.

Description

DETAILED DESCRIPTION OF THE INVENTION Pyrolysis of Hydrocarbon Feeds The present invention relates to the pyrolysis of hydrocarbon feeds as described in The Petroleum Handbook, 6th Edition, Elsevier, 1983, pages 279-281. Pyrolysis of a hydrocarbon feedstock involves heating the feedstock at a pressure in the range of 0.2-5 MPa and a temperature in the range of 390-530 ° C., feeding the feedstock to a reaction chamber and producing a light stream from the reaction chamber. It is separated into a physical distribution and a heavy product distribution, and the heavy product distribution is supplied to a vacuum distillation column to separate the heavy product distribution into a plurality of fractions at a pressure in the range of 1 to 10 kPa and a temperature in the range of 320 to 400 ° C. Consists of separating into. In known methods, conduits are used to flow the heavy product stream to a vacuum distillation column. Since the pressure of the heavy product stream is higher than the pressure in the vacuum distillation column, the pressure drop in the conduit should be equal to the pressure difference between the pressure of the heavy product stream and the pressure in the vacuum distillation column. One way to reduce the pressure considerably in the conduit is to provide the conduit with a restriction opening, for example in the form of a flow control valve. However, rapid vaporization occurs when the heavy product stream is throttled by the flow control valve. Along with this rapid vaporization, very small droplets that are difficult to handle in a vacuum distillation column are formed. The present invention provides a simple way to suppress vaporization at restricted openings. The hydrocarbon feed pyrolysis method of the present invention for this purpose comprises heating the feed at a pressure in the range of 0.2-5 MPa and a temperature in the range of 390-530 ° C., feeding the feed into the reaction chamber and reacting. The flow from the chamber is separated into a light product stream and a heavy product stream, and the heavy product stream is supplied to a vacuum distillation column to produce a heavy product at a pressure in the range of 1 to 10 kPa and a temperature in the range of 320 to 400 ° C. It consists of separating the product stream into multiple fractions, the supply of the heavy product stream to the vacuum distillation column causes the heavy product stream to flow through a restricted opening, the fluid pressure at its ends vaporizing at the bottom. The upward flow of the heavy product stream through a stand tube having a length that suppresses, and then the heavy product stream flows through a transfer conduit opening into a vacuum distillation column, the transfer conduit comprising: , The fluid pressure at the outlet of the conduit in the vacuum distillation column It has equal such structures in the body pressure. As used herein and in the claims, the term "structure of the transfer conduit" refers to the characteristics of the transfer conduit involved in the pressure drop within the transfer conduit, such as the size of the transfer conduit and the bend or U-shaped bend of the transfer conduit. Is used to mean any other flow resistance. The invention will be described in more detail by way of examples with reference to the accompanying drawings. FIG. 1 schematically shows the structure of the method of the present invention. FIG. 2 schematically shows an alternative construction of the method of the invention. See FIG. The inventive method arrangement comprises a furnace 1 with a burner 2 and a chimney 3 and a heater tube 4 arranged in the furnace 1. The heater pipe 4 is connected to an inlet pipe 7 and an outlet pipe 9. The outlet pipe 9 is connected to the inlet of the reaction chamber 15. The reaction chamber is described more clearly in EP 7,656. The outlet of the reaction chamber 15 is connected via a conduit 17 to a separator in the form of a cyclone separator 20. The cyclone separator 20 has two outlets, an outlet 21 for light products and an outlet 24 for heavy products. The light product outlet 21 is connected via a conduit (not shown) to a device (not shown) for further processing of the light product. The heavy product outlet 24 is connected to a vacuum distillation column 30 by a conduit system 26. The vacuum distillation column 30 has a conduit 31 connected to a vacuum pump (not shown), a residual oil outlet pipe 32 for heavy products, and an outlet pipe 33 for intermediate product fractions. The apparatus for supplying a suitable reflux to the top of the vacuum distillation column 30 and a stripping medium stream to the bottom of the vacuum distillation column 30 are not shown. The conduit system 26 includes a conduit section 35 having a restricted opening in the form of a flow control valve 36, a standpipe 38 joined to the conduit section 35 and a transfer conduit 40 opening into the vacuum distillation column 30. . The length of the vertical pipe 38 is determined such that the fluid pressure at the bottom of the vertical pipe 38 suppresses vaporization of the fluid at the bottom of the vertical pipe 38 during normal operation. The term "suppresses vaporization of a fluid" is used herein and in the claims to mean that at most a small amount (less than about 5% by volume) of liquid vaporizes. The structure of the transfer conduit 40 is determined such that the fluid pressure at the outlet end 41 of the transfer conduit 40 is equal to the fluid pressure in the vacuum distillation column 30 during normal operation. This means that the transfer conduit 40 is designed so that the friction caused by the fluid flowing through it is equal to the difference between the pressure at the outlet of the standpipe 38 and the pressure in the vacuum distillation column 30. There is. In this case, the transfer conduit 40 comprises several straight sections 43 joined by a bend connector in the form of a U-shaped connector 44. During normal operation, a hydrocarbon feedstock of 3,000 tons / day is continuously fed into the furnace 1 at a pressure of 3 MPa, which feedstock is heated in the furnace 1 at a temperature of 450 ° C. The heated feedstock is then fed to the reaction chamber 15 where the feedstock undergoes decomposition. In the cyclone separator 20, the product flow from the reaction chamber 15 is 900 tons / day of light products discharged via the outlet 21 and 2,100 tons / day of heavy products discharged via the outlet 24. Is separated into The heavy product is fed via line system 26 to a vacuum distillation column 30 operating at a pressure of 5 kPa and a temperature of 380 ° C. The heavy product stream consisted of a vacuum distillation column 30 with a gas fraction of 200 tons / day discharged via the outlet pipe 31, an intermediate fraction of 400 tons / day discharged via the outlet pipe 33 and residuals. It is separated into 1,500 tons / day of residual oil discharged through the oil outlet pipe 32. The pressure drop of the flow control valve 36 is 150 kPa. The length of the stand pipe 38 is 15 m, and the presence of the liquid in the stand pipe 38 prevents vaporization of the liquid at the downstream end of the flow control valve 36. The transfer conduit 40 has a length of 70 m, the conduit 40 has an average inner diameter of 50 cm, and the transfer conduit includes four U-shaped fittings 44. The fluid pressure at the inlet of the transfer conduit 40 is 60 kPa and the fluid pressure at the outlet of the conduit 40 is equal to the fluid pressure in the vacuum distillation column 30. If the standpipe 38 is omitted, vaporization occurs at or near the flow control valve 36, the vaporization is uncontrollable and very small droplets are formed. Reference is now made to FIG. 2 which shows an alternative construction of the method of the present invention. Members in the configuration similar to the configuration described with reference to FIG. 1 are denoted by the same reference numerals as those in FIG. In the configuration of FIG. 2, the flow from reaction chamber 15 is separated in distillation column 50 into a light product stream discharged via outlet 51 and a heavy product stream discharged via outlet 52. The heavy product stream is then fed to vacuum distillation column 30 via conduit system 26. The apparatus for supplying a suitable reflux to the top of distillation column 50 and a stripping medium stream to the bottom of distillation column 50, respectively, is not shown. The bend connector 44 may have a U-shape as shown in FIGS. 1 and 2, or the connector may have an L-shape. The presence of liquid in the standpipe prevents vaporization of the liquid at the downstream end of the restriction opening. If the standpipe is omitted, vaporization occurs at or near the restricted opening, but this vaporization is uncontrollable and very small droplets are formed. In a vacuum distillation column, these microdroplets cannot be separated from the gas stream, so that the droplets leave the vacuum distillation column via the outlet pipe for the intermediate fraction and are vacuumed via the fraction or outlet pipe. Entrained in the gas stream leaving the head of the distillation column. This entrainment adversely affects the separation efficiency of the vacuum distillation column. The vertical pipe 38 described with reference to FIGS. 1 and 2 is a vertical pipe, and if sufficient liquid is present in the vertical pipe to prevent vaporization during normal operation, the vertical pipe is a tilted pipe. It will be understood that it is good.

─────────────────────────────────────────────────── ─── Continued front page    (81) Designated countries EP (AT, BE, CH, DE, DK, ES, FR, GB, GR, IE, IT, LU, M C, NL, PT, SE), OA (BF, BJ, CF, CG , CI, CM, GA, GN, ML, MR, NE, SN, TD, TG), AT, AU, BB, BG, BR, BY, CA, CH, CN, CZ, DE, DK, ES, FI, G B, HU, JP, KP, KR, KZ, LK, LU, LV , MG, MN, MW, NL, NO, NZ, PL, PT, RO, RU, SD, SE, SK, UA, UZ, VN (72) Inventors Juan Hof, Leonardus Marine             Su Maria             The Hague N'L, Netherlands             2596 Her Elle, Karel Juan Ville             Land Tran 30 (72) Inventor Juan Holst, Willem Corneli             Su Yang             The Hague N'L, Netherlands             2596 Her Elle, Karel Juan Ville             Land Tran 30 (72) Inventor Siribels and Franciscus Antoni             Us Maria             The Hague N'L, Netherlands             2596 Her Elle, Karel Juan Ville             Land Tran 30

Claims (1)

[Claims] 1. Hydrocarbon feed at pressures in the range 0.2-5 MPa and temperatures in the range 390-530 ° C. Heat and feed the feed to the reaction chamber, and then flow from the reaction chamber to a light product stream and heavy Separated into product stream, supply heavy product stream to vacuum distillation column, Separation of the heavy product stream into multiple fractions at pressures and temperatures in the range 320-400 ° C. Pyrolysis of a hydrocarbon feedstock consisting of a heavy distillation product stream to a vacuum distillation column. The feed flows the heavy product stream through a restricted opening, where the fluid pressure at its end is at the bottom end. Up the heavy product stream through a standpipe having a length that suppresses vaporization in To a heavy product via a transfer conduit that opens to the vacuum distillation column and then opens into the vacuum distillation column. The transfer conduit comprises a fluid pressure at the outlet of the conduit. Has a structure such that the pressure is equal to the fluid pressure in the vacuum distillation column. how to. 2. A contract in which the transfer conduit includes a plurality of straight sections joined by a bend connector. The method according to claim 1. 3. The flow from the reaction chamber is light product stream and heavy product in the cyclone separator. The method according to claim 1 or 2, which is separated into a stream and a stream. The method described. 4. The flow from the reaction chamber is separated into a light product stream and a heavy product stream in the distillation column. The method according to claim 1 or 2.