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EP-4577791-B1 - TRANSFER LINE EXCHANGER WITH INLET CONE WITH IMPROVED EROSION RESISTANCE

EP4577791B1EP 4577791 B1EP4577791 B1EP 4577791B1EP-4577791-B1

Inventors

  • LING, Antonio
  • GONIOUKH, ANDREI
  • FRANZEN, Pascal

Dates

Publication Date
20260506
Application Date
20231128

Claims (15)

  1. A transfer line exchanger (1) comprising: a) a shell and tube heat exchanger (3), and b) an inlet cone (2) configured to pass gases from a cracking furnace to the shell and tube heat exchanger, wherein the inlet cone (2) has a i) conically shaped wall (4) extending in an axial direction from an inlet side (2a) to an outlet side (2b) and surrounding a gas flow passageway, the inlet cone (2) being fixed to the shell and tube heat exchanger (3) at the outlet side (2b), and ii) a baffle plate (5) arranged in the gas flow passageway between the inlet side (2a) and outlet side (2b), wherein the conically shaped wall (4) comprises a radially inwards facing inner surface formed from a heat resistant metallic material, wherein the inner surface is exposed to the gas flow passageway, and in that the baffle plate (5) is fixed to said conically shaped wall (4) via fixing means (6, 9), characterized in that conically shaped wall (4) comprises at least one erosion protection rib (7) projecting radially inwards into the gas flow passageway, the at least one erosion protection rib (7) covering at least one fixing means (6) in a top view from the inlet side (2a).
  2. The transfer line exchanger (1) of claim 1, characterized in that at least the inner surface is formed from a high temperature heat resistant material selected from the group consisting of solid cast iron and aluminum doped material.
  3. The transfer line exchanger (1) of any one of claims 1 or 2, characterized in that the inlet cone (2) does not comprise a refractory lining.
  4. The transfer line exchanger (1) of any one of claims 1 to 3, characterized in that the inner surface further comprises an erosion protection coating.
  5. The transfer line exchanger (1) of any one of claims 1 to 4, characterized in that the conically shaped wall (4) is solid between the inner surface and a radially outwards facing outer surface.
  6. The transfer line exchanger (1) of any one of claims 1 to 5, characterized in that the conically shaped wall (4) comprises a hollow volume (10) formed between the inner surface and an outer surface.
  7. The transfer line exchanger (1) of claim 6, characterized in that the hollow volume (10) is filled with a filling material having a lower thermal conductivity than the inner surface and/or outer surface.
  8. The transfer line exchanger (1) of one any one of claims 6 or 7, characterized in that the filling material is at least one of air, ceramic fiber or mineral wool.
  9. The transfer line exchanger (1) of any one of claims 1 to 8, characterized in that the inlet cone (4) further comprises at least one stabilizing bar formed at the outlet side (2b) and being arranged between a front face of the conically shaped wall (4) and the shell and tube heat exchanger (3).
  10. The transfer line exchanger (1) of any one of claims 1 to 9, characterized in that a comb profile gasket (11) is provided between the shell and tube heat exchanger (3) and the inlet cone (2), wherein the gasket (11) comprises a vermiculite sealing face bonded to a serrated metal core or a spiral wounded gasket.
  11. The transfer line exchanger (1) of any one of claims 1 to 10, characterized in that the heat resistant metallic material comprises a Vickers hardness measured at 20°C of at least 100 HV up to 1000 HV measured in accordance with DIN ISO 6507.
  12. The transfer line exchanger (1) of claim 11, characterized in that the baffle plate (5) is axially supported by the at least one erosion protection rib (7).
  13. The transfer line exchanger (1) according to any one of claims 1 to 12, characterized in that tubes of the shell and tube heat exchanger (3) are formed from a first material and the conically shaped wall (4) of the inlet cone (2) is formed of a second material, the first material having a lower heat resistance than the second material.
  14. A process for cracking hydrocarbons, in particular a process for the production of olefins, wherein the cracked gas is passed through a transfer line exchanger of any one of claims 1 to 13.
  15. An apparatus for cracking hydrocarbons, in particular for the production of olefins, the apparatus comprising a cracking furnace and a transfer line exchanger of any one of claims 1 to 13.

Description

FIELD OF THE DISCLOSURE The present disclosure refers to a transfer line exchanger with an inlet cone, a process for cracking hydrocarbons utilizing the transfer line exchanger and an apparatus for cracking hydrocarbons comprising the transfer line exchanger. BACKGROUND The cracking of hydrocarbons is a well-established process for the production of ethylene and propylene which are both important building blocks for other chemicals, in particular plastics. Cracking describes the process of breaking long chains of hydrocarbons down into smaller, often unsaturated, hydrocarbons. In order to gain the desired hydrocarbons, a feedstock of more complex hydrocarbons such as ethane and naphtha is fed into a cracking furnace, in particular into a so-called cracking coils arranged inside the cracking furnace and quickly brought up to a cracking temperature of around 800 to 900 °C with heat supplied from the outside of the coils. As a result of the thermal cracking of the hydrocarbons, carbon deposition occurs on the inside of the coils. This so-called coking leads to an increase pressure drop in the coils and lowers the heat transfer efficiency, eventually causing a reduction in the operation efficiency of the thermal cracking furnace. Due to the decreased heat transfer efficiency, the temperature on the outside of the coils has to be constantly increased in order to achieve the required cracking temperatures on the inside. However, increasing the temperature is only possible up to a maximum temperature which is usually determined by the material of the coils taking into account a certain safety margin. Ultimately, the coke deposition inside the coils has to be removed, referred to as decoking, resulting in an interruption of the whole process. Once a maximum temperature has been reached, decoking must be carried out. However, during the decoking process coke deposits flow with high velocity through the transfer line exchanger and caused significant erosion issues. The gas enters the transfer line exchanger at high velocities and temperatures. In order to protect the transfer line exchanger from overheating, the transfer line exchanger is usually equipped with an inlet cone lined with refractory. However, the cracked gas usually also contains small solid particles, such as coke particles, which causes severe erosion of the refractory lining. KR 101418137 discloses a heat-resistant cone of a heat exchanger which has an inner lining, an outer wall portion formed to surround the inner cylinder at a distance from the outer circumferential surface of the inner cylinder and a refractory material filled in the space between the inner cylinder and outer wall portion. US 4,161,192 relates to an inlet cone for passing gases from the outlet side of a hydrocarbon cracking heater to the tube inside of a heat exchanger, said inlet cone comprising: a generally conical metal wall connectable around the periphery of its larger end to said heat exchanger and connectable around the periphery of its smaller end to said cracking heater, said generally conical wall having an aperture between its said larger end and its said smaller end; a pressure resistant exterior wall of metal, said pressure resistant exterior wall being spaced from said generally conical wall and having its ends connected to said generally conical wall at points above and below, respectively said smaller end and said larger end of said generally conical wall; and a castable refractory fill, said refractory fill occupying the gap between said pressure resistant exterior wall and said generally conical wall and extending inwardly to form a filled aperture, said refractory fill in said filled aperture being approximately flush with the interior of said generally conical wall. US 2021/0190435 describes a heat exchanger for use with a hot fluid stream leaving a high temperature process comprising a hot section and cold section which have no common or adjoining external surfaces wherein one or more heat pipes extend from the interior of the hot section, traverse the open space between the hot section and the cold section at an angle of inclination from 10° to 90° and extend into the cold section. US 6,464,949 B1 relates to a steam-cracking unit that comprises at least one multitube quenching exchanger, equipped with a non-obstructive impact separator for preventing the erosion of the tubular input plate. The impact separator is at least 50% opaque when viewed from transfer pipe. It is arranged inside of an input cone in such a way that there is free passage of at least 40 mm between the periphery of the impact separator and the cone. US 2021/0123683 A1 discloses a heat exchanger including: an inlet portion having a first flow path through which a fluid is introduced; a main body including a shell and a plurality of tubes. The shell has an internal space and one surface that has a plurality of penetration holes and a cross-sectional area larger than a cross-sectional area of