Exxonmobil Chemical Patents Inc.

Subramanian Annamalai

James M Frye

Richard Charles Stell

James N McCoy

Paul F Keusenkothen

Alok Srivastava

David B Spicer

Arthur R Di Nicolantonio

George Stephens

John R Messinger

Jennifer L Bancroft

Arthur R DiNicolantonio

Nicholas G Vidonic

George J Balinsky

David Beattie

Nick G Vidonic

Robert David Strack

William A Aslaner

Caleb M Scherer

Blair H Margot

Stephen J Vande Stouwe

A process for the decoking of a hydrocarbon steam cracking furnace having a firebox, radiant coils, a transfer line exchanger, and an oil quench connection wherein liquid quench oil is injected to directly cool the steam-cracked effluent. Decoking feed comprising steam and air is supplied to the furnace under conditions sufficient to at least partially combust coke accumulated on the interior of the radiant coils, the transfer line exchanger, and the quench connection. Quench steam is supplied and injected into the decoking process effluent in an amount sufficient to cool the decoking process effluent below the metallurgical temperature limit of downstream piping. Also, a pyrolysis furnace for the production of ethylene is also provided.

Process and apparatus for decoking a hydrocarbon steam cracking furnace

The invention relates a process for removing coke formed during steam-cracking of a hydrocarbon feed. The process includes providing a decoking feed to at least one radiant coil of a steam-cracking furnace under conditions to remove at least a portion of coke from the at least one radiant coil to form a decoking effluent. The decoking effluent is cooled with a liquid quench medium to provide an partially-quenched decoking effluent. The partially-quenched decoking effluent is cooled with a gaseous quench medium to provide a quenched effluent. An apparatus configured to perform such a process is also described.

Process and apparatus for decoking a hydocarbon steam cracking furnace

A process for cracking a hydrocarbon feedstream containing non-volatile components in a hydrocarbon cracking furnace having upper and lower convection heating sections within a flue of the furnace, a radiant heating section downstream of and connected to said lower convection heating section, a transfer line exchanger downstream of and connected to said radiant heating section, a furnace box containing furnace burners and said radiant heating section, and a vapor/liquid separator vessel connected between the upper and lower convection heating sections, the process comprising (a) passing said hydrocarbon feedstream into said upper convection section to heat said hydrocarbon feedstream to a first temperature sufficient to flash at least a portion of the hydrocarbons within said hydrocarbon feedstream into a vapor phase to form a vapor/liquid stream; (b) passing said vapor/liquid stream out of said upper convection section and into said vapor/liquid separator to separate said vapor/liquid stream into a hydrocarbon-containing vapor phase and a hydrocarbon-containing liquid phase within said vapor/liquid separator; (c) collecting said liquid phase into a bottoms liquid within said vapor/liquid separator; (d) passing said vapor phase into said radiant heating section and cracking hydrocarbons in said vapor phase to form an olefins-containing effluent stream; and (e) periodically injecting an air-steam mixture into said convection heating section, then through said vapor/liquid separator to incinerate coke formed and passing an incinerated coke residue/air-steam mixture so-formed between the furnace burners within the furnace box.

Process for cracking a heavy hydrocarbon feedstream

Tar is contacted with stripping agent, such as steam or tail gas, in a stripping tower. A product comprising deasphalted tar is recovered as overheads and a product comprising heavy tar is recovered as bottoms from the stripping tower.

Deasphalting tar using stripping tower

An apparatus for on-line cleaning and maintaining the cleanliness of a transfer line exchanger tube is provided. In one embodiment, the apparatus includes a housing having a first end, a second end and a longitudinal axis, the housing further including a first inlet for introducing a flushing fluid to the transfer line exchanger tube, the first inlet disposed proximate the first end of the housing, a second inlet for providing a product effluent comprising hydrocarbons and an outlet for placing in fluid communication with an inlet of the transfer line exchanger tube and a critical flow nozzle or flow control orifice, the critical flow nozzle or flow control orifice in fluid communication with the first inlet of the housing. Systems and processes for cleaning and maintaining the cleanliness of a transfer line exchanger are also disclosed.

Apparatus and method of cleaning a transfer line heat exchanger tube

The invention relates to a process for upgrading tar using a heat exchanger in series with a vapor/liquid separator to separate tar into a heavy tar asphaltenic material and a deasphalted tar material.

Use of heat exchanger in a process to deasphalt tar

A vapor/liquid separation apparatus for treating a flow of vapor/liquid mixtures of hydrocarbons and steam comprises a vertical drum with a side inlet to introduce hydrocarbon/steam mixtures, an overhead vapor outlet, and a lower section in communication with a cylindrical boot of less diameter than the drum, the boot comprising sufficient gas-liquid contact surface, e.g., that provided by one or more sheds, baffles and/or distillation trays, to provide at least a partial theoretical distillation stage, and a lower portion for receiving liquid from the drum, a lower outlet for removing the liquid, and an inlet for introducing a stripping gas such as steam, hydrogen, light crackable hydrocarbon, and/or methane, below the distillation tray and preferably above the level of liquid in the boot.

Vapor/liquid separation apparatus

A process for decoking of a process that cracks hydrocarbon feedstock containing resid and coke precursors, wherein steam is added to the feedstock to form a mixture which is thereafter separated into a vapor phase and a liquid phase by flashing in a flash/separation vessel, separating and cracking the vapor phase, and recovering cracked product. Coking of internal surfaces in and proximally downstream of the vessel is controlled by interrupting the feed flow, purging the vessel with steam, introducing an air/steam mixture to at least partially combust the coke, and resuming the feed flow when sufficient coke has been removed. An apparatus for carrying out the process is also provided.

Process and apparatus for removing coke formed during steam cracking of hydrocarbon feedstocks containing resids

A process for cracking hydrocarbon feedstock containing resid comprising: heating the feedstock, mixing the heated feedstock with a fluid and/or a primary dilution steam stream to form a mixture, flashing the mixture to form a vapor phase and a liquid phase which collect as bottoms and removing the liquid phase, separating and cracking the vapor phase, and cooling the product effluent. The process comprises at least two of the following conditions: (1) maintaining the bottoms under conditions to effect at least partial visbreaking; (2) reducing or eliminating partial vapor condensation during flashing by adding a heated vaporous diluent to dilute and superheat the vapor; (3) partially condensing the vapor within said flash/separation vessel by contacting with a condenser; (4) decoking internal surfaces and associated piping of the flash/separation vessel with air and steam; (5) utilizing a flash/separation vessel having an annular, inverted L-shaped baffle; and (6) regulating temperature in furnace tube banks used for heating by utilizing a desuperheater and/or an economizer. An apparatus for carrying out the process is also provided.

Process and apparatus for cracking hydrocarbon feedstock containing resid to improve vapor yield from vapor/liquid separation

A process and control system for cracking a heavy hydrocarbon feedstock containing non-volatile hydrocarbons comprising heating the heavy hydrocarbon feedstock, mixing the heated heavy hydrocarbon feedstock with a dilution steam stream to form a mixture stream having a vapor phase and a liquid phase, separating the vapor phase from the liquid phase in a separation vessel, and cracking the vapor phase in the furnace, wherein the furnace draft is continuously measured and periodically adjusted to control the temperature of the stream entering the vapor/liquid separator and thus controlling the ratio of vapor to liquid separated in the separation vessel; and wherein in a preferred embodiment the means for adjusting the draft comprises varying the speed of at least one furnace fan, possibly in combination with adjusting the position of the furnace fan damper(s) or the furnace burner dampers(s).

Process and draft control system for use in cracking a heavy hydrocarbon feedstock in a pyrolysis furnace

A vapor/liquid separation apparatus for treating a flow of vapor/liquid mixtures of hydrocarbons and steam comprises a vertical drum with a side inlet to introduce hydrocarbon/steam mixtures, an overhead vapor outlet, and a lower section in communication with a cylindrical boot of less diameter than the drum, the boot comprising sufficient gas-liquid contact surface, e.g., that provided by one or more sheds, baffles and/or distillation trays, to provide at least a partial theoretical distillation stage, and a lower portion for receiving liquid from the drum, a lower outlet for removing the liquid, and an inlet for introducing a stripping gas, such as steam, hydrogen, light crackable hydrocarbon, and/or methane, below the distillation tray and preferably above the level of liquid in the boot.

A process for cracking a heavy hydrocarbon feedstock containing non-volatile components and/or coke precursors, wherein a stripping agent is added to the feedstock to form an enhanced hydrocarbon blend which is thereafter separated into a vapor phase and a liquid phase by flashing in a flash/separation vessel, separating and cracking the vapor phase, and recovering cracked product. The stripping agent increases vaporization of the volatile fraction of the heavy hydrocarbon increasing the maximum feedrate capacity of the furnace.

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Singapore, Singapore

Subramanian Annamalai