High-performance cracker

Abstract

A furnace for thermally cracking hydrocarbon process fluid is provided. The furnace comprises a convection section including a plurality of convection sub-sections, a radiant section comprising a plurality of radiant sub-sections, and an enclosure defining a plurality of discrete sectors. Each discrete sector of the enclosure includes a convection sub-section having at least one convection conduit for carrying hydrocarbon process fluid, at least one radiant sub-section having at least one radiant conduit connected to receive preheated hydrocarbon process fluid from the convection conduit, and a heat source configured to deliver heat into the discrete sector. Adjacent sectors of the furnace are segregated from each other, such that the heat delivered from the heat source is substantially localized in the discrete sector of the enclosure.

Description

FIELD OF THE INVENTION[0001]The present invention relates to a pyrolytic furnace for cracking hydrocarbon process fluid. The pyrolytic furnace includes multiple convection and radiant sub-sections that are arranged in zones for cracking of hydrocarbon process fluid.BACKGROUND OF THE INVENTION[0002]The rapidly expanding global demand for ethylene has necessitated an industry need for efficient, expandable, large capacity pyrolytic furnaces. Generally, pyrolytic furnaces are employed in the petroleum industry to reduce the molecular weight of hydrocarbons by breaking their molecular bonds to yield olefins. Specifically, cracking of hydrocarbons is a petrochemical process that is widely used to produce olefins such as ethylene, propylene, butenes, butadiene, from a hydrocarbon feedstock such as naphtha, ethane, propane, gas oil or other fractions of whole crude oil.[0003]The cracking process is commonly carried out in a pyrolytic furnace (also referred to herein as a cracker or steam c...

AI Technical Summary

Benefits of technology

"The invention is a pyrolytic furnace for thermally cracking hydrocarbon process fluid. The furnace has a convection section, a radiant section, and an enclosure with discrete sectors. Each sector has a convection sub-section with a conduit for carrying the fluid, a radiant sub-section with a conduit for receiving pre-heated fluid from the convection section, and a heat source for delivering heat to the sector. The heat source is designed to deliver heat to the discrete sector, resulting in a more efficient heat transfer and reduced energy consumption. The method involves distributing the fluid into the convection section of a discrete sector and transferring it to the radiant section of the same sector for cracking. The heat is delivered to the radiant section to crack the fluid, resulting in a higher yield of valuable products."

Problems solved by technology

Coke tends to reduce the heat exchange efficiency between the heat sources and the hydrocarbon feed within radiant coils, necessitating a greater quantity of thermal energy to crack the hydrocarbon feed within each radiant coil, consequently increasing the tube wall temperature and the process side pressure drop.

Unscheduled or frequent decoking cycles may lead to a reduction in olefin production, shortened radiant tube life, and higher furnace maintenance costs.

On-line decoking is not a realistic option for many conventional furnaces, however.

Reducing the heat emitted by the heat sources to achieve decoking in some coils, consequently decreases the heat within the radiant section to a level insufficient for cracking the hydrocarbon feed within the other radiant coils at the design flow rate.

Conversely, increasing the heat emitted by the heat sources to achieve cracking of the hydrocarbon feed within the respective radiant coils, may overheat and deform the radiant coils carrying hot air and steam.

Thus, on-line decoking is not a realistic option for many conventional furnaces.

However, because one radiant box is decoking and therefore off-line for production, the furnace is only operating at 50% efficiency.

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