Olefins Production Process Pre-heating Fuel Gas Reduction

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Solution Overview

Problem

The existing pyrolytic cracking process for producing olefins in cracker furnaces is energy-intensive and costly due to high fuel gas consumption, leading to excessive carbon dioxide emission, particularly when using hydrogen as a fuel source, which requires additional energy and resources.

Innovation Solution

Pre-heating the hydrocarbon feed stream outside the cracker furnace and pre-heating the oxygen-containing stream before combustion in the radiant section, reducing the heat duty required for pyrolytic cracking and minimizing fuel gas combustion, thereby decreasing carbon dioxide formation and energy consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If fuel gas is combusted in the burners of the cracker furnace to provide heat for pyrolytic cracking, then the required temperature for olefin production is achieved, but carbon dioxide emissions increase and energy costs rise

Engineering Contradiction:

Improvepyrolytic cracking temperatureVSAvoidcarbon dioxide emissions

Core Design Contradiction:

TemperatureVSObject-generated harmful factors

Solution Approach 1:

The feed stream is pre-heated outside the cracker furnace before entering the radiant section, and the oxygen-containing stream is pre-heated before combustion. This preliminary heating action reduces the heat duty required from fuel gas combustion in the burners, thereby decreasing carbon dioxide emissions while maintaining the necessary pyrolytic cracking temperature

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The pre-heating of the oxygen-containing stream before combustion converts what would otherwise be wasted thermal energy into useful heat, reducing the overall fuel gas consumption and carbon dioxide emissions required to achieve the target cracking temperature

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

2Productivity

If more fuel gas is consumed to ensure sufficient heat for pyrolytic cracking, then the olefin production rate is maintained, but the energy cost and carbon footprint increase

Engineering Contradiction:

Improveolefin production rateVSAvoidfuel gas consumption

Core Design Contradiction:

ProductivityVSUse of energy by moving object

Solution Approach 1:

By pre-heating the feed stream outside the cracker furnace and pre-heating the oxygen-containing stream before combustion, the system reduces the amount of fuel gas needed during actual cracking operation, thereby maintaining olefin production rates while lowering energy consumption and costs

Inventive Principle:

Principle #10Preliminary action

3Loss of energy

If the feed stream is pre-heated outside the cracker furnace, then the heat duty in the radiant section is reduced and fuel gas consumption decreases, but additional pre-heating equipment is required

Engineering Contradiction:

Improvefuel gas consumptionVSAvoidpre-heating equipment

Core Design Contradiction:

Loss of energyVSDevice complexity

Solution Approach 1:

A heat exchanger is introduced as an intermediary device outside the cracker furnace to pre-heat the feed stream and oxygen-containing stream, enabling heat recovery and reduction of fuel gas consumption in the radiant section while managing the added equipment complexity

Inventive Principle:

Principle #24Intermediary (Mediator)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach reduces the total amount of fuel gas needed, lowers carbon dioxide emissions, and maintains a consistent stack temperature, enhancing the thermal efficiency and cost-effectiveness of the process while minimizing the demand for hydrogen production from renewable sources.

Implementation Method 1

The convection section comprises one or more tubes into which the hydrocarbon feed stream is introduced, in which tubes the hydrocarbon stream is pre-heated by hot flue gas which is present outside these tubes and which arises from the radiant section, wherein heat exchange takes place through the walls of said tubes

Methodology Applied

Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 2

Said radiant section comprises one or more burners wherein oxygen, e.g. as present in air, and a fuel gas are contacted and the fuel gas is combusted resulting in heat release, which heat is needed to effect the pyrolytic cracking of the hydrocarbon stream

Methodology Applied

Scientific EffectCombustion: Combustion

Implementation Method 3

In a pyrolytic cracking process, the hydrocarbons containing stream is converted under the influence of heat, and substantially in the absence of oxygen, into an olefins containing effluent

Methodology Applied

Scientific EffectPyrolytic cracking: Pyrolysis

Data Source

PatentUS20240279558A1Olefins production process

Publication Date: 2024.08.22 SHELL USA INC

AI summary

The invention relates to a process for producing olefins from a feed stream containing hydrocarbons by pyrolytic cracking of the hydrocarbons in a cracker furnace, said process comprising: pre-heating the feed stream outside the cracker furnace; feeding the pre-heated feed stream to a tube in the convection section of the cracker furnace; further pre-heating the feed stream in the convection section; feeding the further pre-heated feed stream to a tube in the radiant section of the cracker furnace; pre-heating an oxygen containing stream; contacting the pre-heated oxygen containing stream with a fuel gas in a burner in the radiant section; and pyrolytic cracking the feed stream in the radiant section resulting in an effluent containing olefins.