Steam Cracking Furnace Feed Fractionation for Propylene Yield
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Solution Overview
Problem
Thermal steamcracking processes for converting hydrocarbons into olefin-containing product streams, such as ethylene and propylene, often result in significant amounts of by-products like pyrolysis gasoline, which are difficult to manage, and typically produce lower propylene yields compared to desired levels.
Innovation Solution
The process involves fractionating the fresh feed into two distinct fractions with different compositions, where one fraction is processed in a first cracking furnace under standard conditions and the other in a second cracking furnace under mild conditions, allowing for optimized matching of feed composition and cracking conditions to enhance propylene production while controlling pyrolysis gasoline formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If thermal steamcracking is performed under standard conditions to produce ethylene, then ethylene production is maximized, but propylene yield remains lower than desired levels
Solution Approach 1:
The fresh feed is fractionated into at least two different fractions with different compositions, which are then processed in separate cracking furnaces under different conditions. This segmentation allows one furnace to optimize for propylene production while another optimizes for ethylene production, resolving the contradiction between maximizing propylene yield and maintaining ethylene production efficiency
Solution Approach 2:
Different cracking conditions (temperature, residence time, feed composition) are applied in different cracking furnaces according to the specific requirements for propylene versus ethylene production. Each furnace is locally optimized for its specific product target, with the first furnace operating under conditions favoring propylene formation and the second under conditions favoring ethylene formation
2Quantity of substance
If cracking conditions are optimized for high propylene production, then propylene yield increases, but formation of pyrolysis gasoline by-products increases and becomes difficult to manage
Solution Approach 1:
By fractionating the fresh feed into different composition ranges and processing them in separate furnaces, the formation of pyrolysis gasoline is segmented and controlled. The fractionation ensures that only specific feed components are subjected to conditions that produce high propylene yields, while other fractions are processed under conditions that minimize unwanted by-products
Solution Approach 2:
The feed composition parameters are changed through fractionation, creating distinct feed fractions with different properties. This allows the cracking conditions to be optimized for propylene production from specific fractions while preventing the formation of excessive pyrolysis gasoline from other fractions, thus controlling the harmful by-product formation
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 significantly increases propylene yield relative to the fresh feed, maintains controllable pyrolysis gasoline amounts, and allows for efficient operation of steamcracking plants by optimizing cracking conditions in multiple furnaces, thereby improving overall process efficiency.
Implementation Method 1
Method for converting hydrocarbon feedstocks into olefinic product flows by means of thermal steam cracking
Data Source
AI summary
The invention relates to a process for converting feeds composed of hydrocarbons by thermal steamcracking to at least one olefin-containing product stream comprising at least ethylene and propylene, with at least partial conversion of the feeds in at least one first cracking furnace (1) and in at least one second cracking furnace (2). According to the invention, a fresh feed (B) is fractionated into at least one first and one second fresh feed fraction (B1, B2), and the first fresh feed fraction (B1) is conducted at least partly into the first cracking furnace (1) and the second fresh feed fraction (B2) at least partly into the second cracking furnace (2).