Ethylene Production via Steam Cracking and Extraction
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Solution Overview
Problem
Current ethylene production methods via steam cracking are burdensome in terms of separation technology, leading to high investment and operating costs due to the need for extensive separation of ethane and heavier hydrocarbons.
Innovation Solution
A method where the first feed gas, rich in ethane, and a second feed gas, containing recycled hydrocarbons, are processed in a reactor to produce a cracked gas, which is then treated to form a mixture that feeds an ethylene separation step unseparately with ethane and hydrocarbons with three carbon atoms, reducing the separation effort by including heavier hydrocarbons in the ethylene separation process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If extensive separation of ethane and heavier hydrocarbons is performed in conventional steam cracking processes, then ethylene production purity is improved, but separation technology complexity and operating costs increase
Solution Approach 1:
The invention extracts and removes the debutanization separation step from the conventional process flow. By taking out this specific separation unit that handles hydrocarbons with four and more carbon atoms, the process simplifies the overall separation technology while maintaining ethylene production purity through the remaining essential separation steps.
2Manufacturing precision
If conventional separation processes are used to separate ethylene from ethane and heavier hydrocarbons, then product purity is improved, but energy consumption increases
Solution Approach 1:
The invention removes the energy-intensive debutanization separation step that handles heavier hydrocarbons. By extracting this specific separation unit, the process reduces overall energy consumption while maintaining product purity through optimized remaining separation steps that focus only on necessary separations.
3Manufacturing precision
If conventional separation processes are used to separate ethylene from ethane and heavier hydrocarbons, then product purity is improved, but investment costs increase
Solution Approach 1:
The invention extracts and eliminates the debutanization separation unit from the process configuration. This removal reduces capital investment costs by eliminating unnecessary separation equipment while maintaining product purity through the optimized remaining separation train.
4Productivity
If hydrocarbons with four and more carbon atoms are completely separated before ethylene separation, then separation efficiency is improved, but process complexity increases
Solution Approach 1:
The invention removes the debutanization step that handles hydrocarbons with four and more carbon atoms. By taking out this separation unit, the process reduces complexity while maintaining efficiency through direct feeding of the remaining mixture into the ethylene separation step, where the separation is performed without the intermediate heavy hydrocarbon removal.
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 separation effort, resulting in lower energy consumption and material savings, with specific alternatives offering reductions in shaft power, low-pressure steam requirements, and heat exchanger areas, thereby lowering production and operating costs.
Implementation Method 1
a first feed gas (fresh feed gas) and a second feed gas (recycled feed gas) are fed into a reactor, where they are processed by steam cracking to obtain a product mixture (cracked gas)
Implementation Method 2
a subsequent mixture containing hydrogen, methane, ethane, ethylene and hydrocarbons containing three, four and at least five carbon atoms, and in particular consisting (essentially) of these components, is subjected to separation
Data Source
AI summary
A process (100, 200, 300) for the production of ethylene is proposed in which a first feed gas (A) and a second feed gas (B) are fed to a reactor (1) and processed therein by vapour cracking to obtain a product mixture (C), the first feed gas (A) comprising more than 90 weight percent saturated hydrocarbons and more than 80 weight percent ethane, and wherein the product mixture (C) or a part thereof is subjected to a treatment (2, 3, 4) and the resulting mixture (F) or a part thereof is subjected to a separation (10) to obtain a resulting mixture (F) containing hydrogen, methane, ethane, ethylene and hydrocarbons having three, four and at least five carbon atoms. The separation (10) being provided in that it comprises an ethylene separation step (7) to which at least the ethane, the ethylene and the hydrocarbons having three carbon atoms from the succeeding mixture (F) or a part thereof are fed unseparated from each other in a common separation insert (S, V, X), in which in the ethylene separation step (7) a light fraction (K) containing more than 95 mole percent ethylene is fed, and a heavy fraction (T, W, Y) containing at least a portion of the ethane from the separation insert (S, V, X) and at least 15% by weight of the hydrocarbons having three and four carbon atoms from the separation insert (S, V, X), and wherein the heavy separation product (T, W, Y) from the ethylene separation step (7) or a portion thereof is used as part or to form the second feed gas (B). A corresponding annex is also the subject of this invention.