Methane Conversion to Liquid Hydrocarbons via Dehydrocyclization and Hydrogenation
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Solution Overview
Problem
Current methods for converting methane to liquid hydrocarbons face challenges such as high energy intensity, hazardous combustion reactions, low selectivity to aromatics, and the need for expensive co-feeds, as well as the issue of producing predominantly benzene and naphthalene, which have limited market value and environmental concerns, especially when dealing with natural gas streams high in carbon dioxide.
Innovation Solution
A process involving dehydrocyclization of methane with a catalyst under non-oxidizing conditions to produce aromatic hydrocarbons, followed by hydrogenation to reduce benzene and naphthalene content, and subsequent alkylation or hydrocracking to produce more valuable liquid hydrocarbons like cyclohexane and decalin, while also recycling hydrogen to enhance efficiency and reduce CO2 emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If methane is converted to liquid hydrocarbons via synthesis gas, then liquid hydrocarbons are produced, but the process becomes capital and energy intensive
Solution Approach 1:
The invention extracts and eliminates the synthesis gas generation step from the conventional methane conversion process. By using a dual-function catalyst that performs both dehydrocyclization and hydrogenation reactions in one step, the process directly converts methane to liquid hydrocarbons without requiring the intermediate synthesis gas stage, thereby reducing capital costs and energy consumption associated with synthesis gas production
Solution Approach 2:
The invention merges two separate catalytic functions (dehydrocyclization and hydrogenation) into a single dual-function catalyst system. This integration allows the process to achieve both aromatic hydrocarbon formation and subsequent hydrogenation in one reactor, eliminating the need for separate synthesis gas generation and processing units, thus reducing overall process complexity and energy requirements
2Quantity of substance
If oxidative coupling of methane is used to convert methane to olefins, then liquid hydrocarbons can be produced, but hazardous combustion reactions occur
Solution Approach 1:
The invention employs an inert or reducing atmosphere (using hydrogen or hydrocarbon gases) instead of oxidative conditions for the catalytic conversion of methane. This eliminates the hazardous combustion reactions associated with oxidative coupling while still achieving the desired conversion of methane to liquid hydrocarbons through dehydrocyclization followed by hydrogenation
Solution Approach 2:
The invention converts the typically harmful combustion reaction into a beneficial process by using controlled hydrogenation instead of oxidation. The hydrogen that would otherwise be a byproduct is now utilized as a reactant to hydrogenate the aromatic hydrocarbons, converting potentially harmful high-temperature oxidation into a controlled reduction process that produces valuable liquid hydrocarbons
3Quantity of substance
If dehydroaromatization of methane is used to produce aromatic hydrocarbons, then higher hydrocarbons are obtained, but low selectivity to aromatics occurs
Solution Approach 1:
The invention introduces a dual-function catalyst as an intermediary that first performs dehydrocyclization to form aromatic hydrocarbons, then performs hydrogenation to convert the aromatics to liquid hydrocarbons. This two-stage catalytic process within a single reactor system improves selectivity by controlling the reaction pathway and preventing unwanted side reactions that occur in conventional single-function catalyst systems
Solution Approach 2:
The invention optimizes reaction parameters including temperature, pressure, and gas hourly space velocity to enhance aromatic hydrocarbon selectivity. By carefully controlling these parameters and using a specifically designed dual-function catalyst, the process achieves high selectivity to aromatic hydrocarbons that can be subsequently hydrogenated to liquid products
4Quantity of substance
If benzene and naphthalene are produced from methane, then aromatic hydrocarbons are obtained, but environmental concerns and limited market value arise
Solution Approach 1:
The invention converts the environmentally problematic aromatic hydrocarbons (benzene and naphthalene) into beneficial liquid hydrocarbons through catalytic hydrogenation. The aromatic compounds that would otherwise be harmful or low-value products are transformed into valuable liquid fuels and chemical feedstocks, eliminating environmental concerns while creating marketable products
Solution Approach 2:
The invention changes the chemical state of the aromatic hydrocarbons by performing hydrogenation under controlled conditions. This parameter change transforms the aromatic compounds from harmful substances into valuable liquid hydrocarbons, improving both environmental performance and market value of the process products
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 process effectively increases aromatic hydrocarbon production, reduces the environmental impact of benzene and naphthalene, and generates valuable liquid hydrocarbons with improved market potential and lower CO2 emissions, making it economically viable even in remote locations.
Implementation Method 1
contacting a feed containing methane and at least one of H2, H2O, CO and CO2 with a dehydrocyclization catalyst under conditions effective to convert said methane to aromatic hydrocarbons
Implementation Method 2
reacting at least part of said aromatic hydrocarbons from said first effluent stream with hydrogen to produce a second effluent stream having a reduced benzene and/or naphthalene content
Data Source
AI summary
In a process for converting methane to liquid hydrocarbons, a feed containing methane is contacted with 0 dehydrocyclization catalyst under conditions effective to convert said methane to aromatic hydrocarbons, including benzene and/or naphthalene, and produce a first effluent stream comprising hydrogen and 0t least 5 wt % m>35 aromatic hydrocarbons than said feed. At least part the aromatic hydrocarbons from the first effluent stream is then reacted with hydrogen to produce a second effluent stream having a reduced benzene and/or naphthalene content compared with said first effluent stream.