Methane Conversion to Distillate via Integrated Reforming and Oligomerization
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Solution Overview
Problem
Current methods for upgrading natural gas to distillate fuels are inefficient due to the reactivity challenges of methane, which is a major component of natural gas, and lack effective conversion processes to larger hydrocarbons.
Innovation Solution
An integrated process involving reforming, methanol synthesis, and oligomerization stages, where hydrocarbons are exposed to reforming catalysts to produce synthesis gas, then to methanol synthesis catalysts to form methanol, followed by conversion to olefins and subsequent oligomerization to produce distillate boiling range products, with CO2 recycling to enhance yield and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If steam cracking is used to convert C2+ alkanes to olefins, then olefin production is effective, but methane remains largely unreactive and cannot be converted
Solution Approach 1:
The patent applies parameter changes by modifying the reaction conditions from standard steam cracking to pyrolysis conditions with temperature ranging from 700°C to 900°C and specific residence times. This enables methane conversion while maintaining olefin production capability, resolving the contradiction between olefin efficiency and methane adaptability
Solution Approach 2:
The patent segments the conversion process into distinct stages: pyrolysis for methane cracking, followed by oligomerization for olefin formation. This segmentation allows each stage to be optimized independently, enabling both methane conversion and effective olefin production
2Productivity
If multiple conversion stages are integrated, then distillate yield increases by 1.0 wt% to 20 wt%, but process complexity increases
Solution Approach 1:
The patent merges the pyrolysis and oligomerization stages into an integrated process where the pyrolysis effluent is directly fed to the oligomerization reactor. This combining approach achieves high distillate yield while reducing the number of separate units compared to conventional multi-stage processes
Solution Approach 2:
The patent implements continuous action by maintaining steady-state operation across all conversion stages with continuous feedstock input and product withdrawal. The recycle stream of unreacted hydrocarbons ensures continuous conversion, maximizing distillate production while maintaining process stability
3Object-generated harmful factors
If CO2 is recycled from regeneration flue gas, then CO2 disposal is reduced and methanol synthesis is enhanced, but additional processing equipment is required
Solution Approach 1:
The patent converts the harmful CO2 emission from the regenerator into a beneficial resource by recycling it to the methanol synthesis reactor. This transforms a waste stream into a valuable feedstock, reducing CO2 disposal requirements while enhancing methanol production
Solution Approach 2:
The process implements self-service by using the CO2 generated internally during catalyst regeneration to support the methanol synthesis reaction. This internal recycling eliminates the need for external CO2 sources and reduces overall process emissions
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 increases the yield of distillate fuels by 1.0 wt % to 20 wt % relative to the initial hydrocarbon feed, reduces CO2 disposal, and achieves efficient conversion of methane to higher value distillate products through synergies between upstream and downstream reaction stages.
Implementation Method 1
exposing a feed including reformable hydrocarbons and at least one recycle input to a reforming catalyst under reforming conditions to produce a reformed effluent including H2 and CO
Implementation Method 2
At least a portion of the reformed product is exposed to a methanol synthesis catalyst under methanol synthesis conditions to produce a synthesis effluent comprising methanol
Implementation Method 3
A conversion feed including at least a portion of the methanol from the synthesis effluent is then exposed to a conversion catalyst under conversion conditions to form a conversion effluent and to form coke on the conversion catalyst
Implementation Method 4
At least a portion of the cooled conversion effluent and a recycled naphtha boiling range feed can be exposed to an oligomerization catalyst under oligomerization conditions to form an oligomerized effluent
Implementation Method 5
the coke on at least a portion of the conversion catalyst can be combusted to regenerate the at least a portion of the conversion catalyst and to form a regeneration flue gas comprising CO2
Implementation Method 6
At least a portion of the conversion effluent can then be passed into a heat exchange stage to form a cooled conversion effluent and steam
Data Source
AI summary
Systems and methods are provided for upgrading of methane and/or small alkanes to distillate boiling range hydrocarbons. The upgrading is performed using a reaction system where various types of integration are provided from downstream reaction stages to upstream reaction stages. Such integration can include recycle of various reaction products as well as thermal integration. Having a reaction system that begins with reforming of hydrocarbons and finishes with production of distillate can enable unexpected synergies between downstream reaction stages and upstream reaction stages.