Extruded Acid-Metal Bifunctional Catalyst for Syngas Conversion
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Solution Overview
Problem
Conventional methods for producing dimethyl ether from natural gas are costly due to air separation, autothermal reforming, and internal product recycle, and suffer from catalyst deactivation issues in one-stage processes using bifunctional catalysts with mixed metal and acid catalysts.
Innovation Solution
Development of acid/metal bifunctional catalysts produced by extrusion, comprising a zeolite or metal oxide acid catalyst and a M1/M2/A1 metal catalyst, activated in the presence of hydrogen, which are designed to maintain stability and efficiency in converting syngas to dimethyl ether.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If mixed metal and acid catalysts are used in a one-stage process for converting syngas to dimethyl ether, then the process integration and productivity are improved, but catalyst deactivation occurs due to coke formation and metal migration
Solution Approach 1:
The catalyst is segmented into distinct metal catalyst particles and acid catalyst particles that are separately prepared and then combined in a bifunctional catalyst system. This segmentation prevents direct contact and interaction between metal and acid sites, eliminating coke formation on metal sites and metal migration to acid sites, while still enabling one-stage syngas to dimethyl ether conversion through the协同 effect of both catalyst types.
2Reliability
If conventional two-stage process with air separation and autothermal reforming is used, then catalyst stability is maintained, but operating costs and device complexity increase significantly
Solution Approach 1:
The invention merges the methanol synthesis and dimethyl ether dehydration functions into a single reactor system using a bifunctional catalyst containing both metal and acid catalyst particles. This consolidation eliminates the need for separate reactors, air separation units, and complex recycle systems, reducing device complexity and operating costs while maintaining catalyst stability through the segmented catalyst structure.
3Productivity
If high recycle ratio is used in methanol synthesis, then equilibrium limitations are overcome and conversion is improved, but energy consumption and operating costs increase
Solution Approach 1:
The bifunctional catalyst enables continuous conversion of syngas to dimethyl ether in a single pass through the reactor by providing both methanol synthesis and dehydration functions simultaneously. This continuous conversion process eliminates the need for high recycle ratios to overcome equilibrium limitations, as the in-situ dehydration of methanol to dimethyl ether drives the overall reaction forward, reducing energy consumption associated with recycling unreacted gas.
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
The bifunctional catalysts enhance the stability and carbon efficiency of the process, reducing catalyst deactivation and operational costs by allowing in-situ dehydration of methanol to dimethyl ether, thus improving per-pass conversion and maintaining system equilibrium.
Implementation Method 1
the acid catalyst component is selected from the group consisting of a zeolite, an ion exchanged zeolite, a molecular sieve, a metal oxide, and any combination thereof
Implementation Method 2
the metal catalyst component is a M1/M2/A1 catalyst, wherein M1 is selected from the group consisting of Cu, Cr, Ag, Au, Ru, Rh, Pd, Re, Os, Ir, Pt, and any combination thereof
Implementation Method 3
mixing an acid catalyst, a metal catalyst, a fluid, and optionally a binder to produce a dough; extruding the dough to form an extrudate
Implementation Method 4
calcining the powder to produce an acid/metal bifunctional catalyst
Implementation Method 5
activating an acid/metal bifunctional catalyst in the presence hydrogen at 150° C. to 350° C.
Data Source
AI summary
A method of producing bifunctional catalysts by extrusion may include mixing an acid catalyst, a metal catalyst, optionally a binder, and a fluid to produce a dough; extruding the dough to form an extrudate; producing a powder from the extrudate; and calcining the powder to produce an acid/metal bifunctional catalyst. Such acid/metal bifunctional catalysts may be useful in, among other things, converting syngas to dimethyl ether in a single reactor.