High-Pressure Oxygenate Synthesis for Integrated Gasoline Production
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Solution Overview
Problem
Existing integrated processes for producing gasoline from synthesis gas require recycling unconverted synthesis gas and separate removal of carbon dioxide, which complicates the process and increases costs.
Innovation Solution
Operating the oxygenate synthesis at high pressure (above 4 MPa) to achieve nearly complete conversion of synthesis gas to oxygenates, allowing the entire oxygenate mixture, including carbon dioxide, to be introduced into the gasoline synthesis step without recycling, using catalysts like copper, zinc, and zeolites to convert oxygenates to higher hydrocarbons, and utilizing carbon dioxide as a heat sink to control reaction temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If synthesis gas is converted to oxygenates at low pressure, then the conversion is incomplete requiring gas recycling, but recycling increases process complexity and operational costs
Solution Approach 1:
The patent applies parameter changes by increasing the pressure in the oxygenate synthesis reactor to above 4 MPa (typically 5-10 MPa). This pressure increase shifts the equilibrium and kinetics of the synthesis gas conversion reaction, achieving nearly complete conversion of synthesis gas to oxygenates in a single pass. As a result, gas recycling is eliminated, simplifying the process flow and reducing operational costs while maintaining high productivity
2Productivity
If carbon dioxide is removed from synthesis gas before oxygenate synthesis, then the synthesis efficiency improves, but the process complexity and cost increase
Solution Approach 1:
The patent converts the harmful effect of carbon dioxide (which would normally require removal to maintain synthesis efficiency) into a beneficial heat sink. By allowing CO2 to remain in the synthesis gas and accumulate in the oxygenate synthesis reactor, it absorbs the exothermic heat of reaction, enabling better temperature control. The CO2 is then easily separated from the liquid oxygenate product, eliminating the need for complex pre-removal processes while maintaining high synthesis efficiency
Solution Approach 2:
Carbon dioxide acts as an intermediary substance that mediates between the exothermic oxygenate synthesis reaction and the temperature control requirement. It absorbs excess heat during the reaction and can be easily separated from the liquid oxygenate product through simple phase separation or distillation, serving as a convenient heat management medium without requiring complex removal systems
3Device complexity
If the entire oxygenate mixture is converted to gasoline without separation, then the process is simplified, but temperature control becomes difficult due to exothermic reactions
Solution Approach 1:
Carbon dioxide serves as a heat sink intermediary in the oxygenate synthesis reactor. It absorbs the exothermic heat generated during synthesis gas conversion to oxygenates, preventing excessive temperature rise. This allows the entire oxygenate mixture to be converted to gasoline in a simplified single-pass process while maintaining effective temperature control through the CO2 heat absorption capacity
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 achieves high conversion levels of synthesis gas to gasoline without recycling unconverted gas and eliminates the need for separate CO2 removal, enabling efficient production and recovery of CO2 at elevated pressure for sequestration, reducing energy consumption and operational costs.
Implementation Method 1
reacting the synthesis gas to an oxygenate mixture comprising methanol and dimethyl ether in presence of one or more catalysts which together catalyse a reaction of hydrogen and carbon monoxide to oxygenates
Implementation Method 2
reacting the oxygenate mixture in presence of a catalyst being active in the conversion of oxygenates to higher hydrocarbons
Implementation Method 3
utilizing carbon dioxide as a heat sink to control reaction temperature
Implementation Method 4
separating the effluent of step (d) into a tail gas, a liquid hydrocarbon phase and a liquid aqueous phase
Data Source
AI summary
A process for the preparation of hydrocarbon products comprising the steps of (a) providing a synthesis gas comprising hydrogen, carbon monoxide and carbon dioxide; (b) reacting the synthesis gas to an oxygenate mixture comprising methanol and dimethyl ether in presence of one or more catalysts which together catalyse a reaction of hydrogen and carbon monoxide to oxygenates at a pressure of at least 4 MPa; (c) withdrawing from step (b) the oxygenate mixture comprising amounts of methanol, dimethyl ether, carbon dioxide and water together with unreacted synthesis gas and introducing the entire amount of the oxygenate mixture without further treatment into a catalytic oxygenate conversion step (d); (d) reacting the oxygenate mixture in presence of a catalyst being active in the conversion of oxygenates to higher hydrocarbons; (e) withdrawing an effluent from step (d) and separating the effluent into a tail gas, a liquid hydrocarbon phase containing the higher hydrocarbons produced in step. (d) and a liquid aqueous phase, wherein the pressure employed in steps (c) to (e) is substantially the same as employed in step (b).