Propylene Production via Low-Pressure Metathesis
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Solution Overview
Problem
Current processes for producing propylene from isobutene require high-pressure metathesis reactions, necessitating energy-intensive cooling and pressurization steps, which increase equipment costs and energy consumption.
Innovation Solution
A process involving skeletal isomerization of isobutene using a catalyst like zeolites or metal oxides at moderate pressures, followed by a metathesis reaction with ethylene using transition metal oxides at pressures equal to or lower than isomerization, eliminating the need for cooling and re-pressurizing the stream.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If metathesis reaction is performed at high pressure (200-600 psig), then propylene production is achieved, but energy consumption and equipment costs increase due to required cooling and pressurization steps
Solution Approach 1:
The patent changes the pressure parameter of the metathesis reaction from conventional high pressure (200-600 psig) to low pressure (1-50 psig). This parameter change eliminates the need for energy-intensive cooling and recompression steps while maintaining propylene production effectiveness, directly resolving the contradiction between productivity and energy consumption
Solution Approach 2:
The patent inverts the conventional sequence of operations by performing metathesis at low pressure instead of high pressure. This inversion eliminates the requirement for cooling the isomerized stream and subsequent recompression, transforming a energy-intensive multi-step process into a simpler, more efficient operation that maintains productivity while reducing energy consumption
2Productivity
If metathesis reaction is performed at high pressure, then propylene production is achieved, but equipment costs increase due to additional cooling and pressurization equipment
Solution Approach 1:
By changing the pressure parameter to low pressure conditions, the patent eliminates the need for complex cooling and pressurization equipment, directly reducing device complexity and capital costs while maintaining propylene production capability
Solution Approach 2:
The patent extracts and eliminates the unnecessary cooling and pressurization steps from the conventional process flow. By removing these intermediate steps, the equipment complexity is reduced without affecting the core propylene production function
3Reliability
If cooling and pressurization steps are added to the process, then metathesis reaction can proceed at high pressure, but heat-exchanging requirements and utility usage increase
Solution Approach 1:
The patent changes the pressure parameter to low pressure conditions, which eliminates the need for cooling and pressurization steps. This directly reduces heat-exchanging requirements and utility usage while maintaining sufficient reaction control for reliable propylene production
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 energy and equipment costs by minimizing heat-exchanging requirements, achieving efficient propylene production with reduced heat integration and utility usage.
Implementation Method 1
reacting a feed stream comprising isobutene in the presence of a skeletal isomerization catalyst to obtain an isomerized stream comprising C4 olefins
Implementation Method 2
reacting the isomerized stream with ethylene in the presence of a metathesis catalyst to form a metathesis product stream comprising propylene
Data Source
AI summary
A propylene production process is disclosed. The process comprises (a) reacting a feed stream comprising isobutene in the presence of a skeletal isomerization catalyst to obtain an isomerized stream comprising C4 olefins; and (b) reacting the isomerized stream with ethylene in the presence of a metathesis catalyst to form a metathesis product stream comprising propylene, C4 olefins, and C5+ olefins. The metathesis reaction pressure is equal to or lower than that of the skeletal isomerization.