ODH complex with on-line mixer unit and feed line cleaning
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Solution Overview
Problem
Oxidative dehydrogenation (ODH) of lower alkanes into corresponding alkenes faces challenges such as high energy intensity, expensive processes, coke production, and limited selectivity in steam cracking, while ODH offers advantages like lower temperatures and higher selectivity but is hindered by the risk of catastrophic oxygen-hydrocarbon mixing.
Innovation Solution
A chemical complex with two upstream gas mixer units and a method for cleaning sulfur-containing deposits from gas mixers and feed lines, involving parallel connection of mixers to the ODH reactor, pressure monitoring, and introduction of a cleaning solvent to remove deposits, ensuring safe and efficient operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If steam cracking is used to produce alkenes, then production capacity is achieved, but energy consumption increases and selectivity decreases
Solution Approach 1:
The invention changes the fundamental reaction parameters by using oxidative dehydrogenation instead of steam cracking, operating at lower temperatures (300-600°C vs 700-1000°C) while using oxygen as a reactant to drive the dehydrogenation reaction, thereby reducing energy consumption while maintaining production capacity
Solution Approach 2:
The invention uses oxygen as a strong oxidant to enable oxidative dehydrogenation, where oxygen reacts with the alkane to remove hydrogen and form the alkene, accelerating the reaction and improving selectivity compared to thermal cracking methods
2Productivity
If steam cracking is used to produce alkenes, then production capacity is achieved, but process cost increases
Solution Approach 1:
By changing to oxidative dehydrogenation conditions with oxygen reactant and lower temperatures, the invention reduces fuel demand and extends reactor material life, thereby lowering operational and capital costs while maintaining production capacity
Solution Approach 2:
The invention enables continuous operation without periodic shutdowns for coke removal, as oxidative dehydrogenation does not produce coke, thereby improving process continuity and reducing maintenance costs
3Productivity
If steam cracking is used to produce alkenes, then production capacity is achieved, but maintenance frequency increases
Solution Approach 1:
By operating at lower temperatures (300-600°C vs 700-1000°C) through oxidative dehydrogenation, the invention reduces thermal stress and coke formation, thereby extending reactor operational duration between maintenance cycles
Solution Approach 2:
The invention converts the potential harm of high-temperature operation that causes coke formation and equipment degradation into a benefit by using controlled oxidation that prevents coke formation while maintaining high conversion rates
4Productivity
If steam cracking is used to produce ethylene, then conversion rate is achieved, but ethylene selectivity decreases
Solution Approach 1:
The invention uses oxygen as a selective oxidant that preferentially reacts with the alkane to remove hydrogen and form alkene, achieving high ethylene selectivity (98%) by controlling the oxidation reaction to stop at the dehydrogenation stage without further oxidation of the product
Solution Approach 2:
By changing to oxidative dehydrogenation conditions with controlled oxygen feed and lower temperatures, the invention improves ethylene selectivity from 80-85% in steam cracking to 98%, while maintaining conversion rates around 60%
5Manufacturing precision
If ODH is used to produce alkenes, then selectivity and temperature efficiency are improved, but safety risk increases
Solution Approach 1:
The invention segments the oxygen and hydrocarbon feed streams into separate mixing units with independent control, allowing staged mixing and temperature control to prevent runaway reactions while achieving the required oxygen-hydrocarbon mixture for oxidative dehydrogenation
Solution Approach 2:
The invention introduces an intermediary mixing unit that acts as a buffer between the oxygen and hydrocarbon streams, allowing controlled mixing under monitored conditions before the combined stream enters the reactor, thereby mediating the safety risk of direct mixing
6Ease of operation
If gas mixers are operated without cleaning, then operational simplicity is maintained, but sulfur deposit accumulation increases
Solution Approach 1:
The invention implements preliminary cleaning action by introducing cleaning solvents through injection ports before sulfur deposits significantly accumulate and cause operational problems, thereby preventing harmful buildup while maintaining simple continuous operation
Solution Approach 2:
The gas mixing unit is equipped with self-cleaning capability through integrated cleaning solvent injection ports and circulation systems, allowing the unit to service itself by removing sulfur deposits without requiring external intervention or shutdown
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 solution enables safe and efficient ODH of lower alkanes with high selectivity and reduced maintenance, avoiding the risks associated with oxygen-hydrocarbon mixing and sulfur fouling, thereby improving process efficiency and safety.
Implementation Method 1
an oxidative dehydrogenation catalyst contained within the at least one oxidative dehydrogenation reactor reacts with the mixed feed stock stream to produce a product stream including the corresponding alkene
Implementation Method 2
oxidative dehydrogenation (ODH) of lower alkanes into corresponding alkenes
Implementation Method 3
introducing a cleaning solvent into the first mixer and cycling the cleaning solvent through a cleaning loop until the sulfur-containing deposits are removed
Data Source
AI summary
Oxidative dehydrogenation is an alternative to the energy extensive steam cracking process presently used for the production of olefins from paraffins. Various embodiments of an oxidative dehydrogenation chemical complex designed to allow removal of sulfur containing contaminants that collect in the gas mixer unit and in the feed lines leading to the ODH reactor are disclosed herein.