Hydrocarbon Separation via Dual-Pressure Distillation
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Solution Overview
Problem
The separation of unsaturated and saturated hydrocarbons, particularly those containing 2-6 carbon atoms, requires excessive energy due to low relative volatility differences, leading to inefficient and costly distillation processes.
Innovation Solution
A system integrating a distillation column, compressor, heat exchangers, and a closed-loop cooling system that exploits the natural pressure behavior of hydrocarbons to minimize energy consumption and capital investment, using a combination of low-pressure and high-pressure distillation columns with a compressor to achieve efficient separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional fractional distillation is used to separate unsaturated and saturated hydrocarbons, then separation is achieved, but excessive energy is consumed and excessive number of distillation trays are required
Solution Approach 1:
The distillation process is divided into two separate columns operating at different pressures: a high-pressure distillation column and a low-pressure distillation column. This segmentation allows each column to operate under optimized conditions, with the high-pressure column handling the initial separation and the low-pressure column completing the purification, thereby reducing overall energy consumption while achieving the required separation purity
Solution Approach 2:
The invention changes the pressure parameter of the distillation process by operating one column at high pressure and another at low pressure. This parameter change exploits the pressure-dependent volatility differences between unsaturated and saturated hydrocarbons, enabling more efficient separation with reduced energy input compared to conventional single-column operation at constant pressure
2Manufacturing precision
If traditional distillation columns are used for separation, then hydrocarbon streams are separated, but tall columns requiring excessive capital investment are needed
Solution Approach 1:
The separation task is segmented between two shorter distillation columns operating at different pressures rather than using one tall column. Each column requires fewer trays and less height, reducing capital investment while maintaining separation effectiveness through the coordinated operation of both columns
Solution Approach 2:
The invention adds the pressure dimension to the separation process by operating columns at different pressures. This dimensional change allows separation to be achieved more efficiently in terms of column height and tray count, as the pressure difference provides an additional separation mechanism beyond just the number of theoretical stages
3Loss of energy
If heat pump system is used to compress overheads to provide heat to reboiler, then energy is recovered, but system complexity increases
Solution Approach 1:
The condenser of the high-pressure distillation column and the reboiler of the low-pressure distillation column are merged into a single heat exchange unit. This allows direct heat transfer from the condensing overheads of the high-pressure column to the reboiler feed of the low-pressure column, achieving energy recovery without requiring a separate heat pump system or complex external heating infrastructure
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 consumption and capital investment while maintaining stable and efficient operation, achieving high purity of unsaturated hydrocarbon streams with lower electricity usage compared to traditional methods.
Implementation Method 1
a distillation column, a compressor, heat exchangers for reboiler, condenser systems
Implementation Method 2
The relative volatility difference between the unsaturated hydrocarbon and its saturated counterpart is so low that the separation process invariably consumes excessive energy
Implementation Method 3
employing intermediate compressor and integrating the condenser and reboiler
Implementation Method 4
heat exchangers for reboiler, condenser systems
Implementation Method 5
integrating the condenser and reboiler
Implementation Method 6
exploiting the natural behavior of the unsaturated hydrocarbons and saturated hydrocarbons with respect to pressure to minimize the energy and capital
Data Source
AI summary
Apparatuses, systems and methods for separating highly pure unsaturated olefinic hydrocarbon stream with zero cooling water and or steam consumption, with minimum possible capital investment and uncompromised operational ease are disclosed herein from a mixture of hydrocarbon stream consisting of saturated and unsaturated hydrocarbons. Embodiments of the invention are directed to producing a hydrocarbon stream containing polymer, chemical grade ethylene, propylene, butylenes, isoprene, hexane stream which are of value in manufacturing chemicals, polymers, and rubbers. Embodiments of the process provided can be applied to concentrating ethylene, propylene, butylenes, cyclopentadiene, isoprene, 2 methyl butene-2, isopentane, hexene etc.