Batch Distillation Pressure Control for Narrower Heat Pump Lift
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Solution Overview
Problem
Distillation devices face challenges when the required heating temperature of the reboiler changes over a wide range, leading to inefficient operation and increased power consumption due to the limitations of centrifugal compressors, which are designed for constant flow rates and pressure increases.
Innovation Solution
A distillation method that includes a pressure-regulating step to minimize the temperature pumping range by using a heat pump with a narrower temperature rising range, either through an indirect or direct heat pump mechanism, and incorporates a pressure reducing valve to adjust the distillation column pressure for efficient operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a centrifugal compressor is used to increase pressure and temperature of the heating fluid, then the fluid can be supplied to the reboiler for distillation, but the compressor cannot efficiently operate when the flow rate and pressure increase requirements vary widely
Solution Approach 1:
The invention employs a screw compressor instead of a centrifugal compressor, as the screw compressor can dynamically adjust its compression ratio and operating characteristics to match varying flow rates and pressure requirements. This dynamic adaptability allows the compressor to efficiently operate across a wide range of heating temperature requirements without excessive power consumption, directly resolving the technical contradiction between adaptability and energy use.
2Adaptability or versatility
If the compression ratio is increased to cover the entire heating temperature range, then the temperature pumping range of the heat pump can cover all requirements, but the actual volume flow rate decreases below the normal operating range
Solution Approach 1:
The screw compressor's dynamic compression capability allows it to maintain optimal volume flow rates across varying compression ratios. Unlike fixed-compression-ratio centrifugal compressors, the screw compressor can adjust its internal clearance and compression timing to preserve productivity while achieving the required temperature pumping range, thus resolving the contradiction between adaptability and productivity.
Solution Approach 2:
The invention changes the operating parameters of the compressor by using a screw compressor design that allows variable compression ratios. This parameter flexibility enables the system to maintain high volume flow rates even when operating across a wide temperature range, resolving the contradiction between temperature pumping range coverage and actual volume flow rate.
3Adaptability or versatility
If the suction pressure is increased to raise discharge pressure and temperature, then the compression ratio can be narrowed, but the fluid density increases and volume flow rate decreases
Solution Approach 1:
The screw compressor's dynamic design allows it to compensate for increased fluid density caused by higher suction pressure. The variable compression ratio capability enables the system to maintain optimal volume flow rates even when operating with denser fluids, thus resolving the contradiction between compression ratio narrowing and productivity maintenance.
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 the required power for the compressor and enhances energy efficiency by optimizing the temperature and pressure conditions for distillation, allowing for efficient distillation even when heating temperatures vary widely.
Implementation Method 1
increasing pressure and temperature of a fluid, used to heat the liquid, with a compressor
Implementation Method 2
exchanging heat in the reboiler between the liquid, which has been supplied to the distillation column, and the fluid, which has been increased in pressure and temperature, to heat the liquid
Implementation Method 3
delivering the overhead vapor heated in the heating step to a condenser and condensing the overhead vapor into a condensate through heat exchange
Data Source
AI summary
A distillation method includes supplying a batch type distillation column with a liquid that is a process fluid; increasing pressure and temperature of a fluid, with a compressor and supplying the fluid to a reboiler; exchanging heat in the reboiler between the liquid, which has been supplied to the distillation column, and the fluid, which has been increased in pressure and temperature, to heat the liquid and acquire overhead vapor and to condense the fluid; delivering the overhead vapor to a condenser and condensing the overhead vapor into a condensate through heat exchange, removing the condensate; removing residual liquid from the distillation column; and regulating pressure of the distillation column to distill the liquid with heat generated by a heat pump operated over a narrower temperature rising range in the pressure-temperature increasing step.