Displacement Compressor Flow Control for Batch Distillation
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Solution Overview
Problem
Centrifugal compressors in existing distillation devices struggle to maintain efficient operation when the heating temperature of the reboiler varies widely, leading to reduced actual volume flow rates and increased power consumption, especially in batch distillation systems where the liquid amount decreases during distillation.
Innovation Solution
A distillation device with a displacement compressor and actual volume flow rate regulation mechanism, allowing the actual volume flow rate to be adjusted in accordance with changing heating temperatures, using either a step displacement or stepless displacement control system, to optimize the temperature pumping range and reduce power requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a centrifugal compressor is used to increase pressure and temperature under constant flow rate conditions, then the compressor is designed with a specific impeller shape for the designed point, but when the heating temperature of the reboiler changes over a wide range, the actual volume flow rate decreases below the normal operation range, leading to increased power consumption and reduced efficiency
Solution Approach 1:
The patent applies dynamics by making the compressor type changeable from centrifugal to displacement based on operating conditions. The system dynamically selects the appropriate compressor type according to the required heating temperature range and flow rate conditions, allowing optimal performance across varying distillation stages without being constrained by a fixed impeller design
Solution Approach 2:
The patent changes the fundamental parameter of compressor operation by switching between two distinct compressor types (centrifugal and displacement). This parameter change enables the system to adapt to wide temperature ranges by selecting the compressor type whose characteristics match the current operating conditions, thereby maintaining efficient power consumption
2Temperature
If the compression ratio is increased to cover the entire changing range of required heating temperature, then the temperature pumping range of the heat pump covers the full range, but the increased suction pressure increases fluid density, reducing actual volume flow rate below the designed operation range
Solution Approach 1:
The system dynamically adjusts the compressor type based on the required temperature range and flow rate conditions. During early distillation stages when high flow rates are needed, a centrifugal compressor is used. During later stages when higher temperatures are required but flow rates are lower, a displacement compressor is selected, maintaining productivity across the entire temperature range
3Productivity
If a kickback line is used to circulate fluid and maintain actual volume flow rate at 80% of designed point, then the compressor can operate within normal range, but the compressor must be operated in a power-increased state to cope with the circulated amount of fluid
Solution Approach 1:
The patent extracts the need for kickback circulation by selecting a displacement compressor that can naturally maintain appropriate flow rates without requiring recirculation. The displacement compressor's inherent positive displacement characteristics ensure sufficient flow rate delivery directly, eliminating the energy-wasting kickback line and associated power consumption
4Power
If the impeller shape is designed according to fluid components and flow rate at the designed point, then the compressor achieves optimal performance at the designed point, but when components and flow rate change, the predetermined pressure increasing capacity cannot be obtained
Solution Approach 1:
The patent implements universality by having two different compressor types available in the system, each optimized for different operating conditions. The centrifugal compressor handles early-stage high-flow conditions, while the displacement compressor handles late-stage high-temperature low-flow conditions, ensuring pressure increasing capacity across all distillation stages without requiring a single impeller design to perform all functions
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 efficient distillation with a narrower temperature range, reducing power consumption and maintaining optimal operation by adjusting the actual volume flow rate of the fluid, thus improving energy efficiency.
Implementation Method 1
a displacement compressor that draws in fluid for heating the liquid and increases the fluid in pressure and temperature
Implementation Method 2
The fluid holds condensation heat of the overhead vapor, is increased in pressure and temperature by the compressor, and then transfers the condensation heat to the liquid
Implementation Method 3
The condenser condenses overhead vapor of the distillation column into a condensate
Implementation Method 4
a batch type distillation column, a reboiler that heats liquid supplied to the distillation column to vaporize the liquid
Data Source
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AI summary
A distillation device includes a batch type distillation column, a reboiler that heats and vaporizes liquid, which is a process fluid supplied to the distillation column, into vapor, a displacement compressor that draws in fluid for heating the liquid and increases the fluid in pressure and temperature, and supplies the fluid to the reboiler, a condenser that condenses overhead vapor of the distillation column into a condensate, a distillate withdrawal portion that removes the condensate condensed by the condenser, and a discharged liquid withdrawal portion that removes residual liquid from the distillation column. The compressor includes an actual volume flow rate regulation mechanism that varies an actual volume flow rate of the fluid, which is increased in pressure and temperature by the compressor, in accordance with a change in a required heating temperature of the reboiler during operation of the distillation device.