Pressure equalizing system for air separation purification and control method
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Solution Overview
Problem
The air separation rectification process is disrupted due to the transition from dry nitrogen to dry air during the pressure equalizing step in air separation purification systems, leading to fluctuations in gas components entering the air separation cold box, and this requires frequent adjustments to the main air compressor, resulting in inefficient operation and higher equipment costs.
Innovation Solution
A pressure equalizing system that uses a pressurizing gas pipeline connected to the air main pipe, regulated by a flow regulator and control valve, to maintain a constant flow rate of dry air by mixing pressurizing gas with damp air from the main air compressor, ensuring stable gas components and reducing the need for frequent compressor adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If dry nitrogen is used to pressurize the adsorber during the pressure equalizing step, then the adsorber pressure is restored, but the gas component flowing towards the air separation cold box changes from dry nitrogen to dry air, causing disturbance to the air separation rectification process
Solution Approach 1:
The patent introduces a pressurizing gas pipeline that delivers pressurizing gas to the air main pipe upstream of the adsorber, rather than directly pressurizing the adsorber. This intermediary approach allows the pressurizing gas to mix with damp air from the main air compressor before entering the adsorber, preventing direct contact between dry nitrogen and the adsorber while still achieving pressure restoration
Solution Approach 2:
The system uses the main air compressor's own damp air output to mix with the pressurizing gas, eliminating the need for external gas sources and maintaining system self-sufficiency. The flow regulator on the second air main pipe automatically controls the mixing ratio to maintain constant dry air flow rate
2Productivity
If the air intake guide vane of the main air compressor is frequently adjusted to maintain constant dry air flow rate, then the dry air flow rate remains stable, but the main air compressor cannot operate at substantially constant capacity, resulting in disturbance to the air separation operating state
Solution Approach 1:
The patent employs a flow regulator on the second air main pipe that continuously monitors the dry air flow rate and provides feedback control. When the pressure equalizing step causes a drop in dry air flow rate, the flow regulator automatically adjusts the control valve on the pressurizing gas pipeline to increase pressurizing gas flow, thereby compensating for the loss and maintaining constant dry air flow rate without requiring manual adjustment of the air intake guide vane
Solution Approach 2:
The patent replaces the mechanical adjustment of the air intake guide vane with an automated control system consisting of a flow regulator and control valve. This substitution eliminates the need for frequent manual mechanical adjustments and allows the main air compressor to operate at constant capacity
3Productivity
If a main air compressor of greater capacity is purchased to accommodate pressure equalization requirements, then the dry air flow rate can be maintained, but the equipment investment increases
Solution Approach 1:
The patent changes the parameter of pressurizing gas delivery location from inside the adsorber to the air main pipe upstream. This parameter change allows the pressurizing gas to mix with damp air before adsorption, enabling the use of a smaller main air compressor while still maintaining the required dry air flow rate through the mixing and adsorption process
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 solution stabilizes the air separation cold box process conditions, maintains constant air compressor capacity, and reduces equipment investment by eliminating the need for a larger main air compressor, while simplifying control through existing flow regulators.
Implementation Method 1
mixing pressurizing gas with damp air from the main air compressor
Implementation Method 2
regulated by a flow regulator and control valve
Implementation Method 3
water, carbon dioxide, acetylene and other hydrocarbons, etc. in the damp air are adsorbed to produce dry air
Implementation Method 4
regenerating the adsorbent at atmospheric pressure by introducing heated gas, wherein the hot gas is generally dirty nitrogen from the air separation cold box
Data Source
AI summary
Disclosed in the present invention are a pressure equalizing system for air separation purification, and a control method. The system comprises: a first air main pipe; a pressurizing gas pipeline, which is connected to the first air main pipe and used for receiving a pressurizing gas and delivering same to the first air main pipe; and a control valve, located on the pressurizing gas pipeline, and having a degree of opening regulated by the flow regulator, thereby regulating an air intake amount of the pressurizing gas pipeline. The present invention solves the problem of an air separation rectification process being affected when dry nitrogen is used for pressure equalization of an adsorber; in the switching process of entering an adsorption stage from a regeneration stage, pressurizing dry nitrogen used in a pressure equalizing step previously mixes with damp air from a main air compressor before entering the adsorber, such that the gas components flowing towards an air separation cold box remain substantially unchanged, in order to reduce disturbance in conditions of gas entering a rectification column to take part in rectification due to a gas component gradually changing from dry nitrogen to dry air in the prior art, thus stabilizing the process conditions of the air separation cold box.