Apparatus and process for liquefying gases
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Solution Overview
Problem
Existing liquefaction systems for gases like nitrogen and oxygen require large amounts of electrical power due to the use of numerous compressors and expanders, making them costly and inefficient.
Innovation Solution
An open loop refrigeration system that utilizes the properties of liquid nitrogen to reduce power requirements, using less compressible fluid to achieve runnable pressures, and incorporates a liquefier device that can be retrofitted into existing air separation plants.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If large numbers of compressors and expanders are used to produce transportable liquid gas, then liquefaction capability is improved, but electrical power consumption increases significantly
Solution Approach 1:
The patent extracts and removes the electrical compressors from the traditional liquefaction system, replacing them with a turbine-driven compression system that uses the process gas itself as the working fluid. This eliminates the need for external electrical power for compression while maintaining the required pressure buildup for liquefaction.
Solution Approach 2:
The system uses the process nitrogen or oxygen gas itself to drive the turbine compressors, creating a self-contained energy cycle where the product gas provides the mechanical work needed for compression. The turbine expanders similarly use the high-pressure gas to generate cooling, making the system self-sufficient without external electrical inputs.
2Stress or pressure
If traditional compressors are used to build pressure to 420 PSIG, then required pressure is achieved, but power bill increases
Solution Approach 1:
The patent replaces the electrical motor-driven compressor mechanism with a turbine-driven compressor where the process gas itself provides the mechanical work. This substitution eliminates electrical power consumption for pressure buildup while achieving the required 420 PSIG through adiabatic compression in the turbine compressor stages.
3Productivity
If multiple compressors and expanders are deployed, then liquefaction process is complete, but device complexity increases
Solution Approach 1:
The patent merges the functions of separate compressors and expanders into integrated turbine compression-expansion units. The turbine serves dual purposes: compressing the gas to required pressure and then expanding it to provide refrigeration, eliminating the need for separate mechanical compressors and reducing overall system complexity.
Solution Approach 2:
The turbine unit performs multiple functions simultaneously: it acts as a compressor to build pressure, a heat exchanger to transfer heat, and an expander to provide refrigeration. This multi-functionality reduces the number of discrete components needed while maintaining complete liquefaction capability.
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
Significantly reduces power consumption and production costs while producing saleable liquid gases, allowing for efficient liquefaction without the need for electrical compressors.
Implementation Method 1
The exit of the needle valve provides a two-phase liquid. The fourth step is to cool the liquid and gas down to all liquid, which is done in the flash pot. That is all the refrigeration needed.
Implementation Method 2
The third step is to reduce the flow in pressure through a needle valve causing a Joule Thompson effect. The exit of the needle valve provides a two-phase liquid.
Implementation Method 3
The fourth step is to cool the liquid and gas down to all liquid, which is done in the flash pot. That is all the refrigeration needed.
Data Source
AI summary
A liquefier device which may be a retrofit to an air separation plant or utilized as part of a new design. The flow needed for the liquefier comes from an air separation plant running in a maxim oxygen state, in a stable mode. The three gas flows are low pressure oxygen, low pressure nitrogen, and higher pressure nitrogen. All of the flows are found on the side of the main heat exchanger with a temperature of about 37 degrees Fahrenheit. All of the gases put into the liquefier come out as a subcooled liquid, for storage or return to the air separation plant. This new liquefier does not include a front end electrical compressor, and will take a self-produced liquid nitrogen, pump it up to a runnable 420 PSIG pressure, and with the use of turbines, condensers, flash pots, and multi pass heat exchangers. The liquefier will make liquid from a planned amount of any pure gas oxygen or nitrogen an air separation plant can produce.