Gas adsorption analyzer technical characteristics - Database & Sql Blog Articles

Crystal oscillator

Inductance

The static capacity method used in gas adsorption analyzers involves high-pressure adsorption and desorption isotherms using gases like hydrogen, methane, and carbon dioxide. This technique allows for precise measurement of how much gas a material can adsorb under different pressure conditions.

The volumetric process technique introduces a known amount of gas into an analysis chamber containing the sample. The system records the equilibrium pressure after the sample has reached balance with the adsorbed gas. These data are then used to calculate the adsorbed gas volume. This process is repeated across a set pressure range until the maximum pressure is achieved. The pressure is then gradually reduced to generate a complete isotherm. Each equilibrium point—adsorption amount and corresponding pressure—can be plotted to create a detailed isotherm curve. The use of separate sensors for the manifold and sample chamber ensures high reproducibility and accuracy in measurements.

Technical Characteristics

This system is expandable to a 4-position high-pressure adsorber, equipped with four independent degassing stations for dual free space measurements. This ensures highly accurate isotherm data. It supports NIST REFPROP compression factor corrections for non-ideal gas behavior, enabling interactive spreadsheet automation for generating isotherms and weight percent plots. The software also provides raw data tables showing pressure vs. time, temperature vs. time, and adsorption volume vs. pressure. Real-time charts with all sample information can be generated when using up to three gas components. The system dynamically calculates adsorption rates and performs high-accuracy Langmuir isotherm calculations. It features solid-state pressure sensors with ±0.04% accuracy across the full range and ±0.1% stability. The system can operate at a maximum pressure of 200 bar and includes a hydrogen leak detection system with automatic shutdown for safety.

Applications

In carbon dioxide sequestration studies, it's crucial to measure how much COâ‚‚ is adsorbed by materials such as carbon. The high-pressure setup simulates subsurface conditions for COâ‚‚ injection. The low-temperature/heat bath option allows for testing over a range of stable temperatures, providing data for calculating the heat of adsorption. At higher pressures, COâ‚‚ tends to condense at ambient temperatures, so isotherms are typically analyzed below 50 bar.

For shale gas analysis, high-pressure methane is injected into shale samples to generate adsorption and desorption isotherms. This helps determine the methane content in the shale at specific pressure and temperature levels. Adsorption isotherms are used to calculate the Langmuir surface area and pore volume of the shale. The Langmuir surface area represents the surface area when the gas is assumed to form a monolayer, while the Langmuir adsorption capacity indicates the maximum methane that can be adsorbed at infinite pressure.

In coalbed methane studies, porous coal samples are analyzed using HPVA to assess methane reserves under high-pressure conditions. This provides insights into the adsorption and desorption properties of coal seams, which are essential for estimating hydrocarbon reserves. Kinetic data can also show how quickly methane is adsorbed or released from these materials under various conditions.

COâ‚‚ condenses at higher pressures, making precise control important for accurate measurements. For hydrogen storage applications, this system evaluates the storage capacity of materials like porous carbon and metal-organic frameworks (MOFs). These materials are ideal for hydrogen storage due to their ability to safely adsorb and release hydrogen. MOF-based storage offers higher energy density compared to liquid hydrogen, without the need for extreme cooling. The HPVA software generates weight percent plots to illustrate gas adsorption at different pressures, a standard approach for evaluating hydrogen storage performance.