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Introduction to the constant temperature and constant pressure process for supercritical CO2 extraction

supercritical co2 extraction machine

Supercritical CO2 extraction process, often abbreviated as SC-CO2 extraction, is a cutting-edge technique used in various industries, including food, pharmaceuticals, and cosmetics, to extract valuable compounds from natural sources. It has gained immense popularity due to its efficiency, safety, and environmental friendliness. One crucial aspect of this process is maintaining constant temperature and pressure, which plays a pivotal role in achieving desired results

Before we dive into the constant temperature and pressure process, let’s briefly understand the fundamentals of supercritical CO2 extraction. Supercritical carbon dioxide is a state in which CO2 exists at temperatures and pressures above its critical point. In this state, it exhibits both gas-like and liquid-like properties, making it an ideal solvent for extracting various compounds from natural materials.

The Significance of Constant Temperature

Maintaining Optimal Conditions

In Supercritical CO2 extraction process, maintaining a constant temperature is crucial for achieving optimal results. This temperature typically ranges from 31 to 35 degrees Celsius, depending on the specific application. Consistency in temperature ensures that the solute (the substance being extracted) dissolves effectively in the supercritical CO2, leading to higher yields and better quality extracts.

Avoiding Thermal Degradation

Constant temperature also helps prevent thermal degradation of the target compounds. Unlike traditional extraction methods that use heat, supercritical CO2 extraction operates at lower temperatures, reducing the risk of damaging heat-sensitive compounds. This makes it an excellent choice for extracting delicate natural compounds, such as essential oils and flavorings.

The Importance of Constant Pressure

  1. Enhanced Solvent Power : In addition to constant temperature, maintaining constant pressure is equally vital in supercritical CO2 extraction. The pressure is typically set above 1070 psi (73.8 bar), which is CO2’s critical pressure. At this pressure, CO2 becomes highly dense and possesses exceptional solvent power, allowing it to penetrate plant materials effectively and dissolve the desired compounds.
  2. Preventing Phase Changes : Constant pressure is essential to keep CO2 in its supercritical state. Any deviation from the preset pressure can lead to phase changes, where CO2 transitions between gas and liquid phases. Such phase changes can disrupt the extraction process, leading to lower yields and reduced product quality.

Achieving Precision with Control Systems

To maintain constant temperature and pressure during supercritical CO2 extraction, sophisticated control systems are employed. These systems monitor and adjust the temperature and pressure parameters in real-time, ensuring a stable and reproducible extraction process. They play a pivotal role in the success of this technique.

The Process in Action

Now that we understand the significance of constant temperature and pressure in supercritical CO2 extraction, let’s walk through the process:

  1. Preparation: The material to be extracted, often in the form of ground plant matter, is loaded into an extraction vessel.
  2. Pressurization: Carbon dioxide is pumped into the extraction vessel, raising the pressure above its critical point. This causes CO2 to transition into its supercritical state.
  3. Extraction: The supercritical CO2 is passed through the plant material, dissolving the target compounds.
  4. Separation: The supercritical CO2, now loaded with the extracted compounds, is transferred to a separation vessel. By adjusting temperature and pressure, the CO2 is returned to its gaseous state, leaving behind the extracted compounds.
  5. Collection: The extracted compounds are collected and can be further processed to obtain the final product.

A Comprehensive Guide

For a more comprehensive understanding of the constant temperature and constant pressure process in supercritical CO2 extraction, refer to the table below. It provides a summarized overview of the key parameters and their significance:

Constant Temperature– Ensures optimal solute dissolution
– Prevents thermal degradation
Constant Pressure– Enhances solvent power
– Prevents phase changes
Control Systems– Maintain precision


Supercritical CO2 fluid extraction, with its constant temperature and constant pressure process, has revolutionized the extraction industry. It offers a green and efficient method for obtaining high-quality extracts from various natural sources. By understanding the importance of these parameters and their control, manufacturers can harness the full potential of this technology to create innovative products that meet the demands of today’s market.