A comprehensive guide to PSA biogas purification technology

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Biogas, this renewable and clean energy source, is gaining increasing popularity. It not only helps alleviate energy shortages but also contributes to environmental protection. As human demand for biogas continues to rise, biogas purification technology has advanced rapidly. Biogas purification technology is the process of separating methane from other impurities such as carbon dioxide in biogas produced by biomass fermentation, in order to obtain high-purity bionatural gas. Lvyuan Environmental Protection utilizes PSA (Pressure Swing Adsorption) purification technology, which relies on pressure changes to enable adsorption and regeneration. This technology allows for the effective extraction of methane from biogas, bringing it to quality standards suitable for use as natural gas, while also removing carbon dioxide, thereby facilitating the extraction and utilization of gaseous energy sources. I. Working principle of PSA purification technology: PSA purification technology is a gas separation method based on pressure changes. The gas coming from the desulfurization system is compressed by a compressor to 0.6 MPa; this biogas then enters a cold dryer to have its moisture removed. After that, it goes into a gas-liquid separator. From the bottom of the adsorption tower, it enters a methane decarburization purification unit with a pre-set control timing. The components in the feed gas that are easily adsorbed (CO2) are captured by the adsorbent, while those that are not easily adsorbed (CH4) emerge as the product gas. This gas is sent through a pressure regulator and a precision filter to remove any solid particles, before being fed into the pipeline system. High-boiling-point impurity components remain adsorbed within the adsorbent. The PSA purification technique uses pressure reduction or evacuation for desorption, that is, a portion is separated by reducing the pressure through pressure equalization. To ensure thorough regeneration of the adsorbent, after the pressure equalization process is completed, vacuum pumping is used to further reduce the partial pressure of impurities; once the evacuation process is finished, the regeneration of the adsorbent is complete. After the adsorbent regeneration is completed, the pressure in the adsorption tower is -0.07 to -0.09. To ensure the adsorption efficiency and stabilize system pressure, it is necessary to pressurize the adsorption towers to reach the specified adsorption pressure; simultaneously with this pressure increase, the effective components (CH4) present in the dead spaces of other adsorption towers are recovered, and pressure balance is achieved between the towers in a pair-wise manner. Then, the product gas is used to raise the pressure in the adsorption tower to the adsorption pressure; at this point, the preparation for adsorption in the tower is complete, and the next cycle can begin. Through the above process, continuous, stable, and safe operation of the methane purification unit is achieved. II. Advantages of PSA purification technology: 1. Operation at normal temperature and pressure results in low energy consumption; no large amounts of chemical reagents are required, making the operating costs controllable. 2. High efficiency in separation, with high product purity. 3. It can operate in fully automatic, continuous mode, featuring a high degree of automation and easy equipment maintenance. 4. Delivered in skid-mounted form, it is environmentally friendly and convenient, suitable for biogas projects of various scales. 5. It is environmentally friendly, does not generate secondary pollutants such as wastewater, and meets environmental protection requirements. Lvyuan Environmental Protection is well aware that only through continuous innovation can it remain at the forefront in the highly competitive environmental protection industry. In the future, the development of PSA biogas purification technology will focus more on improving efficiency and reducing costs. Lvyuan Environmental Protection looks forward to cooperating with you to contribute more to gas purification processes and to the preservation of clean environments.