The problem of gas leakage in Biogas Compressors can affect their compression efficiency and operational stability, and even pose safety hazards. The following analyzes the causes of air leakage from the aspects of sealing components, equipment installation, component damage, and operation and maintenance:
Sealing component issue
Seal wear
The piston ring is a common sealing component that constantly rubs against the cylinder wall during the operation of the compressor. As the usage time increases, the piston ring will gradually wear out, and the gap between it and the cylinder wall will increase, causing biogas to leak from the gap during compression. Generally speaking, when the wear of the piston ring exceeds a certain limit (such as the wear thickness reaching 10% -15% of the original thickness), the leakage phenomenon will significantly intensify.
Shaft seals are also prone to wear and tear. Shaft seals are used to prevent biogas leakage along the direction of the compressor shaft. If the material of the shaft seal has poor wear resistance or insufficient lubrication, it will accelerate the wear of the shaft seal, thereby causing air leakage problems.
Seal aging
Seals are usually made of polymer materials such as rubber and plastic, which can age due to factors such as temperature, pressure, and chemical media during long-term use. For example, rubber seals will gradually lose their elasticity under the influence of high temperatures and certain components in biogas, resulting in hardening, cracking, and other phenomena, leading to a decrease in sealing performance and ultimately causing air leakage. In general, the service life of rubber seals is about 1-3 years, and if it exceeds this time, it needs to be replaced in a timely manner.
Improper installation of seals
Failure to follow the correct methods and steps during the installation of seals can also result in air leakage. For example, if the seal is not fully embedded into the sealing groove during installation, or if the installation direction of the seal is incorrect, it will prevent the seal from providing a good sealing effect. In addition, if damage is caused to the sealing components during installation, such as scratches, compression deformation, etc., it will also affect their sealing performance.
Equipment installation issues
Loose connection parts
The various components of the compressor are connected by bolts, nuts, and other connectors. During the operation of the compressor, these connecting components may gradually loosen due to vibration and other reasons. For example, loosening of the connecting bolts between the cylinder head and cylinder block can cause gaps in the sealing surface between the cylinder head and cylinder block, leading to biogas leakage. Generally speaking, after the compressor has been running for a period of time (such as 100-200 hours), it is necessary to inspect and tighten the bolts at the connecting parts.
Insufficient installation accuracy
When installing the compressor, if the installation accuracy of each component does not meet the requirements, it can also cause air leakage. For example, excessive or insufficient clearance between the cylinder and piston can affect the sealing effect. When the gap is too large, biogas is prone to leakage; If the gap is too small, it will increase the friction between the piston and the cylinder wall, accelerate the wear of components, and may also lead to air leakage. In addition, inaccurate installation positions of components such as crankshafts and connecting rods can also affect the normal operation and sealing performance of the compressor.
Component damage
Cylinder wear or cracks
The cylinder is one of the important components of the compressor. During long-term operation, the inner wall of the cylinder will gradually wear out due to the friction of the piston and the pressure of biogas. When the degree of wear is severe, the inner diameter of the cylinder will increase, and the clearance between the cylinder and the piston will increase, leading to air leakage. In addition, the cylinder may also crack due to casting defects, thermal stress, and other reasons, and biogas may leak out from the crack.
Damaged air valve
The air valve includes an intake valve and an exhaust valve, and is a key component for controlling the inflow and outflow of biogas into the cylinder. If the valve plate of the air valve is damaged, the spring fails, or the valve seat seal is not tight, it will cause the air valve to fail to close or open normally, resulting in air leakage. For example, valve plates may experience wear, breakage, and other issues during frequent opening and closing processes, causing the valve to lose its sealing function.
Operation and maintenance issues
Overpressure operation
If the compressor exceeds its designed pressure range during operation, it will subject the seals to excessive pressure, resulting in a decrease in sealing performance and even damage to the seals. For example, when the discharge pressure of the compressor exceeds 10% -15% of the rated pressure, the seal may be compressed and deformed, resulting in air leakage.
Improper maintenance
Regular maintenance is crucial for the normal operation of the compressor. If the compressor is not maintained according to the prescribed time and requirements, such as timely replacement of lubricating oil, cleaning of filters, etc., it will lead to an increase in impurities and wear inside the compressor, thereby affecting the sealing performance. In addition, improper operation during maintenance may also cause damage to seals and other components, leading to air leakage problems.
When gas leakage is found in the biogas compressor, effective measures need to be taken in a timely manner to ensure the normal operation and safe production of the equipment. The following are methods for dealing with air leakage problems caused by different reasons:
Sealing component problem handling
Seal wear
Piston ring wear: When piston ring wear is detected causing air leakage, it is necessary to replace the piston ring in a timely manner. Before replacement, the inner wall of the cylinder should be carefully inspected and measured to ensure that its dimensional accuracy and surface roughness meet the requirements. If the inner wall of the cylinder is severely worn, it may be necessary to perform cylinder boring or replace the cylinder liner. After the installation of a new piston ring, it is generally necessary to perform appropriate running in operation to ensure good sealing effect.
Wear of shaft seal: If the wear of shaft seal causes air leakage, the shaft seal should be replaced immediately. When installing a new shaft seal, it is important to choose a product that matches the specifications of the original shaft seal and strictly follow the installation instructions to ensure correct installation. At the same time, it is necessary to ensure good lubrication of the shaft seal by checking the amount and quality of lubricating oil, and adding or replacing lubricating oil if necessary.
Seal aging
For seals that have lost their sealing performance due to aging, such as rubber seals that have hardened or cracked, they should be replaced in a timely manner. When choosing a new seal, consideration should be given to its material's high temperature resistance, corrosion resistance, and aging resistance to adapt to the working environment of the biogas compressor. After replacing the seal, the installation area should be cleaned and inspected to ensure that there are no impurities or damage, and to avoid affecting the sealing effect of the new seal.
Improper installation of seals
Reinstall the seal and strictly follow the correct methods and steps for operation. Before installation, carefully clean the sealing groove and sealing surface to ensure that there are no impurities or oil stains. During installation, the seal should be completely and smoothly embedded into the sealing groove, and attention should be paid to the correct installation direction of the seal to avoid twisting, deformation, and other situations. After installation, the sealing parts should be inspected to ensure good sealing.
Handling of equipment installation issues
Loose connection parts
Conduct a comprehensive inspection of all connection parts of the compressor, and use appropriate tools (such as wrenches, etc.) to tighten loose bolts, nuts, and other connecting components. During the tightening process, operate according to the specified torque to avoid over tightening or over loosening. For some important connection parts, such as the connecting bolts between the cylinder head and the cylinder block, diagonal tightening should be used to ensure that the sealing surface is evenly stressed. After the fastening is completed, check again whether there is any looseness in the connection part.
Insufficient installation accuracy
If it is found that the air leakage problem is caused by insufficient installation accuracy, the compressor needs to be reinstalled and adjusted. Firstly, professional measuring tools such as dial gauges should be used to measure the installation position and fit clearance of each component, in order to identify any deviations. Then, according to the measurement results, corresponding adjustments are made, such as adjusting the clearance between the cylinder and piston, the installation position of the crankshaft and connecting rod, etc., to ensure that the installation accuracy of each component meets the requirements. After the adjustment is completed, a trial run should be conducted to check if the air leakage problem has been resolved.
Component damage handling
Cylinder wear or cracks
For cases where the cylinder wear is relatively light, the method of boring the cylinder can be used for repair. By enlarging the cylinder inner diameter and replacing the corresponding size of piston and piston ring, the sealing performance of the cylinder can be restored. If the cylinder is severely worn or cracked, a new cylinder needs to be replaced. When replacing a cylinder, it is important to choose a cylinder with reliable quality and matching specifications, and strictly follow the installation process to ensure a tight connection and good sealing between the cylinder and other components.
Damaged air valve
When the air valve is damaged, it should be repaired or replaced in a timely manner. If it is a problem such as valve plate damage or spring failure, the valve plate or spring can be replaced separately; If the valve seat is not tightly sealed, it can be ground and repaired to restore good sealing performance. After repairing or replacing the air valve, it is necessary to check the opening and closing of the valve to ensure its normal operation.
Handling of operation and maintenance issues
Overpressure operation
Immediately stop the overpressure operation of the compressor and adjust the exhaust pressure to the design pressure range of the compressor. Check if the pressure control system of the compressor, such as pressure sensors, safety valves, etc., is working properly. If there is a malfunction in the pressure control system, it should be repaired or replaced in a timely manner. At the same time, training should be provided to the operators to understand the correct operating methods and pressure range limitations of the compressor, in order to avoid the occurrence of overpressure operation again.
Improper maintenance
According to the maintenance manual of the compressor, develop a reasonable maintenance plan and strictly implement it. Regularly replace lubricating oil, clean filters, and maintain cleanliness inside the compressor. During maintenance, it is necessary to carefully inspect the wear and sealing performance of each component, and promptly identify and address potential issues. At the same time, it is necessary to improve the operational skills and sense of responsibility of maintenance personnel to ensure the quality of maintenance work.
