Load issues of piston compressors

To increase the load on the compressor, raising the inlet pressure at the first stage is the simplest and most effective method. If the compressor is domestic, it can generally be made to handle higher pressures; whereas for imported compressors, it is best to operate them according to their designed parameters. LZ’s 2D12 compressor is definitely of domestic manufacture. If the air volume is insufficient, one should first consult the compressor manufacturer to determine whether the issue lies with the manufacturer or with the parameters provided by the user not matching the actual conditions. Regardless of the cause, it is the manufacturer’s responsibility and duty to meet the customer’s requirements. If the air volume is only slightly insufficient, increasing the inlet pressure will suffice; as for by how much it can be increased, it’s better to let the manufacturer decide. If the difference is significant, then the feasibility of modifying the compressor (by enlarging its cylinders) should be considered. Of course, after pressure increase or cylinder expansion modifications, the operating stability of the compressor (with valve failures being the main issue generally) will inevitably be affected, and LZ should make the necessary preparations. :lol

Our factory has two 6M25 compressors manufactured by Shanghai Delaisilan. To increase the load, the inlet pressure rises significantly, but the operation remains normal； Four 6M32 compressors manufactured by Shenqi experienced high vibration and frequent failures after the intake pressure was increased. According to the company, this was because they adopted West German technology with precise design, which led to more problems when operating outside the designed conditions. This time, when our factory purchased the 6M50 compressor, we increased the inlet pressure to make it closer to the actual operating conditions.

The compressor manufacturer closed down a long time ago; it’s a unit from 1987. This issue was only discovered recently after the facility underwent capacity expansion. The process conditions determine that the inlet pressure can be increased to around 27 KPa at most; I wonder if there are any other methods to achieve a higher value.

Model 6M25 should be the model produced by Shanghai Compressor Factory; the models manufactured after Shangya formed a joint venture with Delaiselan are generally ※HHE※. The joint venture caused significant losses to the original Shangya factory.

Upon startup, the pressure is first raised to 27 KPa to see if it can meet the load requirements. To further increase the load, it is possible to lower the temperature of the incoming gas, but it’s not possible to reduce it by much, and the effect will not be significant; you should decide on your own whether to do this ； Also, considering that the engine is an old unit from 1987, after years of use it’s unclear what the condition of its cylinders is – whether the cylinder blocks or liners have been replaced. If they haven’t been replaced (which seems unlikely), then replacing them will definitely lead to a significant improvement in performance: lol. Considering the recent replacement, the air volume still does not meet the requirements even after the pressure is increased; the best solution is obviously to purchase a new unit. If cost savings are a priority, then cylinder modification can be considered.

The adjustment of the air volume at startup for reciprocating compressors is sometimes achieved using load regulators. In actual operation, it is common for the air intake valve to fail to close completely, which affects the air volume delivered by the reciprocating compressor. Our company previously had a compressor of the same specification and model; it experienced problems with insufficient air volume. It was later found that the issue stemmed from the problem mentioned above. Multiple attempts at repair were unsuccessful, so we were forced to use a startup method that involved stepping back gradually, which ultimately resolved the aforementioned problem. Please have the original poster check whether the same problem occurs.

The cylinder liner has just been replaced, and the clearances are all within the acceptable range. Excessive spring force in the air valve can cause the valve disc to fail to open and close in a timely manner, affecting the load; at the same time, it also leads to very high temperatures of the valve disc. But the actual valve temperature is normal. The influence of the valve disc temperature can be ruled out. Regarding the reduction of the inlet temperature by one level mentioned on floor 7, was pipe friction loss taken into account? Is it effective? Doubtful

Check whether the inlet pressure reaches the design pressure? Check whether there is wear in each section of the cylinder? Will imported limescale affect the expansion of piston rings?

A boot method that returns step by step? Could you be more specific? 8th floor