After the cooler operates for a period of time, the filled pebbles will gradually be compacted and sink due to the back and forth impact of the air flow. In addition, the amount of pebbles will also be insufficient due to the abrasion or breakage of pebbles. If the pebbles are not filled tightly, the air flow will drive the pebbles to jump up and down, which is easy to break the internal coil and cause pipe leakage. For the air separation equipment with liquid-air subcooler for biogas purification equipment, part of the liquid in the lower tower and main cooling shall be drained before startup to prevent the liquid-air subcooler from blocking; When the temperature at the cold end reaches - 150 ℃, the circulation flow should be reduced as much as possible to prevent carbon dioxide from blocking the circulation channel; If the biogas purification equipment backfills 1m3 of liquid oxygen into the main cooler, it is equivalent to providing 0.47 from the outside × The cooling capacity of 106kJ is about 5000m3 of expansion air in 2h. Some plants have done tests, filling 20m3 of liquid oxygen into the tower during startup, which can shorten the startup time by 16.5h for 6500m3/h air separation equipment; For 10000m3/h air separation equipment, the start-up time can be shortened by more than 8h.

借助外部冷源也是缩短启动时间的有效办法。当主冷冷却结束，出现液体时，从外部输入液氧、液空或液氮。输液的方法是将液体来源与液氧排放阀接通，打开液氧排放阀，把外部液体注入主冷。当膨胀机进口的比焓为h1，出口的比焓为h2时，单位数量的气体的制冷量即为h1-h2。已知膨胀机进、出口气体的温度和压力，可以从气体的热力性质图上查到相应的比焓值。分子筛是否充填满，并且扒平；认真封好内、外筒人孔，防止相互窜气；分子筛吸附器在运行时，要定期监视分子筛温度曲线和出口二氧化碳的含量，以判断吸附器的工作是否正常；要密切监视吸附器的切换程序、切换压差是否正常。

Using external cold source is also an effective way to shorten the startup time. When the main cooling is over and liquid appears, input liquid oxygen, liquid air or liquid nitrogen from the outside. The method of infusion is to connect the liquid source with the liquid oxygen discharge valve, open the liquid oxygen discharge valve, and inject the external liquid into the main cooler. When the specific enthalpy at the inlet of the expander is h1 and the specific enthalpy at the outlet is h2, the refrigerating capacity of the unit quantity of gas is h1-h2. Given the temperature and pressure of the gas at the inlet and outlet of the expander, the corresponding specific enthalpy value can be found from the thermal property diagram of the gas. Whether the molecular sieve is filled and leveled; Carefully seal the inner and outer cylinder manholes to prevent mutual gas channeling; When the molecular sieve adsorber is running, it is necessary to regularly monitor the molecular sieve temperature curve and the carbon dioxide content at the outlet to determine whether the adsorber works normally; Closely monitor whether the switching procedure and switching pressure difference of the adsorber are normal.

沼气提纯设备阀体内的故障主要是阀顶与阀座的密封面不严而造成阀关不死的现象。常见的是O型橡胶密封圈脱落。这主要与粘结面不清洁，黏结剂质量不好有关。

The main failure in the valve body of the biogas purification equipment is that the sealing surface between the valve top and the valve seat is not tight, which causes the valve to fail to close. It is common that the O-ring falls off. This is mainly related to the uncleanness of the bonding surface and the poor quality of the adhesive.

此外，阀座处有异物；阀杆与阀顶两端的凹凸球面垫圈拧得过死或过松；固定螺帽没有拧紧，造成阀顶松动；阀杆发生弯曲等均可能造成阀关闭不严等现象。沼气提纯设备从实践中知道，只要有温度差存在，就会自发地进行热量传递。而且，热量总是从温度较高的流体传向温度较低的流体。温度差是热量传递的动力。对间壁式、蓄热式和混合式三种换热器的传热过程并不完全相同，但其基本规律还是相同的。

In addition, there are foreign matters at the valve seat; The concave and convex spherical washers at both ends of the valve rod and the valve top are screwed too tightly or too loose; The fixing nut is not tightened, causing the valve top to loosen; The bending of the valve rod may cause the valve to be closed loosely. Biogas purification equipment knows from practice that as long as there is a temperature difference, it will spontaneously carry out heat transfer. Moreover, heat is always transferred from the fluid with higher temperature to the fluid with lower temperature. Temperature difference is the power of heat transfer. The heat transfer processes of the three types of heat exchangers are not completely the same, but their basic laws are the same.