When the ratio of the return flow to the positive flow is larger than the normal value, such as the annular flow is too large or the intermediate pumping volume is too large, the cooling capacity of the return flow gas to the positive flow air is too much, while the positive flow air is too small compared with the return flow gas, resulting in excess cooling capacity of the return flow gas.

对有器外活化条件的用户，按下述步骤进行：1)首先将准备装填的分子筛彻底活化、待填；

For users with external activation conditions, follow the following steps: 1) first, completely activate the molecular sieve to be filled and wait for filling;

2)拆开准备装填分子筛的纯化器顶部的空气进口管和过滤管；

2) Disassemble the air inlet pipe and filter pipe at the top of the purifier to be filled with molecular sieve;

3)把经活化后的分子筛装入器内，装满为止，并注意记下装填分子筛的数量。为了装填密实，可用木锤在筒体的封头上敲击；

3) Put the activated molecular sieve into the container until it is full, and note the quantity of filled molecular sieve. In order to fill compactly, a wooden hammer can be used to knock on the head of the cylinder;

4)分子筛装完后，再装回管路、过滤管和阀门。并应注意：连接法兰的螺钉应均匀、对称地拧紧；阀门需经脱脂后装好填料；氮气加温阀的填料还应采用耐高温的膨胀石墨或石棉线。

4) After the molecular sieve is installed, reinstall the pipeline, filter pipe and valve. It should also be noted that the screws connecting the flange should be tightened evenly and symmetrically; The valve shall be packed after degreasing; The packing of nitrogen heating valve shall also adopt high temperature resistant expanded graphite or asbestos thread.

提纯设备低温空气分离法:先将空气通过压缩、膨胀降温，直至空气液化，再利用氧、氮的气化温度(沸点)不同(在大气压力下，氧的沸点为90K，氮的沸点为77K)，沸点低的氮相对于氧要容易气化这个特性。

Low temperature air separation method of purification equipment: firstly, cool the air through compression and expansion until the air is liquefied, and then use the characteristic that the gasification temperature (boiling point) of oxygen and nitrogen is different (under atmospheric pressure, the boiling point of oxygen is 90K and that of nitrogen is 77K). Nitrogen with low boiling point is easy to gasify compared with oxygen.

提纯设备对于中压空分设备，出主热交换器的低温空气是采用节流膨胀进入下塔的，以保证进塔空气有一定的含湿。对低温液体的膨胀来说，液体节流的能量损失小，膨胀机膨胀与节流膨胀的效果已无显著差别，而节流阀的结构和操作比膨胀机要简单得多，因此，下塔的液体膨胀到上塔时均采用节流膨胀。

Purification equipment for medium pressure air separation equipment, the low-temperature air from the main heat exchanger enters the lower tower through throttling expansion to ensure that the air entering the tower has a certain moisture content. For the expansion of low-temperature liquid, the energy loss of liquid throttling is small, and there is no significant difference between the expansion effect of expander and throttling expansion, while the structure and operation of throttle valve are much simpler than that of expander. Therefore, throttling expansion is adopted when the liquid from the lower tower expands to the upper tower.

提纯设备在自清除性能上，翅片结构具有良好的自清除特性，比蓄冷器为佳；热容量小，可缩短启动时间；设备容积小，切换周期长，切换损失较小；阻力较小。

In terms of the self cleaning performance of the purification equipment, the fin structure has good self cleaning characteristics, which is better than the cold accumulator; Small heat capacity, which can shorten the start-up time; Small equipment volume, long switching cycle and small switching loss; Less resistance.

影响氧产量的因素，除了尽可能减少空气损失，降低设备阻力，以增加空气量；尽可能减少跑冷损失、热交换不完全损失和漏损，以减少膨胀空气量外，这里主要从调整精馏工况的角度，分析一下调整产量的方法。

The factors affecting oxygen production include reducing air loss and equipment resistance as much as possible to increase air volume; In addition to reducing the cold running loss, incomplete heat exchange loss and leakage as much as possible to reduce the amount of expanded air, this paper mainly analyzes the method of adjusting the output from the perspective of adjusting the distillation working condition.

沼气提纯设备如果氩馏分的含氮量太多，一则使粗氩纯度降低，而且会导致粗氩冷凝器的温差减小，甚至使温差为零，此时粗氩塔便停止工作。并且，粗氩中含氮过多将给制取精氩带来困难，所以氩馏分的抽口应该设在含氮尽量少的地方。

If the nitrogen content of argon fraction of biogas purification equipment is too much, the purity of crude argon will be reduced, and the temperature difference of crude argon condenser will be reduced or even zero. At this time, the crude argon tower will stop working. Moreover, too much nitrogen in crude argon will bring difficulties to the preparation of refined argon, so the extraction port of argon fraction should be set at the place with as little nitrogen as possible.