Precautions for starting and stopping the pre-cooling system

Pre-cooling isn’t a big issue; just control the liquid level and temperature, and make sure there’s no liquid present

The main function of the pre-cooling system is to lower the temperature of the air – as the air’s temperature rises after compression – in order to prepare it for adsorption by the molecular sieve. The adsorption characteristic of molecular sieves is that it occurs at low temperatures and high pressures. So the maximum interlock in the pre-cooling system is the outlet temperature. Generally, HH is set at 25 degrees, with slight variations depending on the size of the equipment. In air-cooled towers equipped with direct contact heat exchange, due to the difference in pressure between the air and the cooling water, it is necessary to introduce air first and then water, in order to prevent water from being carried by the air. It is also important to control the liquid level and water flow rate properly. A drain trap is installed after the air separation tower, and the liquid level of this drain trap, hh, also serves as a interlock condition. Some devices are equipped with two cooling water circuits; one of them is the water that passes through the ice maker for cooling. I don’t know much about this aspect. For air separation units equipped with non-contact heat exchange systems (horizontal air-cooled types that function like heat exchangers), it is sufficient to properly control the condensate water supply. In some cases, this water comes from the main circulation system, while in other cases no large water tank is needed; instead, another water source is used. It is important to conduct water quality analyses, as a lower water temperature is not always better due to the risk of crystallization at low temperatures. Additionally, attention must be paid to the switching of water pumps, as well as the regular cleaning of filters. The cold source for water is dry WN and dried high-pressure air from the air compressor (as a backup). An issue that needs to be considered is whether the PID control of the pre-cooling system can keep up after cold blowing with molecular sieves; if it cannot, it may cause fluctuations in tower pressure. Our solution is to force an output opening that is added to the original output value. Specifically, take a look at the logic diagram of your factory

When starting the pre-cooling system, control the liquid level in the air-cooled tower to prevent water from being carried along

It is also necessary to prevent backflow into the air compressor; attention must be paid to the liquid level when starting and stopping it~~