Three flushing methods of rotary evaporator

Three flushing methods of rotary evaporator Rotary evaporator is suitable for reflux operation, rapid evaporation of a large amount of solvent, concentration of trace components and reaction processes that require stirring
.

Before the rotary evaporator starts to work, it is necessary to purge and clean all the process pipelines and equipment that have passed the installation inspection (hereinafter collectively referred to as purge)
.

But usually include the following methods: water flushing, air purging, pickling passivation, oil cleaning and degreasing,
etc.

Next, we will introduce their main features and scope of use
.

1.
Water flushing Water flushing is a method in which water is used as a medium to flush pipes and equipment under pressure by a pump
.

It is widely used in the removal of residual dirt in pipelines that transport liquid media and in towers, tanks and other equipment
.

The water flushing of the pipeline should be carried out at the maximum flow rate that can be achieved in the pipe or a flow rate of not less than 1.
5m/s (this does not include high pressure, pressurized water jet cleaning equipment, and the method of scaling inside and outside the pipe car)
.

General chemical equipment rotary evaporator, pipeline flushing commonly used turbidity less than 10*106, rotary evaporator nitrogen ion content is less than 100*106 clarified water, but for equipment and pipelines using austenitic stainless steel such as urea production equipment, it is To prevent stress corrosion cracking (SCC) of equipment, piping, etc.
due to accumulation of chloride ions (CI-) on the rotary evaporator, deionized water should be used to flush
.

Water flushing has the characteristics of convenient operation and no noise
.

2.
Air purging Air purging is a method of blowing out the remaining dirt and debris on the pipeline conveying the gas medium after the air is used as the medium and is pressurized by the compressor (usually 0.
6-0.
8MPa)
.

When using air purging, there should be enough air volume, so that the flow rate of the purge gas is greater than the normal operating gas flow rate, generally lower than 20m/s, so that the rotary evaporator has enough energy (or momentum) to purge Remove residual attachments in pipelines and equipment to ensure smooth commissioning and safe production of the device
.

Air consumption is generally large during air purging, and the purging time is required
.

Therefore, air purging is usually provided using the larger air compressors in the plant or using the large compressors in the plant that can compress the air (such as cracking gas compressors in ethylene plants, etc.
) air operation
.

For small and medium-sized chemical plants that lack a large amount of continuous purging air, the staged purging method can also be used, that is, the system pipeline is divided into many parts, each part is divided into several sections, and then purged section by section, after purging a section and the system Isolate a section
.

In this way, the rotary evaporator can ensure the purging quality in the case of a small amount of gas source
.

For large-diameter pipes or pipes with dirt that are not easy to blow off, the blasting blowing method can also be used to blow them off
.

Avoid oil pipelines and instrument air pipelines to use oil-free air for purging
.

Nitrogen is generally not used as a purging gas source for ordinary pipelines and equipment due to reasons such as source and cost, but is often used for air purging, protection and replacement of pipelines and equipment after system air drying
.

 　　3.
Steam purging Steam purging is purging with steam with different parameters as the medium, and it is provided by the steam generator as the steam source
.

Steam purging has a very high purging speed, and thus has a large energy (or momentum) (or momentum)
.

The intermittent steam purging method also causes the pipeline to shrink and expand, which is beneficial to the peeling and blowing of the attachments on the inner wall of the pipeline, so it can achieve a better purging effect
.

When purging the power steam pipeline, not only the dirt attached to the pipeline should be blown out, but also the floating rust on the metal surface should be blown off, because once they are entrained in the high-speed steam flow, they will affect the high-speed rotating steam turbine.
Damage caused by vanes, nozzles,
etc.

The steam purging temperature is high, the pressure is high, and the flow rate is fast.
After the pipeline is heated, it will expand and displace, and it will shrink after cooling.
Therefore, the steam pipeline is equipped with compensator, steam trap, pipeline hanger, slideway, etc.
Considering the need for expansion displacement
.

If the non-steam pipeline cannot meet the cleaning requirements with air purging, it can also be purged with steam, but it should consider whether its structure can withstand the influence of high temperature and thermal expansion and contraction and take measures to ensure the safety of personnel and equipment during purging.
Safe
.

 　　The above is the introduction of the purging method of the rotary evaporator.
This article introduces three methods, namely water rinsing, air purging and steam purging.
You can rotate it according to the actual situation, and I hope it will be helpful to you
.