Views: 29 Author: Site Editor Publish Time: 2021-01-18 Origin: Site
The harm of chlorofluorocarbon refrigerants to the ozone layer
Chlorofluorocarbon is a kind of flammable organic substance which is easy to gasify and volatile.
The most common is R22 (HCFC22 is hydrochlorofluorocarbon 22). R12 (CFC12) was commonly used in refrigerators in the last century. Due to the old or damaged circulatory system pipes of air conditioners and refrigerators, chlorofluorocarbon refrigerants Released into the atmosphere, chlorofluorocarbons will naturally decompose and release under sunlight and other factors.
It releases chlorine atoms that destroy the ozone layer, and chlorine atoms catalyze the conversion of ozone into ordinary oxygen.
ODP (Ozone Depression Potential) is used internationally indicators to measure the ability of chemical substances to destroy the ozone layer, taking CFC11 (R11) as the benchmark stipulates that the ODP value of CFC11 is 1.
According to data, if the total amount of ozone in the stratosphere is reduced by 1%, it is expected that the harmful ultraviolet rays reaching the ground will be increased by 2%.
The increase of harmful ultraviolet rays will produce the following chain hazards:
Increase the number of skin cancer and cataract patients, damage human immunity, and cause infectious diseases to develop
The disease rate has increased.
· Destroy the ecosystem. Excessive ultraviolet radiation will cause plant growth and photosynthesis
Repression has reduced crop production. Ultraviolet radiation may also cause sudden changes in certain biological species.
change.
· Cause new environmental problems. Excessive ultraviolet rays can make plastics and other polymer materials more
It is easy to age and decompose, and as a result, it brings photochemical air pollution.
Therefore, developed countries have banned the production and use of chlorofluorocarbon systems on January 1, 1996.
Refrigerant, but some developing countries still use it. The Antarctic ozone hole has continued in recent years
The expansion has aroused great attention from all countries on the protection of the ozone layer, making it a global
Urgent task.
Under this situation, the refrigerant has undergone an innovation in the last century, resulting in a kind of
To make an improved product of HCFCs containing hydrochlorofluorocarbons, because hydrogen atoms are added, compared to the traditional
For CFCs, the number of chlorine atoms is reduced, and the ODP value is greatly reduced. Of which room air conditioner
The ODP value of R22 (HCFC22), which is the most widely used and still in use today, is only 0.055.
A successful transition product, but with the increase in usage, it will still accumulate ozone-depleting chlorine
atom. Therefore, since the 1990s, HFCs (chlorine-free hydrocarbons), which do not contain chlorine, have been introduced
The third generation of atomic refrigerant, chlorine-free refrigerant was born. First in the refrigerator and car empty
The adjustment is applied, that is, the non-chlorine hydrocarbons with ODP value 0 such as HFC134a (R134a) or HC600a (R600a) are used instead of CFC12 (R12). R134a plays an important role in car air conditioners because it is safer and non-flammable than R600a. R600a is only a hydrocarbon and does not contain fluorine atoms, so it is the exclusive refrigerant for fluorine-free refrigerators. Compared with refrigerators and car air conditioners, room air conditioners need to transfer more heat, making room air conditioners chlorine-free refrigerants.
R&D has gone through a longer period of time. It was only introduced to the market in 2006, and it was officially launched in 2010.
And, that is, R410a, a new type of near-azeotropic mixed non-chlorine hydrocarbon composed of two HFCs (HFC32 and HFC125 with the same mass fraction of 50%), is used to replace the traditional R22 (CFC22). At the same time, due to the stronger heat-carrying capacity of R410a, the new generation of energy-saving air conditioners are smaller and more efficient. However, the pressure value of the refrigeration pipeline is increased by 60% relative to R22, which requires higher air conditioner manufacturing and installation. It needs to be fully vacuumed and installed, and the price of charging refrigerant is about twice that of R22, so it has not completely replaced R22.
