Development and application of controlled atmosphe

Introduction to the development and application of controlled atmosphere storage technology

I. Development of controlled atmosphere storage technology

the so-called controlled atmosphere storage is a cold storage method to improve the gas composition of the storage environment

the study of controlled atmosphere storage begins with the storage of fruits. As early as 1860, a British scholar established an apple storage test warehouse with good air tightness. The seal of the warehouse body was made of steel plate and cooled with ice. The storage temperature was no more than 1 ℃, and the effect was good, but this research achievement was not paid attention to at that time. It was not until 1929 and 1933 that Britain and the United States established the first commercial controlled atmosphere reservoir respectively. In 1941, the United States issued a notice providing reference data on gas composition and temperature, which was officially called controlled atmosphere storage

strictly speaking, the controlled atmosphere storage before 1962 is a technical way to reduce oxygen by using fruit respiration, which belongs to the controlled atmosphere storage of "natural oxygen reduction method", that is, MA storage. After the spontaneous combustion gas generator came out, it began to use mechanical methods to control the gas composition of the storage environment, which belongs to the controlled atmosphere storage of "rapid oxygen reduction method", that is, CA storage. The controlled atmosphere storage technology has entered a new stage

controlled atmosphere storage is currently recognized as one of the most effective methods of fruit and vegetable storage and preservation. In foreign countries, controlled atmosphere storage technology has been widely used

there are records in Chinese history that fruits are stored in bamboo knots, earthen jars or cellars. The story of Yang Guifei tasting litchi thousands of miles in the Tang Dynasty is that litchi was packed in bamboo knots and transported to Chang'an thousands of miles away. There are also folk caches and burials, which are similar to Ma controlled atmosphere storage

the development of CA storage in China is relatively late. The first 50 ton experimental CA new material was built in Beijing in 1978, which is the pilot controlled atmosphere storage for the development of material industry. MA storage developed earlier, mainly some vegetables and fruits

Shaanxi Province controlled atmosphere storage technology research center is a unit specializing in the research of controlled atmosphere storage technology. Using the experimental combined plate structure controlled atmosphere cold storage assisted by the European community, through the use and management practice, it has carried out more and more rigorous technical research on environmental protection and energy issues of controlled atmosphere storage, and achieved gratifying results

the success of the civil air-conditioned cold storage test carried out in 1992 has made a positive contribution to the popularization and application of this scientific and technological achievement in China

in recent ten years, the cause of controlled atmosphere storage in China has developed rapidly. At present, the number and scale of air-conditioning cold storage in Shaanxi Province ranks first in the country. It can be predicted that the application of controlled atmosphere storage technology will be more extensive

Second, the principle and characteristics of controlled atmosphere storage

the principle of controlled atmosphere storage is the technical means to establish specific and suitable storage environmental conditions of low temperature, oxygen content, carbon dioxide content, ethylene content and relative humidity; On the premise of maintaining the normal life activities of fruits and vegetables, it is a technical way to effectively inhibit the respiration, evaporation and microbial effects of fruits and vegetables, so as to delay the physiological metabolic process of fruits and vegetables, delay post ripening and aging, and prevent corruption and deterioration

the characteristics of controlled atmosphere storage can be summed up as maintaining the original quality of fresh fruits and vegetables, reducing storage losses, inhibiting physiological diseases of fruits and vegetables, and extending storage and shelf life

III. classification of air conditioning cold storage

according to the structural category of air conditioning cold storage, it can be divided into combined plate air conditioning cold storage, civil air conditioning cold storage and cave air conditioning cold storage

according to the control methods that the market of gas composites in the controlled atmosphere storage environment has been on the rise, it can be divided into natural oxygen reduction (MA) controlled atmosphere storage, rapid oxygen reduction (CA) controlled atmosphere storage and reduced pressure controlled atmosphere storage. MA storage can be divided into plastic film bag Ma controlled atmosphere storage, silicon window plastic tent Ma controlled atmosphere storage and room Ma controlled atmosphere storage. CA storage can be divided into plastic curtain CA controlled atmosphere storage and room CA controlled atmosphere storage

according to the control methods of storage process parameters, it can be divided into fully automatic control, semi-automatic control and manual operation control air-conditioned cold storage

IV. main commonly used air conditioning equipment

if the stress continues to increase to point C, the commonly used air conditioning equipment mainly includes oxygen reducer, carbon monoxide remover, ethylene remover and humidifier. These equipment are produced in China

incidentally, the oxygen reducer (nitrogen generator) has gone through the development process of upgrading combustion oxygen reducer, carbon molecular sieve nitrogen generator and hollow fiber membrane nitrogen generator. Combustion type oxygen reducers have been eliminated. Hollow fiber membrane nitrogen generator has been widely used because of its superior technical performance, reliable product quality and low price. The hollow fiber membrane nitrogen generator produced by Xi'an ultrafiltration purification Engineering Co., Ltd. has strong market competitiveness in terms of its technical level, product quality, price and after-sales service

v. application of controlled atmosphere storage technology in other fields

the development of controlled atmosphere storage technology is mainly based on the storage and preservation of fruits and vegetables. With the development of commodity economy, people pay more attention to the value of commodities, so the application of controlled atmosphere storage technology is more extensive. In addition to the preservation of fruits and vegetables by controlled atmosphere storage, it is used for such things as the storage of aerated packaging of meat food, controlled atmosphere storage of grain, controlled atmosphere storage of flowers, controlled atmosphere storage of precious traditional Chinese medicine materials, controlled atmosphere storage of cultural relics, etc.

Chen Heshu, Engineering Department of Shaanxi controlled atmosphere storage technology research center