Cold chain storage ice making, CA fruit and vegetable storage solution

A: Ice making part:

1、 Block ice production scheme:

Refrigeration system: ammonia refrigeration and R22, etc

Evaporation method: refrigerant (brine or ethylene glycol and others)

Design temperature of refrigerant: - 12 ° C - 15 ° C

Evaporation equipment: ice making evaporator and ice bucket

The selection of refrigeration main machine and auxiliary machine mainly depends on the evaporation temperature of the unit. Generally, an ice storage room should be equipped, and the storage capacity should be determined according to the output. The configuration of the refrigeration system is relatively simple, most of which are single-stage refrigeration.

2、 Ice flake production scheme:

At present, there are many ice flaker products in the market, and appropriate products can be selected according to the output.

B: Air conditioning part:

[Overview of Controlled Atmosphere Storage]

Controlled atmosphere storage (hereinafter referred to as "CA") is to increase the regulation of gas composition on the basis of cold storage. By controlling the temperature, humidity, carbon dioxide, oxygen concentration and ethylene concentration in the storage environment, and inhibiting the respiration of fruits and vegetables, it can delay the metabolism process, better maintain the freshness and commercialization of fruits and vegetables, and extend the storage period and sales shelf life. The proportion of controlled atmosphere storage in high temperature cold storage in the world has accounted for more than 1/3, and even up to 75% in the United States. With the improvement of people's living standards, the requirements for fresh keeping of fruits and vegetables are getting higher and higher, and controlled atmosphere storage of fruits and vegetables will have greater development in China.

[Air conditioning process flow]

[Characteristics of CA storage]

◎ The fruits and vegetables stored in the air-conditioned warehouse have a long storage time, which is 0.5-1.0 times longer than the ordinary cold storage. Users can flexibly grasp the delivery time, capture the sales opportunities and create the best economic benefits.

◎ The fresh and fragile fruits and vegetables can be kept after storage. The water content, VC content, sugar content, acidity, hardness, color and weight of fruits and vegetables are almost the same as those of newly picked ones. The quality of fruits and vegetables is high and they are competitive in the market.

◎ The fruits and vegetables stored in the controlled atmosphere warehouse have a transition from "dormant" state to normal state after delivery. The shelving period of fruits and vegetables after delivery can be extended by 21-28 days, 3-4 times that of ordinary cold storage. The CA fresh-keeping warehouse creates a low oxygen environment, which can inhibit the growth of molds and the occurrence of pests and diseases in fruits and vegetables, and minimize the weight loss of fruits and vegetables and the loss of pests and diseases.

◎ For fruits and vegetables that are difficult to store in general high-temperature cold storage, such as macadamia, jujube, etc., it can achieve excellent storage effect.

[Performance index of CA storage]

◎ Temperature in warehouse: - 2 ℃ - 15 ℃ adjustable.

◎ Relative humidity: RH75% - 95% adjustable.

◎ Oxygen content (O2): 1% - 10% adjustable.

◎ Carbon dioxide (CO2): 1% - 10% adjustable.

◎ Ethylene content: below 10PPM.

◎ Reservoir body air tightness index (domestic): the limited pressure is 10mm water column, and the residual water column height is not less than 5mm after 10min.

◎ Air tightness index of reservoir body (foreign): the limited pressure is 25mm water column, and the residual water column height is not less than 8mm after 30min.

Solution

◎ The controlled atmosphere warehouse is to add air tightness requirements, controlled atmosphere equipment, etc. on the basis of ordinary high-temperature warehouse. The key of CA storage: cooling by refrigeration, CA, air tightness, humidity control.

[※ Refrigeration and cooling]

◎ Ammonia refrigeration system

Cooling capacity of piston compressor: 2AZ10: 36KW ～ 8AS17: 600KW (cooling capacity of a single machine at - 10 ℃)

Screw compressor cooling capacity: JZLG12.5: 163.7KW ～ JZLG25: 1556.2KW (cooling capacity of a single machine at - 10 ℃)

◎ Refrigerant refrigeration system such as R22

Semi enclosed compressor unit (SANYO): LCU-32PJ: 3p~LCU-1000MPJ: 100p

◎ Glycol secondary pressurized indirect cooling system

Ethylene glycol screw compressor unit using ethylene glycol as refrigerant and R22 as refrigerant. The system is fully automatic control, automatically controlling the warehouse temperature. The temperature difference of heat transfer is less than 3 ℃, so the dry consumption of fruits and vegetables is less and the humidity loss is less.

[Air conditioning]

◎ Automatic analysis, automatic control, dynamic simulation of operation status of gas conditioning equipment and automatic recording of operation parameters can be realized for gas composition of gas conditioning warehouse.

◎ The types of gas conditioning equipment that Dalian Iceberg Group can provide include: hollow fiber nitrogen generator, molecular sieve nitrogen generator, carbon dioxide remover, ethylene remover, and gas analyzer (automatic).

◎ Capacity of nitrogen generator ranges from 10m3 to 100m3

[※ Air tightness]

◎ The continuous development and application of sandwich panel technology has promoted the development of the construction technology of modified atmosphere storage. Because sandwich panels have the advantages of light weight, high strength, good airtightness, excellent heat insulation effect and convenient construction of the structural system, which can greatly shorten the construction period and reduce the construction cost, the development direction of fruit and vegetable CA storage is to use polyurethane sandwich panels or polystyrene sandwich panels to build the main structure of CA storage.

◎ The particularity of CA fresh storage warehouse is that its main enclosure structure should have good air tightness. In order to prevent fruits and vegetables from oxygen deficient respiration, the warehouse should be regularly supplemented with an appropriate amount of fresh air, but not more than the amount of oxygen consumed by fruits and vegetables stored in the warehouse due to respiration. At the same time, the content of other component gases should be accurately controlled.

◎ Under the normal operation state of the warehouse, due to the influence of temperature inside and outside the warehouse, sunshine and other factors, the pressure fluctuation of about ± 10mm water column will occur inside the warehouse. Therefore, the bearing strength of the sandwich plate applied to the CA fresh-keeping warehouse should not be less than 50kg/sqm (t<=L/200). At the same time, special treatment methods should be taken for the connection nodes, the floor and the insulation door in the warehouse to ensure the safe operation of the warehouse and good air density.

Humidification

◎ Centrifugal humidifier and ultrasonic humidifier can be provided to realize - 1 ℃ humidification and automatic display and control of humidity in the warehouse.

[Composition of CA storage]

◎ Air conditioning equipment (nitrogen generator, carbon dioxide remover, ethylene catalyst, sulfur dioxide generator, etc.).

◎ Other equipment (air-conditioned warehouse door, safety device, air bag and other auxiliary equipment).

◎ Refrigeration equipment (ammonia system, R22 refrigerant system, glycol system, etc.).

◎ Humidifying equipment in warehouse. Cooling water equipment for frost flushing and refrigeration unit in the warehouse.

◎ Electrical control equipment.

[Assembly of CA storage]

◎ Complete the construction of civil works below the floor insulation layer in the warehouse.

◎ Complete the assembly and construction of steel structure engineering or outer enclosure structure. Complete the construction of the body of the CA silo.

◎ Complete the construction of civil works below ± 0.000 (including ground, thermal insulation layer, waterproof and vapor barrier, etc.).

◎ Complete the installation of the door, safety valve, air bag, refrigeration process equipment, electrical system, water supply and drainage system, air conditioning system, etc.

◎ Complete the coating of sealant inside and outside the warehouse and airtight coating inside the warehouse (with high airtight requirements).

◎ Carry out leak detection and positive pressure acceptance of the warehouse body. Carry out the overall project acceptance of the CA silo.