CN108795391B

CN108795391B - Secondary refrigerant for refrigeration house refrigerating system

Info

Publication number: CN108795391B
Application number: CN201810560445.3A
Authority: CN
Inventors: 李梅
Original assignee: Beijing Zhongleng High Tech Refrigeration Equipment Co ltd
Current assignee: Beijing Zhongleng High Tech Refrigeration Equipment Co ltd
Priority date: 2018-06-04
Filing date: 2018-06-04
Publication date: 2020-07-28
Anticipated expiration: 2038-06-04
Also published as: CN108795391A

Abstract

The invention discloses a secondary refrigerant for a refrigeration house refrigerating system, which comprises 30-45% of potassium formate, 15-27% of pentaerythritol, 10-18% of water dispersible polyisocyanate, 0-3% of propylene glycol, 0-2% of sodium dehydroacetate, 0-2% of potassium sorbate and 15-25% of distilled water or deionized water in percentage by mass.

Description

Secondary refrigerant for refrigeration house refrigerating system

Technical Field

The invention relates to the technical field of low-temperature refrigeration, in particular to a secondary refrigerant for a refrigeration house refrigeration system.

Background

At present, food safety and cold chain construction enter a high-speed development period, and a refrigeration house is used as a central link of low-temperature circulation of food and is very important for all links of the whole cold chain. In the prior art of large-scale cold storages, liquid ammonia and freon are mainly used as refrigerants for refrigeration.

The liquid ammonia refrigerating system generally comprises a refrigerating unit, an ammonia-oil separator, a high-pressure liquid storage device, a condenser, a low-pressure circulating liquid storage barrel, an oil collector, an ammonia pump, an air cooler and the like, although the liquid ammonia refrigerating efficiency is higher, and the operation cost is lower, the system is complex in pipeline, high in operation management difficulty and high in requirement on the professional level of an operator, and meanwhile, due to the fact that automation is difficult to achieve, the system needs 24-hour on-duty operation management of the operator. And the problems of difficult oil return and easy leakage of liquid ammonia in a direct evaporation system exist, and once the ammonia gas is leaked, explosion accidents are easy to occur. The input cost of the Freon refrigeration system is high in the initial construction stage, the Freon refrigeration system is also used as a direct evaporation system, mixed lubricating oil is needed, and when the vertical height or the total length of a connecting copper pipe of an outdoor unit of the refrigeration system is increased, serious oil return unsmooth of the refrigeration system can be caused, so that the refrigeration efficiency is greatly reduced, and the power consumption is greatly increased. Furthermore, since freon refrigerant has no significant characteristics in the case of leakage, the operational cost is significantly increased in the case of leakage repair and filling of refrigerant. In the prior art, the liquid ammonia or Freon is used as a refrigerant to be replaced by direct expansion refrigeration in an indirect refrigeration mode.

The coolant used in the prior art is typically water, brine, ethylene glycol, propylene glycol, methylene chloride or trichloroethylene. Refrigerants containing these substances as main components have a problem of low refrigeration temperature or a problem of high corrosion to pipes. It can be seen that there is a great need in the art for a low temperature coolant that can be used in an indirect refrigeration system.

Disclosure of Invention

One of the technical problems to be solved by the invention is to provide a secondary refrigerant suitable for an indirect refrigeration system to improve the cold storage capacity of refrigeration of a refrigeration house, wherein the secondary refrigerant has the characteristics of low corrosivity and low refrigeration temperature.

In order to solve the technical problems, the invention provides a secondary refrigerant for a refrigeration house refrigeration system, which comprises 30-45% of potassium formate, 15-27% of pentaerythritol, 10-18% of water dispersible polyisocyanate, 0-3% of propylene glycol, 0-2% of sodium dehydroacetate, 0-2% of potassium sorbate and 15-25% of distilled water or deionized water in percentage by mass.

In one embodiment, the mass ratio of potassium formate in the coolant is 30% to 35% when the coolant has an operating temperature of 0 ℃ to-15 ℃.

In one embodiment, the mass ratio of potassium formate in the coolant is 35% to 40% when the coolant has an operating temperature of-15 ℃ to-35 ℃.

In one embodiment, the mass ratio of potassium formate in the coolant is 40% to 45% when the coolant has an operating temperature of-35 ℃ to-50 ℃.

< Indirect refrigeration System >

Fig. 1 is a schematic diagram of the refrigeration system configuration of the present invention. The refrigeration house refrigeration system comprises a first refrigeration cycle system and a second refrigeration cycle system, wherein the first refrigeration cycle system comprises a main refrigeration unit 1, an evaporative condenser 2 and a main refrigeration unit heat exchanger 3, and the second refrigeration cycle system comprises a cold accumulation water pool 5, an adjusting station 6, a refrigeration pump 7 and a refrigeration house heat exchanger 8. And the second refrigeration cycle is filled with the secondary refrigerant of the invention.

< Secondary refrigerant composition >

The middle cooling liquid used in the cold storage water tank is potassium formate-pentaerythritol-water dispersible polyisocyanate-water-based secondary refrigerant, and the middle cooling liquid comprises the following specific components, by mass, 30-45% of potassium formate, 15-27% of pentaerythritol, 10-18% of water dispersible polyisocyanate, 0-3% of propylene glycol, 0-2% of sodium dehydroacetate, 0-2% of potassium sorbate and 15-25% of distilled water or deionized water. The density of the intercooling liquid is 1.04-1.36 g/cm³The specific heat is 0.56-0.746 cal/g DEG C, the viscosity is 2.9-15.9 mPa & s (cp), the thermal conductivity is 0.21-0.47W/m.K, the boiling point is more than 150 ℃, the freezing point is less than-60 ℃, and no flash point exists.

The freezing point of the coolant of the invention is mainly determined by the contents of potassium formate and propylene glycol, and when the content of potassium formate is higher, the freezing point of the coolant is lower.

< preparation of Secondary refrigerant >

The refrigerating medium is prepared by mixing materials in a closed reaction kettle, firstly adding water, pentaerythritol, propylene glycol, sodium dehydroacetate and potassium sorbate into the closed reaction kettle, stirring until the materials are completely dissolved, then adding the water dispersible polyisocyanate, and continuously stirring until the materials are completely dissolved. Finally, potassium formate is added and stirred until it is completely dissolved. And standing the solution, filtering, and storing in a sealed container.

The closed reaction kettle used in the preparation of the secondary refrigerant has the volume of more than 10000L, the design pressure of the kettle body is higher than 1.0Mpa, and the design pressure of the interlayer is higher than 0.6 Mpa.

One or more embodiments of the present invention may have the following advantages over the prior art:

1. the secondary refrigerant has strong cold storage capacity and is suitable for low-temperature refrigeration.

2. The secondary refrigerant disclosed by the invention is non-corrosive, has no flash point and no explosion limit, and is suitable for the requirements of low-cost refrigeration of a refrigeration house.

Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention and not to limit the invention. In the drawings:

FIG. 1 is a schematic system configuration of a refrigeration system according to the present invention;

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail below with reference to the accompanying drawings.

Example 1

In this example, the mass ratio of each component in the coolant is 38% of potassium formate, 21% of pentaerythritol, 16.9% of water-dispersible polyisocyanate, 1.55% of propylene glycol, 1.45% of sodium dehydroacetate, 1.1% of potassium sorbate, and 20% of distilled water.

The preparation process includes setting distilled water 20Kg, pentaerythritol 21Kg, propylene glycol 1.55Kg and sodium dehydroacetate 1.1Kg into closed reactor, stirring for 2 hr to dissolve completely, adding water dispersible polyisocyanate 16.9Kg, raising the temperature of the reactor to 20-35 deg.c, and stirring for 3 hr to dissolve completely. 38Kg of potassium formate is added in two batches, 19Kg of potassium formate is added each time, and the mixture is stirred for 2.5 hours after the potassium formate is added each time. Finally, the solution was left to stand for 4 hours and then filtered.

The density of the refrigerating medium prepared by the embodiment is 1.105g/cm³The specific heat is 0.589cal/g DEG C, the viscosity is 12.5mPa & s (cp), the thermal conductivity is 0.26W/m.K, the boiling point is more than 150 ℃, and the freezing point is less than-60 ℃.

Example 2

In this example, the mass ratio of each component in the coolant is 45% of potassium formate, 18% of pentaerythritol, 12.9% of water-dispersible polyisocyanate, 1.55% of propylene glycol, 1.45% of sodium dehydroacetate, 1.1% of potassium sorbate, and 20% of distilled water.

During the preparation, 20Kg of distilled water, 18Kg of pentaerythritol, 1.55Kg of propylene glycol and 1.1Kg of sodium dehydroacetate, 1.45Kg of potassium sorbate, are put into a closed reaction kettle, stirred for 2 hours until completely dissolved, and then 12.9Kg of water dispersible polyisocyanate is added, the temperature of the reaction kettle is 10-15 ℃, and stirred for 3 hours until completely dissolved. And adding 45Kg of potassium formate into three batches, adding 15Kg of potassium formate each time, and stirring for 2 hours after adding the potassium formate each time. Finally, the solution was left to stand for 4 hours and then filtered.

The density of the refrigerating medium prepared by the embodiment is 1.358g/cm³The specific heat is 0.622cal/g DEG C, the viscosity is 2.9mPa & s (cp), the thermal conductivity is 0.47W/m.K, the boiling point is more than 150 ℃, and the freezing point is less than-60 ℃.

Example 3

In this example, the mass ratio of each component in the coolant is 32% of potassium formate, 24% of pentaerythritol, 18.9% of water-dispersible polyisocyanate, 2.55% of propylene glycol, 1.45% of sodium dehydroacetate, 1.1% of potassium sorbate, and 20% of distilled water.

During the preparation, 20Kg of distilled water, 24Kg of pentaerythritol, 2.55Kg of propylene glycol and 1.1Kg of sodium dehydroacetate, 1.45Kg of potassium sorbate, are put into a closed reaction kettle, stirred for 2 hours until completely dissolved, and then 18.9Kg of water dispersible polyisocyanate is added, the temperature of the reaction kettle is 10-15 ℃, and stirred for 3 hours until completely dissolved. 32Kg of potassium formate is added in two batches, 16Kg of potassium formate is added each time, and the mixture is stirred for 2 hours after the potassium formate is added each time. Finally, the solution was left to stand for 4 hours and then filtered.

The density of the refrigerating medium prepared by the embodiment is 1.04g/cm³The specific heat is 0.56cal/g DEG C, the viscosity is 15.9mPa & s (cp), the thermal conductivity is 0.21W/m.K, the boiling point is more than 150 ℃, and the freezing point is less than-60 ℃.

The above description is only an embodiment of the present invention, and the protection scope of the present invention is not limited thereto, and any person skilled in the art should modify or replace the present invention within the technical specification of the present invention.

Claims

1. The secondary refrigerant for the refrigeration system of the refrigeration house is characterized by comprising 30-45% of potassium formate, 15-27% of pentaerythritol, 10-18% of water dispersible polyisocyanate, 0-3% of propylene glycol, 0-2% of sodium dehydroacetate, 0-2% of potassium sorbate and 15-25% of distilled water or deionized water in percentage by mass.