JPH0348773B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention improves respiration and microorganisms by adjusting the air composition of the atmosphere in which fresh food is placed.
It is used in the field of fresh food storage as a storage device that suppresses the activity of oxygen and other substances.

Conventional technology Conventional storage devices are used, for example, in Kaoru Kato's ``About a new resource-based CA storage system'' (air conditioning and refrigeration).
1974-7P191), the structure was as shown in Figure 3.

That is, fuel supplied from a cylinder or the like is mixed with air 3 supplied from the refrigerator 2 by the circulation blower 1, and the mixture is combusted in the carbon dioxide generator 4 to generate carbon dioxide. Since the carbon dioxide generated by the carbon dioxide generator 4 is supplied to the refrigerator 2, oxygen in the refrigerator 2 is decreased and carbon dioxide is increased. When the carbon dioxide concentration reaches the set value, the scrubber 5 is operated to adsorb excess carbon dioxide. Next, when the oxygen concentration reaches the set value, the carbon dioxide generator 4 is stopped and the oxygen supply blower 6 is operated to maintain a constant air composition in the atmosphere in which the perishables are placed. It is used to store things.

Problems to be Solved by the Invention However, when petroleum-based gas fuel is used as fuel for a perishables storage device with such a structure, the exhaust gas contains a large amount of water vapor, and this water vapor must be condensed. The problem was that a very large condenser was required.

Therefore, if carbon fuel is used as fuel, the problem of water vapor generation can be avoided. However, as the combustion progresses, the oxygen concentration within the refrigerator 2 decreases, and the amount of oxygen that can be used for combustion decreases, resulting in a decrease in fuel consumption. Therefore, an air preheater is provided downstream of the carbon dioxide generator 4 to increase the amount of air in the circulator without lowering the combustion temperature, thereby preventing a decrease in fuel consumption.

However, in such a combustion furnace, the temperature of the upper layer of the carbon fuel is still low at the beginning of combustion, so low-temperature combustion gas containing a large amount of carbon monoxide is discharged from the combustion furnace for a while after combustion starts. Ru. For this reason, the air preheater installed downstream of the carbon dioxide generator 4 cannot fully demonstrate its capacity, and it takes a long time to stabilize the temperature inside the combustion furnace and perform stable combustion. A problem has arisen.

The present invention provides a perishables storage device which has a simple configuration, makes full use of the capacity of the air preheater immediately after the start of combustion, and allows the combustion furnace to perform stable combustion in a short period of time.

Means for Solving the Problems Accordingly, the present invention provides a purification catalyst downstream of the carbon dioxide generator, and further provides an air preheater downstream of the purification catalyst.

Effect The effect of this technical means is as follows.

A purification catalyst is provided downstream of the carbon dioxide generator, and by installing it downstream, the low temperature combustion gas containing a large amount of carbon monoxide supplied from the combustion furnace is converted to carbon monoxide by the purification catalyst. The exothermic reaction converts the air to a high temperature, which is then fed to the air preheater. For this reason, the capacity of the air preheater can be maximized, and high-temperature combustion air that has undergone heat exchange with the air preheater can be supplied to the combustion furnace. This high-temperature combustion air raises the temperature of the carbon fuel and intensifies the reaction, so the temperature inside the combustion furnace stabilizes quickly and the time it takes for combustion to stabilize can be significantly shortened.

Embodiment Hereinafter, an embodiment of the present invention will be described based on the accompanying drawings.

In FIG. 1, a fire grate 9 is provided to partition a combustion furnace 8 of a carbon dioxide generator 7, and a carbon fuel 10 is supplied onto the fire grate 9. Further, an electric heater 11 is provided below the grate 9. At the time of startup, the electric heater 11 is energized, and when the carbon fuel 10 is heated to a temperature sufficient for combustion, the circulation blower 12 is operated to supply combustion air to the combustion furnace 8. Since the carbon fuel 10 is already sufficiently heated, combustion begins as soon as air contacts the carbon fuel 10. The amount of combustion at this time is the surface area of carbon fuel 10,
It is determined by the amount of oxygen supplied to the carbon fuel 10.

High-temperature exhaust gas containing a large amount of carbon dioxide generated by the carbon dioxide generator 7 is purified by a purification catalyst 13 and supplied to an air preheater 14 . In this air preheater 14, the exhaust gas is heat exchanged with the combustion air, and after preheating the combustion air, the exhaust gas is heated in the cooler 15.
supplied to The exhaust gas cooled by the cooler 15 is supplied to the refrigerator 17 through the scrubber 16. Then, the air whose oxygen concentration has decreased due to this is supplied to the combustion furnace 8 again by the circulation blower 12. This cycle continues until the carbon dioxide concentration within the refrigerator 17 reaches the set value.

The scrubber 16 has, for example, a carbon dioxide adsorption layer filled with activated carbon or the like, a regenerator for desorbing the adsorbed carbon dioxide, and a bypass path. When it is detected by a signal from a gas sensor (not shown) provided in the refrigerator 17 that the concentration of carbon dioxide in the refrigerator 17 has reached the set value, the scrubber 16 is operated to maintain the set value of the carbon dioxide generated by combustion. Continues to adsorb excess carbon dioxide.
When it is detected by the signal from the gas sensor in the refrigerator 17 that the oxygen concentration in the refrigerator 17 has reached a set value, the carbon dioxide generator 7, circulation blower 12, and scrubber 16 are stopped. Thereafter, the oxygen consumed by the stored perishables when they breathe is supplied from the oxygen supply blower 18 to the refrigerator 17, and the carbon dioxide generated when the perishables breathe is removed by the scrubber 16. By adsorption, the air composition within the refrigerator 17 is maintained at the set value. The specific operational relationship of the embodiment of the present invention having such a configuration will be described below.

In combustion of carbon fuel, when carbon comes into contact with the surface of the carbon fuel, a reaction occurs where carbon atoms combine with oxygen atoms to generate carbon monoxide. Next, near the surface of the carbon fuel, a reaction occurs in the gas phase in which carbon monoxide and oxygen atoms combine to generate carbon dioxide. In particular, the latter reaction occurs in the high-temperature gas phase, so when the combustion gas undergoing this reaction comes into contact with a cold area, the reaction that changes it to carbon dioxide stops, and carbon monoxide is generated.

FIG. 2 shows the temperature change of the carbon fuel 10 from the start of preheating to immediately after the start of combustion. From this figure, it can be seen that when a large amount of carbon fuel is supplied to the combustion section, a very long period of preheating is required to preheat all the carbon fuel in the combustion section to a combustible state. Therefore, when the temperature of the lower layer of the carbon fuel 10 reaches a combustible temperature, if combustion air is supplied to the combustion section and combustion is started, the carbon fuel ( Although the temperature in Fig. 2 a) is high enough to cause combustion, the carbon fuel in the upper part of the combustion furnace 8 (Fig. 2 c) has a heat value during preheating of the carbon fuel in the middle (Fig. 2 b). As the temperature is being taken away, there is no supply of heat during preheating, and the temperature is extremely low. For this reason, when the combustion gas of the carbon fuel (Fig. 2 a) at the bottom of the combustion furnace 8 where combustion has started comes into contact with the low-temperature carbon fuel, the reaction in which carbon monoxide changes to carbon dioxide stops, and the carbon fuel generated During the combustion reaction, a large amount of carbon monoxide is generated. In particular, when high-temperature sintered carbon fuel, which is less flammable, is used as fuel, the amount of carbon monoxide produced is considerably higher than that of unsintered carbon fuel, and the time required for the combustion furnace to stabilize is longer. Become. In order to suppress the generation of carbon monoxide, the temperature of the carbon fuel in the upper part of the combustion furnace 8 should be raised as quickly as possible to stabilize combustion.

Therefore, in the present invention, by providing a purification catalyst 13 downstream of the carbon dioxide generator 7 and an air preheater 14 downstream thereof, low-temperature combustion containing a large amount of carbon monoxide supplied from the combustion furnace 8 is achieved. The gas is heated to a high temperature by an exothermic reaction in which carbon monoxide is converted to carbon dioxide in the purification catalyst 13 and then supplied to the air preheater 14 . For this purpose, the air preheater 14
Since the combustion gas supplied to the combustion chamber is at a much higher temperature than that of conventional devices, the capacity of the air preheater 14 can be maximized, and the combustion air is heated to a high temperature by the air preheater 14. It can be replaced and supplied to the combustion furnace 8. Since this high-temperature combustion air intensifies the combustion reaction of the carbon fuel 10, the carbon fuel in the upper part of the combustion furnace 8 becomes high temperature in a short period of time, and the temperature inside the combustion furnace 8 quickly stabilizes, resulting in stable combustion. can be significantly shortened.

In particular, when high-temperature sintered carbon fuel, which is difficult to burn, is used as fuel, the time required for combustion to stabilize in the combustion furnace is significantly shorter than when unsintered carbon fuel is used as fuel. be able to.

Effects of the Invention The present invention provides a purification catalyst downstream of a carbon dioxide generator, and further provides an air preheater downstream of the purification catalyst for exchanging heat between exhaust gas from the carbon dioxide generator and combustion air. , the ability of the air preheater can be fully utilized immediately after the start of combustion, greatly shortening the time it takes for combustion to stabilize in the combustion furnace.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of a perishables storage device according to an embodiment of the present invention, FIG. 2 is a time characteristic diagram of the temperature of carbon fuel,
FIG. 3 is a schematic diagram of a conventional fresh produce storage device. 7... Carbon dioxide generator, 8... Combustion furnace, 1
3... Purification catalyst, 14... Air preheater.

Claims (1)

[Claims] 1. A refrigerator, a carbon dioxide generator that supplies carbon dioxide to the refrigerator by burning carbon fuel in a combustion section provided inside the refrigerator, and a carbon dioxide generator that circulates air within the refrigerator as combustion air. A purification catalyst is provided downstream of the carbon dioxide generator, and air preheating is provided downstream of the purification catalyst to exchange heat between exhaust gas from the carbon dioxide generator and combustion air. A fresh food storage device characterized by being equipped with a container.