Known for leaking ammonia happened in ice factory in Lonja de Gandia, in Valencia. It may seem strange that a chemical product should cause this kind of accident in a factory whose task, in a broad sense, is to freeze water.
But there is nothing unusual about this. ammonia is coolant more than usual in the industry. It has disadvantages such as toxicity from which, unfortunately, two employees of the city’s fishing port suffered. However, it also has notable advantages such as high energy efficiency. For this reason, it is still used today, but with strict Security measureswhat now remains is to check whether they have been executed correctly.
In the meantime, and now that we’re experiencing ice shortages across the country, and focusing on science, let’s see how ammonia to ice making.
Very old process
already in 19th century Ammonia has been used to refrigerate foods such as meat, fish, dairy and vegetables during transportation. Since these processes were industrialized, this substance continued to be used, although over time it was superseded by others such as chlorofluorocarbons.
However, after a few years, chemists Mario Molina and Frank Sherwood Rowland found that these substances were among the main culprits in the formation hole in the ozone layer.
For this reason, ammonia has regained its lost position as a popular industrial refrigerant that has reached our days, despite the shortcomings that became apparent after the incident at the ice plant in Gandia.
Ammonia as a refrigerant
Ice factories typically use ammonia in a process known as vapor compression cooling.
This is a method that takes advantage phase changes some substances for cooling. A phase transition is the transition of a substance from one state to another, usually solid, liquid, gaseous or plasma, in rare and very specific cases.
In childhood, we learn that this happens when it is cooled or heated. That is, water at room temperature cools down and, if it falls below 0ºC, it solidifies, turning into ice. And when heated above 100º, it boils, turning into a gaseous state. But from a technical point of view, what usually happens is heat transfer.
This is not the only statement that is commonly made that contains a slight error in terms. For example, we’ve all heard someone say that they can’t sleep without socks because the cold gets in through their feet. But the cold does not penetrate. This warmth is gone.
However, these phase changes can absorb or release heat In the middle. Heat, which, of course, can be used. In the case of ammonia, it is used as a refrigerant because when it evaporates absorbs a large amount of heat without actually changing its temperature. This means that it cools the system very efficiently and therefore has a large cooling capacity.
How the cooling system works
Although not all ice factories use this system, ammonia refrigeration is very common.
It consists of several stages in which the specified substance is subjected to temperature changes, which leads to a change in its phase. release or absorption of heat.
It starts with dry ammonia gas, which goes through the compressor. There, as the name suggests, it is compressed under great pressure, so that the temperature also rises. And it consists in the fact that when the pressure of a gas increases, its temperature also increases, and vice versa. It is easy to imagine it as a balloon, inside which air particles move freely. If the temperature rises, they will move faster, putting more pressure on the walls of the balloon. In fact, the time will come when the balloon will burst.
Returning to the system with ammonia, in this case the so-called evaporation temperature. However, immediately after this ammonia passes through capacitor, in which it is subjected to cooling, which will cause the re-emission of heat. We now have fluid passing through an expansion valve where the pressure drops rapidly. Next, we will have a mixture of liquid and vapor, which will have a lower temperature than the temperature of the enclosed space that we want to cool. As the air gets warmer heat transferwhich will cool the air and heat the liquid, turning it back into a gas.
From there it will continue to pass through various points where pressure and temperature changes They will cause changes of state that will result in the transfer of heat from the ambient air to the coolant itself. The result is a reduction in the temperature of the system, which is used for applications such as the production of air conditioners, the cooling of food and beverages and, of course, the production of ice.
Advantages and disadvantages of making ice with ammonia
Ammonia is listed as a refrigerant under the label R-717. Its use is widespread due to its great benefits. We have already seen some. suggests a big alternative to chlorofluorocarbonsso as not to damage the ozone layer, and this is very effective vigorously.
It is also very cheap and has the advantage that very strong and unpleasant odor; so that if there is a leak, it can be quickly located.
Perhaps this would prevent a greater evil in Gandia Ice Factory. Even so, two people were drunk. And this is a big disadvantage of ammonia. It is highly toxic by inhalation. One breath can bring bronchospasm, shortness of breath, or irritation of the airways. also can irritate the eyes.
The most serious consequences occur with continuous inspiration, as it can severe damage to lung tissueeven requiring a transplant. Fortunately, the factories where they are used are equipped with mechanisms to contain any leak in time. This, along with the fact that it can be detected by anyone with a normal sense of smell, prevents these continuous inhalations. Therefore, most likely, it will remain the preferred coolant for a large number of purposes for a long time to come.
Source: Hiper Textual
