Technology of Cryogenic Grinding at -196°

An intriguing relationship between canned chu-hi and LNG cold energy

An intriguing relationship between canned chu-hi and LNG cold energy

Sayaka Shono
Powder Business Division, Osaka Gas Liquid Co., Ltd.

I went to the address provided, and a huge tank came into sight.
I checked the map, and it showed "Osaka Gas Senboku Terminal."
The tank seemed to be for storing LNG, and adjacent to it was a food factory of Osaka Gas Liquid.
"Welcome, thank you for coming!" Ms. Shono from the Powder Business Division came out to greet me.
"I didn't know your company was located right next to a gas plant."
"It is, because our business utilizes LNG cold energy, which is generated in the process of gas production."
"LNG cold energy?"
"Yes. Just follow me inside, and I'll give you the details."
LNG stands for liquefied natural gas. Do they use something cold from the gas?
How is it related to canned chu-hi production?
Hoping to have these questions answered and clear up my doubts, I listened to her anyway.

An international-standard-compliant grinding factory specializing in food

Canned chu-hi Source: Suntory Spirits Ltd.

Canned chu-hi
Source: Suntory Spirits Ltd.

Let me get straight to the point. How is Osaka Gas Liquid related to the production of -196℃ Strong Zero?
Ms. Shono Well, the fruits used to produce -196℃ Strong Zero are ground at our food factory.
An international-standard-compliant grinding factory specializing in food

Ground foods

Really? In your factory?
Ms. Shono Yes. Suntory entrusts us with the grinding only. The maker supplies us with lemons, limes, and other fruits. We freeze the whole fruits at an ultralow temperature, grind them into powder particles of tens of micrometers, and deliver the powder to Suntory.
Grinding foods at room temperature is a relatively common practice, but that may seriously affect the materials. While being ground in a machine, they are exposed to the intense heat produced from grinding, which may denature the protein. In contrast, materials frozen at ultralow temperature can be ground with their flavors and aromas preserved.
I see. Well, I don't mean to be rude, but do you ensure proper hygiene control?
Ms. Shono Yes, absolutely. Our food factory has a food hygiene area. In 2018, we acquired FSSC 22000 certification, an international standard for food safety control. Which means our factory already meets the requirement of compliance with HACCP (food hygiene control system), which will be mandatory in Japan from 2020.
HACCP-compliant grinding mills that specialize in food are very rare in Japan. It is safe to say we are the only company that has brought this business to commercialization on this scale. Such strict hygiene control is highly reputed, and Suntory trusts us with the work.
Would you like to see how it works at the factory? Seeing is believing, you know.
I'd love to!

An original grinding unit that makes full use of liquefied nitrogen

Is this the grinder?
Is this the grinder?
Ms. Shono This is a complete grinding unit, and the grinder is inside, behind these doors. Let me open them for you. This is how it goes. That funnel-like component on the left is the freezer. It is filled with liquefied nitrogen, and material is fed into the freezer from the top. The liquefied nitrogen is at -196℃, so the material soaked in it freezes hard.
The frozen material passes through the pipe, called a screw feeder, to the cryogenic grinder, where it is ground into powder particles of tens of micrometers.
Wait a second. Judging from what you just said, the heat produced from grinding melts the frozen material, doesn't it?
Wait a second. Judging from what you just said, the heat produced from grinding melts the frozen material, doesn't it?
Ms. Shono We use our ingenuity, too. Liquefied nitrogen at -196℃ is also used when a material is ground, to keep the temperature low and prevent the material from melting. Our grinder is an impact type grinder, called a hammer crusher mill. Hammer crusher mills crush material powerfully into fine particles, but they are not popular because they produce more heat from grinding than other types of grinders. However, we have overcome this disadvantage by blowing liquefied nitrogen to prevent a temperature rise. That is why we can employ a hammer crusher mill.
And one more thing. Oxidation is not good for food. So, we have created an environment that minimizes food exposure to oxygen by surrounding the material with liquefied nitrogen. In this way, we have established a manufacturing process that prevents both thermal and oxidative degradation and enables us to deliver fresh powder.
During the grinding process, the unit freezes, too.

During the grinding process, the unit freezes, too.

Do you grind fruits only?
Ms. Shono No. A wide range of customers entrust us with the grinding of a wide variety of food. However, we have a limited number of grinding units and use one unit to grind different types of food. So, we pay extra attention to unit cleaning. Once a unit finishes grinding one type of food, it is taken apart. The individual parts are carefully cleaned, dried, and then put back together before the next type of food is fed into the unit. Some of the foods we grind are allergens, so we thoroughly ensure that the units return to a completely clean state after every use.

Grinding flow

Poor sales of grinding units led to a change in mindset.

By the way, how did an Osaka Gas group company end up doing food grinding?
By the way, how did an Osaka Gas group company end up doing food grinding?
Ms. Shono Before natural gas is transported from overseas to produce town gas, it is cooled to -160℃ into liquefied natural gas (LNG). In liquid form, gas is smaller in volume, and you can transport more at a time. Before use, the temperature of the LNG is raised to return the liquid to gas. When exposed to air in this process, the LNG is heated while the air is cooled. The cold air separates into about 80% nitrogen, 20% oxygen, and a small amount of argon. These liquefied gases, which are generated in the LNG vaporization process, are the industrial gases we sell.
Hmm. So ...?
Ms. Shono To boost demand for liquefied nitrogen in particular, we came up with an idea of manufacturing and selling high-precision cryogenic grinding units. We expected that once our customers bought the units, they would continually purchase liquefied nitrogen from us to operate the units. That was our starting point.
Uh-huh. So, did the grinding unit sell well?
Ms. Shono Well … actually only in small numbers (said with a wry smile). We didn't want to waste our efforts in developing the unit. So we changed our mindset and decided to keep the units at hand and undertake grinding ourselves. Our grinding business began with rubber, nylon and other plastics, and then gradually expanded into foods.
That's great, but working on plastics and foods in the same factory sounds ...
Ms. Shono Exactly. So, in 2004, the top management at the time made a bold and wise decision to set up a factory dedicated to food. The government imposes strict regulations on food processing businesses. Among the large number of Daigas Group companies, we are the only one that operates the business at its own factory. If we had continued our grinding business only at the plastics factory, the business wouldn't have enjoyed the growth it does today.

Usage image of cold energy and liquefied nitrogen , from LNG tanker to Cryogenic Grinding Center

Drying, powderization of liquids, and other potential businesses are in prospect.

Drying, powderization of liquids, and other potential businesses are in prospect.
Does cryogenic grinding have room for further development?
Ms. Shono I believe this technology still has great potential. Today, we make use of our expertise in granules and work with a wide range of customers to find new applications. We hear our customers' starting points and goals, and more specifically, what material they want to use and how they want to use it. Then we suggest desirable particle sizes, make trial products, present them to the customers for examination, and make improvements to the prototypes.
It sounds like you will be able to expand the range of foods to work with.
Ms. Shono Recently, food waste has been an issue of concern. Our grinding technology allows off-specification vegetables and other so-called throw-away materials to be utilized. In fact, we are entrusted to grind the seeds and skins of squeezed grapes. I believe there is still high potential demand from manufacturers on which food waste reduction targets are imposed.
What is your company's vision beyond that?
Ms. Shono I can't go into the details, but we are undertaking research and development on the drying and powderization of liquids. Drying is expected to provide advantages in transportation costs and long-term preservation. Powderization of liquids carries the potential for a type of processed food that was impossible to exist before.
We won't necessarily stick to grinding. If we can use our core technology of utilizing cold energy to develop higher-quality granulation services and offer them at higher prices, we could say we have achieved our initial goal of effective use of LNG cold energy.
All my questions have been answered. Thank you so much for today.


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