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Process Cooling and the Dairy Industry

Integral to this process are dairy chillers, as they are able to bring the temperature of the milk down enough to preserve it as it is transported to be bottled

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Dairy, Industry, Milk
It is a heat treatment process that removes dangerous bacteria, allowing the produce to be stored for much longer periods. Pixabay

Ensuring milk, yoghurt, cheese and other produce are at the correct temperature is critical in the dairy industry in order to minimize waste. Milk chillers work to eliminate excess heat at important milestones throughout its production, such as the pasteurization process.

It is a heat treatment process that removes dangerous bacteria, allowing the produce to be stored for much longer periods. To do so, the milk must be heated to up to 212 Fahrenheit to stop the bacteria from duplicating. It then requires fast cooling in order to stop the produce from being damaged.

Integral to this process are dairy chillers, as they are able to bring the temperature of the milk down enough to preserve it as it is transported to be bottled.

What is the pasteurization process?

Dairy, Industry, Milk
To do so, the milk must be heated to up to 212 Fahrenheit to stop the bacteria from duplicating. Pixabay

Temperature plays an important role in creating dairy produce that is safe for human consumption. During the process, milk is passed through a range of cold and hot temperatures in order to kill off dangerous pathogens, as well as to preserve proteins and nutrients.

There are two different pasteurization methods that are utilized in the global dairy industry. These are:

  •     High Temperature, Short Time (HTST) – This method is used in the United States and Canada. It works by heating milk up to 161 Fahrenheit for 15 seconds in order to kill off any harmful pathogens and take away unwanted enzymes. Then the milk is process cooled very quickly down to 39 Fahrenheit in order to preserve the desired enzymes and to stop the dangerous pathogens from coming back. The finished produce needs to be kept refrigerated and has a 2 week shelf life.
  •     Ultra High Temperature (UHT) – This method is used in Europe. It works by heating milk up to 280 Fahrenheit for 2 seconds in order to kill off any harmful pathogens and take away unwanted enzymes. Then the milk is process cooled, whilst being sealed air tight, down to 39 Fahrenheit in order to preserve the desired enzymes and to stop the dangerous pathogens from coming back. The finished produce does not need to be kept refrigerated and has a shelf life of between 6 – 9 months. However, it does sometimes have a slight ‘cooked’ flavor to it.

 

What dairy cooling solutions are available?

A dairy chiller is vital in the controlling of heat. If the milk gets too hot it is spoilt. This is the same for cheese also. However, if it does not get enough heat it prevents the pasteurization process from working optimally.

To help with this there are a number of solutions available within the dairy industry – which you can learn more about here: https://northslopechillers.com/process-cooling/dairy/. These include storage tanks with jackets and process chillers. Within the dairy industry, coolant is required to draw the heat from out of the milk in order to drop the temperature to the necessary level.

Type of dairy chillers

Dairy, Industry, Milk
It then requires fast cooling in order to stop the produce from being damaged. Pixabay

When inspecting the type of chillers that can be used for dairy produce there are two main categories. These are:

  •       Vapor compression – The most common type and include both water chillers and air chillers. They use an electric driven mechanism to push a refrigerant through the system.
  •       Vapor absorption – They use heat to push a refrigerant around the system.

As stated, vapor compression chillers are the most common types used within the dairy industry and are placed into two sub category type. These are:

  •       Water chillers – They work by removing heat through the pumping of water, or another fluid, through a condenser and dispersing it through a cooling tower. These chillers are more efficient than air cooled chillers. Thanks to water’s high heat capacity, the process of using water evaporation to dissipate heat is far more energy efficient than blowing cool air across a hot surface. Traditionally, these chillers last longer than air chillers as well.

 

  •       Air chillers – They work by using air to get rid of the heat. Fans blast cool air across the tubes of the condenser to cool it down. This method is much less energy efficient than the water cooling method. These chillers are ideal for when it comes to static cooling. They are very easy to install and can even be installed on the outside of a building, saving space on the inside. However, they are more likely to experience issues with recirculation and blockages than water chillers.

Despite the stated differences, the two types of chillers are actually made up of the same components, which include an expansion valve, an evaporator, a compressor, and a condenser. The mechanics of the two chiller types are also extremely similar.

The compressor starts the refrigeration cycle and begins so by pushing the refrigerant through to the condenser. During this process the low temperature and low pressure refrigerant is compressed and changed into a high temperature and high pressure gas. Whilst in the condenser air or water flows over the coils to remove any heat from the refrigerant. The refrigerant condenses at this point as it loses heat and turns into a liquid form. After leaving the condenser, the refrigerant goes through the expansion valve where it is restricted. Once through the valve, the refrigerant goes into the evaporator where it then begins to evaporate back into a gas state. During this process it gets super cold and absorbs a large amount of heat. This heat is removed from the fluid and transferred in to the refrigerant. This will then enter the compressor and the entire cycle starts over again.

The types of compressors the chiller can utilize are subcategorized as the following:

  •       Reciprocating chillers – Use a chamber and pistons.
  •       Scroll compressor chillers – Utilizes one rotating plate and a stationary plate.
  •       Screw driven chillers – Ideal for medium to smaller loads.
  •       Centrifugal chillers – Mostly water chillers that utilize this.

What are the benefits of a dairy chiller solution?

An effective and robust dairy chiller solution is easy and simple to install, and will work to save time, lower operational costs, save energy and water, and most importantly improve the quality of the product.

 

Next Story

China- Top Contributor in Global Warming

China is the leader in coal and clean energy and is the top emitter of greenhouse gases

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Climate China Coal
In this photo, smoke and steam rise from a coal processing plant that produces carbon black, an ingredient in steel manufacturing, in Hejin in central China. VOA

As world leaders gather in Spain to discuss how to slow the warming of the planet, a spotlight falls on China — the top emitter of greenhouse gases.

China burns about half the coal used globally each year. Between 2000 and 2018, its annual carbon emissions nearly tripled, and it now accounts for about 30% of the world’s total. Yet it’s also the leading market for solar panels, wind turbines and electric vehicles, and it manufactures about two-thirds of solar cells installed worldwide.

“We are witnessing many contradictions in China’s energy development,” said Kevin Tu, a Beijing-based fellow with the Center on Global Energy Policy at Columbia University. “It’s the largest coal market and the largest clean energy market in the world.”

That apparent paradox is possible because of the sheer scale of China’s energy demands.

But as China’s economy slows to the lowest level in a quarter century — around 6% growth, according to government statistics — policymakers are doubling down on support for coal and other heavy industries, the traditional backbones of China’s energy system and economy. At the same time, the country is reducing subsidies for renewable energy.

China solar panel
A solar panel installation is seen in Ruicheng County in central China. VOA

At the annual United Nations climate summit, this year in Madrid, government representatives will put the finishing touches on implementing the 2015 Paris Agreement, which set a goal to limit future warming to 1.5 to 2 degrees Celsius above pre-industrial levels. Nations may decide for themselves how to achieve it.

China had previously committed to shifting its energy mix to 20% renewables, including nuclear and hydroelectric energy. Climate experts generally agree that the initial targets pledged in Paris will not be enough to reach the goal, and next year nations are required to articulate more ambitious targets.

Hopes that China would offer to do much more are fading.

Recent media reports and satellite images suggest that China is building or planning to complete new coal power plants with total capacity of 148 gigawatts — nearly equal to the entire coal-power capacity of the European Union within the next few years, according to an analysis by Global Energy Monitor, a San Francisco-based nonprofit.

Separately, investment in China’s renewable energy dropped almost 40 percent in the first half of 2019 compared with the same period last year, according to Bloomberg New Energy Finance, a research organization. The government slashed subsidies for solar energy.

Last week in Beijing, China’s vice minister of ecology and environment told reporters that non-fossil-fuel sources already account for 14.3% of the country’s energy mix. He did not indicate that China would embrace more stringent targets soon.

“We are still faced with challenges of developing our economy, improving people’s livelihood,” Zhao Yingmin said.

China is alternately cast as the world’s worst climate villain or its potential clean-energy savior, but both superlatives are somewhat misplaced.

As a fast-growing economy, it was always inevitable that China’s energy demands would climb steeply. The only question was whether the country could power a sufficiently large portion of its economy with renewables to curb emissions growth.

Many observers took hope from a brief dip in China’s carbon emissions between 2014 and 2016, as well as Chinese leader Xi Jinping’s statement in 2017 that China had “taken a driving seat in international cooperation to respond to climate change.”

Renewed focus on coal

Today the country’s renewed focus on coal comes as a disappointment.

China Pollution
The pollution in China is at extreme levels. VOA

“Now there’s a sense that rather than being a leader, China is the one that is out of step,” said Lauri Myllyvirta, lead analyst at the Centre for Research on Energy and Clean Air in Helsinki. He notes that several developed countries — including Germany, South Korea and the United States — are rapidly reducing their reliance on coal power.

Fossil fuels such as coal, gasoline and natural gas release carbon dioxide into the atmosphere, trapping heat and changing the climate. Coal is the biggest culprit.

Last year, coal consumption in the United States hit the lowest level in nearly 40 years, according to the U.S. Energy Information Administration.

One place to consider the rise, pause and rise again of China’s coal sector is Shanxi province — a vast mountainous region in central China.

Shanxi is the heart of China’s traditional coal country, dotted with large mines, but also the site of some of the country’s largest solar and wind-power projects, according to state media.

During most of the past 30 years of rapid economic growth, the coal business boomed in Shanxi and nearby provinces. As China’s cities and industries expanded, coal supplied much of that power, and China surpassed the U.S. as the world’s top carbon emitter in 2006.

But after climbing sharply for two decades, China’s emissions stalled around 2013 and then declined slightly in 2015 and 2016, according to Global Carbon Budget, which tracks emissions worldwide. This dip came as Chinese leaders declared a “war on pollution” and suspended the construction of dozens of planned coal power plants, including some in Shanxi.

At the same time, the government required many existing coal operators to install new equipment in smokestacks to remove sulfur dioxide, nitrous oxide and other hazardous substances. About 80% of coal plants now have scrubbers, said Alvin Lin, Beijing-based China climate and energy policy director for the Natural Resources Defense Council, a nonprofit.

Climate change China
This coal processing plant in China produces toxic air pollutants. VOA

As a result, the air quality in many Chinese cities, including Beijing, improved significantly between 2013 and 2017. Residents long accustomed to wearing face masks and running home air-filter machines enjoyed a reprieve of more “blue sky days,” as low-pollution days are known in China.

Annual levels of PM 2.5 — a tiny but dangerous pollutant — dropped by roughly a third across China between 2013 and 2017, from 61.8 to 42 micrograms per cubic meter, according to scientists at Beijing’s Tsinghua University and other institutions. They made the report in November in the Proceedings of the National Academy of Sciences, a peer-reviewed journal.

“That’s a big improvement, although in terms of safe air quality, we’re still not there yet,” Lin said. China’s pollution levels are still well above standards set by the World Health Organization.

While these retrofitted coal plants emit fewer pollutants that harm human health, the scrubbers do not reduce greenhouse gases. “The new plants are good for air quality, but you still have all that carbon dioxide that goes into the atmosphere,” Lin said.

Carbon emissions rising

In the past three years, China’s carbon emissions have begun to rise again, according to Global Carbon Budget.

That trend was evident in the first half of 2019, when China’s carbon emissions from fossil fuels and concrete production rose 4%, compared with the same period last year, according to Myllyvirta’s preliminary analysis of Chinese government data.

The coming winter in Beijing may see a return of prolonged smog, as authorities loosen environmental controls on heavy industry — in part to compensate for other slowing sectors in the economy. Cement and steel production remain both energy intensive and heavily polluting.

Permits for new coal plants proliferated after regulatory authority was briefly devolved from Beijing to provincial governments, which see construction projects and coal operations as boosts to local economies and tax bases, said Ted Nace, executive director of Global Energy Monitor.

“It’s as though a boa constructor swallowed a giraffe, and now we’re watching that bulge move through the system,” said Nace. In China, it takes about three years to build a coal plant.

In November, Premier Li Keqiang gave a speech to policymakers emphasizing the importance of domestic coal to energy security.

But because China’s coal-power expansion is growing faster than energy demand, overcapacity “is a serious concern now,” said Columbia University’s Tu.

And once new infrastructure is built, it’s hard to ignore.

People in China
The highest red alert was issued for heavy smog in several cities in China. VOA

“It will be politically difficult to tear down a brand-new coal plant that’s employing people and supporting a mining operation. It will make it more difficult for China to transition away from coal,” Nace said.

Reliance on China

The world has already warmed by 1 degree Celsius. All scenarios envisioned by the Intergovernmental Panel on Climate Change for holding planetary warming to around 1.5 degrees Celsius involve steep worldwide reductions in coal-power generation.

In that effort, other countries rely on China to manufacture most of the solar panels installed worldwide, according to an analysis in the journal Science co-authored by Jonas Nahm, an energy expert at Johns Hopkins University.

“If we have any chance to meet climate targets, we have to do a lot by 2030 — and we won’t be able to do it without China’s clean-energy supply chain,” Nahm said.

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China’s manufacturing helped bring down the cost of solar panels by 80% between 2008 and 2013. Prices for wind turbines and lithium-ion batteries also dropped significantly, according to Bloomberg New Energy Finance.

“China has a really mixed record. On the one hand, it’s seen rapidly rising emissions over the past two decades,” Nahm said. “On the other hand, it’s shown it’s able to innovate around manufacturing — and make new energy technologies available at scale, faster and cheaper.” (VOA)