How to reduce energy costs in a powder coating plant by up to 40%?
A huge amount of electricity - both gas and electricity - is used in industry. Due to rising energy prices, we are noticing a very strong trend among entrepreneurs to optimise the costs of running powder coating plants. Equally important is the ecological aspect of seeking savings in the energy used in a company. Technology Kairo-SURF allows reduce paint line costs by up to 40%.
Two main sources of energy are used in powder coating plants:
- electricity
- natural gas
There are solutions based on fuel oil combustion on the market, but they represent a minority of appliances, so we will skip them in the following entry.
Gas and electricity prices
Natural gas prices have been rising steadily since last year. We will not describe the causes here, after all we have little influence over them. Unfortunately, the entire paint industry has to deal with the result, i.e. the drastic increase in energy prices and even the termination of contracts by suppliers. Andrzej Szczęśniak (energy market expert) wrote about the rise in gas prices in the industry on 15.12
#ceny #gaz
Natural gas has been unmercifully expensive for several months.
But for this week, it became even more expensive by 25% = by 113 PLN/MWh.8 XII - PLN 455
15 XII - PLN 568A year ago, gas cost £81. I repeat: 81 zł.
Today it is 7 times more expensive. 7 times.
Pure madness.- Andrzej Szczęśniak (@SzczesniakA) December 15, 2021
and already on 22.12 the gas price chart resembles a certain virtual currency.
🤣
It's #gaz earth or bitcoin?The ride up will finish off the smaller, gas-trading companies, if any still survive. pic.twitter.com/3VLcQhk4dj
- Andrzej Szczęśniak (@SzczesniakA) December 22, 2021
The price of electricity is no different, the risk of a blackout in European countries is increasing, more nuclear units are being shut down, production from wind is falling and mines are reducing output. As a result, we have a more than 3x increase in the price of energy from an average of around 500 PLN/MWh at the beginning of October to more than 1600 PLN/MWh at the peak on 21.12.2021.
Energy costs in a powder coating plant
In the paint shop, the largest consumers of gas or electricity appear to be the polymerisation and drying ovens.
In this context, the surface preparation process prior to painting, where the phosphate bath must be heated to temperatures often exceeding 55°C, is often neglected.
A detailed comparison of Kairos technology and phosphating is available in the entry Comparison of Kairo Surf and phosphating technologies
What is the situation with our customers' gas consumption following the implementation of formulations operating at 25-27°C?
Our assumptions spoke of a drop in gas costs of 10-15 % across the entire paint shop. After all, in addition to heating the bath, there are also large burners in the dryer and polymerisation oven. Meanwhile, customers have seen a decrease in gas consumption for the entire paint shop at a level of 30-40%.
This allowed us to feel a great sense of satisfaction. At the same time, we decided to take a closer look at the phenomenon.
Analysis
Conversations with customers yielded a closer look. They pointed out that the burners that heat the bath turn on for a short while (instead of running all the time). Such momentary activations turn out to be sufficient to maintain a bath temperature of 25-27°C.
In the case of paint lines, we are usually dealing with 3 gas burners:
- burner heating the chemical bath
- dryer burner
- polymerisation furnace burner
These burners tend to have comparable powers. Intuition fails in this case, suggesting that the cookers will have burners with significantly higher wattages.
What are the implications of this?
It was mentioned above that the burner that heats the chemical bath to 25-27°C for almost 90% of operating time is switched off. This means that about 1/3 of the energy requirement disappears.
Added to this is the thermodynamics of the heat exchange itself.
Heat transport (and thus heat loss from the wash baths) is driven by the temperature difference between the bath temperature and the ambient temperature on the paint shop floor.
With a bath temperature of 55°C and an air temperature of 28°C - the gradient is 27°C.
The same temperature gradient will be a mere 3°C at a chemical bath temperature of 25°C.
Assuming a constant bath mass, we have much less heat lost when the operating temperature is lower.
Using calculators available on the web, the following data can be obtained
How many kWh of energy is used to heat water
Phosphating
Cold water temperature - 10°C
Heated water temperature - 55°C
Volume or weight of heated water, l - 1000 litres
Heater capacity - 95 %
Energy consumption for heating:55,092 kWh -
Kairo-SURF
Cold water temperature - 10°C
Heated water temperature - 25°C
Volume or weight of heated water, l - 1000 litres
Heater capacity - 95 %
Energy consumption for heating:18,364kWh
Based on the above figures, everyone can calculate their own savings by converting the resulting values by the kWh price. Alternatively, it is even easier to calculate the difference on the basis of a constant value, where it is assumed that it takes approximately 1.16 kWh to heat 1 m3 of water by 1 degree C. Feel free to calculate and contact us. Our customers save up to £10,000 a month on energy costs.
