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How to reduce energy consumption in manufacturing

Engineering services are needed to deliver not just for the sake of “keeping up with the times”, but and a tangible economic benefit to the customer. One of the noticeable results of modern engineering solutions is the reduction of energy used in food production. The experts at Viravix Engineering tell you how you can reduce heat and energy consumption in food industry.
 Electricity Consumption at a Factory

Structure of basic energy costs in production

Almost half of the energy consumption in food production, e.g. in milk processing, is spent on the cleaning of process equipment and pipes. But CIP washing cannot be dispensed with, because without it the required bacteriological purity of the product cannot be ensured.
CIP washing in food processing plants we have already described what mistakes can be made when implementing equipment and how to avoid them.
If you install a CIP station without a clear instruction or with incorrect installation, this can lead to serious problems, including water hammer, breakdowns and the inability to carry out full maintenance.

A process engineer who is faced with accidents, splashing of cleaning solution and conflicts in the cleaning schedule of different equipment will not appreciate the benefits of automation, as he will have to personally control the entire process.

If the washer is installed without taking into account the conditions of production, this can also cause problems for the quality specialist, who may face the presence of "dead zones" on the line and the inability to take samples. To avoid such problems, you need to contact a reliable engineering company that will help you select the equipment and ensure the correct installation.

The owner of the food production will be able to save more on minimizing risks than he pays for the services of such a company.
Approximate energy cost structure for the CIP process:
The first step in selecting technical solutions is to find energy leaks. For this purpose, remote monitoring systems consisting of detectors and software can be used. Sensors are installed on process equipment and process parameters are recorded over a period of time.

  • 85% - heating the cleaning solutions;
  • 8% is water use;
  • 6 % - operation of electric drives;
  • 1 % for compressed air.
As can be seen, heat losses are the main expense, so their analysis is primary for the development of energy saving measures.

Thermal losses from heating consist of losses from hot tank surfaces and piping, from heated liquids, from incorrectly chosen washing parameters - heating, time, water consumption. They are individual for every production, but there are basic energy saving measures which can be applied. It's just that the effect will be different in each case.

Insulating heated surfaces

Heat loss is directly proportional to the temperature difference between the heated media and the ambient air. The solution is to prevent heat exchange between the hot surfaces and the surroundings so that they do not cool down.

This is done by insulating equipment with a temperature above 45 °C:

  • tanks;
  • steam lines and fittings;
  • heat exchangers;
  • pipelines.

In our practice, insulating a 6m3 steam pipeline storage tank has brought about 14 euros in daily financial savings. For such a tank, 10 flushes per day at a temperature of 85 °C are required. The energy consumption is almost 510,000 kcal/day.

The insulation of the body, bottom and lid of the tank has reduced the heat consumption by up to 230,000 kcal/day. The cost of the more expensive insulated storage tank paid for itself within 1.6 years. And the CO2 emissions were reduced to 20 tonnes a year. With a 20 m3 tank, the environmental and economic effects will be even more noticeable.

Thermal insulation of steam distribution systems reduces energy consumption by 90%. And that is the amount of direct losses from hot pipes. According to our calculations, insulating hot water lines pays for itself within a year; condensate pipes within 2 years. Additionally, greenhouse gas emissions are reduced.

Thermal insulation projects for hot surfaces from 60 °C pay for themselves in less than two years.

Reduction of solution heating losses

Reduction of solution heating losses

Re-using the detergent and adjusting the station equipment is another effective energy-saving measure.
In many CIP washing processes it is permissible to reuse liquids, but not every station is equipped for this purpose. It may lack recovery tanks and return lines from washing facilities.

As a result, a new solution must be heated to 85°C for each cleaning. And the used liquid goes down the drain.

Another source of loss in the CIP is the incorrect setting of the flip-flop dead-end valves. The greatest washing effect is achieved when they are pulsed at the moment of opening-closing. And valves are left open for 5 seconds, which increases the consumption of heated solution.

Reducing heating time

The energy loss can be reduced by lowering the tank temperature during the preparation of the lye solution or pauses between wash cycles.
For example, by 10 °C. However, a precise calculation is required to compensate for temperature differences during the process.

The energy consumption for heating is reduced by approx. 1/60th with a reduction of 1 °C. This measure shows the effect of saving steam and resources in the long term.

Selecting the CIP-washing parameters

The principle "Analyse and optimise the wash parameters for the specific operating conditions" always works and leads to a reduction in costs.

The CIP process is directly dependent on three components:

  • mechanical - pressure and flow velocity;
  • cleaning time;
  • the temperatures of the medium.

A rational energy-saving approach involves increasing the mechanical component before washing time and heating. For example, CIP jet washing heads can be used instead of slotted heads for cleaning tanks and reservoirs. In pipelines, increase turbulence with a flow velocity of at least 1.8 m/s.

The choice of CIP washer parameters is always individual, as it depends on the type of contamination, the type of product, the design features of the equipment and the piping. Finding the best option for your production can be done after tests and laboratory flushes.

Example. In dairy processing plants, a good energy saving effect can be achieved by adjusting the cleaning temperature of the equipment.

Reuse of drinking water

It is a valuable resource because its production is also energy-intensive.
Drinking water can be saved by reusing it. For example, the liquid from the last rinse in the CIP wash is used for the first rinse in the next cycle.

In order to realise this, the existing plant needs to be upgraded with the installation of recovery equipment: tanks and pipework.

Reduction of losses from pumps

The most effective measure to reduce electrical losses is to install frequency converters with flow and pressure control.

These are devices that change the frequency of the mains AC current to the desired parameters, allowing the speed of the pump motor to be adjusted to the needs of the process.

The installation of a frequency converter is part of the modernisation of an electrical installation. It is better to have an engineering firm do the design and execution of this work in order to avoid receiving claims from the grid company and the energy regulator. The fact is that frequency converters can impair the quality of electricity in the mains.

Maintenance and upkeep of equipment

Equipment in poor condition costs more to the owner.

Leaky seals, clogged cleaning heads and worn pumps greatly increase the loss of steam, water and electricity. Leaks will nullify the effect of other energy saving measures.

Therefore, timely maintenance, repair and replacement of obsolete equipment is one of the prerequisites for rational heat consumption. Let's take condensate drains as an example.

If they have not been serviced for 3-5 years, about a third of such equipment is in a defective condition, allowing steam to seep into the drainage system. Such figures are confirmed by practice.

To reduce repair and replacement costs, food processing companies are adopting a remote monitoring system. This is a variation of the Industrial Internet of Things, or IIoT. Special sensors collect information about the operating parameters of various equipment and transmit it to the control system. Such monitoring helps to spend money on repairing and replacing equipment that is not working. In our experience, in food processing plants, no more than 5 % of steam traps are defective and steam losses are reduced by 10 %.

Modern models are more energy efficient than those produced decades ago. For example, thermostatic steam traps now have a number of advantages over older models:

they open when the temperature approaches the saturated steam level of plus or minus two degrees;

  • can be used as air vents;
  • emit non-condensable gases after each opening;
  • reduce heating time

The average payback period for replacing a steam trap is less than six months.

In lieu of a conclusion

The energy efficient food production equipment is affected:
  • the correct positioning of the steam temperature elements;
  • heat transfer coefficient;
  • material and type of heat exchanger;
  • the performance of the heat exchanger;
  • the presence of leaks.