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A Case Study - Achieving Efficiencies Through Flash Steam Recovery

13/07/2021

For food and beverage manufacturers who use steam in their production processes, it’s possible to make significant energy and water savings through the recovery of flash steam.

Achieving efficiencies through flash steam recovery – a case study

This case study can be heard in full by listening to Episode 5 of the Talking Steam: Focus on Food podcast. It features Ricardo Murakami, a Technical Manager responsible for Spirax Sarco’s service and engineering teams in Chile and Peru.

The customer is a drinks manufacturer whose plant relies on steam-using processes for the production of beer, water and soft drinks. With an aim to reduce production costs, the manufacturer asked Spirax Sarco to assess opportunities for making energy savings. Although there being no indication of steam losses inside the plant, plumes were highly visible from the outside.

The first step for the team was to carry out an audit to identify and separate the controllable and the unavoidable losses in the customer’s steam plumes. This essential step in helping customers maximise the efficiency of their systems should be carried out by steam experts. Controllable losses are often caused by faulty steam traps and can be eliminated through regular maintenance – you can read more about managing a steam trap population here. Once controllable losses were identified, the team sought to understand the customer’s processes to assess the size of the uncontrollable losses and their potential for incurring savings. 

Known as flash steam, these uncontrollable steam losses occur due to the pressure change of condensate, moving from an area of high pressure to low pressure. As an unavoidable part of many processes, flash steam can be captured and recycled into production. By defining the two types of losses, the team were able to address each issue appropriately, with the ultimate goal of delivering cost savings.

 

 

In terms of energy value, flash steam is equal to live steam at the same pressure, but when it can be recycled and used in the place of steam generated from fossil fuels, it comes without the associated CO2 emissions and cost.

Flash steam is generated by all steam using processes, however, the audit identified two major processes that were generating significant levels of flash steam. These provided further opportunities for making efficiency gains. In terms of energy value, flash steam is equal to live steam at the same pressure, but when it can be recycled and used in the place of steam generated from fossil fuels, it comes without the associated CO2 emissions and cost. The team calculated the kilowatts of heat energy being lost and translated this into potential CO2 savings as well as cost savings for the customer.

In order for the beverage manufacturer to enjoy the maximum benefit of this recovered energy, the team needed to locate the most appropriate heat sink for the flash steam. To get the best return on investment, a heat sink should be located as close to the site of the flash steam plume discharge as possible. An in-depth understanding of the manufacturer’s processes was vital at this stage: with beverage production relying on precise temperatures, the team could not risk the recovery of flash steam generating back pressure on the system as this would affect the rate at which steam delivers heat to the process and increasing production times. An exhaust vapour condenser was selected for its cost-effective ability to recover the energy and water from the flash steam while causing zero back pressure. The recovered flash steam was then used to preheat water used as hot liquor in the front end of the beverage production process.

As an experienced team, the Spirax Sarco engineers were well placed to identify and eliminate controllable steam losses; they could also assess and measure the potential for the unavoidable losses to contribute to better cost-efficiency. One of the biggest challenges for the team was the fact that the beverage plant operated 24 hours a day, seven days a week. This meant the window to install and commission the necessary steam system equipment was tight. Despite this, the team was able to successfully implement flash steam recovery thanks to the simple solution only requiring a short installation time during the next scheduled maintenance window.

The project resulted in overall energy savings of 2-3% for the entire production site – a significant figure for any beverage manufacturer operating at a medium-to-large scale. The expertise of the team and ability to get to grips with the manufacturer’s processes contributed to the energy efficiencies achieved. Furthermore, with steam plumes often posing a reputational risk for manufacturers, the project achieved a reduction in visible plumes at the plant.

Interested in hearing more about this case study? Listen to Episode 5 of the Talking Steam: Focus on Food podcast

How can you optimise heat recovery?

Find out more from our Talking Steam podcast.

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