SUSTAINABILITY in paper plants with spray nozzles is a crucial aspect of the industry’s efforts to minimise environmental impact and promote responsible resource management. By implementing sustainable practices and utilising efficient spray nozzle systems, paper plants can achieve significant improvements in their sustainability performance.
Grant Orsmond, managing director at Spraying Systems Co South Africa says: “One key area of focus is water conservation. Paper production requires a substantial amount of water, and spray nozzles play a vital role in controlling the water usage during various stages of the process.”
“The biggest issue on paper plants regarding water consumption is nozzle wear. It’s not possible to notice with the naked eye when spray nozzles are worn by 10%. But these worn nozzles deliver significantly more water, or chemical than required,” he says.
Benefits of right-sizing spray nozzles
Making sure nozzles are correctly sized for the operation sounds simple. However, many processes tend to use higher capacity nozzles than required. Right-sizing nozzles is a simple intervention that does not disrupt operations and can deliver significant dividends.
Step 1: Establish the flow
Consider the volume of water which flows through spray nozzles every day. Calculating the flow rate of a full cone spray nozzle (based on a 3/8” full jet) at 10.6 litres per minute at 1.5 bar = 5,087 litres per day (based on an eight hour day) = 25,438 litres per week (based on five days per week) which ends up at 1,271,898 litres per year, based on 50 weeks per year.
Most paper plants use hundreds of nozzles in various operations including cleaning, coating, lubricating, moisturising, cooling and more.
In this example, assume 150 nozzles are in use for a cleaning operation. If 1,271,898 litres are used per year x 150 nozzles, a grand total of 190,784,754 litres will be used per year.
Step 2: Reduce the flow
Orsmond proposes that nozzles with a lower flow rate be used in the same cleaning operation without compromising cleaning efficacy. Calculations show that 47,696,188 litres will be saved per year simply by using slightly smaller capacity nozzles — in this case, a 7.9 lpm full cone nozzle spraying at 1.5 bar. If an even smaller nozzle is used (a 4.9 lpm @ 1.5 bar) 88,578,636 litres can be saved per year.
Step 3: Sustainable savings
Orsmond says: “Sustainability assessment programs will help operations become more efficient, productive, sustainable and safe, and it happens on-site with no disruptions to production.”
“Proper maintenance and regular inspection of spray nozzle systems are essential for sustainability in paper plants. Regular cleaning and replacement of nozzles ensure their optimal performance, preventing issues such as clogging or uneven spray distribution. This not only improves the quality of the final product but also reduces the need for rework or additional resources,” says Orsmond.
