New Zealand Sugar company reduces carbon emissions with new evaporation system

Founded in 1884, New Zealand Sugar is one of the country’s top 100 companies. Its products are derived from sugar cane and the refinery still operates from its original site on the seafront at Birkenhead, a suburb of Auckland. 

Proud to operate its facilities in compliance with environmental legislation and regulations, the company has integrated sustainability into its strategy strategies, business plans and operations, and is committed to improving its operational processes to reduce both energy and water use and restrict the generation of solid, liquid, and gaseous waste. 

So, when a decision was made to upgrade the evaporation system at the Birkenhead plant, increasing energy efficiency and cutting carbon emissions were high on the agenda, and the strong focus on sustainability and decarbonization led to the project receiving financial support from its parent company, Wilmar Group, and subsidies from the New Zealand government.  

 Reducing carbon emissions to near zero 

 The existing evaporation system at the plant utilized Thermal Vapour Recompression (TVR) technology, which was installed by Alfa Laval 20 years ago. This system employs a series of boiler-steam-fed TVR units to upgrade the pressure and temperature of vapours coming off the first effect. The resulting mix of boiler steam and vapours are then used to provide heat to the first effect, as well as to several other parts of the process. 

A desire to upgrade this system in 2019 preceded lengthy discussions to scope an optimal solution and the customer’s positive experience of Alfa Laval’s products and technical expertise proved key in their decision to opt for a more energy-efficient AlfaEvap system with Mechanical Vapour Recompression (MVR). 

Mechanical Vapour Recompression (MVR) utilizes a high-speed fan or compressor to re-compress evaporated water vapour – increasing the pressure (i.e., saturation temperature) of the vapour, which can then be reused as heating steam. 

“It is the ability of New Zealand Sugar to evolve and adapt to the change of time, which has enabled us to withstand the test of time over the past 125 years of existence. Today, our biggest challenge is that we must constantly develop to operate an increasingly sustainably business, and the environmental impact of our sugar production obviously plays a big part in this,” says xxx from New Zealand Sugar. “Our relationship with Alfa Laval goes back many years, and it is the strength of our interaction and the mutual confidence in competences, which has now enabled New Zealand Sugar to take this new step in the journey to make the business even more sustainable.” 

Alfa Laval’s MVR technology will enable the New Zealand Sugar to turn to wind-, solar or another renewable power source and thereby cut carbon emissions to near zero and lower natural gas costs at the sugar refinery by drastically reducing the input steam demand of the evaporator and cutting energy consumption by 80%. In concentrating the sugar from 65% to 78% dry solids, the energy consumption of the MVRs is 36 Wh/kg whereas in the existing TVR system, the energy consumption is around 190 Wh/kg. 

The MVR system also ensures efficient evaporator operation over the full range of expected operating conditions, with a smooth and quick start-up and shutdown, and fully automated CIP, culminating with a high sugar product quality with minimal colour formation. Technical, commercial and health & safety risk is minimized, and a cost-effective future upgrade of the equipment is also possible if required. 

Other advantages of the MVR system are a strong financial return on investment, efficient operation, improved control accuracy and operating consistency, and minimized maintenance requirements; all of which underpin a strong alignment with Alfa Laval’s sustainability commitment to the planet and people.