Creating the Bombaderry plant in partnership with Manildra represented more than just a shift in plant location for Supagas, it was a way it could gather sustainable CO2. Food & Beverage Industry News explains.
The ability to source reliable, clean carbon dioxide (CO2) was becoming an urgent issue for Australian gas supplier Supagas. Burning natural gas, up until that point, was the main method Supagas has been utilising to make it.
“We previously had three CO2 manufacturing plants around the country that burned all this natural gas for us to produce the CO2,” said Anthony Gstalter, supply chain manager of Supagas. “When we burned the natural gas, we created CO2 and moisture which we then captured, purified and converted to food grade CO2, however there were some issues with this.”
With the price of natural gas, continuing to increase, as well as concerns for greenhouse emissions on the rise, Supagas knew there must be a better way to source the product.
“We realised we’d been burning natural gas for the product, when there was so much potential from larger, sustainable sources,” said Gstalter. “We also wanted to be able to meet consumer demand for CO2 due to growth in the market, and burning natural gases was no longer feasible. We needed to find a larger, sustainable source.”
A big requirement for them, however, was the need for reliability.
“We wanted to choose a site that had a good up time, so we weren’t letting our customers down,” said Gstalter.
One issue that is found with CO2 production from plants is the downtime required for maintenance by feed suppliers during which CO2 isn’t being produced and companies can’t meet their customer’s needs.
“A lot of sources that produce CO2 have the issue where they don’t have a great up time. You’re getting about a month where you don’t have any CO2 because the plants undertaking maintenance or are experiencing unplanned shutdowns,” said Gstalter.
Manildra makes a move
Manildra came in at the right place and the right time. As an Australian producer of food and industrial products such as wheat, proteins, fats and syrups, they also produce one key product that was the jackpot for Supagas – ethanol.
“What happens is Manildra either grows or ships in grain, which they use to create ethanol by fermenting the wheat,” said Gstalter. “And one of the by-products of that is high-quality CO2; at that stage it is already around 90 per cent pure CO2.”
Supagas then captures the by-product CO2 through a cold-water scrubber and blower that dehumidifies the CO2 and removes any remaining alcohol. The blower then pushes the CO2 gas through an underground pipeline that funnels it to another processing plant. Any residual alcohol captured by the cold scrubber is refunneled back to the ethanol processing plant.
The CO2 then goes through a range of processes including a compressor, which raises the gas pressure to 18 bar, as well as a NOx and Sulphur removal beds.
“We also run the CO2 through a Catox which burns at about 330°C and removes any impurities such as hydrocarbons,” said Gstalter. “It’s basically a CO2 refining plant.”
From there the CO2 is further dried, liquified then turned into food-grade CO2 that is used in Supagas’s products. One of the key applications of CO2 is to produce Dry Ice. This dry ice is used for a range of purposes across the cold chain including freezing foods, transportation of cold goods and increasing shelf life. The CO2 is also used in MAP gases for food packaging, in gases for the carbonation of beer and soft drinks, as well as delivered in bulk to many customers who use it internally for their manufacturing processes.
An estimation done by Supagas before the plant was completed found that the Bombaderry Plant would reduce, on average, about 18,000 tonnes per annum of CO2 emissions during its initial stages, ramping up overtime to double the quantity. Without the Supagas plant the CO2 wouldn’t have an alternative use and would be a direct emission to the atmosphere.
The plant was built at Manildra’s Shoalhaven Starches integrated manufacturing facility in Bombaderry, NSW. The construction took approximately eight months with a majority of the building occurring offsite then being brought on and assembled on site.
“The biggest obstacle was the need to work with the ground structure,” said John Palmer, operational manager of the Bombaderry Plant. “There is a significant amount of underpinning supporting the plant and the transport of the 200 tonne storage vessel to site from Port Kembla was a challenge.”
But the result was worth it – a closed-loop production facility.
A circular system
Beside the ethanol to CO2 production abilities, the Bombaderry plant also operates in other environmentally friendly ways.
Every material processed at the plant has multiple uses, such as the starch being sold to produce food and paper, or further used in syrup production. Leftover materials from the processes, like the gluten and syrup, does not become waste either, instead, it is all put towards the ethanol production that creates the valued CO2.
The CO2, which is left over from Supagas’s processes also get a second life.
The leftover water from these processes is also reused either in the plants, starch processes or in local farmland irrigations to create fodder crops, pastures and cattle grazing.
Wastewater created by the processes are also treated and recirculated at the Manildra’s Wastewater Treatment Plant located on site. During this process 97 per cent of waste in the water is removed, with the water then being reused either for processes at the plant or for crop irrigation.
“What we realised was that we could operate in an environmentally sustainable way,” said Gstalter. “We could reach the same high-quality end product while operating in a way in which we were removing excess CO2 rather than producing it. It really is almost a complete loop.”
With two out of three of the plants shut, Supagas has also experienced the added benefits of decreased utilities usage.
“We are no longer having to invest more power, water and gas to produce the CO2 that we need, it’s coming to us as a by-product,” said Gstalter. “So now what we have here is a reliable, clean source of CO2 with a really great up time that can supply our current market demand and allow growth within the CO2 space.”
Supagas is moving onto greener pastures, or wheat fields, said Gstalter.
“We are working with other sources to expand our markets,” he said. “And using sustainable, reprocessed CO2 is high on our agenda.”