The plant turning grain into ethanol

19th February 2018 11:39 AM
General Manager of Production at Dalby Bio-Refinery, Brett Kuskopf. General Manager of Production at Dalby Bio-Refinery, Brett Kuskopf. Cassandra Glover

This week Rural Weekly took a tour of Australia's first grain to ethanol bio-refinery located at Dalby on the Darling Downs.

The flammable nature of the facility meant the Rural Weekly journalist had to leave all technology at the door, relying on a special camera to take photos inside the factory.

THE Dalby bio-refinery uses 3000-3500 tonnes of grain sorghum a week to produce 1.4 million litres of fuel ethanol.

The refinery is the second largest ethanol distillery in Australia.

General manager of production Brett Kuskopf said it's predominantly growers from the Darling Downs region that supply grain to the factory.

"We utilise up to 190,000 tonne of sorghum a year, so we are a substantial purchaser of grain,” he said.

"Grain we purchase requires less transportation making it more convenient for all parties.

"There's a lot of positives.”

The factory opened in December 2008 and United Petroleum bought the business in October 2011.

The factory produces fuel ethanol as well as by-products including wet and dry-cake for stock feed.

"You build a distillery like this for two main reasons, access to ample grain feed stock, and to provide a customer base for your by-products, given there is a range of different animal feedlots within an economical radius of the factory,” Mr Kuskopf said.

"When I say products, in the case of a grain-based distillery, include a wet distillers grain and solubles or wet-cake, a dry distillers grain and solubles or dry-cake, and syrup.

"The nearby feedlots are our major customers and they are servicing a range of animals - predominantly pork, dairy, and beef cattle.

"When you're in a regional area your fuel ethanol is going to go to cities or port terminal areas where you have appropriate bulk storage facilities for the efficient distribution of fuel. We have approximately 25 ethanol tanker trucks transporting our fuel ethanol product to customers every week, many of them interstate.

"Sorghum is the main raw material input cost to the factory. The seasonal variations in grain pricing can have a big impact on the profitability of the Dalby bio-refinery from year to year.”

Mr Kuskopf said it was a sellers market at the moment due to high prices.

"The drought or the reduced rainfall distribution has affected the season's crop after a relatively poor season last year,” he said.

"There's not a carry over of stock into this season and therefore prices have remained high.”

John Crothers is a local farmer who produces sorghum for the bio-refinery in Dalby. In an average year he produces 7000-10,000 tonnes of sorghum, 100 per cent of which goes to the bio-refinery.

"It's been a great advantage having the ethanol plant to be built in our area,” he said. "We're a very productive sorghum growing area and for ethanol plant to be built here, they've comebecause we're here.

"There's a lot of sorghum growers here, and they've come to be closer to that, so it's a win-win situation.”

Mr Crothers grows sorghum in the Pirrinuan, Yaralla, and Jimbour districts.

"The refinery is situated very close to our farming operation, they offer a very similar price to another user whether that be a feedlot,” he said. "But if you've got someone really close to you, your transport costs are low. So the refinery being on my doorstep is my best option.

"Our closest farm is probably five kilometres away. Some of them range to 17 kilometres. On average it's 7-10 kilometres. It's a great opportunity for us.” Mr Crothers said it had been an up and down season.

"We had a later planting date because it was dry, and then everything wasn't going too bad until Christmas and New Year. December wasn't a bad month rain wise, we had 50mm in the Christmas-New Year period, then the tap pretty much turned off after that,” he said. "The season has gone from being above average to average, and right now, with the heat we're having this week, it's pulling the crops to well below average.

"The heat we're having this week, of 40 degrees, is eating away at the potential yield.”

Mr Crothers said they were in the process of harvesting.

"We've been harvesting on and off for the past two and a half weeks, when certain paddocks are ready we've been harvesting and having a break between paddocks.

"The next ones are not quite ready to go.

"Our earlier planted crop has been harvested and the next stage of our planting window is slowly coming in and as that happens we're harvesting.”


GENERAL manager for production Brett Kuskopf explains turning sorghum into ethanol:

"We take the grain and put it through a hammer mill, which pounds it into a fine powder or flour,” he said. "That flour starts in the liquification process.”

An alpha-amylase enzyme is then added, which breaks the starch down into complex sugars.

"Then the second stage those complex sugars are broken down again with another enzyme, glucose amylase, which breaks those complex sugars down into single sugar molecules or glucose,” he said.

"This is fed to our main fermentation stage along with yeast that has been separately propagated from a dry yeast product.

"The large batch fermenters are filled over an 18 hour period. During fermentation, the yeast is able to break down the glucose directly to ethanol.”

The total fermentation time is 38-42 hours.

"The ethanol concentration in the fermenter is around 11-12 per cent, and the fermented material is referred to as beer,” Mr Kuskopf said.

"The beer is then added continuously to a distillation process to extract the ethanol.

"The first column in the distillation process is (the beer column) where we extract around 50 per cent ethanol vapour through a steam heated process,” he said.

"That 50 per cent vapour goes through additional distillation columns and concentrated to 96 per cent and then finally fed to a molecular sieve dehydration process that produces a 99.6 per cent ethanol percent final product.

"That is then transferred into storage tanks and we add 1-1.5 per cent unleaded petrol to that as a denaturant and that goes out to customers directly.”

Any leftover products from the beer column (minus the ethanol) are turned into animal feed.

"In the beer column you split it into two products, the ethanol vapour and the bottom liquid which is what we call a whole stillage. It has everything left over from the fermentation and the grain,” he said.

"That whole stillage goes through one evaporation process, and that more concentrated whole stillage goes through a centrifuge, which is a high-speed machine that spins out the solids.

"Those solids that get spun out are stored as out wet-cake.

"The liquid that is extracted from the centrifuge process is what we call thin stillage,” Mr Kuskopf said.

"Some of the thin stillage is recycled back into fermentation as water, although it does contain some nutrients from the process, and the remainder goes through further evaporation to a concentration around 24-25 percent solids and we refer to that as syrup.”

Syrup is also added into the wet-cake and dry-cake.

Dry-cake is created when the wet-cake has the moisture reduced from 70 per cent down to 10 per cent.