Heat from steam captured to warm up greenhouse
Discharge from grain driers in Chatham being used to lower grower’s energy costs
CHATHAM The waste heat that will be captured from Greenfield Global’s production facility will not only save money for Truly Green Farms, it will create less odour and steam coming from the stack at the Chatham ethanol plant.
Greenfield has invested $ 10 million in a heat and carbon dioxide (CO2) recovery system at its Bloomfield Road plant so it can be piped across the road to Truly Green Farms’ 18-hectare greenhouse, which will cut its energy costs in half.
Truly Green has been receiving excess CO2 from Greenfield since 2013, which has helped boost tomato yields by five per cent. Greenfield is in the final stages to start selling its waste heat for use in the greenhouse.
“It’s been going fine, now we can supply them with some heat,” said Veselin Nikolov, manager of Greenfield’s Chatham plant.
He said the commissioning of the waste heat transfer system began on Monday to complete the preliminary health and safety review.
“Everything went well and we are ready to start collecting the steam coming out of the stack,” he said.
Nikolov said the condenser that will capture the heat from the stack is “proprietary technology” developed by Greenfield’s engineering and technology team.
“It’s a very, very interesting piece of equipment,” he said. “We actually combined different pieces of equipment from different manufacturers, but the process flow, the engineering, is our design.”
He described the condenser as a giant kettle that captures the steam.
The visible white plume coming from the plant’s stack is excess heat in the form of approximately 2,270 litres of steam per minute that comes from the driers used to dry the distiller’s grains, a byproduct of making alcohol and biofuel from corn. Drying the distiller’s grains is also the source of the odour.
As the process of transferring waste heat from Greenfield’s plant to the greenhouse is gradually ramped up over the next few weeks, the condensed steam plume will slowly reduce in size and the corn odour is expected to decrease as well.
The design has passed rigorous internal technical reviews as well as third-party emission modelling submitted to the Ontario Ministry of the Environment and Climate Change.
Nikolov said Greenfield’s heat transfer system needs to be ready by the first week of December when Truly Green plans to commission the new Dutch technology it has purchased to utilize the waste heat.
Q AND A ABOUT PROJECT
Q: Will the big stack be taken down?
A: No, the big stack will remain to exhaust the left over hot gases that come from the gas-fired driers.
Q: Will there be a visible plume from the stack?
A: Yes, but it will be significantly smaller.
Q: What is the variability of the plume?
A: The plume will be more visible in the cold winter months and less visible in the hot summer months.
Q: Will the odour really go away?
A: Yes, to a great extent. Individual sensory responses vary from person to person. The true test will come after a few months of operation.
Q: If there is residual odour, what will the company do?
A: After the new system steadies out, we are required by MOE regulations to carry out a new set of emission tests. These results will be evaluated for possible future resolution.
Q: Will we see the larger plume ever again?
A: Yes. The larger plume will be visible when we have an outage of the new hot water delivery system to the greenhouse.
Q: How often will we see the larger plume? A: We expect we could have 15 to 20 days per year of down time, resulting in a more visible plume, the same as it is today.
Q: What happens to the water that is condensed from the plume?
A: The water that is condensed has some fine grain that will be removed and treated at our anaerobic digestion plant. The residual waste water is then sent to the Chatham-Kent water treatment plant.
We actually combined different pieces of equipment from different manufacturers, but the process flow, the engineering, is our design.