Industrial kitchen cooking smell exhaust treatment -Ozone treatment 1

[MedicineEng]

Hi All:

We are now looking into some of our industrial kitchens in order to improve the cooking smell exhaust.
Originally we had an electrostatic filter and bag filters installed as cooking smell mitigation process but the performance was pretty poor, as the ESP got clogged with grease and became ineffective fairly fast. This demanded long washing times that are not practical in high volume/24 hours kitchens .
So we retrofitted the installation with a water scrubber which had a much better performance, but still with some cooking smell being exhausted to the exterior.
We are now going to try a hypochlorite dosing system to add to the wet scrubber to see if we can improve the performance.

We've been also looking into ozone generators as well and we've been considering to use it as a final kitchen exhaust treatment step before being discharged to the environment.

As with all technologies, there are plenty literature resources in the internet but most have a stake in one or other technology, which makes their analysis kind of biased.

So I would like to know if anybody here in the forum has experience with ozone as kitchen exhaust treatment, if it is effective, advantages and disadvantages of such system.

Thanks

 

[Gholam Baghery]

I am not sure my experience helps you too much but let me tell it. Water absorbers many particles including the odors' masses. If you spray water in a cage and pass the air through it - obviously using HEPA filter before entering the air in and add some vinegar and soda into the water it would be the best removing smell filter. the liquid will be circulated and you can change it every night. Also putting some blades in the cage to force the air to pass a long way up to outside will be optional.

 

[EnergyProfessional]

Whatever you do, make it cleanable and approved by JHA (grease fire!).

While spraying water in may solve the smell problem (not sure), what do you do with all the greasy water? Need to separate out the grease and dispose off.

 

[Gholam Baghery]

Obviously, you have to consider drainage, and since you have enough time - I assume you will drain it after one day - you can connect the output to a grease interceptor before connecting to the sewer line. Also, you can create a pipe in the body of the cage for washing inside of it.

 

[Gholam Baghery]

This schematic diagram may be helpful

 

[MedicineEng]

Hi all:

Thanks for your suggestions and ideas.

I'm not worried with the drain discharge as the previous ESP unit already had a Clean In Place so the drain is connected to a grease interceptor.

I was more interested in knowing if anybody had experience with ozone as a smell mitigation technology, if it really works and if there are any special care that I have to be aware of.

Given that this industrial kitchen basically works 24/7, any technology that demands a lot of maintenance/downtime to work properly is not an option.

Thanks.

 

[nuuvox000]

Seems like a lot of work. Can you shoot the air 100 ft in the air with a lab-type exhaust fan? Would the smell matter so much if you did this? Sorry, no experience with ozone.

 

[Compositepro]

You will probably need to go with activated charcoal filters.

 

[SAK9]

The purpose of Ozone injection into exhaust duct is to oxidize /break down the fat vapours into water and CO2.This prevents buildup of fat deposits on internal surfaces of ductwork and reduces fire risk.I am not aware of any odour control properties of Ozone.If Odour control is the intent you need a material that can adsorb the odour creating molecules.On one of the projects I worked on few years ago I had to design the kitchen exhaust directed to the street and I was required by law to treat the exhaust air quality to an acceptable level.I specified charcoal filters from this vendor and they worked well:

https://www.aosaus.com.au/products/activated-carbon-filtration-systems/

You would need to do some research on how long they last given the continuous operation of your kitchen.If kitchen exhaust is getting drawn back into air intake of air handlers I would suggest putting in these carbon filters in the fresh air intake duct of AHUs and they would last longer there than in a kitchen exhaust duct and will be more effective in odour control.

 

[MedicineEng]

According with what I know, ozone also is used as technology to break down VOCs and other pollutants and by default, will also reduce the smell perception, as much of it comes from VOCs, fats, greases, etc.

I was trying to go away from activated carbon as my past experience showed it to be a heavy maintenance activity due to the quick turnover and the amount of used filters to be disposed, but SAK9's suggestion of putting in it in the fresh air intake of the nearby AHUs might help extend the service life of the filters.

Thanks.

 

[SAK9]

A while ago I attended a presentation by Airpure and this paper I have linked below gives some good info on how to treat kitchen exhaust:

https://www.airepure.com.au/kitchen-exhaust-filtration-design/