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Hi,
I'm Scott, the senior laboratory analyst at the City of Modesto in Modesto CA. We run our boiler using the gas produced by our anerobic digester. We just had our boiler fail due to excessive solid material in the burner. I've been asked if we can help determine what the material is. It looks like dirt, crumbles like dirt, has no significant odor so it does not smell like dirt, but the smell of dirt is due to bacteria which would not be present in a burner. It has a flakey-ness that suggest a depositing over time. I am planning to have this material analyzed for metals since I would not expect organic material to accumulate in a burner.
Does anyone have any experience with something like this or have any suggestions as to analysis that may be helpful in determining the composition of the solid material?
Any insight would be much appreciated.
Thank you,
Scott Jacobs
Dear Scott,
Thank you for reaching out to us regarding the issue with your reactor. We appreciate the details you’ve provided, and I’d like to offer some initial recommendations to help identify and address the problem.
Recommendations:
- Feedstock Analysis:
Could you please confirm the type of feedstock you are using in the digester? Certain feedstocks can contain high levels of nutrients, which may potentially lead to ash-like deposits. - Odor Source Investigation:
The smell you’re experiencing might be due to:- Hydrogen sulfide (H₂S)
- Volatile organic compounds (e.g., terpenes or other hydrocarbons)
- Siloxanes or other impurities in the biogas
Hydrogen sulfide and siloxanes are particularly concerning as they are corrosive and can cause significant damage to metallic equipment over time. The deposits may be primarily due to corrosion caused by hydrogen sulfide. Additionally, the odor may be exclusively attributed to hydrogen sulfide.
Suggested Analysis:
To better understand the issue, we recommend conducting the following analyses:
- Ash-like deposits (if present): Perform an XRF analysis to identify metal oxide
- Gas composition: Analyze the biogas for its composition, including siloxane levels
We hope that these initial guidance will help you.
Best Regards,
Aliki
