Measuring H2S in CO2 Bottling Gas

OMA H₂S Analyzer 

Reprinted with permission from Applied Analytics

Prior to filling, beer bottles are purged with CO₂ to remove air and protect the taste against oxidation. In the fermentation process, yeast consumes sugar and expels a large amount of CO₂ which can be "reclaimed" and used for this bottle purging purpose. Unfortunately, fermentation often also produces toxic, odorous sulfides which can foam up into the piping and contaminate the reclaimed CO₂.

In order to continue using the great resource of CO₂ byproduct yet avoid contaminating the bottled beer with foul-smelling toxins, the reclaimed gas is run through sulfide removal skids. However, sulfide breakthrough can occur if the gas does not spend enough time in the scrubber. Employees are sometimes tasked with sniff-testing the reclaimed CO₂ , but this is an unhealthy practice and is too discrete to vigilantly prevent product contamination.

An automatic, continuous analysis solution is required in order to immediately divert contaminated CO₂ from use in bottling as well as provide feedback control for the sulfur removal processing time.

The OMA H₂S Analyzer is used to continuously measure concentrations of hydrogen sulfide (H₂S) and dimethyl sulfide (DMS) in the fermentation byproduct gas. This system uses a full-spectrum UV-Vis spectrophotometer to detect the absorbance of sulfides in the reclaimed CO₂ stream, an ideal method as CO₂ has zero absorbance in the UV spectrum. The OMA provides fast response alarms to high-concentration threshold which allows immediate diversion of contaminated CO₂.

For this application, the OMA is typically multiplexed to automatically cycle analysis between multiple sampling points. This maximizes system value by allowing one unit to monitor the raw fermentation gas entering the reclamation system, gas coming off the acid aldehyde scrubbers, and the bottling gas coming off of the sulfur removal beds -- all with sample stream switching at user-defined intervals.

Monitoring Interface Between Compounds in a Pipeline

Applied Analytics™ OMA

In some cases, a single pipeline is used to transport a diverse array of chemical products. When discrete chemicals are moved sequentially through the same pipeline, a mechanical separator known as a “sealing pig” or “batching pig” is inserted between the sequential products to prevent inter-contamination.

Since the pigs are never completely effective at blocking the interface, a significant volume does suffer intermixing and must be removed for reprocessing. The amount of material routed to reprocessing is usually just pre-programmed with a large margin of error on either end of the interface to ensure removal of intermixed products. This is a simplistic model that is unnecessarily wasteful of material and time. 

By using a device such as the Applied Analytics™ OMA industrial analyzer, the chemical concentrations, purity, and physical properties can be measured in a continuously drawn sample from the liquid stream. This allows for real-time analytics of the materials in the pipe, including chemical concentrations, purity, and color. 

The OMA system continuously monitors full-spectrum absorbance in the pipeline stream. A change in this spectrum indicates a change in the purity/composition of the material passing through the pipeline. Therefore, the OMA immediately detects the ‘interface’ point where the material has begun to intermix with the subsequent material in the pipeline. 

Monitoring the 1st derivative of a complete UV-Vis/SW-NIR absorbance spectrum allows the OMA to detect changes in composition with high sensitivity and fast response. The user can define the threshold contamination level which will signal for rerouting of the stream.

For more information, contact Ives Equipment at http://www.ivesequipment.com or call (877) 768-1600.

Monitoring Interface Between Compounds in a Pipeline from Ives Equipment