Abstract
Measuring the performance of propagation tanks is essential to maximize yeast health for transfer to fermentation, and to optimize the levels of Nitrogen and the use of glucoamylase (GA). Achieving the optimal balance of Mash, Nitrogen, GA and thus sugars is key to maximizing overall plant performance. In separate installations, the IRmadillo has proved capable of quantifying the key chemistries, in real time, with great reliability.
Introduction
Yeast is a biological substance and its healthy growth is dependent on managing it’s environment closely. Sugar levels need to be maintained at around 2% to optimize aerobic respiration, minimize ethanol production and sustain the conditions optimal for the multiplication of the yeast. Monitoring the process in real time enables the operator to send the prop to fermentation in a shorter time but at higher quality, thus optimizing fermentation performance. GA is an expensive component in the ethanol process and optimizing it’s use (or minimizing over-use) has significant cost and performance benefits. Urea, or sometimes Ammonia, is used to introduce Nitrogen to the process to encourage metabolism and increase yeast counts.
Spectrometers allow continuous and detailed measurement of chemical concentrations in real time. The majority of process spectrometers are based on near infrared light, which is fundamentally less informative than mid infrared light. Conventional mid infrared spectrometers (which often use a Fourier transform and so are referred to as "FTIR spectrometers") have sensitive moving parts and fragile fiber probes – making them wholly unsuitable for production environments such as ethanol refineries. The IRmadillo is a process analyzer built using FTIR spectroscopy, but with static optics, removing the need for moving mirrors or fiber probes, and dramatically improving stability, reliability, and ruggedness.
Example Use Case
This application note presents data from a European ethanol plant, measuring 10 different chemical species, enabling the precise monitoring of the activity of the GA in breaking down the mash, the production of ethanol and the presence of lactic and acetic acids: indicators of yeast ill-health during propagation. Chemical species, measurement range and accuracy are shown below
