Review of Dissolved CO and H2 Measurement Methods for Syngas Fermentation

Abstract

Syngas fermentation is a promising technique to produce biofuels using syngas obtained through gasified biomass and other carbonaceous materials or collected from industrial CO-rich off-gases. The primary components of syngas, carbon monoxide (CO) and hydrogen (H2), are converted to alcohols and other chemicals through an anaerobic fermentation process by acetogenic bacteria. Dissolved CO and H2 concentrations in fermentation media are among the most important parameters for successful and stable operation. However, the difficulties in timely and precise dissolved CO and H2 measurements hinder the industrial-scale commercialization of this technique. The purpose of this article is to provide a comprehensive review of available dissolved CO and H2 measurement methods, focusing on their detection mechanisms, CO and H2 cross interference and operations in syngas fermentation process. This paper further discusses potential novel methods by providing a critical review of gas phase CO and H2 detection methods with regard to their capability to be modified for measuring dissolved CO and H2 in syngas fermentation conditions.

Downscaling Industrial-Scale Syngas Fermentation to Simulate Frequent and Irregular Dissolved Gas Concentration Shocks

“…The repeated variations in stirrer speed at high frequencies should be controlled, along with possible ramp phases when increasing or decreasing the stirring speed. Ideally, rapid-sampling and/or online measurement for CO and H 2 [61,62] should be applied to make sure that peaks and valleys are obtained in the intended manner. As the peaks and valleys are applied in the secondtimescale, probe lag should be taken into account when analyzing the experimental data.…”

Carbon Monoxide Fate in the Environment as an Inspiration For Biorefinery Industry: A Review

“…This is based on the inhibitory effect of this gas on the activity of the key enzyme, hydrogenase, and hence the H 2 utilization rate (Devarapalli and Atiyeh, 2015). Therefore, in industrial applications, it would be necessary to use fastresponse sensors, which by measuring CO and H 2 concentrations, would be able to accurately determine them online, enabling high yields of ethanol and stability of the process (Dang et al, 2021). However, currently, dedicated sensors are not available on the market; solutions such as membrane-coated electrochemical sensors in the power industry are not suitable for the CO and H 2 concentration measurements required in the process due to the slow reaction time and labor-intensive operation (Dang et al, 2021).…”

“…Therefore, in industrial applications, it would be necessary to use fastresponse sensors, which by measuring CO and H 2 concentrations, would be able to accurately determine them online, enabling high yields of ethanol and stability of the process (Dang et al, 2021). However, currently, dedicated sensors are not available on the market; solutions such as membrane-coated electrochemical sensors in the power industry are not suitable for the CO and H 2 concentration measurements required in the process due to the slow reaction time and labor-intensive operation (Dang et al, 2021). Additionally, the challenge for this type of device is the ability to measure both compounds simultaneously; the cross selectivity of CO and H 2 is currently not developed, which does not allow for the precise differentiation of these gases by one sensor.…”

Syngas Fermentation to Acetate and Ethanol with Adaptative Electroactive Carboxydotrophs in Single Chambered Microbial Electrochemical System

“…Varies conventional strategies such as capture and storage are employed to mitigate the greenhouse gas (GHG) emissions [ 3 , 8 , 9 , 10 ]. Microbial mediated process of carbon sequestration, which is considered a potential strategy, can also play a crucial role in this regard [ 11 , 12 ]. Syngas fermentation through the Wood–Ljungdahl pathway (WLP) owned microbes contributes to the synthesis of short-chain carboxylic acids [ 9 , 13 ] and can sustain the toxic effects of CO [ 14 ].…”