Abstract: Methods and systems are provided for controlling the addition of oxygen in fermentations to achieve a desired oxygen consumption and substrate yield in fermentation cell cultures. In one aspect, the invention provides a method for regulating the addition of oxygen (O2) to a fermentor during a fermentation process, comprising measuring real-time dissolved oxygen (DO) in a fermentation broth, measuring real-time O2 concentration in the fermentor exhaust, and providing the real-time DO measurement and real-time O2 measurement to an adaptive controller configured to regulate O2 flow into the fermentor responsive to the real-time DO measurement and real-time O2 measurement.

Abstract: Aerobic fermentation processes and systems establish, via sensing and regulating, a particular dissolved oxygen (DO) profile throughout fermentation to improve the fermentation processes. For some embodiments, the DO profile may follow one cycle of increasing and decreasing DO level in a fermentation media from lag to stationary phases of microorganisms during the fermentation process. As one example for controlling the DO level in the media, the DO level may increase during growth phase of the microorganisms to a set maximum controlled level and then at about when a maximum growth rate of the microorganisms occurs may decrease to reach a set minimum controlled level at about when growing stops.

Abstract: A method for indirect gas species monitoring based on measurements of selected gas species is disclosed. In situ absorption measurements of combustion species are used for process control and optimization. The gas species accessible by near or mid-IR techniques are limited to species that absorb in this spectral region. The absorption strength is selected to be strong enough for the required sensitivity and is selected to be isolated from neighboring absorption transitions. By coupling the gas measurement with a software sensor gas, species not accessible from the near or mid-IR absorption measurement can be predicted.

Abstract: A method for controlling the CO2 addition in a wet end process utilizing CO2 addition is disclosed. The method includes combining a papermaking composition and CO2 to create a CO2-enriched papermaking composition, measuring or estimating at least one electrical property of either the papermaking composition or of the CO2-enriched papermaking composition, and controlling the rate of addition of CO2 to maintain the at least one electrical property within a pre-selected range of values.

Abstract: A method for indirect gas species monitoring based on measurements of selected gas species is disclosed. In situ absorption measurements of combustion species are used for process control and optimization. The gas species accessible by near or mid-IR techniques are limited to species that absorb in this spectral region. The absorption strength is selected to be strong enough for the required sensitivity and is selected to be isolated from neighboring absorption transitions. By coupling the gas measurement with a software sensor gas, species not accessible from the near or mid-IR absorption measurement can be predicted.

Abstract: The present invention deals with the implementation of advanced controllers that are capable of achieving the desired controlling performance in a polysulfide reactor. These controllers are robust enough to counteract process disturbances as they learn continuously from the measurements of the inputs and outputs. The process comprises controlling the residence time, reaction temperature and oxygen partial pressure using an advanced controller, which adjusts the necessary parameters in order to counteract process disturbances.