‘Continuous Reactor Separator’ (CRS) bio-reactor systems enable the simultaneous production and separation of fermentation products (ethanol, acetone, butanol, etc.) from biomass sugars for increased fermentation efficiencies / conversion rates and higher product concentrations. US Dept. of Energy estimate that commercial CRS bio-reactor systems have reduced energy consumption by more than 100 billion Btu’s per yearand reduce CO2 emmissions by more than 3 million pounds per year (CRS pdf #1 / CRS pdf #2).
Background: In standard fermentation systems there is a trade-off between the final product concentration and fermentation efficiency and conversion rate. Higher product concentrations decrease fermentation efficiencies / conversion and lower product concentrations necessitate greater energy usage in product separation, recovery, and water processing.
Technology Description: CRS bio-reactor is a multi-staged fermentation system that utilizes counter current gas stripping to remove ethanol from each of the stages to produce a solvent rich gas stream. The solvent/gas streams is processed in a low energy absorption / extractive distillation system to recover a higher solvent concentration (6 – 11%) solution in addition to the recovery and reuse of the gas stream.
Applications: The CRS bio-reactor system was developed for increasing the efficiency and profitability of ethanol production from low sugar feedstocks such as lignocellulosic biomass and whey lactose but also has application in corn, wheat, sugar, and waste water fermentation processes. The CRS has value and application in the production of all fermentation solvents (acetone, butanol, ethanol, methanol, etc.), low product concentrations, and high product inhibition effects.
Advantages of the CRS Bio-Reactor Systems:
- Increased Fermentation Rates & Efficiency (2-6x),
- Increased Final Solvent Product Concentrations,
- Increased Process Water Set-Back Levels,
- Increased Rates of Enzyme / Chemical Recycle,
- Decreased Energy / Water / Enzyme Usage Rates,
- Decreased Infections & Cleaning Requirements,
- Allows for multiple / staged fermentation & SSF,
Development History: Over the last 25 years BPI has been developing and improving CRS bio-reactor systems for a range of applications and feedstocks. A multitude of CRS bio-reactor systems have been developed and tested on the lab scale, demonstrated & improved on the pilot scale, and implemented in commercial production systems. The CRS system involves both proprietary and patented owned entirely by Bio-Process.
Technology Maturity: Commercial, CRS bio-reactor systems have been used in the pilot and commercial production of industrial solvents, ethanol / acetone / butanol (ABE), from corn, whey, MSW fiber and lignocellulosic biomass feedstocks.