System and methods for continuous biomass processing

Abstract

This invention is directed to biomass processing. In one embodiment, the biomass is processed by contacting the biomass with a swelling agent as the biomass and swelling agent are transported through a reactor system. In another embodiment, the processed biomass is fermented. Steam is also applied in the biomass processing. The steam can be applied before, during or after the biomass is first contacted with the swelling agent.

Description

RELATED APPLICATIONS[0001]This application claims the benefit of U.S. Provisional Application Ser. No. 60 / 895,673, filed Mar. 19, 2007, which is fully incorporated herein by reference.FIELD OF INVENTION[0002]This invention relates to biomass processing. In particular, this invention is to a process for treating or swelling cellulosic biomass using a swelling agent to swell at least a portion of the biomass.BACKGROUND OF THE INVENTION[0003]It is desirable to develop fuels that are cheap, clean, non-petroleum-based, and renewable. It follows that fuels derived from plant materials are becoming more popular. Plant-derived lignocellulosic biomass materials (cellulose) are known in the art to be useful for fermentation processes to produce, for example, ethanol. Brazil has demonstrated the feasibility of producing ethanol and the use of ethanol as a primary automotive fuel for more than 20 years. Similarly, the United States produces a significant amount of fuel ethanol each year. See, g...

AI Technical Summary

Benefits of technology

[0012]An advantage of the present invention is the ability to continuously provide required residence time and expansion. In one embodiment, residence time is provided by continuous flow of the ammonia / moistened biomass. In a particular embodiment, the process incorporates a retention coil or auger and ammonia expansion occurs across a pressure reduction device (valve, orifice, or other mechanical devices).

[0013]According to one aspect of the invention, there is provided a process for swelling biomass. The process includes contacting the biomass with a swelling agent as the biomass and swelling agent are transported through a reactor system. In one embodiment, the reactor system is at a pressure sufficient to maintain the swelling agent predominantly in the liquid phase, and the contact is for a time sufficient to allow the swelling agent to swell at least a portion of the biomass.

[0014]According to another aspect of the invention, there is provided a fermentation process. The fermentation process includes a pretreatment system in which biomass is contacted with a swelling agent as the biomass and swelling agent are transported through a reactor system. In one embodiment, the reactor system is at a pressure sufficient to maintain the swelling agent predominantly in the liquid phase, and the contact is for a time sufficient to allow the swelling agent to swell at least a portion of the biomass. At least a portion of the biomass that has been contacted with the swelling agent is then fermented.

[0015]In one embodiment of the invention, steam is applied to the biomass to achieve a total moisture content of from 20 wt % to 90 wt % as the steam mixes with the biomass. In another embodiment, steam is applied to the biomass to achieve a temperature of from 60° C. to 200° C. as the swelling agent mixes with the biomass.

[0016]In another embodiment, the steam is applied to the biomass prior to contacting with the swelling agent. In yet another, the steam is applied to the biomass after contacting with the swelling agent. In still another, the steam is applied to the biomass during contacting with the swelling agent, which means that at or near concurrent application of steam and swelling agent with biomass can also be utilized.

[0017]In a preferred embodiment, the biomass is contacted with the swelling agent at a ratio of swelling agent to biomass of from 0.1:1 to 2.5:1 dry weight basis (dwb). The steam can be applied by way of a mixing device to mix the steam with the biomass or by way of a transport device to transport the biomass. Preferably, the steam is applied by way of a mixing and transport device to mix and transport the biomass.

Problems solved by technology

The crystalline structure of cellulose and the physical protection provided by hemicellulose and lignin prevent efficient hydrolysis of these materials.

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