Description:
To
achieve high yields of glucose and other products for use in biofuels and
bio-based chemicals, lignocellulose must first be pretreated. The goal of
pretreatment is to decrease the crystallinity of cellulose, increase the biomass
surface area, remove hemicellulose, and break the lignin seal. Current
pretreatments use liquid ammonia, dilute acid, organosolvents, and steam, among
others. Each of these methods has drawbacks in its ability to effectively and
efficiently pretreat and process lignocellulosic biomass.
Michigan
State University’s invention, Gaseous Ammonia Pretreatment (GAP), uses hot
ammonia gas rather than liquid ammonia to pretreat biomass in a reactor. The hot
ammonia gas condenses on the biomass and reacts with the water that is used to
wet the biomass prior to adding the ammonia gas. During the GAP process, the raw
biomass is more uniformly treated by ammonia and requires much shorter
pretreatment time. Therefore, this method has the potential to be a less
expensive and more effective raw biomass pretreatment process. At present,
pretreatment cost is considered one of the primary bottlenecks for the
development of biorefinery technology.
Benefits
* Faster pretreatment
time: Using the GAP process, it is possible to rapidly reach the
desired pretreatment temperature of 100-150 degrees Celsius instantly, thereby
reducing the biomass residence time to 5-15 minutes in total. Ammonia in the
delivery vessel is preheated and ensures condensation of hot ammonia gas on the
raw biomass, causing an instantan rise in temperature.
* Limited or no ammonia
recovery: Use of hot gaseous ammonia along with hot steam and inert
gas/air limits the need to recover ammonia as is required in other pretreatment
processes. In competing processes, the ammonia recovery step is expensive in
terms of time and energy costs.
* Less temperature degradation of raw
biomass: Current biomass pretreatments, such as dilute acid
pretreatments, tend to “over degrade” the raw biomass due to higher
temperatures.
* Pretreatment residence time
reduction: Competing processes can require long biomass residence
time (hours to weeks), which are expensive and inconvenient to scale
up.
* No impact on downstream
processing: GAP does not inhibit downstream processing of the raw
biomass hence there is no need to wash the biomass to remove
inhibitors.
* Flexibility of GAP
process: Potential exists for coupling the GAP process with other
processes, such as the steam toasting process used in the edible oilseed and
oilcake industry.
Applications
GAP can
impact a number of applications, including:
* Animal
feed production, particularly dairy feed
* Raw
biomass pretreatment for the biofuels industry
*
Building materials industry
*
Bio-based chemicals industry
IP Protection Status
Patent
pending
