초록 ▼

This invention comprises a method for increasing the accessibility of cellulose in lignocellulosic materials to chemical or biochemical reagents. The material is steam cooked for a predetermined time, then rapidly depressurized. A venting sequence is used to remove volatiles from the reactor. Optima

This invention comprises a method for increasing the accessibility of cellulose in lignocellulosic materials to chemical or biochemical reagents. The material is steam cooked for a predetermined time, then rapidly depressurized. A venting sequence is used to remove volatiles from the reactor. Optimal cooking times for normal and acid catalyzed cooking are disclosed, according to the discovery of a novel set of governing equations, wherein optimum cooking times can be determined as a time integration of reactor pressure.

대표청구항 ▼

An improved method for increasing the accessibility of cellulose in lignocellulosic materials, such as hardwoods, bagasse and the like, to rumen bacteria, enzymes, microorganisms and the like, characterized by an optimization of a range of cooking times (tc) which will respond to the actual pressure

An improved method for increasing the accessibility of cellulose in lignocellulosic materials, such as hardwoods, bagasse and the like, to rumen bacteria, enzymes, microorganisms and the like, characterized by an optimization of a range of cooking times (tc) which will respond to the actual pressure conditions in the reactor as they may change over time during a given cooking run and render the cellulose most open for attack by said microorganisms or enzymes, as measured by the rate or extent of their reaction, said method comprising the steps of: (a) feeding lignocellulosic material, in a divided form, into a pressure reactor vessel; and (b) introducing pressurized steam into the vessel during a pressurization time phase so as to reach reactor pressures of between 250 and 1000 psig wherein said reactor pressures does follow a given time profile; and (c) cooking by maintaining the lignocellulosic material at said time variable pressures between 250 and 1000 psig for a total period of time (tc) in seconds, which includes the pressurization phase, wherein t3≤tc≤t4 and the given reactor pressure time profile is used to determine t3 and t4 for that given cook run since t3 is defined implicitly by [Figure] and t4 and defined implicitly by [Figure] wherein Ts is the temperature (°C.) of saturated steam, at the indicated reactor pressures and corresponds to the saturated steam temperature values along the indicated reactor pressure time profile, thereby also making Ts a given function of time (t); and (d) decompressing the cooked lignocellulosic material down to substantially atmospheric pressure at the end of said cooking time, tc.