Acid pre-hydrolysis reactor system

A single stage method of acid pre-hydrolysis of biomass, effecting hydrolysis of hemicellulose to five carbon sugars, comprising the steps of automatically, continuously and sequentially:

• (a) mixing biomass containing hemicellulose with a mineral acid solution of about 0.5-3.0% to form a slurry having a consistency of about 8-12%;
• (b) dewatering the slurry to a consistency of about 35-50;
• (c) heating the dewatered slurry to a temperature of about 250.degree.-350.degree. F., at a pressure of about 30-50 psig, by direct contact with steam;
• and
• (d) retaining the biomass in the dewatered slurry at reaction temperature and pressure conditions for a time sufficient to hydrolyze the hemicellulose of the biomass, but so that hydrolysis of cellulose does not occur, so that primarily five carbon sugars are produced.

A method of acid pre-hydrolysis of biomass, effecting hydrolysis of hemicellulose to sugars, comprising the steps of automatically, continuously and sequentially:

• (a) mixing biomass containing hemicellulose with a mineral acid solution of sufficient concentration to eventually hydrolyze the hemicellulose therein, and to form a slurry having a consistency that insures proper wetting of the biomass with mineral acid;
• (b) dewatering the slurry to a consistency of about 35-50% so as to minimize the amount of steam required to heat the biomass to reaction temperature and to maintain a desired sugar solution concentration after pre-hydrolysis;
• (c) fluffing the dewatered slurry;
• (d) heating the dewatered slurry to reaction temperature, at superatmospheric pressure by direct contact with steam;
• and
• (e) retaining the biomass in the dewatered slurry at reaction temperature and pressure conditions for a time sufficient to hydrolyze the hemicellulose of the biomass.

A method of acid pre-hydrolysis of biomass, effecting hydrolysis of hemicellulose to sugars, comprising the steps of automatically, continuously and sequentially:

• (a) mixing biomass containing hemicellulose with a mineral acid solution of about 0.5-3.0% to form a slurry having a consistency of about 8-12%;
• (b) dewatering the slurry to a consistency of about 35-50%;
• (c) fluffing the dewatered slurry;
• (d) heating the dewatered slurry to a temperature of about 250.degree.-350.degree. F., at a pressure of about 30-50 psig, by direct contact with steam;
• and
• (e) retaining the biomass in the dewatered slurry at reaction temperature and pressure conditions for a time sufficient to hydrolyze the hemicellulose of the biomass.

A method of acid pre-hydrolysis of biomass, effecting hydrolysis of hemicellulose to sugars, comprising the steps of automatically, continuously and sequentially:

• (a) mixing biomass containing hemicellulose with a mineral acid solution of sufficient concentration to eventually hydrolyze the hemicellulose therein, and to form a slurry having a consistency that insures proper wetting of the biomass with mineral acid;
• (b) dewatering the slurry so as to minimize the amount of steam required to heat the biomass to reaction temperature and to maintain a desired sugar solution concentration after pre-hydrolysis;
• (c) heating the dewatered slurry to reaction temperature, at superatmospheric pressure by direct contact with steam;
• (d) retaining the biomass in the dewatered slurry at reaction temperature and pressure conditions for a time sufficient to hydrolyze the hemicellulose of the biomass;
• steps (c) and (d) being practiced in a pressurized vertical reactor;
• and step (c) taking place in a vapor phase at the top of the reactor;
• and
• (e) diluting and cold blowing the biomass from the bottom of the reactor.

A method of acid pre-hydrolysis of biomass, effecting hydrolysis of hemicellulose to sugars, comprising the steps of automatically, continuously and sequentially:

• (a) mixing biomass containing hemicellulose with a mineral acid solution of about 0.5-3.0% to form a slurry having a consistency of about 8-12;
• (b) dewatering the slurry to a consistency of about 35-50%;
• (c) heating the dewatered slurry to a temperature of about 250.degree.-350.degree. F., at a pressure of about 30-50 psig, by direct contact with steam;
• (d) retaining the biomass in the dewatered slurry at reaction temperature and pressure conditions for a time sufficient to hydrolyze the hemicellulose of the biomass;
• steps (c) and (d) being practiced in a pressurized vertical reactor;
• and step (c) taking place in a vapor phase at the top of the reactor;
• and
• (e) diluting and cold blowing the biomass from the bottom of the reactor.

A method of acid pre-hydrolysis of biomass, effecting hydrolysis of hemicellulose to sugars, comprising the steps of automatically, continuously and sequentially:

• (a) mixing biomass containing hemicellulose with a mineral acid solution of sufficient concentration to eventually hydrolyze the hemicellulose therein, and to form a slurry having a consistency that insures proper wetting of the biomass with mineral acid;
• (b) dewatering the slurry so as to minimize the amount of steam required to heat the biomass to reaction temperature and to maintain a desired sugar solution concentration after pre-hydrolysis;
• (c) heating the dewatered slurry to reaction temperature, at superatmospheric pressure by direct contact with steam;
• (d) retaining the biomass in the dewatered slurry at reaction temperature and pressure conditions for a time sufficient to hydrolyze the hemicellulose of the biomass;
• (e) adding mineral acid to the pressate from step (b) to form a mixture of pressate and acid;
• (f) heating the mixture of pressate and acid;
• and
• (g) using the heated mixture as the acid solution source in step (a).

A method of acid pre-hydrolysis of biomass, effecting hydrolysis of hemicellulose to sugars, comprising the steps of automatically, continuously and sequentially:

• (a) mixing biomass containing hemicellulose with a mineral acid solution of about 0.5.3.0% to form a slurry having a consistency of about 8-12%;
• (b) dewatering the slurry to a consistency of about 35-50%, and to produce pressate;
• (c) heating the dewatered slurry to a temperature of about 250.degree.-350.degree. F., at a pressure of about 30-50 psig, by direct contact with steam;
• (d) retaining the biomass in the dewatered slurry at reaction temperature and pressure conditions for a time sufficient to hydrolyze the hemicellulose of the biomass;
• (e) adding mineral acid to the pressate from step (b) to form a mixture of pressate and acid;
• (f) heating the mixture of pressate and acid;
• and
• (g) using the heated mixture as the acid solution source in step (a).