What is solvent pulping?

Solvents. Organosolv pulping involves contacting a lignocellulosic feedstock such as chipped wood with an aqueous organic solvent at temperatures ranging from 140 to 220 °C. The concentration of solvent in water ranges from 40 to 80%. Higher boiling solvents have the advantage of a lower process pressure.

What is Organosolv pretreatment?

Organosolv pretreatment is an attractive method for separating both cellulose and nearly pure lignin from the lignocellulosic material. In a biorefinery, organosolv pretreatment is one of the best options for producing more than one valuable product (bioethanol and lignin) in the same process.

What is kraft pulp used for?

Kraft pulp is darker than other wood pulps, but it can be bleached to make very white pulp. Fully bleached kraft pulp is used to make high quality paper where strength, whiteness, and resistance to yellowing are important. The kraft process can use a wider range of fiber sources than most other pulping processes.

What chemicals are used in kraft pulping?

The 4 processes principally used in chemical pulping are kraft, sulfite, neutral sulfite semichemical (NSSC), and soda. The first 3 display the greatest potential for causing air pollution. The kraft process alone accounts for over 80 percent of the chemical pulp produced in the United States.

How is alcohol cellulose used in the pulping process?

The AlCell (alcohol cellulose) process of Repap enterprises using 50% ethanol and 50% water at 195°C for approximately 1 h has been demonstrated at 15 t/day. One advantage of the system is a relatively simple recovery system (evaporation of the liquor to recover the alcohol) that allows small mills to be economically feasible.

When did the APR process become the Alcell process?

In 1987 the APR process was renamed the Alcell process. The process uses aqueous ethanol solutions (40–60% v/v) to delignifying wood at temperatures from 180–210 °C and 2–3.5 MPa. Solvent is recovered with flash evaporation, vapour condensation and vacuum stripping.

What kind of pulping process do they use?

At present, the chemical pulping industry uses primarily sulfate pulping (Kraft pulping), sulfite pulping, or soda pulping processes for separating lignin on an industrial scale from wood and from some annual plants, such as bagasse, different straw species, flax, hemp, and bamboo.

Is the organosolv pulping process accepted by modern technology?

The Repap Enterprises Alcell mill at Newcastle, New Brunswick, Canada, had a similar fate. It is too early to make a conclusive judgment on the alternatives, but it is clear that Organosolv pulping is not accepted modern technology.