How lignin can be separated from black liquor?

There are several methods to separate lignin from black liquor, but the most common one is the LignoBoost process. This process involves the following steps:

1) Acidification: The black liquor is acidified to a pH of around 2-3 using sulfuric acid. This causes the lignin to precipitate out of the solution as a solid.

2) Washing: The precipitated lignin is then washed with water to remove any remaining black liquor.

3) Dewatering: The wet lignin is dewatered using a press or centrifuge to remove excess water.

4) Drying: The dewatered lignin is then dried using a dryer to remove any remaining moisture.

The resulting dried lignin can then be used for a variety of applications, such as in the production of bioplastics, carbon fiber, and fuel pellets.

Other methods for separating lignin from black liquor include:

* Ultrafiltration: This process uses a semipermeable membrane to separate the lignin from the black liquor.

* Nanofiltration: This process uses a nanoporous membrane to separate the lignin from the black liquor.

* Electrodialysis: This process uses an electrical current to separate the lignin from the black liquor.

The choice of separation method depends on a number of factors, including the type of black liquor, the desired purity of the lignin, and the cost of the process.