Alabama A & M University Filtration and Drying Process Analysis Essay

I have a project and I need some research about the reagents for washing/filtration and the drying process to get a powder. I will attach my project when the question is assigned

The general pulping process involves separating the cellulose fiber and lignin from wood
chips. A digester pressure vessel is operated at high temperature and pressure, and circulated
with a cook acid. The glue (lignin and hemi-cellulose) holding the cellulose fibers together is
dissolved into the liquid phase, while the solid cellulose is physically isolated. The kraft pulping
process has become the dominant production process used for paper production, where the kraft
black liquor product has not been sulfonated, and is composed of kraft lignin and hemicellulose.
For the management of a kraft paper mill, we are focused on converting kraft black liquor
into dried sodium lignosulfonate powder and sold per industry-quality standards for concrete
admixtures. The objective is to design a 20,000 MT/year sodium lignosulfonate manufacturing
plant using the mill’s waste kraft liquor, operating 350 days per year. We can reuse the boiler
and steam from the kraft mill for heating elements, waste products can be returned from our
process to the kraft mill’s wastewater treatment plant or burned in the recovery boiler, and
electrical power can be supplied on-site.
Our preliminary design involves taking kraft black liquor and producing sodium
lignosulfonate for use in concrete admixtures. For this process, unmodified kraft lignin must
first be separated from the kraft black liquor through acidification using CO2 and sulfuric acid.
The extracted kraft lignin must then be sulfonated with sodium sulfite, washed, and filtered to
purify the sodium lignosulfonates. The sodium lignosulfonates are then dried before packaging
the final product as a powder.
The largest critical unknown is the reaction chemistry necessary to extract the lignin from
the kraft black liquor and sulfonate it. This includes knowledge of the reactants, products,
possible catalysts, kinetics, and thermodynamics of the reactions. Once the chemistry is known,
mass and energy balances can be determined, equipment can be selected and sized, power
requirements calculated, and environmental impacts evaluated.