The effects of possible operating variables such as flow rate, surface temperature, bulk temperature, solids contents, sulfate addition and pH on the fouling of sulfite spent evaporators were studied. The study pointed out that the Ca⁺⁺ concentration difference between heated surface and bulk is the most important factor for fouling...
Fume, sub-micron aerosal particles in the combustion gases, have been identified
as a cause of extensive plugging and fouling in the heat transfer section of a kraft
recovery boiler in kraft pulp mills. After the deposition on the heat transfer surface,
fume deposits will undergo the sintering process which causes...
Laminar entrained flow reactor (LEFR) was used to determine the effect of
temperature and residence time on the distribution of carbon, sulfur and nitrogen between
gaseous and condensed phase products from low temperature pyrolysis of kraft black
liquor. The operating furnace temperatures were between 400°C-600°C where the effect
of condensable...
Black liquor recovery boilers experience significant fire-side fouling problems due to the deposition of entrained particulate matter. Increased understanding of the mechanisms by which particles deposit on these surfaces will lead to more effective management of the resultant problems. There is some evidence which suggests that the sub-micron fraction of...
Solubility studies on the heavy metal sulfides in liquid hydrogen
sulfide at room temperature were carried out using the isopiestic
method. The results were compared with earlier work and with a
theoretical result based on Raoult's Law. A relative order for the
solubilities of sulfur and the sulfides of tin,...
A comparison was made of the d.c. conductivity of KCI:Pb²⁺
and KCl:PbO single crystals at temperatures greater than 325°C.
The energy of activation was 0.72 ev for all crystals. Lead concentration
was determined by chemical, optical and electrical methods. The
half band width of the UV absorption band at 273...
The simultaneous diffusion of Ca 2+ and Sr 2+ ions in purified
single crystals of KC1 and NaC1 was studied over the temperature
ranges from 451°C to 669°C in KC1 and from 448°C to 683°C in NaCl.
A radioactive tracer technique was used in two types of measurements:
diffusion from...
The research undertaken in this study deals with three topics related to the prediction of thermodynamic properties of electrolytes in aqueous solutions. In the first, Pitzer ion interaction parameters for 304 single electrolytes were evaluated from recently published osmotic coefficient data at 25°C by using multiple regression analysis to fit...
In designing a solubility based separation process
for solvent recovery of an organosolv pulping process, the
phase behavior of polymeric lignin molecules in alcohol -
water mixed solvent should be known. In this study,
sodium lignin sulfonates (NaLS) samples were fractionated
into three different molecular weight fractions using a
partial...
The non-ideal aqueous electrolyte simulator (NAELS) is composed of
three major parts: a Newton-Raphson non-linear optimization program written
by Weare, et al (1987); an activity coefficient subroutine for non-ideal
electrolyte systems based on Pitzer's model; and an extensive, user expandable
database. It is robust, stable, and requires neither thermodynamic data...
Black liquor gasification is one of the promising alternatives to
eliminate the drawbacks of the conventional recovery unit of the
kraft process. A numerical model has been developed to simulate an
industrial pilot scale entrained-flow gasifier currently operating at
Tampere, Finland. The objective of the model is to investigate the...
Combustion properties of kraft black liquor solids were studied using a laminar entrained flow reactor. The tendency of black liquors to release fume (compounds containing Na⁺, K⁺, Cl⁻, SO₄²⁻, SO₃²⁻, S₂0₃²⁻ and C0₃²⁻) during combustion were observed at 1000°C. Black liquor solids with a size fraction of 63 to 100...