Black Liquor Samples Research Articles

Pyrolysis and steam gasification processes of black liquor

The black liquor composition was assumed to be C 10H 12.5O 7Na 2.4S 0.36, which corresponds to kraft liquor with a molar ratio of S/Na 2 of 0.3. The yields of liquid products from the black liquor pyrolysis increase from 17.2% to 26.5% with increasing temperature from 600 to 800 K. The yields of liquid and gaseous products from pyrolysis of the black liquor samples increase with increasing temperature. The yields of (H 2+paraffins) in the gaseous products from the black liquor steam gasification run (Water/ Black liquor=1.9 ) increase from 38.0% to 50.3% with increasing temperature from 975 to 1325 K. The highest hydrogen rich gas yield was obtained from the catalytic steam gasification run (Water/ Black liquor=1.9 ) at 1325 K.

Multiple headspace extraction–gas chromatographic method for the study of process kinetics

A multiple headspace extraction gas chromatographic technique to automate the study of process kinetics that involves volatile species was developed in this study. The technique was demonstrated by using it to study methanol formation in kraft black liquor samples under an isothermal temperature of 70 °C. The results indicate that methanol formation in kraft black liquors under isothermal conditions follows an exponential decay function. The present method is very simple, efficient and fully automated. It can be easily applied to study slow kinetic processes, such as reaction or adsorption and desorption, involving volatile species in any environmental and industrial samples with complicated matrices.

NMR Studies Part 3: Analysis of Lignins from Modern Kraft Pulping Technologies

This paper examines the changes in lignin structure of kraft black liquor samples isolated during and at the end of the cook. Employing a common wood source a series of conventional kraft pulps, kappa numbers 28, 18, and 13 and extended modified kraft pulps, at kappa numbers of 29, 18, and 14 were prepared. The kraft lignins were isolated and characterized using 13 C and 1 H-NMR methods. These studies confirmed that the pulping procedure influences the structural features of kraft lignins, including the content of phenoxy groups, β-O-aryl ether linkages, and condensed lignin units.

NMR Studies II. Investigation of Process Analytical NMR Techniques for the Pulp and Paper Industry1

The application of a low-field NMR spectrometer, specifically designed for industrial applications, was explored as a means of characterizing the physical properties of kraft black liquors. A variety of proton NMR parameters were determined for black liquor samples, including relative signal intensities and T2 measurements. These values were correlated against the % solids and viscosity values of these samples. Research studies demonstrated that it was readily feasible to measure % solids for a variety of kraft black liquor samples by determining the proton NMR signal intensity for each of these samples.

Direct Observation of Alkali Vapor Release during Biomass Combustion and Gasification. 2. Black Liquor Combustion at 1100 °C

This study details the first application of molecular beam mass spectrometry to investigate the release of sodium, potassium, sulfur, and chlorine during black liquor combustion. Two samples, black liquor with 37.1% dry solids and a sample of dry black liquor solids, were combusted in a quartz-tube reactor at 1100 °C in 5% O2 in helium. The gaseous black liquor combustion products, including alkali metal salts, were monitored continuously and in real time during the combustion event with a molecular beam mass spectrometer (MBMS). Combustion of the dry black liquor solids occurred in multiple phases distinguished as a devolatilization phase and a char combustion phase that was arbitrarily divided into three separate phases. Combustion of the wet black liquor samples occurred in two phases, namely, a combination of water evaporation and devolatilization, and char combustion. NaCl was the most abundant gas-phase alkali-metal-containing species measured during black liquor combustion. The experimental results...

The pyrolysis of extracted solids from oxidized kraft black liquor after lignin precipitation

AbstractA laboratory investigation of the possibilities for the reduction of odor from Kraft mill stack gases by lignin precipitation from oxidized Kraft black liquor and subsequent pyrolysis of the filtrate solids has been carried out. Samples of oxidized black liquor were acidified with sulphuric acid and the lignin precipitate extracted. The extraction scheme indicates that > 90% w/w of the sodium in the original black liquor samples can be retained in the filtrate after lignin removal at final pH 2.0. The evaporated filtrate solids containing the bulk of the black liquor inorganic chemicals were pyrolyzed and the evolved hydrogen sulphide, methyl mercaptan and dimethyl sulphide monitored by gas‐chromatography. Gas‐chromatograph traces displaying the increase and decrease of methyl mercaptant evolution levels on pyrolysis of the filtrate solids to increasing temperatures are shown.A thermogravimetric technique was used to investigate the decomposition rates of the extracted samples and these rates correlated with the levels of sulphur gases evolved on pyrolysis. Heats of combustion were determined by bomb calorimetry. Sulphur losses from the filtrate solids and the Kraft black liquor total solids are compared. The results show a significant decrease in the evolution of organo sulphur gases from samples of ligninextracted black liquor solids in comparison with original total solids samples, an increase in the level of hydrogen sulphide evolution however, presents a problem.