Sven-Ingvar Andersson

Structure of the reducing end-groups in spruce xylan

Abstract Borohydride reduction of spruce meal followed by mild hydrolysis with acid gave a large proportion of 4- O -(α- d -galactopyranosyluronic acid)- d -xylitol. When the reduction was preceded by mild treatment with alkali, galactonic acid end-groups were formed. Enzymic degradation of holocellulose from reduced spruce-meal followed by ion-exchange chromatography led to the isolation of a tetrasaccharide having a xylitol end-group. Its structure revealed that the reducing end-group in spruce xylan has the structure β- d -Xyl p -(1→3)-α- l -Rha p -(1→2)-α- d -Gal p A-(1→4)- d -Xyl, which is the same as that in hardwood xylan.

The effect of temperature on the catalytic conversion of Kraft lignin using near-critical water

The catalytic conversion of suspended LignoBoost Kraft lignin was performed in near-critical water using ZrO2/K2CO3 as the catalytic system and phenol as the co-solvent and char suppressing agent. The reaction temperature was varied from 290 to 370°C and its effect on the process was investigated in a continuous flow (1kg/h). The yields of water-soluble organics (WSO), bio-oil and char (dry lignin basis) were in the ranges of 5-11%, 69-87% and 16-22%, respectively. The bio-oil, being partially deoxygenated, exhibited higher carbon content and heat value, but lower sulphur content than lignin. The main 1-ring aromatics (in WSO and diethylether-soluble bio-oil) were anisoles, alkylphenols, catechols and guaiacols. The results show that increasing temperature increases the yield of 1-ring aromatics remarkably, while it increases the formation of char moderately. An increase in the yields of anisoles, alkylphenols and catechols, together with a decrease in the yield of guaiacols, was also observed.

Evaluation of residue FCC catalysts

Abstract The processing of residues in FCC units has become a field of considerable interest over the past few years. The goal of our own work within this area, which has now extended over several years, has been to identify catalysts which are capable of giving improved process economy. In order to find the most suitable catalysts, and to understand why some catalysts are more suitable than others, a broad range of physical and chemical test methods have been employed. Those test methods employed by us are discussed in the current paper, exemplified by an authentic evaluation. The execution of such a test program involving a broad range of test methods is quite expensive, nevertheless it has been found to be of great value.

Test of magnetically separated catalysts in an ARCO pilot unit

Abstract Two different equilibrium catalysts from a FCC unit have been separated by the MagnaCat™ process, into fractions of different magnetic susceptibility. The results showed that the magnetic separation was influenced by gravity and inertia forces. Large particles had a tendency to accumulate in the accepted, least magnetic fraction which is to be returned to the regenerator. The results also indicated that the two equilibrium catalysts under investigation could respond somewhat differently to the magnetic separation. The equilibrium catalysts and the treated catalysts with the most magnetic fraction removed, were tested and evaluated in a modified ARCO pilot unit. The feed used was a North Sea 375°C+atmospheric residue. The evaluation showed that the catalytic activity increased, resulting in higher gasoline production at the expense of gas and coke, when the most magnetic fraction was removed. The economic evaluation showed a potential for improved cost margins for both catalysts if the benefit of the magnetic separation was used to improve catalyst activity, selectivity and throughput in the FCC unit at constant catalyst make up rate. If on the other hand the benefit of the magnetic separation was used to lower the catalyst consumption the addition of value would rise to a lesser degree.

Discrepancies in FCC Catalyst Evaluation of Atmospheric Residues

Processing of atmospheric residues in fluid catalytic crackers (FCC) is a field of considerable interest today. When this application was new, around 1984, Statoil initiated a test program related to fluid catalytic cracking of North Sea atmospheric residues. Within this program catalysts and feeds are tested in a Micro Activity Test (MAT) reactor at Statoil and in a circulating Arco Pilot Unit at Chalmers. The catalysts are tested with the same atmospheric residue feed that is used in the commercial FCC unit at the Statoil Mongstad refinery in Norway. This is essential because erroneous ranking of the catalysts might otherwise occur. The equilibrium catalyst in a commercial residue FCC unit has normally high metals content. This is simulated by testing the catalysts impregnated by nickel and vanadium and deactivated by the cyclic propene steaming (CPS) method. New catalysts are tested together with a reference catalyst in both the MAT and Pilot Unit reactors. Usually the catalysts show the same ranking in both the MAT and Pilot Unit reactors but there are exceptions. If the matrix properties for two catalysts are different, the ranking of the two catalysts might be different in the MAT and PIlot Unit reactors.

Optimum properties of RFCC catalysts

The zeolite to matrux surface area ratio (Z/M) has proven useful for optimizing catalysts both for vacuum gas oils and North Sea long residues.