Integration of hemicellulose pre-extraction in the bleach-grade pulp production process

TAPPI Journal ◽  
2013 ◽  
Vol 12 (10) ◽  
pp. 55-61 ◽  
Author(s):  
FANG HUANG ◽  
ARTHUR RAGAUSKAS
Keyword(s):  
Boric Acid ◽  
Production Process ◽  
Loblolly Pine ◽  
Room Temperature ◽  
Kraft Pulping ◽  
Cooking Time ◽  
Physical Strength ◽  
Elemental Chlorine ◽  
Pfi Refining ◽  
Pulp Production

Loblolly pine woodchips were first pre-extracted with 6 wt% (percent on original nonextracted o.d. wood weight) sodium hydroxide at room temperature overnight, then treated at 90°C for 90 min, following another 4 h extraction with the addition of 5 wt% boric acid to partially remove hemicellulose. During the subsequent bleach-grade kraft pulping process, the cooking intensity was alleviated, either by decreasing the cooking time (reduced H-factor by 35%) or decreasing the chemical charge by 30%, with the objective of obtaining similar pulp quality as the control cook. After elemental chlorine free bleaching and PFI refining, the results indicated that the pre-extracted pulp could maintain equal or similar brightness and physical strength as the control pulp through this optimization of the pulping process.

Study on Preparation of Dissolving Grade Pulp and its Kinetics of Prehydrolysis

2011 ◽  
Vol 233-235 ◽  
pp. 1479-1484
Author(s):  
Ke Xin Hu ◽  
Guang Ming Zeng ◽  
Hai Chao Zhang
Keyword(s):  
Quality Standards ◽  
Kraft Pulping ◽  
Cooking Time ◽  
Bleaching Process ◽  
First Order ◽  
Pseudo First Order ◽  
P Factor ◽  
Prehydrolysis Kraft ◽  
Kinetics Of ◽  
Pulp Production

The possibilities of dissolving grade pulp production from reed were investigated in this paper. Two – stage prehydrolysis – kraft pulping and CEHA bleaching process of reed for preparation of dissolving grade pulp were studied in laboratory. The optimum cooking and bleaching conditions were found out. The mechanism and its kinetics of reed in prehydrolysis process were also discussed. The results showed that under the laboratory conditions the rate for removal of materials at about 175°C follow approximately a pseudo first order law with two distinct phrases: the bulk removal and the residual removal of the materials. The prehydrolysis-factor (P-factor) was established. The advantage of using P-factor is predict compensating adjustments in cooking time and/or temperature to give the same degree of pulping and to produce pulp with predetermined characteristics. It is found that three distinct delignification rate stages about 75% of pentosans and about 50% of lignin were removed. A CEHA four stage bleaching is used for dissolving grade pulp. Total chlorine charge in bleaching is 6% (to oven-dry pulp). The results show that all of the indices fitted the quality standards of dissolving grade pulp.

Polysulfide-borohydride modification of southern pine alkaline pulping integrated with hydrothermal pre-extraction of hemicelluloses

TAPPI Journal ◽  
2011 ◽  
Vol 10 (7) ◽  
pp. 9-16
Author(s):  
SUNG-HOON YOON ◽  
HARRY CULLINAN ◽  
GOPAL A. KRISHNAGOPALAN
Keyword(s):  
Loblolly Pine ◽  
Sodium Borohydride ◽  
Kraft Pulping ◽  
Hot Water ◽  
Pulp Yield ◽  
Paper Strength ◽  
Southern Pine ◽  
Two Stage ◽  
Simultaneous Treatment ◽  
Process Modification

We studied three process modifications to investigate their effects on the property and yield recovery capabilities of kraft pulping integrated with hemicellulose pre-extraction of southern pine. Loblolly pine chips were pre-extracted with hot water until the sugar extraction yield reached the targeted value of 10% and then subjected to conventional and modified kraft pulping. Modification included polysulfide pretreatment; polysulfide-sodium borohydride dual pretreatment, and polysulfide followed by polysulfide-sodium borohydride dual pretreatment two-stage pretreatments prior to kraft pulping. In the first modification, about 5% of the lost pulp yield (total 7%) caused by hemicellulose pre-extraction could be recovered with 15%-20% polysulfide pretreatment. Complete recovery (7%) was achieved with simultaneous pretreatment using 15% polysulfide and 0.5% sodium borohydride with 0.1% anthraquinone in polysulfide-sodium borohydride dual pretreatment. Two-stage pretreatment using recycled 15% polysulfide followed by simultaneous treatment of 6% polysulfide and 0.4%–0.5% sodium borohydride with 0.1% anthraquinone also achieved 100% yield recovery. Continuous recycling of 15% polysulfide employed in the two-stage process modification maintained its yield protection efficiency in a repeated recycling cycle. No significant changes in paper strength were found in handsheets prepared from the three process modifications, except for a minor reduction in tear strength.

Inactivation of Poliovirus 1 and Coxsackievirus B-2 in Broiled Hamburgers

1975 ◽  
Vol 38 (8) ◽  
pp. 473-475 ◽  
Author(s):  
R. SULLIVAN ◽  
R. M. MARNELL ◽  
E. P. LARKIN ◽  
R. B. READ
Keyword(s):  
Thermal Stability ◽  
Cell Cultures ◽  
Kidney Cell ◽  
Room Temperature ◽  
Cooking Time ◽  
Monkey Kidney Cell ◽  
Beef Patties ◽  
Coxsackievirus B ◽  
Viral Plaque ◽  
Thermal Stability Of

Thermal stability of two enteroviruses, poliovirus 1 and coxsackievirus B-2, inoculated into ground beef patties was investigated using household broiling procedures. Internal temperatures during cooking were monitored by thermocouples placed in the centers of patties. The appearance of the centers of hamburgers correlated with the temperatures reached: red-pink-rare, 60 C (140 F); pink-brown-medium, 71 C (160 F); and brown-well-done, 76.7 C (170 F). Cooked and uncooked virus-inoculated patties were assayed for viral plaque forming units produced in Vero monkey kidney cell cultures. No viruses were detected in patties cooked to 60 C (140 F) and held at room temperature for 3 min. However, virus was recovered from 8 of 24 patties cooked to 60 C (140 F) and immediately cooled to 23 C (74 F). No viruses were detected in patties heated to 71 C (160 F) or 76.7 C (170 F) internal temperatures. Results indicate that the cooking time and temperatures used to prepare rare hamburgers wherein the center meat remains red may not be sufficient to inactivate viruses that might be present in the sample especially if the hamburger is consumed or cooled within 3 min of cooking. When frozen or partially defrosted patties are cooked, extensive external cooking can occur with little or no visible change in the coloration of the center meat.

Hydroxylation of anthraquinones in oleum and in sulfuric acid

1978 ◽  
Vol 31 (10) ◽  
pp. 2271 ◽  
Author(s):  
HJ Banks ◽  
DW Cameron ◽  
WD Raverty
Keyword(s):  
Sulfuric Acid ◽  
Boric Acid ◽  
Room Temperature

The anthraquinone emodin (9) was rapidly and efficiently converted into catenarin (13) by treatment with a mixture of oleum and boric acid at room temperature. Chrysophanol (15) similarly gave islandicin (16), while related anthraquinones were hydroxylated in essentially the same way, though none as rapidly as emodin. The specificity of such processes is synthetically useful in generally involving substitution of the less highly hydroxylated ring. This is in contrast to hydroxylation with persulfate in sulfuric acid which, for emodin, occurred chiefly in the more highly hydroxylated ring, as did sulfonation.

Viscosity of Prehydrolysis Liquor of a Hardwood Kraft-Based Dissolving Pulp Production Process

2013 ◽  
Vol 52 (11) ◽  
pp. 3974-3979 ◽  
Author(s):  
Haitang Liu ◽  
Huiren Hu ◽  
Ashwini Nairy ◽  
M. Sarwar Jahan ◽  
Guihua Yang ◽  
...  
Keyword(s):  
Production Process ◽  
Dissolving Pulp ◽  
Pulp Production

ROOM TEMPERATURE STABILIZATION OF RADIATION-PRODUCED FREE RADICALS IN BARBITURIC ACIDS

1961 ◽  
Vol 39 (4) ◽  
pp. 514-533 ◽  
Author(s):  
J. A. R. Cloutier
Keyword(s):  
Free Radicals ◽  
Boric Acid ◽  
Experimental Evidence ◽  
Room Temperature ◽  
Barbituric Acid ◽  
Experimental Results ◽  
Temperature Stabilization ◽  
Barbituric Acid Derivatives

Experimental evidence has shown that a boric acid glass may be used to stabilize at room temperature organic free radicals produced by radiation in a number of barbituric acid derivatives. The method and the experimental results are discussed.

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