• Applied Chemistry for Engineering
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• v.29 no.3
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• pp.350-355
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• 2018

In this study, the effect of biomass torrefaction on the thermal and catalytic pyrolysis of cork oak was investigated. The thermal and catalytic pyrolysis behavior of cork oak (CO) and torrefied CO (TCO) were evaluated by comparing their thermogravimetric (TG) analysis results and product distributions of bio-oils obtained from the fast pyrolysis using a fixed bed reactor. TG and differential TG (DTG) curves of CO and TCO revealed that the elimination amount of hemicellulose in CO increased by applying the higher torrefaction temperature and longer torrefaction time. CO torrefaction also decreased the oil yield but increased that of solid char during the pyrolysis because the contents of cellulose and lignin in CO increased due to the elimination of hemicellulose during torrefaction. Selectivities of the levoglucosan and phenolics in TCO pyrolysis oil were higher than those in CO pyrolysis oil. The content of aromatic hydrocarbons in bio-oil increased by applying the catalytic pyrolysis of CO and TCO over HZSM-5 ($SiO_2/Al_2O_3=30$). Compared to CO, TCO showed the higher efficiency on the formation of aromatic hydrocarbons via the catalytic pyrolysis over HZSM-5 and the efficiency was maximized by applying the higher torrefaction and catalytic pyrolysis reaction temperatures of 280 and $600^{\circ}C$, respectively.

• Journal of the Korean Wood Science and Technology
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• v.20 no.1
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• pp.60-71
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• 1992

To investigate the delignification behaviour in solvolysis pulping process, Populus alba ${\times}$ glandulosa H. and Pinus Kuraiensis S. et Z. were cooked with p-cresol and vater solvent(2:8, 5:5, 8:2 v/v) at $175^{\circ}C$ for 9 cooking time levels(20, 40, 60, 80, 100, 120, 140, 160, 180, min). Pulp yield, residual lignin content, de lignification rate, decarborhydration rate were determined. Delignification behaviours were analyzed by TEM. 1. The p-cresol-water solvent cooking of P. alba ${\times}$ glandulosa showed good delignification at the solvent system which the mixture ratio of p-cresol and water were 2:8(v/v), while the cooking of P. koraiensis with the p-cresol and water mixture ratio of 5:5 was no good. 2. P. alba ${\times}$ glandulosa showed three step-delignification phenomena at the solvent system which the mixture ratio of p-cresol and water were 2:8(v/v) anti 5:5(v/v). But P. koraiensis showed a first order delignification reaction at the same mixture ratio of p-cresol and water solvent system. 3. In TEM micrograph obtained for the solvent system which the mixture ratio of p-cresol and water was 5:5(v/v), the partial delignification of the cell corner of P. alba ${\times}$ glandulosa and P. koraiensis were observed at 60min. of cooking time. Complete delignification at the cell corner of P. alba ${\times}$ glandulosa was observed at 160min. and that of P. koraiensis was observed of 180min. of cooking time. 4. In optical microscopic observation, fiber separation of P. alba ${\times}$ glandulosa occured at 120min. and that of P. koraiensis began at 140min. of cooking time. 5. At the solvent system which the mixture ratio of p-cresol and water was 5:5(v/v), middle layer on secondary wall($S_2$) and cell corner of P. alba ${\times}$ glandulosa were more selectively delignified than primary wall(P) and outer layer on secondary wall($S_1$). However P. koraiensis did not showed any difference in delignification between cell wall layers and cell corner.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.31 no.4
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• pp.49-57
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• 1999

In CLO2 delignification and bleaching process, formation of chlorate corresponds to a loss of 20-36% of the original CKO2 charge. Because chlorate is inactive and harmful to environmental, it will be of benefit to find methods that can reduce the formation of chlorate during chlorine dioxide bleaching. Chlorate is mainly formed by the reaction HCIO +ClO2 $\longrightarrow$H+ + Cl_ +ClO3-2 On the other hand, AOX in chlorine dioxide bleacing is formed also due to the in-situ produced hypochlorous acid. THus both AOX and chlorate could be reduced by addition of hypochlorous acid. Some paper son the reduction of AOX by additives appeared , but systematic data on chlorate reduction as well as pulp and effluent properties are not available. THus this paper of focused on the effects on the reduction of chlorate and chlorine dioxide bleachability. The additives, fulfamic a챵, AMSO, hydrogen peroxide, oxalic acid were found to eliminate chlorine selectively in chlorine and chlorine dioxide mixture.However, when they were added to bleaching process, sulfamic acid and DMSO showed significant reduction of chlorate formation but hydrogen peroxide and oxalic aicd did not, and significant amount ofhydrogen peroxide was found resided in the bleaching effluent , In addition, sulfamic acid and DMSO decreased the bleaching end ph values while hydrogen peroxide and oxalic acid did not, which also indicated that hydrogen peroxide and oxalic acid were ineffective. The difference might be ascribed to the competitives of hypochlorous acid with lignin, chlorite (CKO2) and additives. Sulfamic acid and DMSO showed better pulpbrightness development but less alkaline extraction efficiency than hydrogen peroxide , oxalic acid and control, which means that insitu hypochlorous acid contributes to the formation of new chromophore structures that can be easily eliminated by alkaline extraction. DMSO decreased the delignification ability of chlorine dioxide due to the elimination of hypochlorous acid, but sfulfamic acid did to because the chlroinated sulfamic acid had stable bleachability. In addition, sulfamic acid, and SMSO shwed decreased color and COD of bleaching effluents, hydrogen peroxide decreased effluent color but not COD content, and oxalic acid had no statistically significant effects. No significant decreases of pulp viocosity were found except for hydrogen peroxide. Based on our results , we suggest that the effectiveness of hydrogen peroxide on the reduction of AOX in literature might be explained by other mechanisms not due to the elimination of hypochlorous acid , but to the direct decomposition of AOX by hydrogen peroxide.

• Applied Chemistry for Engineering
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• v.31 no.4
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• pp.443-451
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• 2020

In this study, the physico-chemical properties and pyrolysis kinetics of livestock mature solid fuel were investigated to know its feasibility as a fuel. Ultimate and proximate analysis results showed that livestock mature solid fuel has high contents of volatile matter (64.94%), carbon (44.35%), and hydrogen (5.54%). The low heating value of livestock mature solid fuel (3880 kcal/kg) was also higher than the standard requirement of solid fuel (3000 kcal/kg). Thermogravimetic analysis results indicated that livestock mature solid fuel has three decomposition temperature regions. The first temperature zone (130~330 ℃) was consisted with the vaporization of extracts and the decomposition of hemicellulose and cellulose. The second (330~480 ℃) and third (550~800 ℃) temperature regions were derived from the decomposition of lignin and additional decomposition of carbonaceous materials, respectively. The activation energy derived from model free kinetic analysis results including Friedman, Flynn-Wall-Ozawa (FWO), and Kissinger-Akahira-Sunose (KAS) methods for the pyrolysis of livestock mature solid fuel was in the range of 173.98 to 525.79 kJ/mol with a conversion rate of 0.1 to 0.9. In particular, the activation energy increased largely at the higher conversion than 0.6. The kinetic analysis using a curve-fitting method suggested that livestock mature solid fuel was decomposed via a multi-step reaction which can be divided into five decomposition steps.

• Korean Chemical Engineering Research
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• v.54 no.4
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• pp.443-447
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• 2016

The microalgae have cellulose as a main structural component of their cell wall and the lignin content in microalgae is much lower than other lignocellulosic biomass. Therefore, fermentable sugar production from microalgae (Tetraselmis KCTC 12236BP) can be carried out under pretreatment without high temperature and high pressure. It was investigated that the effect of hot-water pretreatment using sulfuric acid for lipid extracted algae which is expected to be a next generation biomass. The effects of three major variables including extraction temperature, acid concentration and time on the enzymatic hydrolysis were investigated. Among the tested variables, temperature and acid concentration showed significant effects and optimum pretreatment conditions for the economic operation criteria were obtained as follows: reaction temperature of $120^{\circ}C$, sulfuric acid concentration of 2 mol and pretreatment time of 40 min. Under the optimum conditions of acidic hot water pretreatment, experimentally obtained hydrolysis yield were 95.9% which showed about 2.1 fold higher compared with enzymatic hydrolysis process. Therefore, acid pretreatment under mild condition was proven to be an effective method for fermentable sugar production from lipid extracted microalgae.

• Korean Chemical Engineering Research
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• v.47 no.1
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• pp.89-95
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• 2009

Because of high contents of cellulose (~37 wt%) and hemicellulose (~17%), rice straw seems to be a potential lignocellulosic biomass for production of bioethanol. In this study, Ammonia Recycled Percolation (ARP) pretreatment of rice straw was extensively investigated. In particular, the experimental study included the effects of temperature, reaction time and concentration of ammonia on compositions and enzymatic digestibility of the resulting solid residues; the ranges of pretreatment conditions were, in turn, $150{\sim}190^{\circ}C$, 10~90 min and 0~20 wt%. Through ARP pretreatment, the lignin content was reduced by as high as ~84% while 20~80% of the hemicellulose was also solubilized. The solid residue resulted from the pretreatment with 15 wt% aqueous ammonia solution at $170^{\circ}C$ for 90 mim showed as high as ~90% of digestibility with 15FPU/g of glucan enzyme loading. Supplement of xylanese to cellulase led to a notable enhancement of digestibility, indicating a discernable inhibitory role of hemicellulose. Simultaneous Saccharification and Fermentation (SSF) and Simultaneous Saccharification and Co-Fermentation (SSCF) were performed to obtain ethanol productions of 13.8 g/L (corresponding to 81% yield) and 15 g/L (corresponding to 89% yield), respectively.

• Journal of the Korean Wood Science and Technology
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• v.32 no.1
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• pp.28-34
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• 2004

This study was performed to evaluate the characteristics of the carboxymethylated substrate from high reactive autohydrolyzed cellulose (HRC) and those of commercial α-cellulose (CAC) and refiner mechanical pulp (RMP). Saccharification rates of HRC substrate were achieved over 70% with 12 hr hydrolysis, about 90% with 24 hr, and 99.5% with 72 hr. CMCase and avicelase activities of cellulase onozuka were 4.09 ㎛ G/mg·min and 14.0 ㎛ G/mg·min, respectively. There were no any significant changes in cellulase activities with this substrate. The saccharification rates of CAC and RMP were very low, 57% and 38% with 72 hr, respectively. Those lignin-zero autohydrolyzed substrates, HRC and CAC, were highly carboxymethylated at the high alkali concentration, near 30%, for 3 hr. reaction, and resulted in 1.13-1.15 of D.S., besides 0.85 of D.S. from RMP. Water solubilities of carboxymethylated substrates were increased with an increase of D.S., 98-98.5% from HRC and CAC and 31.5% from RMP. RMP which has low specific surface area showed lower water retention values, compared to high values of 435 and 321% from CAC and HRC, respectively. There were no direct relationship between surface area and swelling ratio of the substrates.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.48 no.2
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• pp.34-45
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• 2016

Global warming and climate change have been caused by combustion of fossil fuels. The greenhouse gases contributed to the rise of temperature between $0.6^{\circ}C$ and $0.9^{\circ}C$ over the past century. Presently, fossil fuels account for about 88% of the commercial energy sources used. In developing countries, fossil fuels are a very attractive energy source because they are available and relatively inexpensive. The environmental problems with fossil fuels have been aggravating stress from already existing factors including acid deposition, urban air pollution, and climate change. In order to control greenhouse gas emissions, particularly CO2, fossil fuels must be replaced by eco-friendly fuels such as biomass. The use of renewable energy sources is becoming increasingly necessary. The biomass resources are the most common form of renewable energy. The conversion of biomass into energy can be achieved in a number of ways. The most common form of converted biomass is pellet fuels as biofuels made from compressed organic matter or biomass. Pellets from lignocellulosic biomass has compared to conventional fuels with a relatively low bulk and energy density and a low degree of homogeneity. Thermal pretreatment technology like torrefaction is applied to improve fuel efficiency of lignocellulosic biomass, i.e., less moisture and oxygen in the product, preferrable grinding properties, storage properties, etc.. During torrefacton, lignocelluosic biomass such as palm kernell shell (PKS) and empty fruit bunch (EFB) was roasted under an oxygen-depleted enviroment at temperature between 200 and $300^{\circ}C$. Low degree of thermal treatment led to the removal of moisture and low molecular volatile matters with low O/C and H/C elemental ratios. The mechanical characteristics of torrefied biomass have also been altered to a brittle and partly hydrophobic materials. Unfortunately, it was much harder to form pellets from torrefied PKS and EFB due to thermal degradation of lignin as a natural binder during torrefaction compared to non-torrefied ones. For easy pelletization of biomass with torrefaction, pellets from PKS and EFB were manufactured before torrefaction, and thereafter they were torrefied at different temperature. Even after torrefaction of pellets from PKS and EFB, their appearance was well preserved with better fuel efficiency than non-torrefied ones. The physical properties of the torrefied pellets largely depended on the torrefaction condition such as reaction time and reaction temperature. Temperature over $250^{\circ}C$ during torrefaction gave a significant impact on the fuel properties of the pellets. In particular, torrefied EFB pellets displayed much faster development of the fuel properties than did torrefied PKS pellets. During torrefaction, extensive carbonization with the increase of fixed carbons, the behavior of thermal degradation of torrefied biomass became significantly different according to the increase of torrefaction temperature. In conclusion, pelletization of PKS and EFB before torrefaction made it much easier to proceed with torrefaction of pellets from PKS and EFB, leading to excellent eco-friendly fuels.

• Korean Journal of Agricultural Science
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• v.12 no.1
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• pp.75-85
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• 1985

This study is intended to find out the influence of Lignosulfonic Acid Type Admixture on compressive, tensile, flexural strength and dispersing action of mortar, and fixation of by-product of pulp industry. 1. The more Pozzolith-84 is added, the larger flow value is. The admixture of lignosulfonic acid type adhere to cement particles and the surface potential of particles is generated. On account of the repulsion among the cement particles, they are dispersed and the mortar get workable, so the production cost of precast product is curtailed and the amount of cement is reduced in a certain workability of mortar. 2. The strength of mortar is greater than plain mortar when P/C added is 0.2 and 0.4%. As time passed the potential energy is reduced and the distance of particles which lignosulfonic acid adhered to get near according as the amount of adhesion is increased. The setting and hardening reaction of morter is occurred in close state, so the strength of mortar is increased a little. The strength of mortar is less than plain mortar when amount P/C added is 0.8%. Pozzolith-84 is mainly composed of lignosulfonic acid and lignin does not influence the hardening of mortar, therefore the remained $SO_3$, $SO_3H$ are the reason of decrease of strength. 3. There is high significance between specific gravity and compressive strength. The larger specific gravity is, the more compressive strength is increased. There is high significance between 7 day's strength and 28 day's strength. The larger compressive strength is, the more tensile and flexural strength are increased. 4. Since Pozzolith-84 is a by-product of pulp industry, by using the Pozzolith-84 admixture the concreate quality is improved. The water pollusion is reduced according to fix by-products in concrete structure.

• Korean journal of applied entomology
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• v.24 no.2 s.63
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• pp.51-60
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• 1985

This paper was performed to study the nature of varietal resistance of some Korean-new rice cultivars to the brown planthopper (BPH), Nilaparvata lugens ($ST{\AA}L$). The rice cultivars tested were Cheongcheong, Gaya, Hangangchal, Samgang, Nampoong and Yeongpoong which have been reported as having resistant genes for the BPH. The check varieties were Jinheung, Sangpoong and Chucheong for susceptible and IR-36 for resistant. The factors studied were referred to the seedling responses, preference in feeding and oviposition of BPH, antibiosis (nymphal development, adult emergence and sex ratio, adult body weight, population build-up, feeding amount and amylase activity), and chemical composition (inorganic components, chlorophyll contents, cell wall components, amino acids and esterase isozymes) of leaf- sheath and/or roots of rice plants. In conclusion, the natures of varietal resistance of rice cultivars to the BPH were not only correlated with the resistant reaction of rice plant, but also they were related with the non preference in feeding and oviposition and those resistant cultivars had the antibiotic effects to the insects. Their antibiotic effects of rice cultivars to the BPH would be related with some of the chemical components of rice plants, such as the contents of magnesium oxide (MgO), and chlorophyll and the different esterase isozymes.