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1.
The principal deterrent of general acceptance of weak black liquor oxidation by mills pulping southern pine is the extensive foam produced during the oxidation of the liquor. The foam results from relatively high concentrations of fatty and rosin acid soaps remaining in the black liquor after roughly 75% of these compounds have been removed by skimming as marketable by-products. The foaming propensity of black liquor can be used to advantage to provide additional by-product recovery while the black liquor is being oxidized. This paper will report the results of foam fractionation studies on such black liquors conducted in this laboratory.  相似文献   

2.
A historical record of monthly chemical makeups for a North American pulp mill has been analyzed by time series methods. The analysis yields estimates for the reduction in sulfur makeup resulting from each of three separate pollution abatement moves: black liquor oxidation, blow heat recovery, and cooking liquor sulfidity reduction. Further analysis yields estimates of sulfurous emissions and of the substantially lower emissions which could have been achieved if sulfidity management had been incorporated in the program.  相似文献   

3.
酸化法提取木素在造纸黑液治理中的应用探析   总被引:9,自引:0,他引:9  
提出了采用酸化法从造纸黑液中提取木素的最佳工艺条件,并结合生产实际进行了分析。黑液经酸化后,能大除大量有机物,对减轻黑液污染具有明显的效果,同时回收木素创造了较好的经济效益,实践证明,酸化法提取木素是中小型造氏厂草浆黑液治理的一条可行途径。  相似文献   

4.
The principal sources of odor in the kraft pulping process are the digester, the direct evaporator, and the recovery furnace. Control of odor from the digester requires the confinement of the noncondensable gases and their destruction by chlorination, burning, or by some other means. Control of odor from the direc’ evaporator depends on efficient black liquor oxidation. The recovery furnace, which potentially can be the worst source of air pollution, must be operated properly within its rated capacity. The chemistry of various control measures is discussed.  相似文献   

5.
采用无机膜过滤和磷酸酸析 2种方法来处理草浆造纸的黑液 ,比较了 2种方法的截留和分离效果。膜滤COD的截留率高于酸析 ,但从木素以及硅脱除的角度看 ,酸析的效果较佳。酸析后滤液可以苛化利用 ,以提高经济效益 ;而无机膜过滤是一个物理过程 ,工艺相对简单 ,流程短 ,其渗透液可以考虑直接回用。  相似文献   

6.
本文通过对造纸制浆黑液资源化处理回收木糖粉技术应用的实例分析 ,系统介绍了其技术工艺、设备特点 ,详细分析了它的环境效益和社会效益。本技术对中小型制浆造纸企业治理黑液提供了有益的借鉴  相似文献   

7.
电渗析法处理造纸黑液回收碱的试验研究   总被引:32,自引:0,他引:32  
进行了单阳膜电渗析法从造纸黑液中回收碱液试验,结果表明该法回收吨碱的电渗析电单耗可稳定在3000kWh左右,比氯碱厂生产烧碱和黑液燃烧法回收碱的能耗都低。当回收终点pH为7时,Na^2+回收率为50%,阳极黑液含Na^+为5000 ̄7000mg/L,可直接回用于生产工段。而本试验所采用的钛涂镣电极使用耐久性欠佳,尚有待改进。但该法仍不失为处理造纸黑液的可选方案。  相似文献   

8.
酸析-活性炭纤维吸附预处理精制棉黑液   总被引:2,自引:0,他引:2  
采用酸析-活性炭纤维吸附工艺去除精制棉黑液中的有机物,先用酸析法去除木质素,再用活性炭纤维吸附黑液中的剩余有机物。采用紫外-可见(UV-vis)吸收光谱、傅立叶转换红外吸收光谱(FTIR)和明亮发光菌水质急性毒性法等手段分析处理前后的精制棉黑液。研究表明,黑液中主要有机成分为愈创基(G-)和羟苯基(H-)木质素。在pH为2.0,活性炭纤维用量为90 g/L,温度为40°C,吸附时间为5 h的条件下,COD去除率可以达到85%。活性炭纤维对酸析后精制棉黑液的吸附热力学符合Redlich-Peterson经验吸附模型,吸附动力学符合伪二级动力学模型,吸附为吸热过程。酸析-吸附过程使精制棉黑液急性毒性去除率达到95%以上,为后续生物法处理提供了有利条件。  相似文献   

9.
The profiles of chlorinated terpenes in Finnish environmental samples were compared by GLC-SIM technique with those of toxaphene and Eastern European “dark”. The profiles in the seal blubber in the Northern and in the Eastern Baltic Sea proved to be similar. Chlorinated terpenes were found to be present in Finnish human milk.The spent bleach liquor of pine kraft pulp mill contained components having similar retention times and responses to those from toxaphene components.  相似文献   

10.
Title III of the 1990 Clean Air Act Amendments designated methanol as a pollutant to be regulated. The U.S. Environmental Protection Agency (EPA), through a contract with Research Triangle Institute, has developed a method for measuring methanol emissions from stationary sources. The methanol sampling train (MST) consists of a glass-lined heated probe, two condensate knockout traps, and three sorbent cartridges packed with Anasorb 747. Samples are desorbed with a 1:1 mixture of carbon disulfide (CS2) and N,N-dimethylformamide (DMF). Condensate water and CS2/ DMF samples are analyzed by gas chromatography with flame ionization detection. The MST has a practical quantitation limit of approximately 3 ppm for a 20-L sample. Samples were shown to be stable for at least two weeks after collection. Field tests of the MST and the National Council of the Paper Industry for Air and Stream Improvement (NCASI) methanol sampling method were conducted at two pulp and paper mills. Sampling and analysis procedures followed EPA Method 301 requirements. The sampling location for the first field test was the inlet vent to a softwood bleach plant scrubber, where the methanol concentration was approximately 30 ppm. The mean recovery of spike was 108.3% for the MST method and 81.6% for the NCASI method. Although neither method showed significant bias at the 95% confidence level, the between-methods bias was significantly different. A second field test was conducted at a vent from a black liquor oxidation tank where the methanol concentration was approximately 350 ppm. Mean spike recoveries were 96.6 and 94.2% for the MST and NCASI methods, respectively. The biases of the two methods and the between-methods bias were not significantly different for the second field test.  相似文献   

11.
Abstract

Title III of the 1990 Clean Air Act Amendments designated methanol as a pollutant to be regulated. The U.S. Environmental Protection Agency (EPA), through a contract with Research Triangle Institute, has developed a method for measuring methanol emissions from stationary sources. The methanol sampling train (MST) consists of a glass-lined heated probe, two condensate knockout traps, and three sorbent cartridges packed with Anasorb® 747. Samples are desorbed with a 1:1 mixture of carbon disulfide (CS2) and N, N-dimethylformamide (DMF). Condensate water and CS2/ DMF samples are analyzed by gas chromatography with flame ionization detection. The MST has a practical quantitation limit of approximately 3 ppm for a 20-L sample. Samples were shown to be stable for at least two weeks after collection.

Field tests of the MST and the National Council of the Paper Industry for Air and Stream Improvement (NCASI) methanol sampling method were conducted at two pulp and paper mills. Sampling and analysis procedures followed EPA Method 301 requirements.

The sampling location for the first field test was the inlet vent to a softwood bleach plant scrubber, where the methanol concentration was approximately 30 ppm. The mean recovery of spike was 108.3% for the MST method and 81.6% for the NCASI method. Although neither method showed significant bias at the 95% confidence level, the betweenmethods bias was significantly different.

A second field test was conducted at a vent from a black liquor oxidation tank where the methanol concentration was approximately 350 ppm. Mean spike recoveries were 96.6 and 94.2% for the MST and NCASI methods, respectively. The biases of the two methods and the between-methods bias were not significantly different for the second field test.  相似文献   

12.
Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) Karst.) seedlings were transported to five forest sites at increasing distances from a pulp mill emitting mainly SO(2). Levels of compounds which may have nutritional or defensive value for aphids on pine and spruce seedlings were studied. Glucose and fructose concentrations were significantly increased in pine and spruce needles near the pulp mill. There were no changes in sucrose and starch concentrations. In pine shoots, total free amino acid concentration and the concentrations of ornithine, lysine, histidine and arginine were significantly negatively correlated with the distance from the pulp mill, while in spruce only the individual amino acids glycine, ornithine, lysine and histidine showed a significant negative correlation with distance. There were no changes in total phenolic, catechin, total monoterpene and total resin acid concentrations. However, in pine seedlings monoterpenes beta-pinene and sabinene and in spruce seedlings resin acid palustric acid were significantly correlated with the distance from the pulp mill. The results indicate that SO(2) disturbs carbohydrate metabolism in spruce and pine seedlings. The elevated concentrations of arginine may be the result of the combinations of SO(2), NO(3) and NH(3) emissions of the pulp mill. The emissions did not have any impact on total amounts of defensive substances in trees. Thus, the possible susceptibility of conifers to herbivores appears to be due to changes in nutritive value rather than to reduced chemical resistance.  相似文献   

13.
以氯化镁和造纸草浆黑液为原料,采用物理活化法制得"氧化镁/活性炭"新型吸附剂,其比表面积(BET)为388.96 m2/g、总孔容积为0.40 mL/g。测定了这种吸附剂对水中Cr(Ⅵ)的吸附性能,考察了吸附时间、pH值、吸附剂投加量、初始浓度等因素对Cr(VI)的吸附量和脱除率的影响,研究所得吸附水溶液中Cr(Ⅵ)的最佳条件为:吸附时间为120min,吸附剂投加量为2 g/L,pH值为2。"氧化镁/活性炭"新型吸附剂对Cr(Ⅵ)的吸附过程符合Freundlich等温式。  相似文献   

14.
造纸黑液酸析法回收木质素   总被引:18,自引:0,他引:18  
研究了加酸沉淀回收碱法草浆黑液中木质素的工艺,探讨了酸浓度,温度,pH值及加酸速度对木质素回收量的影响,得出的最佳条件是:硫酸浓度为50%,温度为40℃ ̄50℃,pH值为3.0左右,加酸速度以控制不使产生大量泡沫为准。在上述条件下,木质素的回收效果最佳。  相似文献   

15.
以氯化镁和造纸草浆黑液为原料,采用物理活化法制得“氧化镁/活性炭”新型吸附剂,其比表面积(BET)为388.96 m2/g、总孔容积为0.40 mL/g。测定了这种吸附剂对水中Cr(VI)的吸附性能,考察了吸附时间、pH值、吸附剂投加量、初始浓度等因素对Cr(VI)的吸附量和脱除率的影响,研究所得吸附水溶液中Cr(VI)的最佳条件为:吸附时间为120 min,吸附剂投加量为2 g/L,pH值为2。“氧化镁/活性炭”新型吸附剂对Cr(VI)的吸附过程符合Freundlich等温式。  相似文献   

16.
The impact of industrial heavy metal pollution on Scots pine (Pinus sylvestris L.) and black pine (Pinus nigra Arn.) populations was investigated. Sampled pine stands, which were located in Upper Silesia (southern Poland) in an area strongly polluted by heavy metals, consisted of resistant and sensitive trees. To evaluate the adaptation process, genetic structure and diversity was tested using isozyme analysis. Higher levels of Zn, Pb, Cd and Cu were detected in needles of sensitive trees compared with resistant ones. With respect to morphology, Scots pines were more distinctly impaired than black pines. Although black pines had lower heavy metal concentrations, levels in 1-year-old needles, other than Cu, significantly exceeded “reference plant” values (Markert 1994). In both species, resistant trees demonstrated a lower degree of genetic variation than metal-sensitive trees with respect to some enzyme loci (SHDH A, PGI, PGM, MDH C and DIA). This observation was corroborated in sensitive trees by the smaller number of identified alleles and alleles per locus, absence of private alleles and significant excess of homozygotes in relation to expected Hardy–Weinberg equilibrium values. Assuming that only resistant trees of both species survive under conditions of prolonged soil contamination, the observed genetic structure implies that remaining populations will be depleted of some alleles of unknown adaptive value to future selection pressures. Genetic changes induced by heavy metals suggest an important role for specific enzymes—FEST, SHDH A and B, GOT B and PGI—in the adaptation process. Our results may serve as a basis for selection and propagation of individuals appropriate for re-cultivation of areas chemically degraded by industrial activity.  相似文献   

17.
通过对亚铵法麦草浆黑液性质的研究 ,提出了蒸发浓缩 +生物活性有机肥生产的新技术路线 ,并结合生产实践对该技术加以研究、归纳 ,并进行了经济分析。实践证明 ,运用该技术不仅能实现亚铵法麦草浆黑液的回收和污染治理达标 ,而且能为企业带来可观利润 ,使企业走上可持续发展之路。  相似文献   

18.
This paper presents the performance of two bench scale Upflow Anaerobic Sludge Blanket reactors (UASB) used for the treatment of synthetic substrates that simulate bleached and unbleached cellulose pulp plant wastewaters. The control reactor was fed with diluted black liquor and the treatment reactor with the same substrate plus a mixture of chlorinated organics. The total concentration of the chlorinated compounds was gradually increased from 2.5 mg l-1 to 15.0 mg l-1. The average COD removal efficiency during the last phase of the experiment was 81% in the control reactor and 76% in the treatment reactor. These results indicate the capability of UASB reactors to treat this kind of wastewater and the low impact of the chlorinated organics on COD removal efficiency. The minimum overall chlorinated organics removal efficiency was 71% and the maximum was 99.7%. The experiment indicates that under the conditions used in this research the presence of chlorinated organics does not negatively impact the treatment process.  相似文献   

19.
Abstract

Data obtained from 24 of the 31 sites of the Pacific Northwest Regional Visibility Experiment Using Natural Tracers (PREVENT) study were analyzed by the Receptor Model Applied to Patterns in Space (RMAPS) multivariate receptor model. Four spatial patterns were found and interpreted as showing the effect of the coal-fired power plant in Centralia, WA; transport from the northwest; the Se-attle-Tacoma urban area; and transport from the southeast. In Mt. Rainier National Park, up to one-third of the sulfate can be attributed to the Centralia power plant. In the North Cascades National Park, 65-82% of the sulfur is accounted for by transport from Canada. The model was applied separately to sites in the northern and southern sections of the study area. The southern sites were affected only by the Centralia, urban, and southeast transport sources; the northern sites were affected only by the northwest transport, urban, and southeast transport sources. This gave two independent estimates of the normalized source contributions of the urban and southeast transport factors, which had a correlation coefficient of more than 0.90.  相似文献   

20.
Endosulfan is a cyclodiene organochlorine currently widely used as an insecticide throughout the world. This study reports that the endosulfan isomers can be readily dissipated from aqueous systems at neutral pH in the absence of biological material or chemical catalysts, in the presence or absence of oxygen. The study showed that aldrin, dieldrin, and endosulfan exhibit bi-phasic loss from water in unsealed and butyl rubber sealed vessels. Half-lives are substantially increased for endosulfan I when oxygen is removed from the incubation vessel. The study conditions, where PTFE was used, were such that loss due to volatilization and alkaline chemical hydrolysis was eliminated. Half-lives determined from these data indicate that the parent isomers are much less persistent than the related cyclodienes, aldrin and dieldrin, confirming the findings of previous studies. The major oxidation product of endosulfans I and II, endosulfan sulfate, is less volatile and can persist longer than either of the parent isomers. Endosulfan sulfate was not formed in any of the treatments suggesting that it would not be formed in aerated waters in the absence of microbial activity or strong chemical oxidants. Since endosulfan sulfate is formed in many environments through biological oxidation, and is only slowly degraded (both chemically in sterile media and biologically), it represents a predominant residue of technical grade endosulfan, which finds its way into aerobic and anaerobic aquatic environments. The data obtained contributes to and confirms the existing body of half-life data on endosulfan I and II and its major oxidation product, endosulfan sulfate. The half-life data generated from the current study can be used in models for predicting the loss of chlorinated cyclodiene compounds from aqueous systems. The findings also highlight the importance of critically reviewing half-life data, to determine what the predominant processes are that are acting on the compounds under study.  相似文献   

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