30-50吨/日横管式连续蒸煮器的设计和应用

自从国际上第一套横管式连续蒸煮器投产以来,历经考验和改进,取得了很大的发展,其使用价值已经得到充分肯定。七十年代以来,国外的横管式连续蒸煮器的生产规模日趋扩大;国内外有一部分人认为,小规模生产采用横管式连续蒸煮器是不经济的。那么,规模较小,例如30～50吨/日横管式连续蒸煮器,在现阶段的使用价值及其前景究竟如何?本文将结合国情对这一问题进行讨论。     

草浆横管式连续蒸煮器的特性及其工艺

横管式连续蒸煮器(简称连蒸器)是连续蒸煮器中的一种类型,它具有生产效率高,蒸煮浆的质量好,纸浆得率高等优点,特别是对于草类纤维采用横管式连续蒸煮器则效益更为显著。国内在这方面做了不少工作。近年来由于有关部门和单位的关注和重视,     

横管式连续蒸煮器（又称潘迪亚式）在国内非木材纤维制浆的推广应用

本文介绍了连续蒸煮器的种类与发展，对横管式连续蒸煮器应用于国内非木材原料制浆的发展、配套设备选择及工艺要求作了详细阐述。     

横管式连续蒸煮器的运行实践

正确的操作与维护是横管式连续蒸煮器正常运行的首要条件,本文分析和研究了国内主要几台横管式连续蒸煮器使用中出现的问题与原因,并相应提出了正确的操作方法及设备的改进意见。     

改进螺旋进料器设计的几点看法

螺旋进料器是横管连续蒸煮系统的关键设备,它不仅关系到整个系统能否连续进料、稳定运转,而且对纸浆的强度也有明显的影响。因此,自从螺旋进料器被应用于横管连续蒸煮系统以来,人们一直在努力设法提高和改进其使用性能,且主要是从设计着手的。迄今,螺旋进料器主要是靠经验设计,     

对横管式连续蒸煮器的实践与认识

一、概述横管式连续蒸煮器已应用于各种纤维原料的蒸煮,从半化浆到全化浆都能生产。但是它最适合的是草类纤维。草类纤维的一个共同特点是组织疏松,木素含量低。因此可以用较少量的化学药剂,通过短时间高温蒸煮,制得质量好、得率高的浆料。由我国自己设计制造的横管式连续蒸煮     

横管连续蒸煮器连续运转的基本条件

着重探讨了原料净化与横管连续蒸煮系统的关系以及系统的设备选型、操作、系统流程及设备布置设计的要点；介绍了一种适合于连蒸系统的有效的湿法备料技术，并指出保证横管连蒸器正常运转的最基本条件。     

连蒸螺旋进料器堵塞和技改对策

从芬兰引进的Pandia横管连续蒸煮器，由于生产原料的变化，使其螺旋进料器堵塞的现象日趋严重，本文介绍了滑差电机拖动系统技改的想法与做法。     

国产连蒸设备用于中性亚铵法制半化学棉杆浆

我厂由天津轻工机械厂制造的日产30吨双横管连续蒸煮器,经过近3个月的紧张安装及20多天的蒸煮试验,对其设备使用性能有了一定的了解.并初步摸索了采用中性亚铵法制半化学浆的生产工艺. 一、连续蒸煮工艺流程示意图     

双转鼓计量器的设计和使用范围

横管式连续蒸煮器正常运转的先决条件之一是要求进料连续、均匀。为此,在原料进入连续蒸煮器主体设备时,要先经过计量或限料装置,特别是使用的原料为草类纤维时,计量装置更是不可缺少。用于蒸煮草类纤维的计量装置或限料装置,有双转鼓计量器、单转鼓计置器、双螺旋计量器、单螺旋计量器和齿辊式喂料器等多种。 双转鼓计量器的计量准确率较高,适用原料品种也较多。美国BC公司设计采用的大多数是这种型式;我国横管连续蒸煮系统也多数采用这种计量装置。通过多年生产实践,国产双转鼓计量器的性能已可与国外同类产品媲美。     

不同蒸煮设备的能耗分析

介绍了化学法蒸煮木浆的卡米尔连蒸、碱法立锅、酸法立锅的热效率和能量效率及化学法蒸煮草浆的横管连蒸、蒸球的热效率和能量效率。     

深度脱木素技术的发展

本文介绍了深度脱木素的基本原理及其在连续蒸煮器和间歇蒸煮器中应用的发展情况。     

减轻亚硫酸铵法制浆对蒸球的腐蚀

叙述了亚硫酸铵法制浆用的蒸球、蒸煮药液和正确的操作方法，以减轻对蒸球的腐蚀。     

Effect of temperature on the fate of genes encoding tetracycline resistance and the integrase of class 1 integrons within anaerobic and aerobic digesters treating municipal wastewater solids

The objective of this research was to investigate the ability of anaerobic and aerobic digesters to reduce the quantity of antibiotic resistant bacteria in wastewater solids. Lab-scale digesters were operated at different temperatures (22 °C, 37 °C, 46 °C, and 55 °C) under both anaerobic and aerobic conditions and fed wastewater solids collected from a full-scale treatment facility. Quantitative PCR was used to track five genes encoding tetracycline resistance (tet(A), tet(L), tet(O), tet(W), and tet(X)) and the gene encoding the integrase (intI1) of class 1 integrons. Statistically significant reductions in the quantities of these genes occurred in the anaerobic reactors at 37 °C, 46 °C, and 55 °C, with the removal rates and removal efficiencies increasing as a function of temperature. The aerobic digesters, in contrast, were generally incapable of significantly decreasing gene quantities, although these digesters were operated at much shorter mean hydraulic residence times. This research suggests that high temperature anaerobic digestion of wastewater solids would be a suitable technology for eliminating various antibiotic resistance genes, an emerging pollutant of concern.     

Effects of temperature and hydraulic retention time on anaerobic digestion of food waste

A modified three-stage methane fermentation system was developed to digest food waste efficiently. This system consisted of three stages: semianaerobic hydrolysis, anaerobic acidogenesis and strictly anaerobic methanogenesis. In this study, we examined the effects of temperature and hydraulic retention time (HRT) on the methanogenesis. Operation temperature was adjusted from 30 degrees C to 55 degrees C, and the HRTs ranged from 8 to 12 d. The rate of soluble chemical oxygen demand (sCOD) removal correlated with digestion time according to the first-order kinetic model developed by Grau et al. [Water Res., 9, 637-642 (1975)]. With liquor food waste, thermophilic digesters showed a higher rate of sCOD removal than mesophilic digesters. The rates of biogas and methane production by thermophilic digesters were higher than those by mesophilic digesters regardless of HRT. Although maximum biogas production occurred when an HRT of 10 d was used, the methane yield was the highest in the reactor when an HRT of 12 d was used (223 l CH4/kg sCODdegraded). However, digestion stability decreased when an HRT of 8 d was used. The concentration of NH3-N generated in this experiment did not inhibit anaerobic digestion.     

Applicability of random cloning method to analyze microbial community in full-scale anaerobic digesters

Microbial communities were analyzed in six full-scale anaerobic digesters and a lab-scale digester using the random cloning method. The purposes were to confirm the applicability, reproducibility, and error range of this method; to discuss the difference in the dominant microbes determined by this method in different operational conditions of temperature (mesophilic and thermophilic) and substrate (garbage, sewage sludge, and livestock waste); and to determine key microbes in each digester. Each sample was analyzed in triplicate. In one of the samples, 373 clones were analyzed to study the composition of microbial community in the digester. Time course analysis was conducted from the start-up period for approximately one year in one of the digesters. Similar microbial diversity was obtained corresponding to the type of substrate change (sewage sludge to garbage). Operational taxonomic units (OTUs) closely related to Coprothermobacter sp. and unidentified bacterium clones TUG14 and TUG22 disappeared during the first 40 d, while OTUs closely related to Bacillus sp. and Clostridium sp. increased later. Microbial diversity in digesters is strongly affected by the operational conditions, and similar microbial diversity can be obtained in triplicate analysis and under similar operational conditions. The present study verified the applicability of this method to discuss the overall difference in microbial communities.     

Digesters and demographics: identifying support for anaerobic digesters on dairy farms

The dairy industry in the United States is amidst a long-running trend toward fewer, larger dairy farms. This development has created a backlash in some communities over concerns such as odor, waste management, and environmental degradation. Separately, anaerobic digestion has advanced as a waste management technology that potentially offers solutions to some of these issues, providing odor control and a combustible biogas among other things. These digesters require significant capital investments. Voluntary consumer premiums for the renewable energy produced have been used in some instances as a means to move adoption of such systems toward financial feasibility. This project employed a survey to measure Ohio consumers’ willingness to pay a premium for renewable energy produced by anaerobic digesters on dairy farms. Cluster analysis was used to segment consumers by willingness to pay, age, education, income, self-identified political inclination, and a composite variable that served as a proxy for respondents’ environmental stewardship. Four distinctive groups emerged from the data. Older, less educated respondents were found to have the least amount of support for digesters on dairy farms, whereas politically liberal, environmentally proactive respondents demonstrated the strongest support. Well-educated, affluent respondents and young respondents fell between these 2 groups. Most large dairy farms are generally met with fairly negative responses from their local communities; in contrast, this research finds some popular support for anaerobic digestion technology. Going forward, establishing a positive link between support for anaerobic digesters and for their use on large dairies could open up a new route for less-contested large dairy farm developments. Evaluation of community demographics could become an important part of finding an optimal location for a large dairy farm.     

常规立锅蒸煮的污热水系统运行和问题探讨

介绍某浆厂立锅蒸煮污热水系统生产运行情况,重点对设备选型进行计算分析,分析了系统水垢问题的成因,提出并探讨了相应采取的措施.     

提高糖化生产能力的新工艺

采用湿法粉碎、新型高效过滤槽、两个煮沸锅等新的工艺流程和技术，不改变原料配方和原料等级，只增加少量投资，可提高糖化生产能力和麦汁质量。     

Anaerobic digestion of dairy manure influenced by the waste milk from milking operations

It is not uncommon that a significant amount of milk from milking operations is discharged to manure digesters on dairy farms. To understand the effect of milk on the digester performance, experiments using batch digesters (500-mL flasks) were carried out in this study to co-digest milk and dairy manure at different milk levels for biogas production and pollutant reduction, and a total of 8 treatments were examined [i.e., control (without milk) and 1, 3, 5, 7, 9, 14, and 19% milk additions]. The temperature for all digesters was maintained at 37 ± 0.5°C throughout the experimental period, which was 28 d. The results showed that co-digesting milk with dairy manure could increase biogas productivity, with the percent cumulative biogas volume increased by 5.6, 16.3, 26.5, 40.8, 50.2, 79.9, and 103.8%, as compared with the control, for milk addition of 1, 3, 5, 7, 9, 14, and 19% (vol/vol), respectively. However, the CH₄ content in the biogas decreased slightly as the milk content increased (from 66.5% for the control to 63.5% for 19% milk treatment), implying that the added milk could promote CO₂ production. To avoid that, the milk content in the manure should be controlled below 3%. A linear relationship for the total biogas volume produced with the milk content in the manure was revealed, with a correlation coefficient of 0.99. An improved removal efficiency of chemical oxygen demand was observed for milk-treated digesters. Good linear regressions between the total biogas production and the percent chemical oxygen demand decrease and the substrate carbon/nitrogen ratio were also obtained (correlation coefficients: 0.93 and 0.99, respectively). Besides, co-digestion of dairy manure and milk was found to improve substrate solids breakdown, but had little effect on percent volatile fatty acid decrease. In summary, the waste milk co-digested with dairy manure may not cause negative effects on anaerobic digester performance.