Experience in the Introduction of Steam-Water-Oxygen Cleaning, Passivation, and Preservation at the TÉTs-23 Cogeneration Plant of the Mosénergo Company

Conditions of the process of steam-water-oxygen cleaning, passivation, and conservation (SWOC, P, and C) of internal heating surfaces of the boiler and the high-pressure feed heater (HPFH) piping over the steam side are presented. The process produces partial cleaning of the internal heating surfaces from scale and yields a corrosion-resistant protective film that hinders corrosion processes both in the operation of the boiler and in the idle period.     

Results of steam-water-oxygen treatment of boiler units for the 300-MW power-generating sets at the Novocherkassk State Area Power Station

A steam-water-oxygen treatment, passivation, and preservation (SWOT, P, and Pr) of the internal heating surfaces of TPP-110, P-210, and P-210A boilers for the 300-MW power-generating sets have been successfully introduced at the Novocherkassk State Area Power Station (SAPS). The condition of the treated heating surfaces of the boilers while in service or on stand-by was investigated to determine the required periodicity of the SWOT, P, and Pr under the service loads and existing water-chemical regime. Specific results of the investigation are presented. __________ Translated from élektricheskie Stantsii, No. 2, February, 2007, pp. 40–42.     

Cleaning of boiler heating surfaces

Basic methods and facilities for the external cleaning of the heating surfaces of boilers designed for the combustion of low-grade solid fuels are discussed. Water and steam blastings, which are the basic means of cleaning furnace shields, and semi-radiative and convective heating surfaces have the greatest range of application. __________ Translated from élektricheskie Stantsii, No. 7, pp. 29–32, July, 2006.     

同步化学在线清洗技术在发电厂的应用

利用化学在线清洗技术，采用Y—CH107清洗剂和辅助生物黏泥剥离、清洗及钝化一体化在线清洗工艺，在不影响机组发电的情况下，pH值控制在4—5，实施了3×390MW机组循环冷却水系统的同步在线清洗，有效控制系统内不同材质的腐蚀速率并取得了满意的效果。以杭州华电半山发电有限公司3×390MW燃气一蒸汽联合循环汽轮发电机组为例，简述了循环水系统化学在线清洗的技术运用情况及其实施过程和清洗效果，对产生的经济效益进行了分析。     

Tests of a P-67 boiler for an 800 MW unit

The rebuilding of the P-67 boiler for an 800 MW unit at the Berezovskaya GRéS, as well as changes in the thermal engineering characteristics of the coal from the Berezovskii-1 seam and its slagging properties, are described. The results of balance tests of the boiler and changes in the thermal efficiency of heating surfaces during 2006 – 2008, including after mechanical cleaning and modernization of the combined cleaning system, as well as with coal dust coarsening and loading of the lower burner layers and downward blast, are discussed.     

Results of Combined Cleaning of the Internal Heating Surfaces of High-Pressure Heaters

The technology, flow diagram, and results of combined cleaning of deposits from the internal heating surfaces (tubes) of high-pressure heaters are describe     

高寒地区碾压混凝土坝岸坡坝段保温方案研究

高寒地区某碾压混凝土重力坝岸坡坝段，原温控设计提出在上、下游面采用喷涂12cm厚聚氨酯进行永久保温。根据工地现场左右岸坝段开挖较深的实际情况，对原上、下游面的保温方案进行了优化，提出对上、下游面喷涂聚氨酯结合填土的保温方案，但在回填填土前，应对坝体上下游面、浇筑水平层面做好临时保温工作，临时保温采用3cm厚聚氨酯发泡被。三维有限元仿真计算结果表明，本方案能达到较好的越冬保温效果，有效防止上、下游面表面裂缝的产生，且施工方便、节约投资，可为类似工程的保温提供借鉴。     

S15标渠道混凝土机械衬砌施工试验

南水北调中线京石段应急供水工程全面开工，渠道机械衬砌施工工艺都在不断的试验阶段，结合渠道项目S15标衬砌试验的全过程，从衬砌基面清理，保温板及土工膜铺设，机械衬砌混凝土，混凝土的振捣、抹面、切缝等几个方面，对机械衬砌的施工工艺方法进行了总结归纳，确定了其中的工艺参数，为今后的类似工程提供借鉴和参考。     

Cleaning the Zakharkovo quarry of technogenic sediments from the Rublevo water-works plant by hydromechanization

A method is given for the cleaning of water bodies silted by pipeline sediment. __________ Translated from Gidrotekhnicheskoe Stroitel’stvo, No. 7, July 2007, pp. 14–16.     

Biological coating of EPDM-membranes of fine bubble diffusers.

Biological coatings on EPDM-membranes are a problem on many large wastewater treatment plants, as the oxygen supply of the micro-organisms is no longer guaranteed. Investigations prove that the pressure loss and the Shore A-hardness of the EPDM-membranes increase while on the other hand their softener content decreases accordingly. The detected coatings on the membrane surfaces and in the slits or holes of the membranes show extra-cellular organic substances (EPS), which, compared with fibrillar/filamented EPS usually found on surfaces in wastewater treatment plants, are viscous to a much greater extent. As, besides primary organic parts (carbon), the coatings on the membranes as well as in the slits or holes also consist of inorganic constituents (magnesium, silicon, and others), the authors assume that, the separating agent (and also inactive filler) talcum (magnesium silicate), used when producing the membranes, supports at least a first beginning of the coating. Superfine dust constituents and fibres, input via the compressed air, will build up inside the coating and consequently lead to a gradual clogging of the holes or slits. Besides chemical cleaning measures, the exchange of the EPDM-membranes against membranes of silicone would also be a possible measure to solve this problem. The market will decide, if, in the future, a cleaning or an exchange of the EPDM-membranes against membranes of silicone will be applied, but it has to be considered that the loss of softener is irreversible.     

Behavioural study of the golden apple snail (Pomacea canaliculata) in a Tropical Lake,Chenderoh Reservoir,Malaysia

A survey on the egg deposition behaviour of the golden apple snail (Pomacea canaliculata) was conducted at Chenderoh Reservoir in Malaysia. The distribution of P. canaliculata and medium preferences for egg deposition in the lake were recorded. The egg deposition mediums included aquatic plants, rocks and boats and other artificial structures. The number of egg clusters on the aquatic plants was counted to examine the preferred plant species for egg deposition, being collected thereafter for hatching test. This study findings indicated P. canaliculata laid eggs on the stems and leaves of aquatic plants, with a 43% occurrence compared to the other hard medium surfaces such as boats, rocks, fish cages and emerged bamboo piles, with a 14% occurrence recorded for each medium. A total of 65% of the eggs were deposited on the stems, and 35% on the leaves, of the aquatic plants. Phragmites australis (41%) of the Poaceae family was the most preferred plant for egg deposition, whereas the least preferred plant for egg deposition was Neptunia oleracea (3%) of the Fabaceae family. There was no significant difference (p < 0.5) in the percentage of hatched egg between the submersed and nonsubmersed hatching tests. The incubation period of the egg to hatch period was approximately 14 days upon the hardening of the calcium shell. In addition, about 60% of the eggs hatched, even though the eggs were immersed in the water. As the invasive P. canaliculata is considered to be in the top 100 of the “World Most Invasive Alien Species,” these types of behavioural studies are needed to better understand and control the snail, reducing the economic loss, especially in the agriculture sector, as well as facilitating a healthier lake environment.     

Factors controlling the establishment of Fremont cottonwood seedlings on the Upper Green River,USA

Declines in cottonwood (Populus spp.) recruitment along alluvial reaches of large rivers in arid regions of the western United States have been attributed to modified flow regimes, lack of suitable substrate, insufficient seed rain, and increased interspecific competition. We evaluated whether and how these factors were operating during 1993–1996 to influence demographics of Fremont cottonwood (P. deltoides Marshall subsp. wislizenii (Watson) Eckenwalder) along reaches of the Green and Yampa Rivers near their confluence in northwestern Colorado. We examined seedling establishment, defined as survival through three growing seasons, at three alluvial reaches that differed primarily in the level of flow regulation: a site on the unregulated Yampa, an upper Green River site regulated by Flaming Gorge Dam, and a lower Green River site below the Green–Yampa confluence. Seed rain was abundant in all sites, and led to large numbers of germinants (first‐year seedlings) appearing each year at all sites. The regulated flow in the upper Green River reach restricted germination to islands and cut banks that were later inundated or eroded; no seedlings survived there. Mortality at the lower Green River site was due largely to desiccation or substrate erosion; 23% of 1993 germinants survived their first growing season, but at most 2% survived through their second. At the Yampa River site, germinants appeared on vegetated and unvegetated surfaces up to 2.5 m above base flow stage, but survived to autumn only on bare surfaces at least 1.25 m above base flow stage, and where at least 10 of the upper 40 cm of the alluvium was fine‐textured. Our studies of rooting depths and the stable isotopic composition of xylem water showed that seedlings in the most favorable locations for establishment at the Yampa site do not become phreatophytic until their third or fourth growing season. Further, the results of experimental field studies examining effects of shade and competition supported the hypothesis that insufficient soil moisture, possibly in combination with insufficient light, restricts establishment to unvegetated sites. Collectively, the demographic and experimental studies suggest that, in arid regions, soil water availability is at least as important as light level in limiting establishment of Fremont cottonwood seedlings. We hypothesize that in cases where arid land rivers experience large spring stage changes, recruitment is further constrained within bare areas to those sites that contain sufficient fine‐textured alluvium, saturated during the spring flood, to provide the flood‐derived soil moisture normally necessary for late‐summer seedling survival. Copyright © 1999 John Wiley & Sons, Ltd.     

An experimental assessment of the effectiveness of gravel cleaning operations in improving hyporheic water quality in potential salmonid spawning areas

Dissolved oxygen (DO) conditions within the hyporheic zone were investigated in a gravel stream (River Sieg) in North Rhine Westphalia, Germany, populated in the spawning season by recurring migratory fish species, like Atlantic salmon (Salmo salar L.) and sea trout (Salmo trutta trutta L.). The gravel bed was cleaned at three sites in an area of approximately 150 m² to a depth of 50 cm, reducing the quantity of grains <2 mm to below 0.2%. DO concentrations in cleaned and uncleaned sediments were monitored in situ at 10, 20 and 30 cm sediment depth from the end of November 2001 to the end of April 2002. DO showed only minor fluctuations at the cleaned sites and steadily decreased at all uncleaned sites over time. Fine sediment accumulation over 5 months in the cleaned sites was comparable to the proportion of material within the bed prior to the experimental cleaning and probably influenced the DO concentrations of the hyporheic water. Decreasing DO concentrations at all sites coincided with increasing water temperatures towards the end of the study period. The cleaning operation significantly improved the conditions of DO in the hyporheic zone of the three study sites. Copyright © 2008 John Wiley & Sons, Ltd.     

Short- and long-term fouling characteristics of reverse osmosis membrane at full scale leachate treatment plant

This research is focused on characterizing the foulants on a reverse osmosis (RO) membrane taken from a full-scale leachate treatment plant in Thailand. The system consists of a physico-chemical pre-treatment unit and RO system and has been in operation for 2 years. Ferric chloride (FeCl(3)) was added to the open-jet sedimentation tank at 2.0-2.5 g/l dosage for chemical coagulation. The supernatant from the sedimentation tank was polished using a pressurized sand filter prior to entering the RO system. The RO unit consists of seven pressurized vessels and 42 membrane elements (6 elements in each vessel). The recovery ratio and operating pressure in the RO system were maintained at 50% and 1.5-2.5 MPa. Fouled membranes obtained from short-term (6 months) and long-term operation (2 years) were taken from the system and analyzed by autopsy and sequential cleaning methods. The analysis of foulants on the membrane surfaces revealed that Fe deposits at 3.11 g/m(2). For short-term operated membranes, water cleaning could recover 32.14 and 7.45% of initial pure water flux on the 1st and 6th membrane elements. NaOH cleaning, however, recovered more than 90% of initial flux, much higher than that of HCl solution in both elements. For long-term operated membranes, pure water flux recovery was below 5% for both 1st and 6th elements. Sequential cleaning by NaOH followed by HCl yielded the best results. Nevertheless, flux recovery through sequential cleaning of long-term operated membranes was only 35.3 and 19.1% for the 1st and the 6th elements, respectively.     

Increasing the corrosion resistance of equipment due to the use of film-forming amines

Results of a study of tube specimens cut from hot-water boilers show that film-forming octadecyl amine (ODA) used in the process of preservation removes deposition from the surface of the metal. An ODA film is preserved on the surface after repeated washing of the latter with hot water. The concentration of chlorides at the surface of the metal after treatment with ODA is lower than before the treatment. __________ Translated from élektricheskie Stantsii, No. 11, November 2005, pp. 15–18.     

Results of heat tests of the TGE-435 main boiler in the PGU-190/220 combined-cycle plant of the Tyumen’ TÉTs-2 cogeneration plant

Special features of operation of a boiler operating as a combined-cycle plant and having its own furnace and burner unit are descried. The flow of flue gases on the boiler is increased due to feeding of exhaust gases of the GTU into the furnace, which intensifies the convective heat exchange. In addition, it is not necessary to preheat air in the convective heating surfaces (the boiler has no air preheater). The convective heating surfaces of the boiler are used for heating the feed water, thus replacing the regeneration extractions of the steam turbine (HPP are absent in the circuit) and partially replacing the preheating of condensate (the LPP in the circuit of the unit are combined with preheaters of delivery water). Regeneration of the steam turbine is primarily used for the district cogeneration heating purposes. The furnace and burner unit of the exhaust-heat boiler (which is a new engineering solution for the given project) ensures utilization of not only the heat of the exhaust gases of the GTU but also of their excess volume, because the latter contains up to 15% oxygen that oxidizes the combustion process in the boiler. Thus, the gas temperature at the inlet to the boiler amounts to 580°C at an excess air factor α = 3.50; at the outlet these parameters are utilized to T _out = 139°C and α_out = 1.17. The proportions of the GTU/boiler loads that can actually be organized at the generating unit (and have been checked by testing) are presented and the proportions of loads recommended for the most efficient operation of the boiler are determined. The performance characteristics of the boiler are presented for various proportions of GTU/boiler loads. The operating conditions of the superheater and of the convective trailing heating surfaces are presented as well as the ecological parameters of the generating unit. __________ Translated from élektricheskie Stantsii, No. 12, December 2006, pp. 26–32.     

Removal of organic sediments from reservoirs and lakes and their processing

The experimental-industrial cleaning of Latvian lakes and the removal of sapropel at its in situ moisture content by a suction-tube dredge with a chambered pneumatic pump made by the Italian firm Pneuma, and also a new procedure for production of commercial sapropel are described.     

Application of the Regional Flood Frequency Analysis to the Upper and Lower Basins of the Indus River,Pakistan

The paper presents results of an application of the L-moments based regional flood frequency analysis to annual maximum peak (AMP) flows observed at seven stations (Tarbela, Kalabagh, Chashma, Taunsa, Guddu, Sukkur and Kotri) located on the main stream of the Indus River, Pakistan. The results of Run-test and lag-1 correlation coefficient showed that the data series at given sites is random and has no serious serial correlations respectively. Furthermore, the results of Grubbs and Beck test illustrated that there are no irregularities (abrupt variations) except low outlier(s) in the data series at various sites. To avoid their undue influence, these low outliers have been discarded and the sample information has been re-summarized using the idea of left censored type A ^′ partial probability weighted moments. L-moments based regional heterogeneity measure (H) showed that the region, defined by seven stations, is heterogeneous; therefore, it has been sub-divided into two homogeneous regions (Region 1 and Region 2 consist of four (Tarbela, Kalabagh, Chashma and Taunsa) and three sites (Guddu, Sukkur and Kotri, respectively) using Ward’s clustering method based on the site characteristics only. The results of various goodness-of-fit measures (L-moment ratio diagram, average weighted distance and Z ^DIST measures) showed that Region 1 has four candidates: generalized normal (GNO), generalized logistic (GLO), generalized extreme-value (GEV) and Pearson type III (PE3), while Region 2 has only one candidate; GLO, as regional distribution. Based on the results of different accuracy measures (regional average absolute relative bias, relative bias and relative root mean square error) of the estimated regional growth curves and quantiles, obtained from simulation experiments, PE3 is the robust distribution for Region 1, while for Region 2, GLO distribution can be used for the estimation of flood quantiles. Moreover, the results of the simulations study have been extended to obtain standard errors of the estimated quantiles at each site of the sub-divided homogeneous regions.     

印尼ASAHAN No.1水电站清污机设计特点

通过对印尼Asahan No.1水电站清污机设计特点及运行概况介绍,指出电站取水口清污设备的布置及选型对电站的安全运行和经济效益十分重要,清污设备布置恰当、设计合理不仅给电站的运行管理带来方便,更能创造出良好的经济效益。     

浅论水质样品的保存方法

在水质检测工作中,正确合理的水样采集和保存方法,是确保检测数据准确和公正的首要条件,除了现场进行的检测项目外,水样在测定前由于物理、化学、生物的作用会发生不同程度的变化[1]。本文着重介绍不同条件下天然水样的保存方法对几种水质参数测定的影响情况,分析水质参数发生变化的原因,进而对天然水样如何进行合理的保存,以及其应注意的相关问题进行探讨。