钢铁行业超低排放改造无组织排放控制难点分析

钢铁行业规模大、污染强是显著特点,传统工艺模式已经不能满足国家节能降耗要求,必须进行超低排放改造。通过论述钢铁行业超低排放具体的要求和超低排放改造无组织排放控制难点,提出了钢铁行业超低排放改造无组织排放控制策略,包括要坚持源头削减、过程控制和末端治理相结合,资源配置与技术改造同步进行,健全制度与环境监督并举,达到突出无组织排放控制的效果。     

梅山矿业污染物综合排放达标

据从宝钢集团梅山矿业公司环保部门报道,2002年至今,该公司废水污染物综合排放、废气污染物综合排放、燃煤锅炉烟尘排放、燃煤锅炉烟气SO2排放、硫酸厂尾气SO2排放合格率均为100%,环境污染事故为零。梅山矿业污染物综合排放达标     

机动车尾气和非尾气排放多环芳烃及其衍生物的影响因素研究进展

机动车尾气排放多环芳烃(PAHs)及其衍生物主要源于化石燃料的不完全燃烧,排放特征随燃烧条件和燃料种类变化而有所不同.随着尾气排放控制标准日益严格和新能源汽车的逐渐普及,非尾气排放污染对交通大气污染的贡献逐年加大.因此,包括刹车磨损、轮胎磨损、道路扬尘再悬浮和路面磨损在内的非尾气排放过程作为城市环境PAHs的重要污染源,其占比不容忽视.机动车来源PAHs及其衍生物的排放特征主要受燃烧条件、路面条件和机动车部件材料种类等多种因素影响.本文对国内外现有的机动车尾气排放以及非尾气排放PAHs及其衍生物的数据进行了梳理和总结.总的来说,对于尾气排放,严格的排放标准导致PAHs及其衍生物排放量降低;冷启动、加速等工况下,发动机燃烧效率降低,排放量增大;柴油车排放量远高于汽油车;汽油直喷发动机比气道喷射发动机排放更高;车辆行驶里程增加排放量增加.且研究发现刹车片化学成分、制动情况、轮胎材料和路面条件等均会影响排放,具有高度的不确定性,有待进一步研究.本文旨在分析机动车来源PAHs及其衍生物在不同影响因素下的排放特征,为排放控制技术发展和政策标准制定提供科学依据.     

电解锰生产企业温室气体排放核算方法与源解析

电解锰生产是我国工业企业中重要的温室气体排放源之一,而缺乏系统规范的核算方法制约了国家和行业对电解锰生产企业温室气体排放的研判和认识。根据电解锰生产特点,提出电解锰生产企业温室气体排放核算边界、排放源和计算方法,形成完整的核算方法。源解析表明,案例企业生产1 t电解锰产品排放5.36 t CO₂,矿石中碳酸盐分解和电力消费是主要排放源,分别占22%和74%;制液和电解过程是温室气体排放的主要生产工序,分别占30%和67%。降低电解过程的电力消耗、提高碳酸锰矿石品位是电解锰行业减少温室气体排放的优化路径。本研究可为电解锰行业开展温室气体排放核算和减排研究提供重要参考。     

钢铁流程结构及对CO_2排放的影响

温室气体排放引起的气候变暖已经成为全球性的重要命题。介绍了国内钢铁工业温室气体(主要是CO2)的排放情况,指出能源消耗是造成钢铁工业CO2排放的主要原因。在对比两类典型钢铁生产流程的CO2排放情况的基础上,深入分析了钢铁工业的能源结构及不同流程中原燃料来源结构对CO2排放的影响;最后对新一代钢铁制造流程的CO2排放进行了估算。     

辽宁钢铁行业脱硫工程启动年可减排20万t

近年来，随着辽宁省工业经济的快速发展，二氧化硫增量给污染减排带来巨大压力。据统计，辽宁省钢铁行业所排放的二氧化硫占全省非电行业二氧化硫排放总量的50％以上，而烧结机所排放的二氧化硫占钢铁行业排放总量的70％以上。     

铅锌等6项污染物排放新标准发布等简

铅锌等6项污染物排放新标准发布 新华社北京2013年12月27日消息,环保部27日会同国家质检总局发布了《铅、锌工业污染物排放标准》等6项有色金属行业排放标准修改单,增设了大气污染物特别排放限值。     

湖南省铅冶炼行业SO2烟气排放系数研究

对湖南省铅冶炼行业SO2烟气排放开展了全面的数据调研,分别计算了各工序实际SO2烟气有组织排放系数及理论排放系数,采用权重值计算得到湖南省铅冶炼行业SO2烟气综合排放系数,并对该系数与现有可参考的全国污染源排放系数的偏差进行了原因分析。     

钢铁工业污染物超低排放及对策思考

根据生态环境部发《钢铁企业超低排放改造工作方案(征求意见稿)》,分析研究了方案出台的背景,对照超低排放标准,分析研究了现有标准与超低排放标准之间的差距,确定了超低排放的改造重点和难点,提出了超低排放技术改造路线选择原则,为钢铁企业超低排放改造提供基本对策。     

钢铁工业钢渣处理工序无组织排放治理思考与实践

作为钢铁工业的重要组成部分，钢渣处理过程产尘量大、产尘点多、烟尘湿度大，超低排放改造难度大，是钢铁工业超低排放改造的重要环节。通过对宝钢湛江钢铁钢渣处理中心超低排放改造前钢渣转运、工艺降温、破碎分选工序无组织排放源的分析、治理措施的思考到最后的改造实施，使得全工序通过了超低排放评估审核。通过对钢渣处理过程无组织排放治理的思考与实践，为相同或相似工序提供借鉴与参考。     

洋鸡山金矿露天矿排水技术创新

文中介绍对洋鸡山金矿露天矿排水系统,是利用原坑采的坑道工程进行的技术创新。该技术降低了排水扬程３２．８ｍ缩短了排水管道近３００ｍ,改二级排水为一级排水,简化了现场管理,改善了排水状况。     

Interactive Effects of Controlled Drainage and Riparian Buffers on Shallow Groundwater Quality

As a result of recent surface water quality problems in North Carolina, riparian buffers and controlled drainage are being used to reduce the loss of nonpoint source nitrogen from agricultural fields. The effect of controlled drainage and riparian buffers as best management practices to reduce the loss of agricultural nonpoint source nitrogen from the middle coastal plain has not been well documented. The middle coastal plain is characterized by intensive agriculture on sandy soils with deeply incised or channelized streams. A 2-year study was conducted to determine the effectiveness of controlled drainage, riparian buffers, and a combination of both in the middle coastal plain of North Carolina. It was hypothesized that raising the water table near the ditch would enhance nitrate-nitrogen reduction through denitrification. On the sandy soils studied, controlled drainage did not effectively raise the water table near the ditch to a greater degree than observed on the free drainage treatment. Due to random treatment location, the free drainage treatment was installed along a ditch with a shallower impermeable layer compared to the impermeable layer on the controlled drainage treatments (2 m versus 3- to 4-m deep). This resulted in a perched or higher water table on the free drainage treatment. Over 17 storm events, the riparian buffer (free drainage) treatment had an average groundwater table depth of 0.92 m compared to 0.96 and 1.45 m for the combination (riparian buffer and controlled drainage) and controlled drainage treatments, respectively. Nitrate concentration decrease between the field wells and ditch edge wells averaged 29% (buffer only), 63% (buffer and controlled drainage), and 73% (controlled drainage only). Although apparently more nitrate was removed from the groundwater on the controlled drainage treatments, the controlled drainage treatment water table near the ditch was not raised closer to the ground surface compared to the free drainage treatment. Nitrate removal effectiveness was attributed to local soil and landscape properties, such as denitrification in deeper reduced zones of the soil profile.     

Percutaneous drainage of subperiosteal abscess: a potential treatment for osteomyelitis

OBJECTIVE: Intravenous antibiotics and surgical drainage are the accepted methods of treating osteomyelitis complicated by abscess formation. The objective of this study was to determine whether percutaneous drainage of subperiosteal abscess is a potential treatment for osteomyelitis. MATERIALS AND METHODS: Three pediatric patients with subperiosteal abscesses from acute osteomyelitis had percutaneous drainage with sonographic and fluoroscopic guidance using a Seldinger technique and an 8-F catheter. RESULTS: Two patients required no further intervention and had the drainage catheter removed after 72 h. After completing a course of antibiotics they healed completely. One patient, after a week of purulent drainage, required open drainage including a bone debridement of an area of septic necrosis. CONCLUSION: Percutaneous drainage of subperiosteal abscess may be an alternative to surgical drainage when medical therapy alone is inadequate. Development of intraosseous abscess, necrosis or persistent drainage suggests further intervention may be necessary.     

城门山铜矿采区排水设备安装工艺优化与实践

湖滨露天矿的排水,是采矿过程中的一项重要工作。它将随露天采区深度的增加和采区汇水面积增加,带来的汇水量增加,随之难度变大。以三面环湖的城门山铜矿为例,该矿为提高排水能力,将采区原排水系统升级为新型排水系统。运行一段时间后,发现新的排水设备在安装工艺方面存在弊端。该矿优化排水设备安装工艺,为其他露天金属矿山排水系统提供相应参考。     

气驱排渗技术及其在膏体尾矿筑坝工程的应用

果郎沟尾矿库为甲玛铜多金属矿二期工程配套尾矿库,采用初期坝+膏体上游法堆坝形式,实际运行过程中存在尾砂渗透系数低、不固结,且坝体浸润线埋深仅10 m左右等问题.华泰龙矿业公司采用气驱排渗技术,在坝体均匀布设特殊结构的竖直和水平排渗管,采用高压气驱和重力自流的联合排渗方式,大大提高了坝体排渗效率,浸润线埋深快速降低至20...     

Drainage Reduction under Land Retirement over Shallow Water Table

The retirement of land from agricultural production as a means of reducing the volume of subsurface drainage generated in the Western San Joaquin Valley, Calif., is under consideration. Reticence among local farmers and water managers renders only willing-seller land retirement feasible. There is an interest to acquire land that will generate the maximum possible drainage reduction relative to a “no retirement” baseline. An investigation was conducted to determine the drainage reduction potential of the retirement of (1) parcels that span land underlain by tile drains and land free of drainage infrastructure; (2) a “downgradient” parcel plagued by shallow ground water and equipped with subsurface tile drains; and (3) an “upgradient” parcel overlying well-aerated soil requiring no drainage. Long-term modeling with a deforming finite-element model suggests that the contiguous retirement yields the greatest drainage reduction. For single parcels, the 31% drainage reduction potential of downgradient retirement appears more attractive than the 16% drainage reduction associated with upgradient retirement.     

Applying MODFLOW Model for Drainage Problem Solution: A Case Study from Jahir Irrigated Fields, Israel

High water table and soil salinization processes are common in irrigated fields in Israel. Subsurface drainage systems are a common technique to solve soil salinity problems. Subsurface drainage models can contribute to the efficiency of the drainage system as it can assist in the selection of the proper drainage system and its proper placement in the field. In this study we used the MODFLOW groundwater flow model to simulate groundwater levels in Jahir irrigated fields, the Jordan Valley, Israel. Using a three-layer groundwater flow model, the most efficient drainage system was found to be a combination of deep drains with relief wells and a pump placed in the area with soil salinity problem and upward hydraulic pressure. It was found that simulated drainage system can yield nearly 200,000?m3 of water per year. Given certain information, a spatially distributed groundwater flow model such as MODFLOW can provide more reliable information than different analytical solutions for planning of an effective subsurface drainage system.     

Effects of three trans isomers of eicosapentaenoic acid on rat platelet aggregation and arachidonic acid metabolism

PURPOSE: To compare in a randomized, prospective manner infectious complication rates associated with presacral drainage versus no drainage in the presence of penetrating rectal injury. METHODS: During a 45-month period, 48 patients with penetrating rectal injuries were entered into a randomized, prospective study at an urban Level I trauma center. The patients were randomized to a presacral drainage group or a nondrainage group. Randomization was performed after detection of the rectal injury. Forty-four injuries were identified by proctoscopy (92%), with the rest detected intraoperatively or by physical examination. All patients with rectal injuries were included regardless of age, associated injuries, time from injury to operation, blood loss, severity of rectal injury, other abdominal organs injured, or hemodynamic stability. Rectal injuries were defined as those injuries to the large bowel distal to the peritoneal reflection. All rectal injuries underwent fecal diversion, and all drainage was accomplished using closed Jackson-Pratt drainage. RESULTS: Forty-eight patients were studied, of whom 25 were randomized to no drainage and 23 were randomized to presacral drainage. The average age for the nondrainage group was 21.9 years, and the average age for the presacral drainage group 26.0 years. The average Penetrating Abdominal Trauma Index score was 34.3 for the nondrainage group and 32.4 for the presacral drainage group. There were two (8%) septic complications (one perirectal and one perivesical abscess) associated with the rectal injuries in the presacral drainage group. The abscesses in the drainage group resolved after computed tomography-guided drainage. There was one (4%) septic complication (rectocutaneous fistula) in the nondrainage group, which was associated with a retained missile fragment. The fistula resolved after bedside percutaneous removal of the missile fragment. CONCLUSION: We conclude that presacral drainage for penetrating rectal injuries has no effect on infectious complications associated with the rectal injuries.     

Economics of Nitrate Losses from Drained Agricultural Land

Some of the highest losses of nitrate to surface waters come from drained agricultural land. This research studied, for Belgian farming conditions, (i) the effect of subsurface drainage density on nitrate losses and (ii) the economics of nitrate losses, using the nitrogen version of the program DRAINMOD-N. DRAINMOD was used to simulate the performance of the drainage system of the Hooibeekhoeve experiment, situated in the sandy region of the Kempen (Belgium) for a 14-year (1985–1998) period. A continuous cropping with maize was assumed. Daily NO3-N losses were predicted for a range of drain spacings and depths, two drainage strategies (conventional and controlled), and three fertilizer application rates (225, 275, and 325 kg?N?ha?1). Losses of N in subsurface drainage were assumed to occur almost entirely in the NO3-N form. Losses of organic and inorganic N in the form of NO3-N in surface runoff are small and were neglected. Hydrologic results indicated that increasing drain spacing or decreasing drain depth reduces drainage discharge while it increases runoff. The use of controlled drainage reduces subsurface drainage and increases runoff. Results also revealed that increasing the drain spacing or decreasing the drain depth reduces nitrate-nitrogen (NO3-N) drainage losses and net mineralization, while increasing denitrification and runoff losses. Controlled drainage caused a predicted reduction in drainage losses and an increase in denitrification and runoff losses. The optimal combination of drain density and management is one that maximizes profits and minimizes environmental impacts. Simulated results indicated that NO3-N losses to the environment could be substantially reduced by reducing the drainage density below the level required for maximum profits based on grain sales. The study concluded that, if the environmental objective is of importance equal to or greater than profits, drainage systems can be designed and managed to reduce NO3-N losses while still providing an acceptable profit.     

End-to-end pancreaticoduodenostomy: an alternative reconstruction for partial resection of the head of the pancreas

BACKGROUND: The mainstay of the management of liver abscesses has been intravenous antibiotics and radiologically guided percutaneous drainage. However, not all abscesses are treated successfully in this way, and some require surgical drainage. Laparoscopic drainage of liver abscesses may be an alternative to open surgical drainage. METHODS: Twenty consecutive patients with liver abscesses treated by laparoscopic drainage in combination with intravenous antibiotics were studied prospectively. Fifteen had had failed percutaneous drainage previously. RESULTS: There were 13 right lobe and seven left lobe abscesses ranging from 6 to 25 cm in diameter. Mean operating time was 38 min. Seventeen patients were drained successfully. Three patients developed recurrent symptoms of which two resolved with conservative measures, but one required a second laparoscopic procedure. There were no intraoperative or other postoperative complications in the 20 patients. Follow-up ranged from 5 to 12 months. CONCLUSIONS: Laparoscopic drainage of liver abscesses, in combination with systemic antibiotics, is a safe and viable alternative in all patients who require surgical drainage following failed medical or percutaneous treatment, and in those with large abscesses.