Resource productivity enhancement as means for promoting cleaner production: analysis of co-incineration in cement plants through a life cycle approach

The objective of this paper is to assess the environmental effectiveness of a strategic measure aimed at resource productivity enhancement. The cement industry has been identified as a relevant sector for this global issue, since the related production process enables the use of waste in partial substitution of raw materials and in substitution of traditional fuels. The analysis of the cement production sector in Italy has been here performed, investigating the recovery of energy from waste through co-incineration. In terms of air emissions, the emission performances of cement kilns appear independent from the use of alternative fuels at the percentages usually employed. However, in order to measure the cleanliness of a production system, systematic analysis with global perspective is needed. For this aim, the principles of Life Cycle Assessment (LCA) have been used for a case study analysis of an Italian active plant using an amount of recovered plastics as an alternative fuel resource. The improvement on the investigated process has been quantitatively measured as a way for cleaner production, first in terms of gross energy requirement, and then through an environmental performance comparison with a sector benchmark. The analysis has highlighted the benefits on the global environmental balance for the practice of co-incineration in the cement production process.     

塑烧板除尘器在精轧机除尘系统中的应用

为满足环境治理的要求以及更好地保证钢板表面质量,日照轧钢有限公司1580带钢厂及新余钢铁有限责任公司1580热轧带钢生产线均采用塑烧板除尘器处理热轧过程中产生的大量的氧化铁粉、油雾、水蒸汽烟气。结合精轧生产线的工艺特点,选用第三代塑烧板作为清灰滤料,比较了两种吸尘罩对除尘系统运行效果的影响。     

Integration of biological method and membrane technology in treating palm oil mill e uent

Palm oil industry is the most important agro-industry in Malaysia, but its by-product–palm oil mill e uent (POME), posed a great threat to water environment. In the past decades, several treatment and disposal methods have been proposed and investigated to solve this problem. A two-stage pilot-scale plant was designed and constructed for POME treatment. Anaerobic digestion and aerobic biodegradation constituted the first biological stage, while ultrafiltration (UF) and reverse osmosis (RO) membrane units were combined as the second membrane separation stage. In the anaerobic expanded granular sludge bed (EGSB) reactor, about 43% organic matter in POME was converted into biogas, and COD reduction e ciency reached 93% and 22% in EGSB and the following aerobic reactor, respectively.With the treatment in the first biological stage, suspended solids and oil also decreased to a low degree. All these alleviated the membrane fouling and prolonged the membrane life. In the membrane process unit, almost all the suspended solids were captured by UF membranes, while RO membrane excluded most of the dissolved solids or inorganic salts from RO permeate. After the whole treatment processes, organic matter in POME expressed by BOD and COD was removed almost thoroughly. Suspended solids and color were not detectable in RO permeate any more, and mineral elements only existed in trace amount (except for K and Na). The high-quality e uent was crystal clear and could be used as the boiler feed water.     

SZD/2-1600型组合式电除尘器在西北高寒地区水泥磨上的应用

介绍了SZD/2—1600型组合式静电除尘器的优良性能及特点。通过现场实践与改进,着重介绍了该技术的运用效果及几点体会,意在进一步推广该技术的应用。     

Removal of phenol by activated carbons prepared from palm oil mill effluent sludge

The study was attempted to produce activated carbons from palm oil mill effluent （POME） sludge. The adsorption capacity of the activated carbons produced was evaluated in aqueous solution of phenol. Two types of activation were followed, namely, thermal activation at 300, 500 and 800%, and physical activation at 150% （boiling treatment）. A control （raw POME sludge） was used to compare the adsorption capacity of the activated carbons produced. The results indicated that the activation temperature of 800℃ showed maximum absorption capacity by the activated carbon （POME 800） in aqueous solution of phenol. Batch adsorption studies showed an equilibrium time of 6 h for the activated carbon of POME 800. It was observed that the adsorption capacity was higher at lower values ofpH （2--3） and higher value of initial concentration of phenol （200--300 mg/L）, The equilibrium data were fitted by the Langmuir and Freundlich adsorption isotherms. The adsorption of phenol onto the activated carbon POME 800 was studied in terms of pseudo-first and second order kinetics to predict the rate constant and equilibrium capacity with the effect of initial phenol concentrations. The rate of adsorption was found to be better correlation for the pseudo-second order kinetics compared to the first order kinetics.     

预处理-IC-氧化沟-气浮工艺处理再生纸废水

介绍了预处理-IC-氧化沟-气浮工艺在再生纸废水处理工程中的应用。工程运行结果表明:该系统处理效果好、性能稳定、维护管理方便,出水pH为7.39～7.52,COD为57.6～58.7 mg/L,BOD5为12.5～15.8 mg/L,SS为18～19 mg/L,出水水质达GB3544—2008《制浆造纸工业水污染物排放标准》表1标准;通过制浆回收和废水再生循环利用,降低了运行成本;对同类型造纸废水的治理有一定的借鉴意义。     

生物—物理化学法处理制浆黑液的试验研究

采用酸中和—厌氧—好氧—生物活性炭或化学混凝综合法处理制浆黑液,探讨了酸中和处理的影响因素及厌氧处理对后段好氧处理的影响.结果表明:两种综合处理工艺对黑液中木质素及COD_(Cr)的去除有显著效果;厌氧处理比好氧处理对木质素的降解更为有利.     

Coupled modeling of cement/claystone interactions and radionuclide migration

The interactions between cement and a clayey host-rock of an underground repository for intermediate-level radioactive waste are studied with the reactive transport code HYTEC for supporting performance assessment. Care is taken in using relevant time scales (100,000 years) and dimensions. Based on a literature review, three hypotheses are considered with respect to the mineralogical composition of the claystone and the neo-formed phases. In the long term, the pH is buffered for all hypotheses and important mineral transformations occur both in cement and the host-rock. The destruction of the primary minerals is localized close to the cement/claystone interface and is characterized by the precipitation of secondary phases with retention properties (illite, zeolite). However, beyond the zone of intense mineral transformations, the pore water chemistry is also disturbed over a dozen meters due to an attenuated but continuous flux of hydroxyl, potassium and calcium ions. Four interdependent mechanisms control the profile in the whole system: diffusion of the alkaline plume, mineralogical buffering, ion exchange and clogging of the pore space at the cement/claystone interface. The migration of a selected group of radionuclides (Cs, Ra, Tc and U) is explicitly integrated in the simulations of the strongly coupled system. Theoretical profiles of distribution coefficient (Kd) and solubility limit values are derived from the simulations, and their sensitivity with respect to the system evolution is estimated.     

扬州电厂200MW机组烟气脱硫石灰石制粉系统

介绍了扬州电厂石灰石制粉系统、主要设计参数及其核心设备的技术特点，为同类工程提供参考。     

Analytic hierarchy process helps select site for limestone quarry expansion in Barbados

Site selection is a key activity for quarry expansion to support cement production, and is governed by factors such as resource availability, logistics, costs, and socio-economic-environmental factors. Adequate consideration of all the factors facilitates both industrial productivity and sustainable economic growth. This study illustrates the site selection process that was undertaken for the expansion of limestone quarry operations to support cement production in Barbados. First, alternate sites with adequate resources to support a 25-year development horizon were identified. Second, technical and socio-economic-environmental factors were then identified. Third, a database was developed for each site with respect to each factor. Fourth, a hierarchical model in analytic hierarchy process (AHP) framework was then developed. Fifth, the relative ranking of the alternate sites was then derived through pair wise comparison in all the levels and through subsequent synthesizing of the results across the hierarchy through computer software (Expert Choice). The study reveals that an integrated framework using the AHP can help select a site for the quarry expansion project in Barbados.