炼化企业热媒水低温余热回收利用方案

对典型炼化企业热媒水的温度、压力、流量及气分、伴热装置的蒸汽使用情况等进行调研,根据低温余热的利用原则,简化低温余热回收利用系统建立步骤,提出适合本企业、有针对性的低温余热回收利用方案。方案实施后,可为企业节省各类蒸汽3.6×105 t/a,年增加经济效益近4 000万元。     

Deactivation and regeneration of ZSM-5 zeolite in catalytic pyrolysis of plastic wastes

In this work, a study of the regeneration and reuse of ZSM-5 zeolite in the pyrolysis of a plastic mixture has been carried out in a semi-batch reactor at 440 °C. The results have been compared with those obtained with fresh-catalyst and in non-catalytic experiments with the same conditions. The use of fresh catalyst produces a significant change in both the pyrolysis yields and the properties of the liquids and gases obtained. Gases more rich in C3-C4 and H₂ are produced, as well as lower quantities of aromatic liquids if compared with those obtained in thermal decomposition. The authors have proved that after one pyrolysis experiment the zeolite loses quite a lot of its activity, which is reflected in both the yields and the products quality; however, this deactivation was found to be reversible since after regeneration heating at 550 °C in oxygen atmosphere, this catalyst recovered its initial activity, generating similar products and in equivalent proportions as those obtained with fresh catalyst.     

我国再生镁产业的可持续发展

我国是世界上镁资源最丰富的国家,随着镁合金应用技术的不断提高,镁及镁合金在各个行业的用量日益增大,为废镁和废旧镁合金的回收与利用提供了巨大的发展空间,也推动了我国再生镁产业的可持续发展。     

利用物联网打造再生资源社会回收平台

"阿拉环保"再生资源公共服务平台立足于打造上海品牌,在全国首先尝试利用物联网技术打造再生资源社会回收平台,突破了传统的回收模式,理念新颖,促进电子废物社会回收步入规范化、科学化发展轨道。     

内蒙古乌拉特后旗新兴矿业城市循环经济发展模式研究

内蒙古乌拉特后旗2001年之前一直是国家级贫困县,2003年以来,该旗将矿产资源优势转变为资产优势,通过发展矿业产业经济,一跃成为人均GDP超上海的富裕县,从农牧业为主县转变为工业为主县。这一转变是对草原及生态环境的巨大威胁。通过实地考察,调查研究齐华矿业公司经济发展经验,提出资源综合开发利用与生态平衡发展模式,该模式达到了工业发展起点高、污染破坏最小化的目标,同时经济得到了可持续发展。     

Aromatization of waste polyolefin pyrolysate over H-ZSM-5 zeolite-supported gallium oxide catalysts

H-ZSM-5 zeolite-supported gallium oxides were studied as aromatization catalysts for polyolefin pyrolysate. The catalysts were prepared by a conventional physical mixing method with a gallium content of 1.0 and 4.5 wt% and were reduced in flowing hydrogen at 585°C. To test their activity, a polyolefin sample was pyrolyzed and passed over a heated catalyst layer; the product was analyzed by gas chromatography/mass spectrometry. A continuous-flow fixed-bed reactor was used for aromatization of a model gas of polyolefin pyrolysate. For chlorine-free sources at 450°C, the catalyst with only 1.0 wt% gallium exhibited activity comparable to a gallium silicate catalyst. For chlorine-contaminated sources, the catalyst with 4.5 wt% gallium sustained catalytic activity for long periods. From the activity test results, it was found that zeolite-supported gallium catalysts prepared by the physical mixing method are suitable for converting polyolefin into aromatic hydrocarbons.     

WASTE MANAGEMENT AND SUSTAINABLE DEVELOPMENT IN SOUTH AFRICA

Waste management is emerging as a key sector for sustainable development in South Africa with opportunities for enhancing investments in carbon credits that target reduction of methane from landfills and moveable assets in relation to environmentally sound equipment required for effective waste management. In the past, the waste management sector was dominated by private sector with selective operations in what makes business sense through recycling of saleable products. Materials mostly recycled included paper and hard board, plastics, glass, tinplate and aluminum. The rest of the waste materials estimated at 10.2 million tons of both general and hazardous end up in landfills. This trend is now getting reversed as development agencies such as Deutsche Gesellschaft für Technische Zusammenarbeit Gmbh (GTZ), Danish International Development Agency (DANIDA), Danish Co-operation for Environment and Development (DANCED) and Development Bank of Southern Africa (DBSA) are identifying opportunities in the sector for sustainable development purposes. Two key areas for investments include capturing methane emissions from landfills for trading in carbon markets and financing both physical and moveable assets to enhance sustainable development. However, the challenges for cost-effectiveness, efficiency and sustainability in the sector prevail in relation to lack of sound knowledge to design and implement integrated programmes that incorporate environment, development and sustainability. Also, inadequate capacity at municipal levels to administer waste management programmes and inability to collect rates and taxes for effective management of landfills constraint effectiveness and efficiency of the sector. Overall, financial resources are imperative to waste management and sustainable development as the sector requires capital investments for necessary infrastructure.     

发展资源再生产业是中国资源战略的一场革命

中国已经成为资源消耗大国，实施再生型资源战略，发展循环经济是我国的必然选择。资源再生产业与“循环经济”取代“线性经济”、经济全球化形成“国际大分工”和“国际大循环”的发展趋势同步，是解决资源和环境问题的根本出路。资源再生产业是一座“富矿”，没有“资源再生”就没有中国的“环境保护”。中国资源再生产业的发展为什么步履艰难？它和进口渠道不畅。国民对资源短缺认识不足、传统的“线性思维方式”的影响，来自国内外“利益集团”的阻力，以及政策不刭位等因素密切相关。因此，提出中国发展资源再生产业的对策和建议：①在经济相对滞后、交通便利的地区建立“资源再生加工区”；②建立畅通的全球物质回收“绿色通道”；③建立“国际再生资源交易市场”；④成立“国际资源再生促进会”；⑤改变“线性经济”背景下的传统观念。     

水处理技术发展对电力工业水循环利用的经济性影响

讨论了一些为提高生产力和降低成本而发展起来的废水零排放或水回收循环利用前沿技术,并将这些技术的经济性与原有的水循环利用系统进行比较.     

Analysis of Products Generated from the Thermal and Catalytic Degradation of Pure and Waste Polyolefins using Py-GC/MS

The possibility of transforming waste plastics into valuable hydrocarbons via catalytic cracking and reforming is attracting increasing interest. Pyrolysis coupled with Gas Chromatographic separation and Mass Spectrometry detection (Py-GC/MS) has been used in this work to study the product selectivity of various catalysts in the conversion of pure and residual polyethylene samples into hydrocarbon products. Five acid solids of comparable aluminium contents but different textural and acid properties were tested as catalysts, including three zeolites (standard ZSM-5, nanocrystalline n-ZSM-5 and Beta) and two mesostructured solids (Al-MCM-41 and Al-SBA-15). Thermal cracking of the pure and residual polymers generated a similar range of products to each other, with a high proportion of linear paraffins and olefins of varying lengths. The presence of zeolitic materials resulted in complete elimination of heavy linear products, an increase in the light hydrocarbon fraction and a marked selectivity towards the formation of single-ring aromatic species, particularly benzene, toluene and xylene. Aromatic formation was particularly notable with the small crystal size n-ZSM-5 (aromatic selectivity up to 53.9%) and less marked in the case of standard ZSM-5 (up to 36.4%) and Beta zeolite (up to 35.0%). Mesostructured catalysts like Al-MCM-41 and Al-SBA-15 favoured the production of light C₂–C₅ hydrocarbons (up to 57.9%) while the formation of aromatic products was significantly lower than with zeolitic materials. The paper examines the extent and the causes for this product selectivity and discusses its connection with the acid and textural properties of each catalyst. It was also observed that, under the experimental conditions employed, the products generated were not significantly affected by the nature and origin of the polymers employed.