Thermal and catalytic coprocessing of waste tires with coal

Thermal and catalytic coprocessing of waste tires and coal was performed using waste tires from two sources and coals of three different ranks. Bituminous coals yielded higher conversions than either subbituminous coal or lignite when coprocessed with waste tire. In this study waste tires from tire buffing processes were used. One of these materials provided by Rouse Rubber represented the typical composition of most automotive tires while the other material supplied by Uniroyal contained a substantial amount of mineral fillers because the material obtained from buffing the white lettering on the sidewall of the tire. Each of these waste tires when used as a solvent in coprocessing had different solvent qualities; the Rouse waste tire was typically a much better solvent for coal than Uniroyal waste tire. Catalytic coprocessing of waste tires with coal using slurry phase hydrogenation catalysts increased total and coal conversions compared to thermal reactions. Addition of carbon black to the coprocessing system had minimal effect on the conversion or product distributions, while the addition of the heat-treated residue from the liquefied waste tires resulted in enhanced conversion and hexane solubles production from coprocessing systems. The mineral-rich Uniroyal residue was more active than the carbon black-rich Rouse residue. Combining the residues with slurry phase hydrogenation catalysts enhanced their activity even further.     

The biological and chemical desulfurization of crumb rubber for the rubber compounding

The disposal of used car tires has become a major environmental problem, especially in densely populated countries that use motor vehicles as the principle means of transportation. Widespread recycling of waste tires has not taken place because it has not proven to be cost effective. Although there are obvious environmental reasons for recycling waste tires, to date it has not proven to be economically valuable. The aim of this study is to find a more economical way of recycling used car tires. This was done by the “unvulcanization” of vulcanized crumb rubber by two different treatments; chemical treatment with di‐(cobenzanidophenyl)disulfide, and microbial treatment with T. peromatabolis. The experimental results indicate that the processing of crumb rubber, as well as the end‐product properties, were enhanced by both these treatments, with the microbial treatment being the most effective. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 72: 1543–1549, 1999     

The use of recycled elastomeric materials for sustainability in circular economy

The use of scrapped elastomeric goods primarily service failed or worn-out tires is a challenging task for the rubber society. To address this issue, recycling and reusing of these tires by different technique bring major relief toward environmental concern. Recycling technology generates secondary raw materials, which are important resources for manufacturing industries and contribute significantly for the sustainability in circular economy. In this work, an effort was made to understand the retention of physical properties as a function of crumb rubber loading and particle size. Four different sizes of cryogenically shredded crumb rubber particles (120, 140, 200, and 270 mesh) were physicochemically characterized and incorporated by 10 phr of each in two different grades of carbon black–filled, natural rubber–based tread compound. The mixed compounds were characterized and compared with the control one. Optical microscope and scanning electron microscope analyses concluded that the finer the particle size, the better is the dispersion of crumb rubber particles which provide superior mechanical, extrusion, and wear properties. Tensile properties were retained around 95%–97% for both 270-mesh loaded compounds, which indicates that reduction in particle size can increase the volume of recycled product utilization.     

Manufacture of low-molecular-weight hydrocarbons by the hydrogenation of coals in a mixture with tire rubber

The behavior of a polymer-containing material (scrap rubber tires), the structure of which can be tentatively considered equivalent to the structure of the organic matter of coal whose fragments are joined in multimers as a result of electron donor-acceptor interactions, was studied in order to convert rubber tires into low-molecular-weight compounds suitable for the manufacture of motor fuels and chemical products. An analysis of the results obtained by the hydrogenation of industrial rubber articles in a mixture with coal from the Kansk-Achinsk Basin showed that raw materials of this kind can be deeply converted into low-molecular- weight hydrocarbons under certain conditions, which can be generated without high hydrogen pressures (20–30 MPa), which are used in foreign industrial practice.     

Selection of microporous adsorbents for the clean-up of manufacturing waste water

Conclusions -- A procedure has been developed for selecting microporous sorbents for the clean-up of waste water, which takes into account overall the diverse technological characteristics of adsorbers.-- The procedure has been checked out as applicable to selecting carbon sorbents for cleaning up caprolactam-containing waste water in the manufacture of polyamide fibres.Translated from Khimicheskie Volokna, No. 5, pp. 24–27, September–October, 1990.     

Sorption of petroleum products by carbon sorbents

A comparative study of the adsorption of petroleum products by micro- and macroporous carbon sorbents was performed. For this purpose, four carbon sorbent samples prepared from various raw materials by various processing techniques were used. The pore structures and adsorption capacities of these sorbents for petroleum products were studied. It was found that the adsorption of petroleum products on porous and nonporous carbon sorbents occurred in different manners. In this case, macroporous sorbents with a weakly developed structure of sorbing micro- and mesopores exhibited a maximum capacity for petroleum products.     

Pyrolytische Rohstoff-Rückgewinnung aus Sonderabfällen

Pyrolytic recovery of raw materials from special wastes . The pyrolytic techniques developed especially for producing smelting coke from coal and in petroleum refining can be applied to the thermal decomposition of waste materials having a high organic content. Fluidized bed reactors and rotary kilns are particularly suitable as universally applicable pyrolysis units for continuous operation. Highly aromatic pyrolysis oils for use as chemical raw material, heating gases for the autothermic operation of the pyrolysis unit, and carbon and solids containing nonferrous metals are obtained from plastics waste, used tires, old cable, shredder wastes, and acid resins at reactor temperatures of about 700°C. Largescale applicability and economics of the process have yet to be proved.     

废旧轮胎/橡胶回收利用技术研究进展

近几年来,废旧轮胎/橡胶所引起的环境问题得到人们的重视,回收利用已成为我国乃至世界研究的热点。从裂解、催化裂解、轮胎原料、反应动力学以及工艺条件等方面概述了废旧轮胎/橡胶回收利用技术最新研究进展。催化裂解成为废旧轮胎/橡胶回收利用的主要方式,研究较多的催化剂主要是ZSM-5、MCM系列以及ITQ系列。     

Preparation of carbon sorbents from certain types of biomass

An integrated study of olive pits and walnut shells as raw materials for conversion into carbon sorbents was performed. The results of thermogravimetric studies and proximate and ultimate analyses of the raw materials allowed us to choose a processing technique and the performance characteristics of carbonization. The sorbents based on the test plant waste materials were found to exhibit high strength and well-developed pore structure with a high specific surface area of micropores and sufficiently developed mesoporosity. These sorbents were superior to high-quality active carbons in terms of adsorption capacity for substances with various molecular sizes.     

球磨改性热解炭吸附磺胺甲唑

针对热解炭颗粒大、表面活性弱、吸附能力差的问题,本文提出了一种机械球磨表面改性方法,探讨了不同球磨改性参数下热解炭对磺胺甲唑（SMZ）的吸附效果。以废橡胶连续热解炭为原料,采用不锈钢球磨制得具有不同表面性质的球磨炭,分析了球磨前后热解炭的结构、表面性质及表面形貌,并对比了球磨改性前后的SMZ吸附性能。结果表明,球磨改性过程可以有效改善废轮胎热解炭结构及表面性质,球磨处理2h的热解炭对SMZ的吸附效果最好,吸附量达到59.37mg/g,吸附动力学符合伪二级吸附模型。     

废物燃料对燃料型NOx排放的影响

研究了废皮革、废轮胎与煤在管式电炉中燃烧对燃料型NOx排放的影响。结果表明,在900℃富氧条件下,废皮革中的氨基酸氮比烟煤中的六元杂环氮更易于转化为燃料型NOx,而废轮胎生成的燃料型NOx浓度较低。废皮革与烟煤混烧产生的燃料型NOx浓度低于两者各自燃烧所生成的NOx排放浓度总和。废轮胎与烟煤混烧,不仅低于两者各自燃烧所生成的燃料型NOx排放浓度总和,而且还低于烟煤单独燃烧所生成的燃料型NOx排放浓度。另外,水泥生料会促进烟煤、废皮革及废轮胎生成燃料型NOx。     

废橡胶颗粒沥青混合料级配组成的优化

应用星点设计-效应面优化法进行废橡胶颗粒沥青混合料级配组成的优化设计,运用SPSS软件分析实验结果,描绘了橡胶颗粒掺量、粗集料用量和粗橡胶颗粒用量等影响因素的效应面,建立了相应的数学模型,得到了橡胶颗粒沥青混合料的最优级配组成。结果表明,当橡胶颗粒掺量为2.0%~6.0%、粗集料用量为60.0%~75.0%、粗橡胶颗粒用量为30.0%~60.0%时,橡胶颗粒沥青混合料综合性能最优;将星点设计-效应面优化法应用于橡胶颗粒沥青混合料的级配组成优化是可行的。     

Granulated sorbents from wood waste

An integrated study of various wood-utilization wastes as raw materials for the production of carbon adsorbents was performed. A technology was developed, and granulated sorbents from various wood wastes were prepared and characterized. The regularities of pore-structure formation and the physicochemical properties of sorbents were found depending on the used raw material, binding agents, granulation conditions, and the process parameters of the thermal treatment of granules.     

Use of waste tire steel beads in Portland cement concrete

Large quantities of waste tires are generated every year. The proper disposal of the tires creates an increasing problem that needs to be addressed. Many researchers have investigated the use of recycled tire products in several traditional Civil Engineering materials. The use of crumb rubber and tire chips in Portland cement concrete has been the subject of many research projects over the last years. This study is focusing on the use of steel beads, a by-product of the tire recycling process, in concrete mixtures. Different concrete specimens were fabricated and tested in uniaxial compression and splitting tension. The main variable in the mixtures was the volumetric percentage of the steel beads. The experimental results indicate that although the compressive strength is reduced when steel beads are used, the toughness of the material greatly increases. Moreover, the workability of the mixtures fabricated was not significantly affected.     

松木屑与废橡胶化学链共气化特性试验

在自行设计的两级固定床反应器上,对以天然贫铁矿石为载氧体的松木屑与废橡胶化学链共气化特性进行了研究。考察了载氧体的存在、废橡胶掺混比例、一级反应器温度、水蒸气流量等因素对生物质化学链共气化过程的影响。结果表明：载氧体的存在能显著改善气化效果;掺混一定量的废橡胶可以显著提高低位热值和碳转化率,并且呈现协同效应。本试验中最佳的废橡胶掺混比例为20%;共气化过程中的产气率、碳转化率均随温度的增加（750～950℃）而逐渐升高,但热值随温度的升高而有所下降;水蒸气流量的增加能显著提高合成气中H₂的含量,进水流量保持在0.66g/min时,能实现生物质共气化过程产气率、碳转化率、低位热值等各项指标的最佳平衡。通过扫描电镜（SEM）、X射线衍射（XRD）等表征分析,发现天然贫铁矿石在长时间运行中表现良好的反应性和耐磨损性。     

废旧有机丝制备活性炭纤维的研究

活性炭纤维是以高聚物为原料,经高温炭化和活化而制成的一种纤维状高效吸附分离材料.利用废旧有机丝为原料,探索在不同工艺条件下制取活性炭纤维的可行性.经扫描电镜、X射线衍射、红外分光光度计及亚甲基蓝吸附实验分析得出优化的工艺条件为:炭化温度,650℃;用CO2活化,活化温度为950℃,活化时间为60min,制得吸附性能优良的活性炭纤维.     

Investigation into the removal of sulfur from tire derived fuel by pyrolysis

There is growing interest in the use of scrap tires as both a fuel and a feed material for petroleum feedstocks due to their abundance and their chemical composition. However, the sulfur content of scrap tires is a potential obstacle to scrap tires utilization as a fuel. In this paper, the partitioning of sulfur was investigated from the two major pyrolytic products from passenger car tires, liquid oils and solid chars, and the potential of producing a low sulfur char for fuel applications. The removal of sulfur during tire pyrolysis offers the greatest potential for the separation of sulfur products from the evolved gases and vapors. The influences of heating rate and pyrolysis temperature were investigated from 325 to 1000 °C, a range where substantial devolatilization occurs. The pyrolysis char and derived oil were analyzed for sulfur, and compared to the original parent sulfur content in tire derived fuel (TDF) samples. The results of sulfur determination verify that the overall desulfurization from the pyrolysis reaction is essentially unaffected by the heating rate but is affected by the ultimate pyrolysis temperature.     

经济角度论证水泥窑燃料替代技术发展路径选择

随着双碳政策的不断推进,作为我国高能耗的行业之一,水泥行业的节能减排面临越来越大的压力。国内目前已有多条水泥窑完成替代燃料入窑项目的建设,并分别进行了工业废纺、农林垃圾、炭黑、轮胎等物料的燃煤替代尝试。本文将对替代燃料来源、原料预处理、入窑方式、煤价波动等影响因素进行经济可行性综合分析,探索适合我国水泥行业燃煤替代全流程建设路径。     

Obtaining a rubber-bitumen asphaltic concrete pavement binder by the thermocatalytic processing of petroleum residues in a mixture with rubber crumb in the presence of zeolites and organo-mineral activators

It has been ascertained that qualitative rubber-bitumen asphaltic concrete pavement binders can be obtained at one stage by the method of the catalytic thermolysis of residual oil in the mixture with rubber crumb of worn-out tires in the presence of synthetic or natural zeolites or pyroshale that adsorb coke besides catalyzing the process. The mineral part of pyroshale and zeolite powder with adsorbed coke and soot forming during the decomposition of rubber are a thin-disperse modifier of paving bitumens. The catalytic thermolysis of residual oil with adding 30–40% of rubber crumb proceeds under comparatively soft conditions (a temperature of 350–375° C, isothermal exposure with a duration of 10–30 min) in the presence of 1–3% of zeolite or pyroshale. The yield of a high-qualitative rubber-bitumen binder with the content of 18–20% of mineral and organic modifiers can reach 50–60 wt % of the used raw material. Rubber crumb is utilized completely. There are no foreign analogs of the suggested technology. An experimental-industrial installation with a capacity of 9000–10000 t of bitumen component/year was created in the city of Kudepsta in the Krasnodar Territory.     

Rubberized geopolymer composites: A comprehensive review

The construction sector has been addressing the issue of integrating sustainability into production processes over the last few years, either through solid waste materials as aggregates in concrete or the search for more eco-friendly raw materials. Besides, the global trends group focused on developing an alternative to cement, which is a significant contributor to pollution of the environment due to its greenhouse gas emissions. Geopolymer (GP) is one of the most acceptable solutions for utilizing all industrial by-products containing an alumino-silicate (A-S) source material. However, one method to recycle waste rubber tires is incorporating them into geopolymer concrete (GPC) as an alternative to natural aggregates. Recently, the potential of combining the advantages of GPC with rubberized concrete to produce rubberized geopolymer concrete (Ru-GPC) as a viable, sustainable building material has been recognized. This paper presents a state-of-the-art review of the waste rubber's environmental and economic impact, resources, recycling, classifications, and physicochemical properties. Besides, this article provides in-depth studies on the behaviors and properties of Ru-GPC composites, such as their basic components, preparation and curing processes, fresh and physical properties, mechanical properties, dynamic properties, durability properties, microstructures, and insulation properties. The effect of crumb rubber (CRu) substitution on critical properties is addressed critically. Also, it highlights the applications, embodied CO₂ emissions, and cost analysis of Ru-GPC. Moreover, gaps in the literature and recommendations for future study have been identified to support further developments in the investigation and future publication of Ru-GPC materials in practice.