Development of a Range of Modified Multifunctional Residual Current Systems and Their Industrial Implementation

The developments of the AltSTU have been reviewed in the area of creating a new technology for preventing technogenic hazards based on the residual current devices. The residual current devices are intended for protecting people from electric shock in case of contact with conductive parts of the electric appliances and shall facilitate reduction of fire risks caused by a prolonged flow of leakage currents and fault currents resulting from them. The results of creating different modifications of protective trip circuits and their industrial use are provided.

Power mode of axisymmetric high-speed combined extrusion of bimetallic road milling picks

The article presents a simplified three-stage model of the transition from a flat to axisymmetric deformation during high-speed, combined extrusion of bimetallic road milling picks. The transition is based on the principle of equality of areas, according to which the area of a figure during a flat deformation is replaced by an equal area of a circle. In this case, it is assumed that the kinematically possible field of the slip lines remains unchanged. This approach makes it possible to reduce the number of necessary calculations and at the same time maintain a high degree of correctness of the obtained equations. The first stage shows the transition to a special case of a flat problem, in which a stepped rectangular part is extruded from the original square blank, in which one of the sides is equal to the square side of the original blank. At the second stage of the transition, a flat-step part having square sections along its entire length is extruded from the original square-section blank. Directly at the third stage, the final transition to the axisymmetric deformation of the cutter is formed, in which the area of the square is replaced by the equal area of the circle. The dependences obtained because of solving the axisymmetric problem can be recommended for calculations in the industrial implementation of the technology of high-speed combined extrusion of bimetallic milling picks.

Heterogeneous Strategies For Selective Conversion of Lignocellulosic Polysaccharides

Lignocellulosic biomass is the most abundant renewable carbon resource on earth, for which many efforts have been made to convert it using various chemocatalytic processes. Heterogeneously chemocatalytic conversion conducted based on reusable solid catalysts is the process with the greatest potential studied presently. This review provides insights into the representative achievements in the research area of heterogeneous chemical catalysis technologies for the production of value-added chemicals from lignocellulosic polysaccharides (cellulose and hemicellulose). Popular approaches for the conversion of lignocellulosic polysaccharides into chemicals, including hydrolyzation (glucose, xylose and arabinose), dehydration (5-hydroxymethylfurfuran, furfural and levulinic acid), hydrogenation/hydrogenolysis (sorbitol, mannitol, xylitol, 1,2-propylene glycol, ethlyene glycol and ethanol), selective oxidation (gluconic acid and lactic acid), have been comprehensively reviewed. However, technological barriers still exist, which have to be overcome to further integrate hydrolysis with the refinery processes based on multifunctional solid catalysts, and convert ligncellulosic polysaccharides into value-added fine chemicals. In general, the approaches and technologies are discussed and critically evaluated in terms of the possibilities and potential for further industrial implementation.

The technology of wastewater sludge vitrification in comparison with other processing methods

Специалистами компании ООО «НТЦ «Экопромтех» разработана инновационная технология остеклования илового осадка сточных вод, позволяющая значительно сократить объем отходов и получить на выходе безопасный остеклованный материал для использования в строительстве. Приводится сравнение технологии остеклования с другими способами переработки осадка: депонированием, сбраживанием осадка в метантенках, сушкой, пиролизом, каталитическим и классическим сжиганием. В России более 90% образующихся иловых осадков депонируются. При сохранении этой тенденции неизбежен рост плеча перевозки осадка. Использование необработанного илового осадка в качестве удобрения повышает риск загрязнения почвы. Финансовые модели проектов с внедрением метантенков за счет продажи биогаза или электроэнергии не окупаются. В случае применения метода сушки для получения топлива из осадка расходуется практически столько же тепловой энергии, сколько содержится в конечном продукте. Поэтому себестоимость высушенного илового осадка как топлива не будет меньше стоимости природного газа, а с учетом других операционных затрат, включая доставку до потребителя, превысит стоимость газа в 2–3 раза. Пиролиз с получением ликвидных продуктов находится на стадии разработки, что потребует проведения большого количества исследований. Технология каталитического сжигания осадка без предварительной сушки не решает основные проблемы любого сжигания и приводит к определенным трудностям: риск эмиссии суперэкотоксикантов сохраняется, золу необходимо утилизировать, затруднено поддержание автотермического режима, катализатор изнашивается и требует замены. Технология остеклования имеет ряд преимуществ, готова к масштабированию и промышленному внедрению. The experts of Ekopromtekh R & D Centre, LLC have developed an innovative technology for vitrification of wastewater sludge that provides for reducing significantly the volume of wastes and obtaining a safe vitrified material to be used in construction. A comparison of the vitrification technology with other methods of sludge processing is given: depositing, sludge digestion in digesters, drying, pyrolysis, catalytic and classical incineration. In Russia, more than 90% of the generated sludge is landfilled. If this trend persists, an increase in the sludge hauling distance is inevitable. Using unprocessed sludge as fertilizer increases the risk of soil contamination. Financial models of projects that envisage using digesters and selling biogas or electricity do not pay off. In case of using the drying method to obtain fuel from sludge, almost the same amount of thermal energy is consumed as the final product contains. Therefore, the cost of dried sludge as a fuel will not be less than the cost of natural gas, and taking into account other operating costs, including delivery to the consumer, will exceed the cost of gas by 2–3 times. Pyrolysis to obtain marketable products is under development and involves a lot of research. The technology of catalytic incineration of sludge without preliminary drying does not solve the main problems of any incineration process and causes certain difficulties: the risk of emission of superecotoxicants remains; the ash must be disposed of, the autothermal regime is difficult to maintain, the catalyst wears out and requires replacement. The vitrification technology has a number of advantages, it is ready for scaling and industrial implementation.

Enzymatic textile recycling – best practices and outlook

Recently, textiles and their end-of-life management have become the focus of public and political attention. In the European Union the revised waste framework directive defines textiles as municipal waste and stipulates their separate collection by 2025. In the context of these developments, this paper summarises briefly the current state-of-the-art in textile recycling. It is evident that recycling methods are not yet fully developed. This is especially the case with multi-material textiles, which are composed of two or more polymers that are incompatible for recycling. In the practical part of the communication, results are presented which show that enzymatic hydrolysis is a suitable process for recycling textiles made of cotton and polyester. After a complete removal of cotton, the remaining pure polyester fibres undergo a re-granulation and post-condensation step. The so obtained recycled polyester is fed back into the textile processing chain and finally towels are obtained. The main steering parameters of the enzymatic hydrolysis process are described. The study proves that solutions in accordance with the Circular Economy in the textile sector are available but an industrial implementation has not yet been realised.