Integration of life cycle assessment and life cycle costing for the eco-design of rubber products

Rubber hoses are a category of rubber products that are widely and intensively employed in construction sites for concrete conveying. There has been lack of study to investigate the life cycle environmental and economic impacts of the rubber hoses as an industrial product. In this study, we analyze four types of rubber hoses with the inner layer made of different rubber composites to resist abrasion, i.e., Baseline, S-I, S-II and S-III. Tests of the wear resistance are carried out in the laboratory and S-III shows high abrasion resisting performance with the concrete conveying volume up to 20,000 m3 during the service life. Life cycle assessment (LCA) and life cycle costing (LCC) models are established for evaluating the four types of rubber hoses. A target function is developed to integrate LCA and LCC by converting the LCA results to the environmental costs. It is found that S-III can save 13% total cost comparing to Baseline. The production stage is the largest contributor to the environmental single score, while the use stage is the largest contributor to the life cycle cost. Sensitivity analyses are conducted and the results of this study are validated with the previous studies. The integrated method of LCA and LCC developed in this study paves a way for the eco-design of industrial rubber hoses and is potentially applicable to other rubber products.

Experimental studies into the effect of air pressure on the atomization characteristics of coal-water slurries

The paper studies the effect of atomizing agent pressure on the spray characteristics after spraying coal-water slurry that contains small additives of liquid waste from the pyrolysis of industrial rubber goods and used engine oil. The conducted experiments used automobile tires as the indicated rubber products; spraying was carried out employing an internal mixing pneumatic atomizer. Following the atomization of considered fuels, droplet size changes were studied using the interferometric particle imaging (IPI) technique. The spray angle was determined by means of a Photron high-speed camera. In addition, coal-water slurry containing liquid waste from the pyrolysis of industrial rubber goods and used engine oil (3–12 wt%) was sprayed to study the effect of atomizing agent pressure on the spray characteristics. A decrease in air pressure was found to reduce the spray angle by less than 6%, which resulted in the formation of rather large droplets exceeding 600 µm in size. It is experimentally confirmed that more fine droplets are formed at similar fuel and air pressures when using a spraying device equipped with an internal mixing chamber for slurry and air. The number of droplets, in this case, is 2–9% higher as compared to a typical two-component coal-water slurry fuel, with the spray angle of the sprayed coal slurry having the greatest value. When using an atomizer having an internal mixing chamber for slurry and an atomizing agent, fuel droplet breakup occurs due to the aerodynamic drag forces of the environment. Thus, the use of such atomizers reduces the number of possible breakup mechanisms for sprayed fuel droplets.

Study of composition and properties of carbon-containing industrial rubber waste pyrolyzates

The study of mining industry rubber waste pyrolyzates and the search for new opportunities to expand the areas of their application remains an urgent research task. The study of the solid residue of industrial rubber waste pyrolysis is presented in the work. Possibilities of improving the quality characteristics of solid carbon residue are considered. The results of studying the composition by various methods are presented. The adsorption properties of the obtained product are studied and the content of oxygen-containing functional groups in the initial and the upgraded carbon residue of pyrolysis are determined.

Crumb Rubber as a Secondary Raw Material from Waste Rubber: A Short Review of End-Of-Life Mechanical Processing Methods

Despite technological developments, modern methods for the disposal of end-of-life tires most often involve either their incineration in cement kilns or the destruction of tires in special landfills, demonstrating a lack of sustainable recycling of this valuable material. The fundamental role of recycling is evident, and the development of high-efficiency processes represents a crucial priority for the European market. Therefore, the investigation of end-of-life rubber processing methods is of high importance for both manufacturers and recyclers of rubber materials. In this paper, we review existing methods for processing of end-of-life tires, in order to obtain rubber crumb, which can later be used in the production of new industrial rubber goods and composites. We consider processes for separating end-of-life tires into fractions (in terms of types of materials) using chemical, mechanochemical, and mechanical methods to process the materials of used tires, in order to obtain crumb rubber of various fractions and chemical reactivities.