ResumoO uso de entulhos, entre outros rejeitos industriais e domésticos, pela construção civil vem sendo prática comum em diversos países desenvolvidos, em razão tanto do aumento da quantidade de rejeitos e conseqüente esgotamento de espaços apropriados para seu destino final, quanto da constante e cada vez mais rigorosa fiscalização e punição pelos organismos ambientais competentes. Antecipando maneiras para solução desses problemas, propôs-se o estudo da reciclagem e imobilização de rejeitos de porcelanas elétricas em concreto, em substituição parcial aos agregados graúdos e miúdos naturais. A vantagem não foi total por causa do indício de reações expansivas que poderiam prejudicar determinadas aplicações. Assim, foi proposto o estudo das condições ideais de dosagem para mitigar os efeitos de tais reações pela presença de contaminantes destes rejeitos. Os resultados demonstraram a efetiva promoção de reações do tipo álcali-agregado, e que o uso de cimentos especiais poderá diminuir o efeito prejudicial dos subprodutos formados. Palavras-chave: reciclagem secundária, rejeitos de porcelana elétrica, concreto, reações expansivas. Abstract The use of rubbish and other kinds of domestic and industrial wastes on civil construction has been a common practice in many developed countries, due either to the increase in the amount of waste and the resultant reduction of appropriate places to itsfinal disposal, as well as to the severity and steadiness of environmental inspection organizations. In order to provide beforehand manners to solve or reduce these problems, study of recycling and co-disposal of waste from porcelain electrical insulators in concrete was proposed. Besides the occurrence of expansive reactions, which may be harmful to the stability of important structures, the overall results were encouraging. Some contaminants found in the three phases of porcelain contributed to the happening of alkali-aggregate reaction, which can easily inhibited by the using of special cements, such as a sulfur-resistant one.

The defossilization of the electricity and heat supply in the chemical industry poses a significant challenge. In particular, the intended feed-in of volatile renewable electricity into the chemical processes may conflict with the need for a constant, secure and affordable electricity and heat supply for chemical plants. Adapted concepts for the operation of the cogeneration plant, which is located at the chemical site, play a central role. The present work defines a so-called ideal-typical utility infrastructure (iUI). The iUI is a means to exemplarily investigate the operational behavior of utility infrastructures and furthermore to identify defossilization options for process steam and electricity supply at chemical sites.

Ambitious greenhouse gas reduction targets and the currently surging energy prices pose significant challenges for the chemical industry. In this paper, the integration of molten salt thermal energy storage into the chemical site utility infrastructure is proposed to enable decarbonized and cost-effective electricity and process steam supply. The storage system is electrically charged and produces combined steam and electricity during discharge. A model of a utility infrastructure including all required input parameters was developed and implemented in the software Top-Energy® to perform operational optimizations and minimize operating costs. Simulation studies were carried out for different storage system configurations and the years 2020 to 2050. Attractive payback periods and net present values can be achieved with the described concept. Variable operating costs are largely reduced by the electrification of steam generation.