Bell e net vidre. Producción, distribución y consumo de vidrio en el reino de Valencia durante la Baja Edad Media

El presente artículo analiza el desarrollo de la industria vidriera valenciana entre los siglos XIII y XV. Para ello se recurre a un centenar de documentos de carácter notarial, normativo, judicial y fiscal, procedentes de distintos archivos valencianos. Estos permiten estudiar la localización de los hornos de vidrio en el reino de Valencia y las formas de trabajo de los vidrieros, así como los procesos de distribución y los sistemas de venta del vidrio doméstico. Finalmente, se aborda la demanda y el consumo de estos bienes y sus usos en las viviendas de diferentes sectores sociales de la época. Todo ello invita a reconsiderar la relevancia de esta industria en el reino de Valencia, mucho menos estudiada que sus homólogas catalanas y mallorquinas, en el contexto de la Corona de Aragón y del Mediterráneo noroccidental durante la Baja Edad Media. This essay analyses the development of the Valencian glass industry between the 13th and the 15th centuries. For this purpose, it turns to around a hundred documents from notarial, normative, legal and tax records, placed in various Valencian archives. These reveal the location of glass furnaces in the kingdom of Valencia and the glass-makers’ activities, as well as the sale and distribution systems of domestic glass. Finally, it addresses the demand and consumption of these goods and their usage within the dwellings of various social strata of the period. This all leads to reconsider the relevance of this industry in the kingdom of Valencia, far less studied than its counterparts from Catalonia and Majorca, in the context of the Crown of Aragon and the north-western Mediterranean during the later middle ages.

ADVANCED TYPES OF CHECKERWORK OF REGENERATIVE HEAT EXCHANGERS FOR GLASS FURNACES

One of the ways to increase glass furnaces energy efficiency is to apply heat exchangers for flue gases thermal potential utilization. Flue gases losses is up to 25-40 % of the total amount of heat supplied in the furnace. These losses are influences by such factors as fuel type, furnace and burners design and manufactured product type. Regenerative heat exchangers with various types of heat storage packing is more efficient for high-power furnaces. Such types of regenerator checkerwork as Cowper checkerwork, two types of Siemens checkerwork, Lichte checkerwork and combined checkerwork have already been sufficiently researched, successfully applied and widely used for glass furnaces of various designs. All of its are made of standard refractory bricks. Basket checkerwork and cruciform checkerwork that are made of fused-cast molded refractory materials have been widely used recently as well. Further improvement of regenerative heat exchangers thermal efficiency only by replacing the checkerwork does not seem possible unless their size being increased. But this enlarging is not always realizable during the modernization of existing furnaces. From this point of view heat storage elements with a phase transition, where metal salts and their mixtures are used as a fusible agent look promising for glass furnaces. These elements can accumulate additional amount of heat due to phase transition, which allows to increase significantly heat exchanger thermal rating without its size and operating conditions changing. However, it is necessary to carry out additional studies of this type of checkerwork dealing with analysis of complex unsteady heat exchange processes in regenerators and selection of appropriate materials that satisfy the operating conditions of regenerative heat exchangers so that the checkerwork can be widely used for glass furnaces.

Efficiency Criteria for Thermal Insulation Structures of Glass Furnaces

The optimal operation of high temperature reactors such as glass furnaces requires many factors to be considered. These are, for example, the duration of the campaign, operating costs, heat losses, trouble-free operation of units and many others, presented in the article. The aim of this study is to synthesize an efficiency criterion for optimizing the heat-insulating construction of a glass-melting furnace (HICGF), as well as obtaining the optimal values of the efficiency criterion for HICGF, which for the furnace under study are about 3.8 billion rubles. In the course of the study, the phenomenological heuristic-evolutionary optimization method by G. E. Kanevets (PHEOM.GEK), which has a number of advantages over other evolutionary methods. As the main generalizing criterion, taking into account the most significant production (volume, cost of the produced glass mass) and financial (costs for the construction and operation of the HICGF, the monetary equivalent of heat losses) indicators, the maximum gross income for the furnace campaign was adopted, which differs from prototypes in that it allows to take into account most fully the peculiarities of the work of the insulated side fence of the glass furnace. Using the software complex created on the basis of PHEOM.GEK complex systems for the side fence of a glass-melting furnace, the optimal set (sequence of location and thickness) of thermal insulation materials HICGF was determined, which allow maximizing the furnace campaign with minimal heat losses. The reliability of the data obtained is achieved by the correct use of the theory of heat and mass transfer and PHEOM.GEK. An efficiency criterion is proposed, which, by solving an optimization problem, made it possible to determine the optimal HICGF. The solution of the optimization problem in conjunction with the calculation of the duration of the furnace campaign makes it possible to form recommendations for the development of optimal HICGFs in the construction of new and cold repair of existing glass furnaces by specialized institutes and industrial companies