تجزیه و تحلیل عملکرد در تقطیر چند اثر جدید به همراه ترانسفورماتور حرارتی جذب باز هدایت شده توسط انرژی حرارتی تلف شده

In this paper, a new water distillation system, which consists of either a single- or multi-effect distiller combined with an open absorption heat transformer (OAHT), has been proposed. The new integrated system can be used for distilling waste water with high amounts of SiO2 from heavy oil production, and the resultant distilled water can be supplied to steam boilers to produce high quality steam which in turn is injected into oil reservoirs to assist with heavy oil recovery. The thermodynamic cycle performances for these new integrated distillation systems were simulated based on the thermodynamic properties of the aqueous solution of LiBr as well as the mass and energy balance of the system. The results indicate that combined with OAHT, the waste heat at 70 °C can be elevated to 125 °C and thereby produce steam at 120 °C in the absorber, which is able to drive a four-effect distiller to produce distilled water. For a single-effect and four-effect distiller, the coefficients of performance (COP) are approximately 1.02 while the performance ratios are 2.19 and 5.72, respectively. Therefore, the four-effect distillation system combined with an OAHT is more thermally effective and is an ideal option to process the waste water in oilfields.

Steam injection is becoming a common method for enhancing oil recovery efficiency. 100% quality steam is required to be injected into the oil reservoir, to heat heavy oil and thereby to reduce its viscosity. Meanwhile, a lot of hot waste water with high amounts of SiO2 will be produced in the separating process of crude oil from the oil–water mixture. In order to remove SiO2 and other salts or contaminants from the produced waste water and meet the quality standards for feed water of steam boilers, some common physical and chemical technology of waste water processes are employed in heavy oil production. Recently the mechanical vapor compression (MVC) distillers, which mainly consist of a compressor and a distiller (or evaporator) were proposed [1]. In order to enhance the thermo-economy of the water purification process or desalination process, a common closed absorption heat pump (AHP) or an absorption heat transformer (AHT) are combined into a single-effect or multi-effect desalination [2], [3], [4], [5], [6], [7], [8] and [9]. The multi-effect thermal desalination system which is coupled with an open absorption heat pump driven by a high temperature heat source was analyzed recently [10]. The multi-effect thermal desalination system coupled with the absorption-compression heat pump was also analyzed [11]. In this paper a new thermal distiller, which is combined with an open absorption heat transformer (OAHT) and driven by low grade waste heat, is proposed. The OAHT has the coupled thermal absorber and evaporator. Compared with the MVC thermal distiller, the electric consumption of this new thermal distiller is much smaller because it is mainly driven by waste heat rather than electric power. Up till now the articles or reports on this new integrated thermal distiller have not been found. In order to further develop this thermal distillation method and to optimize the operating parameters, it is necessary to analyze its thermodynamic cycle performance based on the thermodynamic properties of the aqueous solution of lithium bromide and on the mass and energy balance for each component in the system.

The low-temperature waste heat (about 70 °C) can be effectively elevated to a higher temperature level (125 °C) by the coupled thermally absorber and evaporator. The available absorption heat at a higher temperature level is used to produce steam at 120 °C, which is used as the heating source to drive a single-effect distiller or a multi-effect distiller for distillating the waste water produced in heavy oil production, and thereby supplying distilled water for steam boilers. The COP of the new thermal distillation system is around 1.02 and remains constant with an increase of the absorption temperature. The available temperature of heat released from the absorber increases with an increase of the generation or the evaporation temperature, while in reverse decreases with an increase of the condensation temperature. Performance ratio of single- and four-effect distiller combined with an OAHP can reach 2.19 and 5.72, respectively.