Tác giả: Dương Ngọc Bích. Prof. Jau – Huai Lu (người hướng dẫn khoa học).

National Chung Hsing University. Năm: 2015.

Mô tả: 90Tr. Kích thước: 30cm. Số định danh:

Abstract

One of the excellent methods employed not only to recover waste heat from combustion furnaces is using regenerative heat exchanger that can help facilities significantly reduce fossil fuel consumption, as well as reduce associated operating costs, but also to control the Volatile Organic Compounds (VOCs) that consists of different kinds of chemical being adverse environment and health effects. The purpose of this study is to investigate the effects of operating and design parameters, two crucial variables in thermal performance of regenerative heat exchanger with two alternative working beds, on the efficiency of thermal exchange and the pressure drop through heating and cooling process. It is clearly that an extensive knowledge and thorough understanding of the heat transfer phenomena in the regenerator is essential. This study used numerical and analytical methods to simulate heat transfer process of regenerator brought out expected results for the temperatures of gases and solid material as function of time and space presented for the general asymmetric and unbalanced case.

In particular, the thermal recovery efficiency is affected by the operating parameters as cycle duration (2% difference in each concerned semi-cycle duration), specific mass flow rate G (approximately 7% difference of the thermal effectiveness between G =1 and G =0.25 kg.m-2 .s-1 ). On the other hand, it is investigated that design parameters also influenced on regenerator performance such as ball size (thermal recovery efficiency is higher 97% for balls with diameter of 6mm and lower 95% for that of 15mm), bed height (about 2% disparity of thermal effectiveness of 0.8m, 1m, 1.5m, and 2m height of regenerator), bed void-age (about 4% disparity of thermal efficiency between 44% and 64% in porosity). These listed parameters also impact considerably to the pressure drop, namely the increase the ball size reduces the pressure drop whereas the decrease the specific mass flow rate enlarges the pressure drop of whole furnace.

Moreover, comparison the capacity of thermal recovery of a uniform particle and that of a non-uniform particle as well as the similarity of thermal storage performance between the modified radius of non-uniform particle and the uniform are also illustrated in this paper.

Last but not least, the comparison of real regenerator as a waste heat recovery device of real model (regenerative furnaces in a glass factory) to the simulation model for fixed bed will bring us the deep and clear overview to thermal distribution of regenerator about the thermal recovery efficiency.

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