Analysis of the performance of direct contact heat exchange systems for application in mine waste heat recovery

2021 ◽  
Author(s):  
Hosein Kalantari ◽  
Leyla Amiri ◽  
Seyed Ali Ghoreishi‐Madiseh
Keyword(s):  
Heat Exchange ◽  
Direct Contact ◽  
Heat Recovery ◽  
Waste Heat Recovery ◽  
Waste Heat ◽  
Mine Waste ◽  
Contact Heat ◽  
Contact Heat Exchange

Experimental Study of Natural Gas Combustion Flue Gas Waste Heat Recovery System Based on Direct Contact Heat Transfer and Absorption Heat Pump

2013 ◽  
Author(s):  
Xian Zhou ◽  
Hua Liu ◽  
Lin Fu ◽  
Shigang Zhang
Keyword(s):  
Heat Exchanger ◽  
Flue Gas ◽  
Direct Contact ◽  
Heat Recovery ◽  
Waste Heat Recovery ◽  
Waste Heat ◽  
Contact Heat ◽  
Absorption Heat Pump ◽  
Return Water ◽  
Recovery System

Condensing boiler for flue gas waste heat recovery is widely used in industries. In order to gain a portion of the sensible heat and latent heat of the vapor in the flue gas, the flue gas is cooled by return water of district heating through a condensation heat exchanger which is located at the end of flue. At low ambient air temperature, some boilers utilize the air pre-heater, which makes air be heated before entering the boiler, and also recovers part of the waste heat of flue gas. However, there are some disadvantages for these technologies. For the former one, the low temperature of the return water is required while the utilization of flue gas heat for the latter one is very limited. A new flue gas condensing heat recovery system is developed, in which direct contact heat exchanger and absorption heat pump are integrated with the gas boiler to recover condensing heat, even the temperature of the return water is so low that the latent heat of vapor in the flue gas could not be recovered directly by the general condensing technologies. Direct contact condensation occurs when vapor in the flue gas contacts and condenses on cold liquid directly. Due to the absence of a solid boundary between the phases, transport processes at the phase interface are much more efficient and quite different from condensation phenomena on a solid surface. Additionally, the surface heat exchanger tends to be more bulky and expensive. In this study, an experimental platform of the new system is built, and a variety of experimental conditions are carried out. Through the analysis of the experimental data and operational state, the total thermal efficiency of the platform will be increased 3.9%, and the system is reliable enough to be popularized.

Optimization of an Organic Rankine Cycle-Based Waste Heat Recovery System Using a Novel Target-Temperature-Line Approach

2021 ◽  
Vol 143 (9) ◽  
Author(s):  
Md. Zahurul Haq
Keyword(s):  
Heat Exchange ◽  
Heat Recovery ◽  
Waste Heat Recovery ◽  
Waste Heat ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Optimum Operating ◽  
Working Fluid ◽  
Operating Parameters ◽  
Target Temperature

Abstract Organic Rankine cycle (ORC)-based waste heat recovery (WHR) systems are simple, flexible, economical, and environment-friendly. Many working fluids and cycle configurations are available for WHR systems, and the diversity of working fluid properties complicates the synergistic integration of the efficient heat exchange in the evaporator and net output work. Unique guidelines to select a proper working fluid, cycle configuration and optimum operating parameters are not readily available. In the present study, a simple target-temperature-line approach is introduced to get the optimum operating parameters for the subcritical ORC system. The target-line is the locus of temperatures satisfying the pinch-point temperature difference along the length of the heat exchanger. Employing the approach, study is carried out with 38 pre-selected working fluids to get the optimum operating parameters and suitable fluid for heat source temperatures ranging from 100 °C to 300 °C. Results obtained are analyzed to get cross-correlations between key operating and performance parameters using a heat-map diagram. At the optimum condition, optimal working fluid’s critical temperature and pressure, evaporator saturation temperature, effectivenesses of the heat exchange in the evaporator, cycle, and overall WHR system exhibit strong linear correlations with the heat source temperature.

An Innovative Heating Energy System Planning and Design: Case of Yinchuan City

2013 ◽  
Author(s):  
Zhonghai Zheng ◽  
Lin Fu ◽  
Zi Wu ◽  
Xiling Zhao ◽  
Yanting Wu
Keyword(s):  
Energy Efficiency ◽  
Heat Exchange ◽  
Heat Recovery ◽  
Waste Heat Recovery ◽  
Waste Heat ◽  
Economic Cost ◽  
Heating System ◽  
High Energy ◽  
Large Temperature ◽  
Energy Structure

The current heating system in Yinchuan city, the capital of the Ningxia Autonomous Region in northwest China, is investigated and analyzed. Lacking an integrated planning, the heating systems have developed with low energy efficiency, high environment emission and economic cost. The choice of heating energy structure vary between coal and gas, the heating modes including gas-fired CHP, coal-fired CHP, gas-fired boiler and coal-fired boiler are facing challenges. In this paper, several innovative planning scenarios are proposed to achieve high energy efficiency, low environment emission and reasonable economic cost. In the heating schemes, three innovative technologies are designed. The first technology is waste heat recovery based on the Co-generation-based absorption heat-exchange (Co-ah) cycle. The waste heat can be both from circulating water or flue gas in CHP heating system and the industrial waste heat recovery. The second technology is the heating network with large temperature difference. The third technology is the gas distributed peak-shaving, gas-driven absorption heat-exchange in the substation.

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