scholarly journals Electrothermal Desiccant Regeneration Technique for Air Dehumidification

Processes ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 1082
Author(s):  
Chih-Hao Chen ◽  
Yu-Hao Kang ◽  
Jing-Hung Lu ◽  
Ming-Lang Hung ◽  
Jyi-Ching Perng ◽  
...  
Keyword(s):  
Heat Loss ◽  
Waste Heat ◽  
Dew Point ◽  
Compressed Air ◽  
Activated Alumina ◽  
Regeneration System ◽  
Relative Humidity Condition ◽  
Exhaust Waste Heat ◽  
Actual Use ◽  
Industrial Use

Adsorption dehumidification and drying equipment is essential general equipment for domestic and industrial use. The most commonly used type in industry is the compressed air adsorption dryer. The analysis results show that the heat loss of the traditional heat air regeneration system of the compressor dryer is 39.4%, and the exhaust waste heat is 32.4%. The actual use of heat energy for desiccant regeneration is only 28.2%. Therefore, this study uses an innovative electrothermal adsorbent unit (ETAU) to regenerate the desiccant. By directly heating the adsorbent, heat loss can be effectively improved. On the other hand, the composite arrangement of zeolite and activated alumina is used. The inlet compressed air is firstly treated by the activated alumina, which has a high adsorption capacity in the high relative humidity condition, then a zeolite is used as a second part to make the dew point reach –40 °C. In the regeneration step, the airflow direction is reversed, whereby the zeolite is regenerated by the ETAU, and the waste heat of the exhaust air is used to regenerate the activated alumina, which reduces the temperature of the exhaust air. Compared with the traditional heat air compressed air system, the two technologies can save about 27% energy in total.

scholarly journals Recovery of Exhaust Waste Heat for ICE Using the Beta Type Stirling Engine

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Wail Aladayleh ◽  
Ali Alahmer
Keyword(s):  
Internal Combustion Engine ◽  
Waste Heat ◽  
Combustion Engine ◽  
Internal Combustion ◽  
Stirling Engine ◽  
Gas Temperature ◽  
Ic Engine ◽  
Exhaust Waste Heat ◽  
Useful Power ◽  
Shaft Power

This paper investigates the potential of utilizing the exhaust waste heat using an integrated mechanical device with internal combustion engine for the automobiles to increase the fuel economy, the useful power, and the environment safety. One of the ways of utilizing waste heat is to use a Stirling engine. A Stirling engine requires only an external heat source as wasted heat for its operation. Because the exhaust gas temperature may reach 200 to 700°C, Stirling engine will work effectively. The indication work, real shaft power and specific fuel consumption for Stirling engine, and the exhaust power losses for IC engine are calculated. The study shows the availability and possibility of recovery of the waste heat from internal combustion engine using Stirling engine.

scholarly journals Ethylene Glycol Regeneration Plan: A Systematic Approach to Troubleshoot the Common Problems

2013 ◽  
Vol 27 ◽  
pp. 21-26 ◽  
Author(s):  
Md Emdadul Haque
Keyword(s):  
Ethylene Glycol ◽  
Gas Flow ◽  
Salt Content ◽  
Dew Point ◽  
Circulation Rate ◽  
Water Volume ◽  
Processing Plant ◽  
Regeneration System ◽  
Column Temperature ◽  
Flow Rates

Mono Ethylene Glycol (MEG) is used primarily at low-temperature processing plant for extracting natural gas liquids. Typically a physical process plant comprises with gas dehydration system which allows for physical separation of water saturated gas by simple dew point depression and water condensation brought about by chilling from cross exchange with propane refrigerant. The resultant wet gas is prevented from freezing by injection of liquid desiccants to inhibit hydrate formation. The resulting dehydrated gas stream will have a dew point preciously equal to the saturated water volume of the gas at its coolest temperature. Mono Ethylene Glycol has been chosen as hydrate inhibitor because of its low volatility, low toxicity, low flammability, good thermodynamic behavior, and simple proven technology requirement and availability. But it has two common characteristic problems in regeneration plant that is fouling of equipment by iron carbonate, Ca+2/Mg+2 salt deposits and cross contamination of MEG and condensate contamination. MEG in condensate causes condensate specification problems, fouling of condensate stabilization equipment and contamination of wastewater streams. Condensate in MEG causes stripping effect due to condensate vaporization, lower operating temperature, higher MEG purities, and contamination of wastewater streams from MEG Regeneration system and burping of column due to condensate buildup. Another common problem is glycol losses due to carryover with dehydrated gas and which finally accumulates in pipelines and causes corrosion. Other reasons of glycol losses are higher column temperature, foaming, leaks at pump or pipe fittings, operated with excessive gas flow rates and rapid changes in gas flow rates. Column Flooding occurred if feed glycol circulation rate exceeded design limit and it does not allow proper separation of glycol and water separator and much glycol losses through vent line. This paper presents an experimental study of glycol losses. Effort has been made to investigate the causes and the study suggests some mitigation plans. Current study suggests the efficiency of the dehydration process depends on a large extent on the cleanliness of the glycol and the regular monitoring of glycol parameters such as glycol concentration, hydrocarbon content, salt content, solids content, pH stabilization, iron content, foaming tendency etc. Losses due to vaporization from reboiler can be minimized by adjusting operating parameters. By developing monitoring procedure and periodic maintenance about 90% operating problems of Glycol Regeneration Plant can be reduced. DOI: http://dx.doi.org/10.3329/jce.v27i1.15853 Journal of Chemical Engineering, IEB Vol. ChE. 27, No. 1, June 2012: 21-26

scholarly journals Performance Characteristics of Solid-Desiccant Evaporative Cooling Systems

Energies ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 2574 ◽  
Author(s):  
Ramadas Narayanan ◽  
Edward Halawa ◽  
Sanjeev Jain
Keyword(s):  
Air Conditioning ◽  
Natural Ventilation ◽  
Waste Heat ◽  
Numerical Study ◽  
Evaporative Cooling ◽  
Peak Load ◽  
Dew Point ◽  
Low Grade ◽  
Subtropical Climate ◽  
Cooling Systems

Air conditioning accounts for up to 50% of energy use in buildings. Increased air-conditioning-system installations not only increase total energy consumption but also raise peak load demand. Desiccant evaporative cooling systems use low-grade thermal energy, such as solar energy and waste heat, instead of electricity to provide thermal comfort. This system can potentially lead to significant energy saving, reduction in carbon emissions, and it has a low dew-point operation and large capacity range. Their light weight, simplicity of design, and close-to-atmospheric operation make them easy to maintain. This paper evaluates the applicability of this technology to the climatic conditions of Brisbane, Queensland, Australia, specifically for the residential sector. Given the subtropical climate of Brisbane, where humidity levels are not excessively high during cooling periods, the numerical study shows that such a system can be a potential alternative to conventional compression-based air-conditioning systems. Nevertheless, the installation of such a system in Brisbane’s climate zone requires careful design, proper selection of components, and a cheap heat source for regeneration. The paper also discusses the economy-cycle options for this system in such a climate and compares its effectiveness to natural ventilation.

scholarly journals Energy and Exergy Analysis of Different Exhaust Waste Heat Recovery Systems for Natural Gas Engine Based on ORC

2019 ◽  
Author(s):  
Guillermo Valencia ◽  
Armando Fontalvo ◽  
Yulineth Cardenas ◽  
Jorge Duarte ◽  
Cesar Isaza
Keyword(s):  
Natural Gas ◽  
Heat Recovery ◽  
Waste Heat Recovery ◽  
Exergy Analysis ◽  
Waste Heat ◽  
Natural Gas Engine ◽  
Exhaust Waste Heat ◽  
Energy And Exergy ◽  
Energy And Exergy Analysis ◽  
Net Power Output

One way to increase overall natural gas engine efficiency is to transform exhaust waste heat into useful energy by means of a bottoming cycle. Organic Rankine cycle (ORC) is a promising technology to convert medium and low grade waste heat into mechanical power and electricity. This paper presents an energy and exergy analysis of three ORC-Waste heat recovery configurations by using an intermediate thermal oil circuit: Simple ORC (SORC), ORC with Recuperator (RORC) and ORC with Double Pressure (DORC), and Cyclohexane, Toluene and Acetone have been proposed as working fluids. An energy and exergy thermodynamic model is proposed to evaluate each configuration performance, while available exhaust thermal energy variation under different engine loads was determined through an experimentally validated mathematical model. Additionally, the effect of evaportating pressure on net power output , absolute thermal efficiency increase, absolute specific fuel consumption decrease, overall energy conversion efficiency, and component exergy destruction is also investigated. Results evidence an improvement in operational performance for heat recovery through RORC with Toluene at an evaporation pressure of 3.4 MPa, achieving 146.25 kW of net power output, 11.58% of overall conversion efficiency, 28.4% of ORC thermal efficiency, and an specific fuel consumption reduction of 7.67% at a 1482 rpm engine speed, a 120.2 L/min natural gas Flow, 1.784 lambda, and 1758.77 kW mechanical engine power.

scholarly journals The Role of the Recuperator in High Performance Gas Turbine Applications

1978 ◽  
Author(s):  
C. F. McDonald
Keyword(s):  
High Temperature ◽  
Heat Exchanger ◽  
Gas Turbine ◽  
Gas Turbines ◽  
High Performance ◽  
Waste Heat ◽  
Closed Cycle ◽  
Exhaust Waste Heat ◽  
Prime Movers

With soaring fuel costs and diminishing clean fuel availability, the efficiency of the industrial gas turbine must be improved by utilizing the exhaust waste heat by either incorporating a recuperator or by co-generation, or both. In the future, gas turbines for power generation should be capable of operation on fuels hitherto not exploited in this prime-mover, i.e., coal and nuclear fuel. The recuperative gas turbine can be used for open-cycle, indirect cycle, and closed-cycle applications, the latter now receiving renewed attention because of its adaptability to both fossil (coal) and nuclear (high temperature gas-cooled reactor) heat sources. All of these prime-movers require a viable high temperature heat exchanger for high plant efficiency. In this paper, emphasis is placed on the increasingly important role of the recuperator and the complete spectrum of recuperative gas turbine applications is surveyed, from lightweight propulsion engines, through vehicular and industrial prime-movers, to the large utility size nuclear closed-cycle gas turbine. For each application, the appropriate design criteria, types of recuperator construction (plate-fin or tubular etc.), and heat exchanger material (metal or ceramic) are briefly discussed.

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