An Exhaust Gas Temperature Increase Technique Using EGR Device for the Application of Waste Heat Recovery Technology on a Lean Burn Gas Engine

2018 ◽  
Author(s):  
Yasuhisa Ichikawa ◽  
Hidenori Sekiguchi ◽  
Oleksiy Bondarenko ◽  
Koichi Hirata
Keyword(s):  
Temperature Increase ◽  
Heat Recovery ◽  
Waste Heat Recovery ◽  
Waste Heat ◽  
Combustion Efficiency ◽  
Exhaust Gas ◽  
Gas Temperature ◽  
Lean Burn ◽  
Gas Engine ◽  
Exhaust Gas Temperature

This study aims to develop an exhaust gas temperature increase technique of a lean burn gas engine, to improve the performance of the waste heat recovery devices that potentially can be installed in the future. This paper shows the exhaust gas temperature increase technique using an EGR device. In our experiments, the lean burn gas engine has the rated power output of 400 kW with spark-ignition and pre-chamber systems. The EGR device was developed and installed to the gas engine. The experimental results showed that the exhaust gas temperature was increased to +30 °C at the EGR rate of 15 % with maintained NOx emission and CA MFB 50% by decreasing the relative air/fuel ratio (Λ) and advancing the ignition timing (θig). In addition, the gross generation efficiency was slightly increased with increasing the EGR rate. This result was explained using three factors; the internal engine efficiency, the combustion efficiency, and the recirculated energy rate.

scholarly journals Experimental Study on Operation Regulation of a Coupled High–Low Energy Flue Gas Waste Heat Recovery System Based on Exhaust Gas Temperature Control

Energies ◽  
2019 ◽  
Vol 12 (4) ◽  
pp. 706 ◽  
Author(s):  
Jiayou Liu ◽  
Fengzhong Sun
Keyword(s):  
Flue Gas ◽  
Heat Recovery ◽  
Waste Heat Recovery ◽  
Gas Flow ◽  
Waste Heat ◽  
Exhaust Gas ◽  
Gas Temperature ◽  
Waste Heat Recovery System ◽  
Recovery System ◽  
Exhaust Gas Temperature

Controlling the exhaust gas temperature (EGT) of coal–fired boilers at a reasonable value is beneficial to ensuring unit efficiency and preventing acid corrosion and fouling of tail heating surfaces in power plants. To obtain the operation regulation of coupled high–low energy flue gas waste heat recovery system (CWHRS) under a given EGT, experimental equipment was designed and built. Experiments were carried out to maintain the exhaust gas temperature under different flue gas flow, flue gas temperature and air temperature conditions. As the flue gas flows, the flue gas temperatures and air temperatures increased, and the bypass flue gas flow proportions or the water flows of the additional economizer were increased to maintain the EGT at about 85 °C. An improved low temperature economizer (LTE) and front located air heater (FAH) system were put forward. As the flow of the crossover pipe increased, the EGT and the inlet water temperature of the LTE increased. As the flow of the circulating loop increased, the EGT and the inlet water temperature of the LTE decreased. Operation regulations of LTE–FAH system under four cases were given. The operation regulations of CWHRS and LTE–FAH system can provide references for power plant operation.

Energetic Based Organic Fluid Selection for a Solid Oxide Fuel Cell-Organic Rankine Cycle Combined System

2012 ◽  
Vol 622-623 ◽  
pp. 1162-1167
Author(s):  
Han Fei Tuo
Keyword(s):  
Fuel Cell ◽  
Solid Oxide Fuel Cell ◽  
Heat Recovery ◽  
Waste Heat ◽  
Solid Oxide ◽  
Exhaust Gas ◽  
Oxide Fuel ◽  
Gas Temperature ◽  
Selection For ◽  
Exhaust Gas Temperature

In this study, energetic based fluid selection for a solid oxide fuel cell-organic rankine combined power system is investigated. 9 dry organic fluids with varied critical temperatures are chosen and their corresponding ORC cycle performances are evaluated at different turbine inlet temperatures and exhaust gas temperature (waste heat source) from the upper cycle. It is found that actual ORC cycle efficiency for each fluid strongly depends on the waste heat recovery performance of the heat recovery vapor generator. Exhaust gas temperature determines the optimal fluid which yields the highest efficiency.

scholarly journals Comparative analysis of working fluids for efficient waste heat recovery

2021 ◽  
Vol 2057 (1) ◽  
pp. 012102
Author(s):  
D Ye Lola ◽  
A Yu Chirkov ◽  
Yu A Borisov
Keyword(s):  
Heat Recovery ◽  
Waste Heat Recovery ◽  
Waste Heat ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Exhaust Gas ◽  
Water Cooling ◽  
Working Fluids ◽  
Gas Recovery ◽  
Recovery System

Abstract The paper analyzes the implementation of plants with an organic Rankine cycle (ORC) on the example of the circuit of the regenerative gas turbine unit and exhaust gas recovery system of the compressor system of the gas-compressor unit. The theoretically achievable values of power generated by the ORC-installations are determined. A criterion is presented for comparing the working fluids according to the efficiency of use in ORC-installations. To evaluate the overall characteristics of the system, the parameters of heat exchangers for air and water cooling were determined. As a result, it is concluded that the use of ORC-installations allows to utilize up to 23% of the heat of exhaust gases (convert into useful work).

Use of Early Exhaust Valve Opening to Improve Combustion Efficiency and Catalyst Effectiveness in a Multi-Cylinder RCCI Engine System: A Simulation Study

2014 ◽  
Author(s):  
Anand Nageswaran Bharath ◽  
Nitya Kalva ◽  
Rolf D. Reitz ◽  
Christopher J. Rutland
Keyword(s):  
System Simulation ◽  
Combustion Efficiency ◽  
Exhaust Valve ◽  
Exhaust Gas ◽  
Gas Temperature ◽  
Flow Rates ◽  
Low Load ◽  
Valve Opening ◽  
Engine System ◽  
Exhaust Gas Temperature

Low Temperature Combustion (LTC) strategies such as Reactivity Controlled Compression Ignition (RCCI) can result in significant improvements of fuel economy and emissions reduction. However, they can produce significant carbon monoxide and unburnt hydrocarbon emissions at low load operating conditions due to poor combustion efficiencies at these operating points, which is a consequence of the low combustion temperatures that cause the oxidation rates of these species to slow down. The exhaust gas temperature is also not high enough at low loads for effective performance of turbocharger systems and diesel oxidation catalysts (DOC). The DOC is extremely sensitive to exhaust gas temperature changes and lights off only when a certain temperature is reached, depending on the catalyst specifications. Uncooled EGR can increase combustion temperatures, thereby improving combustion efficiency, but high EGR concentrations of 50% or more are required, thereby increasing pumping work and reducing volumetric efficiency. However, with early exhaust valve opening, the exhaust gas temperature can be much higher, allowing lower EGR flow rates, and enabling activation of the DOC for more effective oxidization of unburnt hydrocarbons and CO in the exhaust. In this paper, a multi-cylinder engine system simulation of RCCI at low load operation with early exhaust valve opening is presented, along with consideration of the exhaust aftertreatment system. The combustion process is modeled using the 3D CFD code, KIVA, and the heat release rates obtained from this combustion are used in a GT-Power model of a turbocharged, multi-cylinder light-duty RCCI engine for a full system simulation. The post-turbine exhaust gas is fed into GT-Power’s aftertreatment model of the engine’s DOC to determine the catalyst response. It is confirmed that opening the exhaust valve earlier increases the exhaust gas temperature, and hence lower EGR flow rates are needed to improve combustion efficiency. It was also found that exhaust temperatures of around 457 K are required to light off the catalyst and oxidize the unburnt hydrocarbons and CO effectively. Performance of the DOC was drastically improved and higher amounts of unburnt hydrocarbons were oxidized by increasing the exhaust gas temperature.

Energy-Saving Analysis of 215MW Cogeneration Boiler Adding Low Temperature Economizer

2013 ◽  
Vol 448-453 ◽  
pp. 2777-2780 ◽  
Author(s):  
Yan Feng Liu ◽  
Shi Ping Li ◽  
Xiang Hong Li
Keyword(s):  
Low Temperature ◽  
Flue Gas ◽  
Waste Heat ◽  
Natural Circulation ◽  
Peak Load ◽  
Exhaust Gas ◽  
Gas Temperature ◽  
Bag Filter ◽  
Actual Operation ◽  
Exhaust Gas Temperature

A 215MW cogeneration B&W670/13.7-M type high-pressure natural circulation boilers, the exhaust gas temperature is set as 143 °C, while in the actual operation, the average exhaust gas temperature is 155 °C, and when the unit is running at full capacity in summer the highest exhaust gas temperature is 169.6 °C. In order to satisfy the normal operating temperature of bag filter in summer peak load, and recover low temperature waste heat of fule gas, low temperature economizer is added to the thermal system. Therefore, low-temperature economizers are respectively added in four flues which are between the outlet of the air preheater and the entrance of the bag filter, this will achieve the purpose of reducing flue gas temperature by transferring heat between condensate and flue gas, ensuring the units safe operating and improving the overall operating performance of the boiler.

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