• 동력기계공학회지
• /
• 제5권1호
• /
• pp.11-20
• /
• 2001

Super-critical type steam power plant, which operates with steam pressure above the super-critical point, has a good reputation recently and is adopted as a new standard of the Korean Electric Power Corporation. The reason for the good reputation lies in it's superior power efficiency. However, the field data of the new power plant for the verification of it's performance are still insufficient, and more empirical data are needed to acquire technologies on the effective operation of it. In this study, the authors analyzed the field test data on power efficiencies got in a super-critical type steam power plant, and evaluated the excellency of the new plant by comparing the efficiency data with the one got in a conventional sub-critical type steam power plant.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2004년도 추계학술대회
• /
• pp.1676-1681
• /
• 2004

The main reason for applying positive pressure variable clearance packing in fossil power plant is high efficiency and energy saving movement in the government. This study intends to analyze the turbine efficiency through the shaft packing improvement in thermal power plant and makes its comparison to that of the each packing type

• 한국수소및신에너지학회논문집
• /
• 제29권1호
• /
• pp.11-18
• /
• 2018

A high efficiency integrated reforming system for improving the efficiency of the 5 kW PEMFC system used as the back up power of building was studied. The separated reforming system consisted of three parts - A steam reformer with two stage concentric circular shape, a heat exchanger type steam generator and a CO shift reactor. Temperature and steam carbon ratio (SCR) were control variables during operation. The operating conditions were optimized based on the thermal efficiency of the steam reformer as reformate gas composition changes at different temperature. In experiments, water was fully vaporized in the steam generator up to SCR 3.5 and the maximum thermal efficiency was achieved at the operating temperature around $700^{\circ}C$ in the steam reforming reactor. With the results of the separated reforming system research, we improved the shape of high efficiency integrated reformer. The performance evaluation of the integrated reformer was based on optimized operating conditions in SCR 3.5. As a result, the developed integrated reforming system maintained an efficiency of 76% and constant performance over 3,000 hours.

• 대한설비공학회:학술대회논문집
• /
• 대한설비공학회 2009년도 하계학술발표대회 논문집
• /
• pp.1397-1405
• /
• 2009

In recent decades, exergy analysis has been holding spotlight as a useful tool in the design, assessment, optimization, and improvement of energy system. This paper presents the results of the energy and exergy analysis of a steam turbine cogeneration system for industrial complex using two efficiency concepts of conventional one and exergetic one. In order to obtain the destroyed exergy of each component, mathematical analysis is conducted by using exergy balance and the second law of thermodynamics, according as the parameters are changed, such as the ratio of returned process steam, process steam supplied, temperature and pressure of boiler and power. The computer program developed in this study can determine the efficiencies and exergy destroyed at each component of cogeneration system. As a result of this study, a component having the largest destroyed exergy was boiler. And closed and opened feedwater heater had the lowest one. The affects to the cogeneration system due to the variation of process steam flow and return rate of condensed water is shown that the total electric power efficiency(${\eta}_E$) is decreased as increasing the return rate of condensed water under constant process steam flow. As the boiler pressure is increased for the more production of electricity, the efficiency of cogeneration system was decreased.

• 한국추진공학회지
• /
• 제13권4호
• /
• pp.45-54
• /
• 2009

열효율과 비동력을 대폭 향상시킬 수 있는 잠재성을 가진 증기분사 재생 가스터빈 시스템에 대해 엑서지 해석을 수행하였다. 열역학 제2법칙을 근거로 한 해석 모델을 이용하여 압력비, 증기분사율, 주위 온도, 터빈입구온도 등 주요 설계변수들의 변화에 따라 엑서지 효율, 열교환기의 엑서지 회수율, 엑서지 파괴율 및 손실률 등 시스템의 성능과 최대 엑서지 효율에 미치는 영향을 조사하였다. 계산 결과 재생 증기분사 가스터빈 시스템은 시스템의 엑서지 효율을 대폭 증대시키고 비가역성을 감소시킨다는 사실을 확인하였다.

• 설비공학논문집
• /
• 제28권11호
• /
• pp.434-443
• /
• 2016

The evaporation of water from an aqueous solution is widely used in the food, desalination, pulp, and chemical industries. Usually, a large amount of energy is consumed in the evaporation process to boil off water due to atmospheric pressure. As a way of improving the energy efficiency of the evaporation process, the combination of multiple effect evaporation and thermal vapor recompression has been proposed and has become a successful technique. In this study, 4 multiple-effect falling film type evaporators for sugar solution are designed and the energy efficiency of the system is analyzed in response to the selection of the steam ejector position. Energy efficiency is increased and vapor is more compressed in the steam ejector as the Thermal Vapor Recompression (TVR) is arranged in the rear part of the evaporator system. A simplified 0-dimensional evaporator model is developed using non-linear equations derived from mass balances, energy balances, and heat transfer equations. Steam economy is calculated to compare the evaporation performance of the 4 proposed evaporators. The entrainment ratio, compression ratio, and expansion ratio are computed to check the ejector performance.

• 한국염색가공학회지
• /
• 제18권6호
• /
• pp.69-79
• /
• 2006

The washing characteristics of steam jet heating process have been compared with other washing processes, such as low temperature process(standard process, below $40^{\circ}C$) and high temperature process(boiling process, up to $95^{\circ}C$) with the standard soil fabric, EPMA 105. Steam jet heating process showed almost the same washing efficiency as high maximum temperature process for pig's blood and wine. This result can be explained with the higher surface temperature of washing materials in steam jet process compared with direct boiling process. In terms of the energy and water consumption, the steam jet washing process showed significant savings compared with direct boiling type washing process.

• 한국응용과학기술학회지
• /
• 제37권2호
• /
• pp.173-182
• /
• 2020

본 연구에서는 주류공장 내 고농도 CO₂ 제거 및 포집을 위해 L-alanine 흡수제를 적용하여 CO₂ 흡수, 탈리 효율을 평가 후 재생 성능을 확인하였다. 탈리공정의 효율적인 처리를 평가하기 위해 실험실 규모에서 Hot plate, Steam 두가지 탈리 방법을 비교하였으며 Hot plate는 약 10%, Steam의 경우 약 60%의 재생효율을 확인하였다. 따라서 주류공장 내 100㎥/min 실증화 규모에 Steam-Tower 탈리공정을 적용하여 최적조건을 평가한 결과 탈리 유량 4L/min 이하, Steam 온도 160℃ 이상, 탈리효율 85.5%로 확인할 수 있었다.

• 한국연소학회지
• /
• 제16권1호
• /
• pp.36-45
• /
• 2011

The heat-flow characteristics and reforming efficiency of steam reformer with combustor are numerically investigated at various operating conditions. SCR(Steam to Carbon Ratio) and GHSV(Gas Hourly Space Velocity) are adopted as important operating conditions. User-Defined-Function(UDF) was used to simultaneously calculate reforming and combustion reaction. Numerical results show that hot burned gas rise by a buoyant force and heat exchange between reforming reactors and cocurrent flow occurs in the combustion region. The results also indicate that an increase of SCR leads to decrease the mole fraction of hydrogen at the reactor outlet. As GHSV increases, conversion rate decreases.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2001년도 추계학술대회논문집B
• /
• pp.867-871
• /
• 2001

The main reason for reviewing the condensate water return system in the auxiliary steam system is to obtain the thermal high efficiency of the power plant and thus save the fossil energy in power plant. This study intends to analyze the thermal efficiency of the power plant and predict the increasing in the generator output by the return system reformation of auxiliary steam line in the thermal power plant.