We present the concept of a novel thermal power plant process in conjunction with low-temperature selective catalytic reduction (SCR). This process can be employed to achieve modern standards for NOx emissions and solve problems related to post-gas cleaning processes, such as thermal fatigue, catalyst damage, and an increase in differential pressure in the boiler. Therefore, this study is aimed at evaluating the performance of a novel flue-gas cleaning process for use in a thermal power plant, where a low-temperature SCR is implemented, along with the existing SCR. We developed a process model for a large-scale power plant, in which the thermal power plant was divided into a series of heat exchanger block models. The mass and energy balances were solved by considering the heat transfer interaction between the hot and cold sides to obtain the properties of each material flow. Using the process model, we performed a simulation of the new process. New optimal operating conditions were derived, and the effects that the new facilities have on the existing process were evaluated. The results show that the new process is feasible in terms of operating stability and cost, as well as showing an increase in the boiler thermal efficiency of up to 1.3%.

In this study the NOx reduction capability of reburning three biomasses (i.e., wood pellet, torrefied biomass, and empty fruit bunch) via 12 cases (i.e., four reburning ratios for every biomass) is investigated in a 1 MW_th-scale pilot-scale furnace. These reburning cases are compared with 12 cofiring cases presented in the Part 1 paper on a consistent basis. It is found that, for every cost to purchase and prepare biomass, reburning technology provides significantly better NOx abatement performance than cofiring (up to 3.4 times). NOx reduction effectiveness as high as 4.9 could be achieved by reburning, which means the percent of NOx abatement could be 4.9 times higher than the percent of reburning ratio. It is found that the highest NOx reduction per thermal unit of biomass happens at the lowest reburning ratio, and increasing the reburning ratio leads to a reduction in NOx abatement effectiveness in an exponential decay manner. Unlike cofiring technology, reburning was found to have little dependence on the fuel characteristics, such as fuel ratio or fuel-N, when it comes to NOx abatement potential.

This study was investigated co-firing of biomass and coal for NOx reduction using 1 MWth multi-burner furnace. NOx acts as a precursor of particulate matter formation and the minimization of its release from coal combustion has becomes an urgent issue. Three biomass types (wood pellet, torrefied biomass, and empty fruit bunch) were tested at different ratios through direct co-firing with coal and separate feeding as reburn fuel. It was found that the NOx reduction was achieved by up to 25% by direct co-firing and up to 50% by reburning. Although co-firing biomass as reburn fuel was more efficient for NOx reduction, further investigation is required for its applications in commercial plants.

심우현 • 이재욱 • 양원 • 채태영 • 류창국 • 김이태 • 정윤아 1. 서 론 식량농업기구(Food and Agriculture Organization)에 따르면, 인간이 소비하기 위해 전 세계적으로 생산되는 식 품의 약 3분의 1이 낭비되고 있다[1-3]. 앞으로 적절한 정 책 변화가 시행되지 않으면 음식물류 폐기물의 비율은 2050년까지 두 배로 늘어날 것으로 예상된다[4]. 음식물 쓰레기가 분해되면 온실가스 배출, 식량 불안, 자원 낭비 등 심각한 환경적, 사회 경제적 문제를 야기한다. 이에 따 라, 음식물 폐기물을 청정 고형 연료로 변환하여 에너지 생산까지 가능하도록 할 수 있는 다양한 연구들의 필요성 이 늘어나고 있다[4,5]. 음식물류 폐기물에는 다량의 수분이 함유되어 있기 때 문에 연료화를 위해서는 전처리가 필수적이다. 음식물류 폐기물에 포함된 다량의 수분은 수분 손실을 증가시켜 보 일러 효율을 저하시킬 수 있으며[6], 염소 함량이 높기 때 문에 부식을 유발할 뿐만 아니라 다이옥신 및 다이옥신 유