Ali Bahadır OLCAY, Murat KAHRAMAN, Selçuk ATAŞ

NUMERICAL AND EXPERIMENTAL INVESTIGATION OF A PULVERIZED COAL MILL DUCT SYSTEM IN THE SOMA B THERMAL POWER PLANT BY PLANT PERFORMANCE TESTS

Pülverize kömür yakan bir termik santralde kömür, hava ve gaz karışımı ocak bölgesine değirmen kanal sistemi ile beslenir. Verimli bir yanma için kömür/hava dağılımının ideale yakın derecede homojen olarak sağlanması gerekmektedir. Değirmen kanal sisteminde kömür/hava akışı olayı kazan verimliliği açısından oldukça önemli bir konu olup bu proses hala derinlemesine anlaşılamamış durumdadır. Bu çalışmada, kazan performansını değerlendirmek amacıyla Soma B Termik Santralinin değirmen kanal sistemindeki kömür/hava/gaz karışımlarına ait akış incelenmiş olup kazan veriminin özellikle taban külü partikülleri bünyesindeki 500 µm üstü yanmamış karbon miktarından direkt olarak etkilendiği görülmüştür. Soma B Termik Santralı değirmen kanal sistemindeki kömür/hava akışı kömür partikülleri ve gaz karışımının akış davranışını karakterize etmek üzere nümerik olarak modellenmiştir. Model saha ölçümleri ile elde edilen gerçek zamanlı santral işletme verileri ile doğrulanmıştır. Simülasyon sonuçlarına göre 230 µm üstü partiküllerin alt seviye yakıcı kanalları arasındaki dağılımının homojen olmadığı görülmüştür. Doğrulanmış model baz alınarak homojen olmayan kömür/hava dağılımının temel sebepleri araştırılmış ve bu sorunları çözmek için iki adet yeni değirmen kanal sistem alternatifi (ND-01 ve ND-02) tasarlanmıştır. Mevcut durum ve alternatif tasarımlara ait simülasyon sonuçları karşılaştırılmış ve özellikle 230 µm üzeri partiküller için ND01 tasarımı ile değirmen kanal sisteminde daha homojen bir partikül dağılımı elde edildiği görülmüştür.

SOMA TERMİK SANTRALİNDE KÖMÜR DEĞİRMEN KANAL SİSTEMİNİN SANTRAL PERFORMANS TESTLERİ YARDIMIYLA NÜMERİK VE DENEYSEL OLARAK İNCELENMESİ

In a pulverized coal-fired (PCF) thermal power plant (TPP), mixture of coal, air and gas is supplied into the furnace volume via the mill duct system and coal/air distribution should ideally be maintained as homogeneous as possible to ensure an efficient combustion. The phenomenon of coal/air flow in the mill duct system has been so far an important issue in terms of boiler efficiency while this process has not been deeply understood yet. In this study, the flow of coal/air/gas mixtures in the mill duct system of Soma B TPP boiler was investigated to evaluate the performance of the boiler and it was found that boiler efficiency was directly affected by the high unburned carbon ratio especially with particle sizes larger than 500 µm in the bottom ash particles. Coal/air flow in the mill duct system in the Soma B TPP was numerically modeled to characterize the flow behavior of the coal particles and gas mixture. The model was validated with plant real time operation data obtained from field measurements. Particle distribution between the lower level burner ducts was found to be non-homogenous particularly sizes larger than 230 µm based on the simulation results. The main reasons behind the non-homogenous coal/air distribution were studied according to the validated model and two new mill duct system design alternatives (ND-01 and ND-02) were designed to resolve these issues. Base case and alternative design simulation results were compared with each other and it was realized that more homogenous particle disturbance was obtained in the mill duct system especially for the particle sizes larger than 230 µm in ND-01 design

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