Yatay deşarj edilen soğuk-yoğun atıksuların bazı deşarj parametrelerinin belirlenmesi

Year 2018, Volume: 24 Issue: 3, 494 - 499, 29.06.2018

Naim Sezgin

Abstract

Termal
kirlilik, okyanus, göl veya nehir gibi sucul alanlarda ortam sıcaklığının insan
faaliyetleri sonucunda artması veya azalması olarak tanımlanır. Termal
kirliliğe, enerji santralleri, sıvılaştırılmış doğalgaz terminalleri (LNG) ve
endüstriyel tesislerin ısıtma veya soğutma amaçlı kullanılan daha sonra alıcı
ortamlara deşarj edilen suları neden olur. Alıcı ortamlara deşarj edilen termal
atıksuların en önemli kaynaklarından biri LNG gazlaştırma terminallerinden
kaynaklanan soğuk sulardır. Soğuk sular genellikle kıyısal sulara deşarj
edilirler. Bu sular deşarj edildikleri alıcı ortamlara göre yoğunluklarının
yüksek olması nedeniyle bir çeşit negatif yüzen (batan) jetlerdir. Alıcı ortam
canlı türlerine olumsuz etkilerinden dolayı soğuk sular, yüksek seviyede
seyrelme sağlayacak şekilde deşarj edilmelidir. Bu çalışmada, yatay olarak
deşarj edilen soğuk-yoğun suyun birinci seyrelme ve çarpma noktası gibi bazı
deşarj parametreleri laboratuvar ortamında dairesel deşarj portu kullanılarak
belirlenmiştir. Soğuk-yoğun atıksuyun alıcı ortam içerisindeki davranışını (jet
geometrisini) belirlemek için renk maddesi olarak Rhodamin B ilavesi
yapılmıştır.  Renklendirilmiş soğuk-yoğun
atıksuyun anlık fotoğraflarını çekmek için yüksek çözünürlüklü kamera ve atıksu
jet merkezinde meydana gelen sıcaklık değişimlerini (seyrelmeler) ölçmek için
de hassas termal problar kullanılmıştır. Farklı atıksu yoğunlukları elde etmek
için -3 °C, -5 °C ve -7 °C gibi üç değişik sıcaklık fark değerleri
uygulanmıştır. Bu çalışmada elde edilen sonuçlara göre soğuk su deşarjlarının
tabana çökme eğilimde olan negatif yüzen (batan) jet gibi davrandığı
belirlenmiştir. Ayrıca bu çalışmada, ortalama normalize edilmiş çarpma noktası
mesafesi ve birinci seyrelmenin 2.333 ve 0.491 olduğu bulunmuştur.

Keywords

Termal kirlilik, Yoğun jet, Soğuk su deşarjı, Birinci seyrelme, Negatif yüzen jet

Determination of some discharge parameters of horizontally discharged cold-dense wastewaters

Abstract

Thermal
pollution is defined as increase or decrease in temperature of an aquatic
environment which may be ocean, lake or river by human influence. A common
cause of thermal pollution is the use of water as a cooling and heating system
by power plants, liquefied natural gas (LNG) re-gasification terminals and
industrial manufacturers. One of the important sources of thermal effluents is
cold water discharges, which are mainly originated from LNG re-gasification
terminals from open cycle heating units. Cold water can be frequently
discharged into coastal waters. Due to its high density, cold water discharge
is a kind of negatively buoyant jet. Because of some undesired effects of cold
water on receiving water species, should be discharged properly into the marine
environment with a high level of initial dilution. Some discharge parameters of
horizontally discharged cold-dense wastewater such as initial dilutions,
impingement points were   determined in a
laboratory system using circular port in this study. To determine the behavior
of the cold-dense wastewater (wastewater jet geometry) Rhodamine B as a
colorant was added to the wastewater. A high-resolution camera was used to take
snapshots of the colored cold-dense wastewater. Temperature changes (dilutions)
in the cold-dense wastewater jet centerline were detected with sensitive
thermal probes. To gain different densities, three discharge temperature
differences were used as -3 °C, -5 °C and -7 °C. According to the results of
this study, it was determined that the cold water discharges behaved like a
negative buoyant jet. In addition, it was calculated that the averages of the
normalized impingement point and initial dilution of the cold water were found
2.333 and 0.491, respectively.

Keywords

Thermal pollution, Dense jet, Cold water discharge, Initial dilution, Negatively buoyant jet

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