一、NOx氮氧化物的生成機制
對于天然氣鍋爐來說,Nox的產生主要來自空氣中的氮氣和過量氧氣產生的熱力型Nox,熱力型NOx的產生和燃燒的溫度呈指數型關系,通常在燃燒溫度高于1000攝氏度的時候開始產生,而在1400度以上NOx的生成速度會急劇增加。下圖反映的是燃煤型鍋爐的NOx排放和溫度的關系,其中熱力型Nox的溫度關系同樣適合于天然氣鍋爐燃燒器。
燃煤型鍋爐的NOx排放和溫度的關系基于以上NOx的生長機制,
低氮燃燒器的控制NOx的技術也主要著眼于兩個方向:
1、降低火焰溫度;
2、降低氧含量。
The formation mechanism of NOx nitrogen oxides
For natural gas boilers, the production of Nox mainly comes from the thermodynamic Nox produced by nitrogen in the air and excessive oxygen. The production of thermodynamic Nox has an exponential relationship with the combustion temperature, which usually starts when the combustion temperature is higher than 1000 degrees Celsius, and the generation speed of Nox above 1400 degrees will increase sharply. The figure below reflects the relationship between NOx emission and temperature of coal-fired boilers, in which the temperature relationship of thermal NOx is also suitable for natural gas boiler burners.
The relationship between NOx emission and temperature of coal-fired boilers is based on the growth mechanism of NOx mentioned above. The technology of controlling NOx of low-nitrogen burners also focuses on two directions:
1. Reduce the flame temperature;
2. Reduce oxygen content.
二、低氮燃燒器和超低氮燃燒器類型
傳統的天然氣鍋爐燃燒器通常的NOx排放在120~150毫克左右。低氮燃燒器通常是指NOx排放在30~80毫克的燃燒器。NOx排放在30毫克以下的通常稱為超低氮燃燒器。
傳統的燃燒器的高NOx排放主要源于下述幾個原因:
1、為了保證燃燒充分,采用了較大的過量空氣;
2、燃燒溫度通常在1800度左右。
Types of low-nitrogen and ultra-low nitrogen burners
Conventional gas boiler burners typically emit about 120 to 150 milligrams of NOx. Low nitrogen burners are usually defined as NOx burners that discharge between 30 and 80 mg. NOx emissions below 30 mg are commonly known as ultra-low nitrogen burners.
The high NOx emission of traditional burners is mainly caused by the following reasons:
1. In order to ensure sufficient combustion, large excess air is used.
2. The combustion temperature is usually around 1800 degrees.
三、低氮燃燒器三、低氮燃燒器通?;谙铝屑夹g
1.電子比例調節和氧含量控制技術;來精確控制氧含量;
2.FGR煙氣再循環技術,來降低火焰溫度和氧含量;
3.全預混的表面燃燒技術來降低火焰溫度和實現充分燃燒;
上述技術中,通常是低氮燃燒器的必須配置?;谏鲜黾夹g,市場的低氮燃燒器主要分為以下類型:
Low nitrogen burners low nitrogen burners are usually based on the following technologies
1. Electronic proportional regulation and oxygen content control technology; To precisely control the oxygen content;
2.FGR flue gas recirculation technology to reduce flame temperature and oxygen content;
3. Fully premixed surface combustion technology to reduce flame temperature and achieve full combustion;
In the above technology, it is usually necessary to configure the low nitrogen burner. Based on the above technology, the market for low-nitrogen burners is mainly divided into the following types:
四、各
低氮燃燒器優缺點介紹
1、FGR低氮燃燒器
FGR低氮燃燒器通常能夠將NOx在全火范圍內控制到65毫克,極限大約在40毫克左右,進一步降低NOx排放可能導致燃燒不穩定,或者犧牲可調比等弊端。
2、表面燃燒超低氮燃燒器
表面燃燒超低氮燃燒器通常能夠將NOx在全火范圍內控制到30毫克以內,其優點是安裝簡單,不需要FGR煙氣再循環管道;其主要缺點是需要過濾空氣,加大了維護工作量;同時氧含量在7%左右,降低了部分燃燒效率。
3、表面燃燒+FGR超低氮燃燒器
表面燃燒+FGR超低氮燃燒器結合了表面燃燒的NOx控制優點和FGR降氧含量優點,可以實現在全火范圍控制NOx到20毫克水平,同時控制氧含量在3%以內,最大化燃燒效率。其主要短處是設備成本提高。
The advantages and disadvantages of each low nitrogen burner are introduced
1. FGR low nitrogen burner
FGR low nitrogen burners can usually control NOx to 65 mg in full fire range with a limit of about 40 mg. Further reduction of NOx emissions may lead to combustion instability or sacrifice of adjustable ratio and other disadvantages.
2. Ultra-low nitrogen combustion burner is burned on the surface
Surface combustion ultra-low nitrogen burners can usually control NOx within 30 mg of full fire range. Its main drawback is the need to filter the air, increased maintenance work; At the same time, the oxygen content is around 7%, which reduces the partial combustion efficiency.
3. Surface combustion +FGR ultra-low nitrogen burner
The surface combustion +FGR ultra-low nitrogen burner combines the advantages of NOx control of surface combustion with the advantages of reducing oxygen content of FGR. It can control the level of NOx to 20 mg in the whole fire range and the content of oxygen within 3% to maximize the combustion efficiency. Its main shortcoming is the increase of equipment cost.
如果想了解更多關于
低氮燃燒器相關知識,請咨詢
北京眾誠永源節能環保技術有限公司。
For more information on low nitrogen burners, please consult Beijing chuangwei electromechanical equipment co., LTD.