SCR Heat Exchanger of Air Preheater

Basic Info.

Product Description

As an important part of the national industry, the steel industry has increasingly strict requirements on its environmental protection. The results show that the total amount of NOx emitted by various equipment in the iron and steel plant occupies the second place in the fixed source. Among them, the NOx emission of sintering process accounts for about half of the total NOx emission of iron and steel plants. Therefore, strict control of NOx emission from sintering flue gas can effectively reduce NOx emission from steel plants.

In the denitration system, as an important high-efficiency heat exchange equipment, GGH can effectively carry out heat recovery, improve the temperature of flue gas entering the denitration reactor, and improve the efficiency of denitration catalyst.

Due to the large flow and fluctuation of sintering flue gas, high dust concentration and high viscosity, and complex flue gas composition, the traditional rotary regenerative GGH has the problem of leakage in principle due to the unreliable axial and radial mechanical seals due to the rotary motion, and the leakage rate deteriorates seriously after operation. Ammonium bisulfate is adhered on the surface of the whole heat exchange element, resulting in serious ash deposition.

Based on this, Wintech technology has developed a fully welded plate structure, which can ensure zero leakage operation due to the use of fully welded inter wall heat transfer mechanism. The surface of the plate is smooth and the flue gas passage is straight, so it is not easy to form ash deposition and has less resistance loss. At the same time, the high-pressure water or steam cleaning nozzle is designed and arranged on the upper side of the plate to form an impact flow with pressure up to 1MPa to clean the ash.

Advantage

1. Efficient heat transfer performance: The plate type heat transfer component has an overall heat transfer coefficient 1-3 times higher than that of tubular heat transfer component and 30%~100% higher than that of heat tube type. In view that the temperature and size change before and after the heating process, variable flowing channel is designed to ensure optimized overall heat transfer coefficient and minimized resistance drop.

2. Low pressure drop: With same heat exchange area, the flow area of plate type is 5 times bigger than that of conventional heat tube type preheater. When the medium flows in the plate type preheater, it encounters less resistance drop thanks to the straight channel, bigger flow area and shorter distance. Variable flowing channel is designed to ensure optimized overall heat transfer coefficient and minimized resistance drop. Compared with heat pipe type preheater, the plate type reduced the resistance drop by 20%-60%, which is only 40%-60% of the tubular type.

3. Good resistance against high temperature: The heat transfer component of plate preheater is made of high heat resistant stainless steel and can operate safely at a temperature up to 450ºC.

4. High reliability: The plate preheater design prevents dew point corrosion and the construction material is highly resistant against high temperature. The flow channel design takes the coal gas characteristics into account and eliminates dead area. The gas inlet nozzle is jacked and coated and a proper flow velocity is applied to avoid abrasion to the plate sheets. All these contribute to greatly improved reliability

5. Low fouling: With special corrugated design and smooth heat transfer surface, the plate type preheater hardly has soot accumulated.

6. Compact structure: The plate preheater is of high compact ratio. For tubular type (heat pipe type), it is about 60m²/m³ while for plate preheater, it is 160m²/m³, which is around 3 times higher.