High-temperature returned ash cooling and conveying system for cyclone dust removal

I. Working Principle

The cyclone dust removal high-temperature ash cooling and conveying system is a new product developed by our company according to users' actual demands. It is used for cooling and conveying bottom ash from boiler flue ducts, cyclone separators, superheaters and other equipment. The ash accumulated at these positions and similar locations usually enters the ash conveying system directly without cooling. Due to the high temperature of the ash (approximately 700℃-900℃), it brings many adverse impacts on the ash conveying system:

1. High-temperature ash tends to damage valves and instruments in the conveying route, increasing maintenance costs.

2. High-temperature ash scours pipelines and accelerates pipeline wear. Safety accidents are likely to occur once pipelines leak due to wear.

3. High-temperature ash contains abundant heat energy, which is wasted without recovery.

In addition, pneumatic ash removal systems generally feature a compact structure, leaving insufficient space for other bulky ash coolers with complex structures. Therefore, it is necessary to develop an ash cooler with small footprint, simple operation, high efficiency and practicality. Through system upgrading and reconstruction, a vertical ash cooler can completely solve the above problems.

Working Principle: Under the action of gravity, high-temperature hot ash flows into the cylinder of the ash cooling device through the ash inlet pipe. An ash inlet expansion joint is installed between the ash inlet pipe and the cylinder of the ash cooling device, which can absorb displacement caused by high temperature of the ash inlet pipe. Multi-layer and multi-row serpentine tubes filled with cooling water are arranged inside the cylinder. Heat exchange takes place between hot ash and condensed water through heat exchange tubes to cool the high-temperature ash. The cooled ash flows into the bin pump below the outlet, and is then transported to the ash silo by the pneumatic ash conveying device. This makes the originally heavily polluted ash discharge system clean, tidy and environmentally friendly. Hot ash flows naturally under gravity, causing extremely slight abrasion to the inner wall of the vertical ash cooler cylinder and the internal heat exchange tubes. Hence, the service life of all components for heat exchange with hot ash inside the vertical ash cooler can be guaranteed.

The vertical ash cooler enables heat exchange between boiler condensed water and incoming ash. While lowering the ash temperature to meet pneumatic conveying requirements, it raises the temperature of condensed water. It not only reduces damage to pneumatic conveying equipment caused by high-temperature ash, but also fully recovers heat from ash to achieve dual-effect energy saving.

Through overall evaluation and comparison with conventional ash cooler conveying systems, this product delivers remarkable energy-saving effects with reasonable and compact layout. The original storage yard has been converted for ash loading and unloading at the ash silo, which is convenient and eco-friendly.

II. Energy Saving Comparison Table

Calculated based on a 48MW, 85-ton boiler: the cyclone separator discharges about 1 ton of ash at 900℃ per hour. Heat conversion by the ash cooler saves approximately 28 kg of coal per hour, equivalent to 672 kg per day. Calculated over 180 days, the coal saving reaches around 120 tons. With the delivered coal price at about 350 yuan per ton, roughly 42,000 yuan can be saved in one heating season. If a drum-type ash cooler is adopted, the power consumption is about 5 kWh per hour and 120 kWh per day. At a cost of 1 yuan per kWh, 21,600 yuan can be saved in one heating season. Manual ash discharge used to incur labor costs of about 15,000~20,000 yuan. Overall, the cyclone dust removal high-temperature ash cooling and conveying system can save approximately 85,000 yuan every year. The investment cost can be recovered in around three heating seasons while meeting environmental protection requirements.

III. Drawing of Ash Conveying System of Ash Cooler

四、膜式壁冷灰器

五、产品结构特点和优点

六、成品 照片和三维效果图

山东现场安装图

车间膜式壁冷灰器成品图