Air cooled condenser (ACC) for biomass power plant

In regions which are remote from water resources, air cooled condenser (ACC) is an important player of a condensing equipment. This machine utilizes ambient air to absorb heat out of exhaust steam for thermal or biomass power plants. Generally, applying another type that is water-cooled condenser in an insufficient-water area needs to make a water reservoir to collect the water for serving cooling tower. Thus, Air cooled condenser (ACC) will help reduce capital cost of such a water reservoir, save water consumption cost during operation, also solve the problem of diverting water from the community.

Principle of Air cooled condenser

The concept of Air Cooled Condenser is to distribute the exhaust steam from the steam turbine straightly to the stream condensers in several rows through ducting. At the same time, the large axial-flow fans intake air and sweep over the tube bundles externally to carry away heat. In tube bundles, the exhaust steam gradually changes to condensates and is kept in the condensate tank through the bottom headers. Moreover, the vacuum of the whole Air cooled condenser (ACC) covers by the air evacuation system. For this reason, the steam turbine can  activate smoothly and confirm power generation efficiency. 

The steam condensers consist of two types of tube bundles: parallel- flow and counter-flow tube bundles.

In the parallel-flow, most of the steam is condensed, meanwhile the non-condensing gas is extracted in counter-flow tube bundles. There is the bottom headers to connect between the parallel-flow and counter-flow tube bundles 

Additionally, the advantages of Air cooled condenser (ACC) is occupying less floor area, various anti-freezing methods and flexible arrangement

 Advantage of Single-Row Tube 

Single-Row Tube is one of the best selective innovations, which is applied in our product, Shuangliang  Air Cooled Condenser (ACC) . Due to its characteristics such as welded large flat tube and aluminum snake-like fins, these are more following advantages of Single-Row Tube: 

1.High heat transfer efficiency

The large size of flow area at steam side effects low pressure loss. Moreover, the heat exchange at both sides of tube bundle is fully activating, so the heat transfer efficiency is extremely high.  

 

2. Strong resistance to corrosion 

To have strong corrosion resistance, the external surface of base tube and heat exchange fins for the tube bundle are coated with aluminum alloy. After that process, aluminum oxide protective layer will gradually be forming

3. High strength and good cleaning ability 

Welding several single-row fin tubes and tube-sheet was also applied in order to strengthen all the structures. Moreover, this process would help facilitate installation and transportation. Another distinctive characteristic, using straight-line type in single-row tube fins is easy to wash because this type cleans with high-pressure water without any deformation. 

4. Good anti-freezing performance 

In order that the condensate runs freely, we create a large length-width ratio of the base tube. Furthermore, this specific characteristic is able to reduce the extent of sub-cooling and the risk of tube freezing in winter.  

 Weld treatment of Air cooled condenser

About weld treatment, the base tube of the single-row tubes of our product, Shuangliang Air cooled condenser (ACC) locates at the arc of the flat tube. These are beneficial features:

• If the pressure is between 10kPa and 0.14MPa, there will be no deformation apparently. In the other hand, if the pressure goes to 0.48MPa, the flat tube will become round, and the fins will be cracked.
• No need to be worried about the leak occurring during the operation since it can be repaired immediately without removing the entire tube bundle or replacement. We do believe in “Easy maintenance, low maintenance costs” 
• The arc spray aluminum coating has the better welding strength.

Fatigue test of Air cooled condenser

Evacuated by vacuum pumping, the tube bundle will be reached to vacuum condition and then returned to normal pressure. After that, cycle tests will evaluate the number of cycles (fatigue life) in which the change occurs abruptly in the single-row tube. 

To ensure reliance of Shuangliang Air cooled condenser (ACC), the qualified value of the product fatigue life should be more than 1,000 times, more than ten times the actual fatigue times. Due to qualified value, our customers can assure that our product’s safety lasts the 30-year design life. 

Tube bundle cleaning 

Seeing that the single-row tube fin ventilation channel is linear, the tube and fins can be cleaned easily with high-pressure water and without deformation. 

THREE MAJOR TEST DEVICES

 1. Performance testing device on tube bundles of Air cooled condenser (ACC) 

Performance testing device on tube bundles of Air cooled condenser (ACC) normally applies for experimenting heat exchange performance of various types of fined tube bundle structure and online random test of finished products. After pressure and temperature of the stream are gradually reducing, the testing device will simulate several operating backpressures of the steam turbine and evaluate the heat exchange performance and resistance loss of the tube bundle. It also obtains the heat exchange coefficient and air resistance of tube bundle at different air speed and internal flow resistance of tube bundle at different steam low speed. Furthermore, to test actual performance of tube bundle, the testing device is also utilized for examining thermal performance of tube bundle. 

2. The unique environmental test laboratory : 1×4 Air cooled condenser (ACC) environmental test device 

In order to simulate the summer operating conditions and winter operating conditions of Air cooled condenser (ACC) , the unique environmental test laboratory will imitate ambient temperature of 50oC~-25oC. Therefore, there are two operating conditions to test in different situations. One is the summer operating condition .It’s for testing the heat transfer performance of the tube bundles of the Air cooled condenser (ACC) and provides the basis for the design of the actual Air cooled condenser (ACC). The other is the winter operating condition. It is for evaluating whether the control program of Air cooled condenser (ACC) is valid for antifreeze protection measures during operating conditions. For example, the machine is able to start, stop and low load operating conditions. Finally, it could test the minimum antifreeze steam flow under different temperature conditions. 

3. The unique large full-performance test bed: Hot-state test device for one unit of 1000MW Air-cooled condenser (ACC)

The unique large full-performance test bed can imitate the main operating conditions of power station and test the performance of Shuangliang Air Cooled Condenser (ACC) , including system reliability, stability, heat exchange performance and economy. Moreover, Air cooled condenser (ACC) can operate capacity at summer full load and winter anti-freezing running reliability. 

NINE FUNDAMENTAL RESEARCHES 

Achieving the great leap forward of Air cooled condenser (ACC) for power plants from theoretical R&D to engineering application isn’t an easy thing. To solve several errors in our industry, we conduct nine fundamental research to provide design support for Air cooled condenser (ACC) for power station. It’s more suitable for Chinese national circumstance.

 1.Research on heat exchange performance of heat exchange component

References in conventional power plant

1. Air -cooled condenser Project for Siemens 4×1200MW New Capital CCPP in Egypt   (ACC for the largest CCPP in the world)
2. Botswana project (4×150MW)
3. Guohua Dingzhou Power Plant in Hebei Province (2×660MW)
4. Guohua Hulunbeier Power Plant (2×600MW)
5. Wison Cathay Power plant for 1 × 60,000 ASU of Wison Cathay
6. Air-cooled condenser unit for 4×60,000 ASU of Zhongmei Yulin Energy Chemical Co., Ltd.
7. Air-cooled condenser for 4×60000 ASU for coal-to-alkene project of Shenhua Baotou Energy Co., Ltd.
8.  China Coal Tuke Energy Chemical Project for 2×40,000 ASU of China Coal Tuke Energy Chemical Co., Ltd.
9. Air -cooled condenser for 4 × 48,000 ASU of Datang Keqi Coal-to-Gas Co., Ltd.
10. Air cooled condenser unit for 1 × 35,000 ASU of Shenhua Yulin Energy Co., Ltd.
11. Zero Water Consumption CHP System (ZWCCHP) in LATAM market