Author:Wu Yuyuan,Yan Zhengui,Chen Liufang,Mao Yangping,Jiang Chunrong,Liu Yongzhong
School:Xian Jiaotong University,School of Energy & Power Engineering
Introduction: A new type of condenser ¨Cevaporator (CE) is developed with small temperature difference (STD) and large heat transfer coefficient (LHTC).
There are mainly two kinds of traditional CE, i.e. the plate-fin CE and the tabular one. Due to their backward mechanism of heat transfer, the temperature difference of heat transfer is so large and the heat transfer coefficient is so small that the diameter of the CE is larger than the allowed standard for railway transportation.
The invention makes a breakthrough in the traditional mechanism of nucleation boiling heat transfer whose liquid flow occupies the most part of the boiling channel, and it innovates a new structure accordingly. It creates a new mechanism of boiling heat transfer with quasi-annular flow, whose gas phase flow occupies the most part of the boiling channel. Thus it enables the boiling channel to be operated at an optimum state of boiling heat transfer with quasi-annular flow in boiling channel, which is called stimulati on state of boiling transfer. It not only increases the critical heat flux of the boiling channel greatly up to 10000W/m 2 , but also makes the heat transfer coefficient come up to the maximum and makes the temperature difference come to the minimum of 0.57K compared with the current products.
The invention also makes a breakthrough in the traditional mechanism of condensing heat transfer with laminar condensing liquid film, and creates a new mechanism of the enhanced condensing heat transfer with turbulent condensing liquid film. Besides, it also innovates a new structure of condensing channel.
All the main technical parameters of the new CE are superior to the current products. In comparison with the designing standard set by the most advanced companies in the world, the heat transfer coefficient is increased by 50%, the output of the oxygen production is increased by 15~20%. The total temperature difference for heat transfer is only 0.57K, which is the minimum one among the same products currently operated in the world.
The invented new CE has fully substituted for the tubular CE with sintered porous surface in 150m 3 /h oxygen production plant.
The invention has been successfully applied in large-scale oxygen production plants, whose outstanding performances are superior to all the current products in the world. The manuf act urer has made 44 sets of air separation plant s and got economical benefit of 0.92 billion yuan RMB. The consumers of the plants have got economical benefit of 5.985 billion yuan RMB.
The invention could be extensively applied in petrochemical industry and other areas, such as the large-scale ethylene production plant, the large-scale ammonium nitrate plant and the large-scale urea production plant. The CE could be used also in natural gas liquefaction plant, and so on.
By changing the boiling and condensing mechanism of heat transfer and accordingly modifying the structure of boiling and condensing channels the new CE has become more efficient to operate, more compact in structure, advantageous to environmental protection, beneficial to energy saving and economical in manufacturing costs. Its working state is stable, easier to be achieved from start and convenient to be adjusted, and could be rapidly recovered after an undesired shutdown.
The invention could be used in many engineering areas to get a great deal of economic profits potentially.
The invention has received a Second Grade of State Technical Invention Award .in 2001. |
A New Type of Quasi-Annular Flow Condenser and Evaporator