High-Efficiency Falling Film Evaporator/Reboiler

Introduction

Most of the evaporators (reboilers) used in the petrochemical industry, pharmaceutical and water treatment plants adopt conventional evaporators (reboilers) with the disadvantage of low heat exchange efficiency and relatively high energy consumption. Compared with conventional equipment, WCE’s high-efficiency falling film evaporator (reboiler) can potentially reduce energy consumption by over 30%.

The Falling Film Evaporator features a large concentration ratio, wide viscosity range, very low to negligible pressure drop, excellent heat transfer coefficient, large treatment capacity etc. It is widely used in the petrochemical plants for production of glycol, ethanolamine, caprolactam, styrene, alkylphenol, acrylic fiber, polyester, chlor alkali, polycarbonate, and water treatment as well as in the light and food industry.

Technical Principles
  • A falling film evaporator is a vertical tubular heat exchanger. Under gravity, the fluid flows along and down the inner wall of the tube in a thin film to achieve evaporation and heat transfer.
  • A liquid distribution device is positioned in the upper channel, consisting of a liquid distribution plate and film distributor at the heat exchange tube end opening.The liquid in the tube and the hot steam outside the tube both flow downward in a co-current direction.
  • Due to the short event time, the heat sensitive materials are not degraded by the high coefficients.
  • It is very important for the operation and efficiency of the equipment that the tube inner surface is fully wetted with the liquid.
Key Features

(1)Combined hydraulic design and structure optimisation of the liquid distribution device in the channel/the film distributor at the tube end opening.

(2)Guided flow forming model for the hydrodynamic calculation for the new film distributor at the tube end opening.

(3)Achieve design selection and optimisation of the falling film evaporator is achieved by our in-house developed non-dimensionalised correlations of the minimum liquid falling film forming flow.

(4)The enhanced heat transfer calculation model of fluted heat exchanger tubes.

(5)The thermal process calculation software and structure design technology of the new type efficient falling film evaporation equipment.

The coordinated design technology of the structure optimization and hydraulic calculation of the liquid distribution device in the tube box and the film distributor at the mouth of the heat exchanger is formed. The forming technology and the enhanced heat-transfer calculation model of longitudinal groove heat exchange tube is developed. And the thermal process calculation software and structure design technology of the new type high efficiency falling film evaporation equipment is developed.

Patents and Recognitions
  • 9 patents have been granted.
  • In 2017 it was listed in the national recommended catalogue for key energy-saving technologies (provided by National Development Reform Commission) and key energy-saving technology and equipment (provided by the Ministry of Industry and Information Technology of the PRC).
  • In January 2018, the technology passed the technical appraisal of the China Petroleum and Chemical Industry Association. The technology was first used in China, breaking the international technology monopoly.
  • In 2018 the technology was awarded the Third Science and Technology Advancement Award from China Petroleum and Chemical Industry Association.
Technology Application and Development
In 2014, the first ever solution was used in a petrochemical plant. Compared with traditional equipment, its heat transfer efficiency was increased by 40%, its energy consumption was reduced by 30%, and it has demonstrated to have s significant energy saving effect. At present, its performance and benefits have been demonstrated in 8 sets of domestic devices. This solution can replace import equipment entirely, and provide considerable economic and social benefits.
  • February 2019

    100000 T glycol divice of Dushanzi Petrochemical Branch of Petrochina Company Limited
  • August 2019

    0.26 mtpa polycarbonate project of Sinopec Sabic Tianjin Petrochemical Co., Ltd.
  • April 2019

    1 # and 2 # EOEG devices in 3.2 mtpa aromatics comprehensive processing and utilization project of Lianyungang Petrochemical Co., Ltd.
  • January 2019

    1 mtpa ethylene and petroleum refining reconstruction and expansion project and 0.2/0.5 mtpa ethylene oxide/glycol device of Sinochem Quanzhou Petrochemical Co., Ltd.
  • January 2019

    0.4 mtpa syngas CTMEG project of Shenhua Yulin Energy and Chemical Co., Ltd.
  • November 2018

    100000 T ethanolamine device of China Sciences of Group in Zhanjiang, Guangdong,
  • September 2018

    0.24 mtpa CTEG device of Shaanxi Yanchang Petroleum Group
  • May 2018

    15000 T PM / PMA waste liquid recovery device of Jiangsu Dynamic Chemical Co., Ltd
  • March 2018

    0.1 mtpa caprolactam device in Putian, Fujian province
  • January 2018

    0.24 mtpa CTEG device in Yigao, Inner Mongolia autonomous prefecture
  • May 2017

    0.16 mtpa acrylic fiber device of Sinopec Shanghai Petrochemical Company Limited in Jinyang
  • November 2016

    0.1 mtpa ethanolamine device of Jiangsu Silbang Petrochemical Co., Ltd.

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