Take a look at the “cutting-edge technology” on the device: 32 – Recycled pressure from circulating water for power generation

The circulating water tower in the chemical plant operates 24 hours a day; the water that circulates back carries kinetic energy as it flows into the circulation pipes and enters the next cycle, where this energy is converted into electrical power for reuse. Is it possible to recover energy by using methods to reduce consumption, by converting the pressure energy of the remaining return water in the circulating water system into electrical energy?

This post was last edited by Zhi Zi Ming on 2021-1-9 at 17:56. Case 1: To implement the green development concept of \"clean, efficient, low-carbon, and circular,\" Sinopec has stepped up its efforts to reduce energy consumption and emissions by carrying out special campaigns aimed at saving energy and cutting costs. Include the “Circulating water residual pressure power generation project” in the projects aimed at improving quality and efficiency as well as achieving breakthroughs and results. As pilot project units, Nanhua Company and Guangzhou Petrochemical have carried out feasibility studies on the utilization of residual pressure energy from axial flow turbines; by installing a three-phase fully axial flow turbine generator set on the return water main of the cooling tower, the residual pressure energy of the circulating water is converted into electrical energy for recovery.

The investment in the circulating water residual pressure generator set is approximately 2 million yuan. Benefits become apparent after initial operation; currently, it generates 145 kW of electricity per hour, resulting in an annual electricity generation profit of 828,000 yuan. The investment cost can be recovered within three years of the project’s operation. This measure not only helps the company save energy and reduce consumption, thereby generating economic benefits for the enterprise, but also brings environmental benefits to society.

Introduction to excess pressure power generation technology: Excess pressure power generation refers to the technology of generating electricity by utilizing the excess pressure energy of fluids. Such energy resources include the excessively high pressure energy inherent in gases or liquids at the time of generation, the excess portion of pressure required to meet the needs of transportation and end-use, or the remaining pressure energy left over after discharge. The initial form of pressure-based power generation originated from using excess gas generated during iron smelting to produce electricity, that is, generating power from the pressure at the top of blast furnaces. Over the years, this approach has evolved to include the use of saturated steam and the pressure from water bodies for power generation. The pressure-based power generation method recommended here involves utilizing turbines to capture the pressure remaining in the tower, with the resulting electricity being fed into the internal low-voltage power grid for use by other devices.

Case 2: The third circulating water system in the Guangzhou Petrochemical Refining Area consists of 8 cooling towers. The pressure of the return water before the valve leading to the tower is 0.37 MPa (at a height of approximately 0.8 meters above the ground level where the pressure is measured). The total flow rate of the circulating water, both supply and return, is about 14,500 m³/h. According to calculations, with the use of excess pressure power generation technology, each unit can generate 833,600 kWh of electricity per year, resulting in annual energy savings worth 503,000 yuan. The images show the scene before and after the renovation.

Here, the residual pressure from the returning water is used via a turbine to drive the fans in the cooling tower, thereby reducing electricity consumption; this can also be considered an energy-saving measure

This energy-saving method is more direct, with lower renovation costs.