Low temperature waste heat power generation technology in China has achieved breakthrough

Industrial residual heat above 60°C will stabilize power generation. Recently, the low-temperature residual heat generator set independently researched and developed by Tianjin University and Shanxi E-Tune Energy Technology Group Co., Ltd. has undergone more than one year of process improvement to achieve large-scale production. According to experts, this product technology fills the gap of 60-70°C waste heat power generation in the world, and has great potential for energy conservation and application prospects.

Data show that China's overall energy utilization rate is only about 33%, energy consumption per unit of GDP is 1.9 times the world average, 3 times to 4 times that of developed countries, and about 67% of energy is directly emitted in industrial production.

Zhao Baoming, chairman of Shanxi Yitong Ring Energy Technology Group Co., Ltd., said that half of the energy that is emitted is a low-grade medium-low temperature heat source, that is, flue gas below 200°C, water below 100°C, and exhaust gas. Including cooling towers of power plants, steel rolling water of steel plants, and cooling water of chemical plants. Due to lack of technology and equipment, a large number of low- and medium-temperature heat sources have been wasted for a long time.

"Reducing the power generation temperature is the key to maximizing the utilization of industrial waste heat," said Zhang Yufeng, a professor of thermal energy at Tianjin University. The lower the power generation temperature is, the more fully utilized waste heat is, and the larger the power generation, the greater the economic efficiency. obvious. At present, the minimum temperature of waste heat power generation technology in the United States, France and other countries is 80°C. The low-temperature residual heat generating units independently developed by Tianjin University and Shanxi E-Tong Group have reduced the minimum temperature of power generation to 60°C by upgrading the performance of thermoelectric conversion media, filling the gap in China's technology in this field.

It is understood that this technology is the research result of the National “973 Project” undertaken by Tianjin University and has now entered the stage of industrialization. The maximum stand-alone capacity is 500 kilowatts. Zhang Yufeng said that low-temperature waste heat is used to generate electricity, which can save power consumption, turn waste into treasure, and bring about economic benefits. It is also the main way to reduce comprehensive energy consumption and solve environmental heat pollution.

According to estimates by the China Academy of Science and Technology Development Strategy, if the technology is widely promoted, the nation’s industrial waste heat is effectively used. China’s overall energy consumption rate is expected to decline by 5 percentage points, equivalent to saving 300 million tons of standard coal.

Take the Huabei Oilfield as an example. At present, there are 1,470 oil production wells in the Huabei Oilfield. Oil wells need to be filled with oil in the dry season and there is a large amount of water discharged every day. Affected by geothermal heat, after the separation of oil and water produced at depths of 2,000 meters, the water temperature is around 80°C. Except for part of the recharge, a large amount of low-temperature well water is discharged every day. Under this technical support, each well can be equipped with 100 kilowatts, and the entire Huabei Oilfield can have an installed capacity of about 150,000 kilowatts, which will increase revenue by about 300 million yuan annually.

However, after some units installed the power generation equipment, they encountered difficulties in grid connection. Some of the units were even forced to idle. Zhao Baoming said that he had installed 100 kilowatts of low-temperature waste heat power generation equipment for a geothermal well in the eastern coastal city, used 80 degrees of water temperature to generate electricity, and discharged 65 degrees of water for residential heating. However, due to the slow recovery of the grid connection, the generator set did not work properly. After the onset of the heating season, the local government was forced to put forward the requirement of “not having to generate electricity to make the machine idling and cooling the water”.

“Low-temperature waste heat power generation project investment recovery period is generally about 3 years, and the initial investment amount is relatively large, generally tens of millions or even billions, a huge one-time investment on the formation of resistance to waste heat power generation.” Zhao Baoming said that with the state With the promotion of energy-saving and emission-reduction policies, high-energy-consuming industries and enterprises are paying more and more attention to the use of energy-saving equipment and technology. The government should actively implement various preferential policies for energy conservation and environmental protection, increase financial support for low-temperature waste heat utilization projects of enterprises, ensure that energy-saving subsidies are put into place, and solve the problem of low-temperature waste heat power generation and grid connection.