A carbon dioxide temperature swing adsorption and desorption system and method based on low-grade heat energy

Abstract

The invention provides a carbon dioxide variable-temperature adsorption and desorption system based on low-grade heat energy and a method, and belongs to the technical field of carbon dioxide capturing.The system comprises an air compressor, a flue gas analyzer, a carbon dioxide collecting tank, an adsorption and desorption device, a first valve set, a second valve set, two pressure meters, three flowmeters and three thermometers.According to the system and the method, recyclable, economical and reliable zeolite 13X is adopted as an adsorbent, the carbon dioxide adsorption and desorption process is synchronously performed while the low-grade heat energy is utilized, the heat exchange efficiency is improved, and the double-effect energy-saving effect of waste heat utilizing and carbon dioxide capturing is achieved; the low-grade heat energy in fuel gas is taken as an energy source, circulating adsorption and desorption is achieved by combining physical temperature changing, the efficiency is improved, the system running time is saved, about 60% of system energy consumption is reduced, environmental pollution caused by the flue gas of a thermal power plant is reduced, and the carbon dioxide capturing concentration after three steps of absorption can reach 90%.

Description

technical field [0001] The invention belongs to the technical field of carbon dioxide capture, and in particular relates to a carbon dioxide temperature-swing adsorption-desorption system and method based on low-grade heat energy. Background technique [0002] In recent years, CO 2 Emissions are on the rise, and the emissions are huge. In 2014, the global CO 2 Emissions are 32.3 billion tons; in response to global warming caused by greenhouse gases, CO 2 Capture technology continues to evolve; CO 2 The capture technology mainly includes physical adsorption method, chemical absorption method, membrane separation technology and low temperature separation technology; among them, the physical adsorption method is realized in a packed fluidized bed by using the attraction between the gas and the surface active points of the adsorbent, and has equipment Compared with other adsorption methods, it is more in line with the idea of ​​energy saving and emission reduction, and is mor...

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Problems solved by technology

[0004] However, in the temperature swing adsorption process, due to the large specific heat capacity of the adsorbent, the energy consumption in the process of continuously heating and cooling the adsorption column is large, and the heating and cooling time of the adsorption bed is also long, which has become the main factor limiting the development of temperature swing adsorption. Factors have also become a problem that scholars are committed to solving; and the selection of chemical adsorbents will bring certain environmental pollution, which is not conducive to the development of circular economy; the electric swing adsorption method proposed in recent years is an improvement on the traditional temperature swing adsorption method , the principle is to heat the adsorbent with electrical conductivity, so that the temperature rise rate of the adsorbent is accelerated, and the desorption process under high temperature conditions has the advantages of fast heating speed, low energy consumption, and easy automatic control, but due to the additional The electrical energy also consumes a considerable amount of energy, so there are still problems of energy consumption and resource waste in this process; at the same time, a large amount of low-temperature (100-200°C) flue gas is produced in the production of thermal power plants, and this part of the low-level The thermal energy content is huge, but it is difficult to directly reuse it in actual production, and it is often discharged directly into the environment, which not only causes thermal pollution of the environment, but also wastes energy

[0005] At present, most of the existing carbon dioxide temperature variable adsorption and desorption systems use heat pumps. However, the use of the first or second type of absorption heat pump alone cannot provide high-temperature hot water combined with the existing high-temperature combined heat and power system. Energy consumption Too high, a waste of resources, and the adsorption material cannot be recycled, the adsorption and desorption process cannot be matched and controlled, the adsorption and desorption efficiency is relatively low, the equipment runs for a long time, and the cost is relatively high

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