Method for determining convection heat transfer coefficient of oxygen-enriched combustion boiler

Abstract

The invention discloses a method for determining a convection heat transfer coefficient of an oxygen-enriched combustion boiler. The method comprises the following steps: calculating the smoke flow rate of a convection heating surface; calculating the volume dose of each smoke component on the convection heating surface when smoke is recycled to achieve a balance state; establishing a fitting formula of the physical property parameter of each smoke component; according to the physical property parameter and the volume dose of each smoke component, calculating the physical property parameter of smoke; and according to the physical property parameter of the smoke and the smoke flow rate, determining the convection heat transfer coefficient. Through the method provided by the invention, the accurate convection heat transfer coefficient can be determined so as to be favorable for the design of the arrangement, the position, the amount and the structure of the convection heating surface to realize the purposes of obtaining stable combustion and optimal economic benefit.

Description

technical field [0001] The invention relates to a method for determining the convective heat transfer coefficient of an oxygen-enriched combustion boiler. Background technique [0002] Oxygen-rich combustion (O 2 / CO 2 Cyclic combustion) carbon capture is a carbon capture technology in combustion, which uses high-purity oxygen or oxygen-enriched gas mixture to replace combustion air, and uses flue gas circulation to adjust the medium flow rate and heat transfer characteristics in the furnace. In this way, it can be obtained CO-enriched up to 95% volume concentration 2 The dry flue gas, so that it can be compressed and purified at a small cost to achieve CO 2 permanent storage. This new type of combustion method has a good technical compatibility with the combustion method of existing power plants, and can be used in the transformation of existing power plants and new power plants. This technology can also greatly reduce NO x , SO 2 It is a clean coal-fired utilization ...

AI Technical Summary

Problems solved by technology

In the oxygen-enriched combustion mode, the composition of the flue gas will change, and the physical parameters of the flue gas, such as: heat capacity, thermal conductivity, kinematic viscosity, Planck number, etc. will all change greatly. The volume ratio is much higher than that under the air, and the concentration of carbon dioxide has increased sharply, and the amount of flue gas has decreased, which has also led to a decrease in the flue gas flow rate on the heating surface of the boiler.

These will greatly change the convective heat transfer characteristics of the flue gas, resulting in a great difference between the heat transfer of the flue gas in the oxygen-enriched recirculation mode and the heat transfer in the air atmosphere

[0004] Therefore, in the oxygen-enriched recirculation mode, the convective heat transfer coefficient is still determined according to the volume ratio of water vapor in the flue gas, which will inevitably lead to a large error, which will inevitably affect the layout, position, quantity and structure of the convective heating surface of the boiler etc., making it difficult to achieve stable combustion and the best economic benefits, and even leakage of the heating surface may occur

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