A fully premixed water-cooled combustion shell-type gas boiler

Abstract

The invention discloses a fully premixed water-cooled combustion shell-type gas boiler, which comprises a burner, a furnace gall, a shell cylinder, a condenser and a shell assembly. The flue gas after combustion in the furnace flows out from the connected one-way flue pipe, turns upwards 90° to collect and reverses 180° to flow through the condenser, and finally discharges from the flue gas outlet. The burner is composed of a blower, a premixer and a conical water-cooled combustion head. The water-cooled combustion head is made of several spiral water-cooled tubes coiled side by side, leaving gaps in between. The water-cooled combustion head is arranged in a conical shape, so that the annular flow area formed between it and the furnace gradually increases along the flue gas flow direction, avoiding the deflagration problems caused by gas plugs and tempering; the water-cooled combustion effectively reduces the combustion temperature and achieves super Low nitrogen emission is not only applied to new boilers, but also suitable for low nitrogen transformation. The single-tube heat exchange of the pot shell and cylinder, no turning smoke box, the air interlayer isolates the heat loss of the environment, and the thermal efficiency is extremely high.

Description

technical field [0001] The invention relates to the technical field of gas boiler equipment, in particular to a fully premixed water-cooled combustion shell-type gas boiler. Background technique [0002] In recent years, my country's energy structure has continued to improve, and the proportion of coal-fired has been declining, while the proportion of clean fuels dominated by natural gas in the overall energy structure has continued to rise, reaching a historic 6.9% in 2017, but still far below The international average level is 23.7%. With the continuous advancement of my country's green and low-carbon energy strategy, natural gas is an important way to develop low-carbon and clean energy, and its proportion in the energy structure will continue to rise. According to the development plan of the National Energy Administration, the proportion of natural gas in the primary energy consumption structure in my country will reach 15% by 2030, which also points out the direction for...

AI Technical Summary

Problems solved by technology

[0005] 1. In the design and production process of shell boilers, in order to fully absorb the sensible heat in the high-temperature flue gas, a combustion chamber is usually arranged behind the furnace, and the second or third tube pass of the smoke tube is added at the same time, but the smoke tube mostly uses light Pipe or threaded pipe, affected by the thermal properties of the flue gas, the convective heat transfer coefficient is relatively small, which leads to a small heat flux density on the pipe wall. purpose of temperature

However, the smoke tubes of the second tube pass and the third tube pass are usually arranged inside the boiler shell, which undoubtedly increases the diameter of the pot shell and the overall volume of the boiler. consumption, reducing the overall operating efficiency of the boiler

[0006] 2. In order to improve the compactness of the traditional two-pass and three-pass gas-fired boilers, the length of the boiler, the diameter of the boiler shell and the furnace tank are reduced as much as possible in the design to reduce the volume and floor space of the boiler, while reducing steel consumption and improving the shell. The competitiveness of the gas-fired boiler, too small furnace diameter for ultra-low NO x ≤30mg / m 3 This is mainly because the shell boilers are equipped with a cylindrical furnace radiant heating surface, and the diffusion burner with post-mixing of gas and air is generally selected, and the local combustion temperature can be controlled. Up to 1900°C, to achieve ultra-low NO x ≤30mg / m 3 , it is necessary to add tail flue gas recirculation FGR, causing many troubles such as reduced combustion efficiency, corrosion of condensed water, increased boiler resistance, especially for users who have completed technical transformation.

[0007] 3. Some technicians try to choose the metal fiber fully premixed gas burner to replace the original diffusion burner, but the metal fiber fully premixed gas burner is generally a cylindrical cylindrical burner, and the high temperature flue gas continues during the combustion process. Radially outward along the length of the cylinder, to the end of the cylindrical barrel burner, all the flue gas needs to be sprayed through the annular space between the cylindrical barrel and the furnace, which will inevitably cause the end of the cylindrical barrel burner to be exposed to high temperature There is a danger of backfire due to the pressure of smoke gas, so it is difficult to implement technical transformation or new construction

[0008] 4. The design form of the existing shell-type gas boiler is relatively primitive, lacking modular and integrated design concepts and beautiful designs, and not paying attention to the rationality of the layout and the mutual cooperation between the modules, resulting in unreasonable planning between the subsidiary modules , the original shell-type gas-fired boilers on the market did not consider the deep condensation of flue gas before, and recovered a large amount of latent heat of condensed water in the flue gas. The top of the shell-type gas boiler is equipped with a condensing heat exchanger to form a "backpack" structure, which affects the appearance, and at the same time cannot really guarantee the condensation efficiency of water vapor in the flue gas

In addition, the existing shell-type gas boilers cannot be converted between vertical and horizontal structures at will. For different operating environments, it is impossible to make installation adjustments according to local conditions. Usually, according to the actual needs of users, for horizontal and horizontal The vertical structure is designed separately, which increases the design and development expenditure

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