Blending combustion gas system of melamine coal-fired molten salt furnace

Abstract

The utility model discloses a blending combustion gas system of a melamine coal-fired molten salt furnace, and belongs to the technical field of melamine molten salt furnaces. The combustion chamber is arranged below the furnace body; the combustion system is used for supplying a heat source to the combustion chamber; the combustion system comprises a fire grate arranged in the combustion chamber; wherein the combustion chamber is located above the fire grate and is provided with a fuel gas inlet, the fuel gas inlet is communicated with a combustion engine, so that fuel gas and fire coal are combusted in the combustion chamber in a mixed mode, and the purposes of saving energy, reducing carbon and improving the energy efficiency of the device are effectively achieved.

Description

Technical Field

[0001] The utility model relates to the technical field of melamine molten salt furnaces, in particular to a melamine coal-fired molten salt furnace mixed combustion gas system. Background Art

[0002] The molten salt furnace is a key device in the melamine production line. Its function is to heat the molten salt sent from the molten salt tank, and then send it to the triamine reactor and other equipment for heat preservation and circulation heat exchange. The molten salt furnace mainly consists of two parts: one is the molten salt furnace body with coils on the upper part; the other is the burner on the lower part. The burner burns and heats to generate heat, and transmits the combustion heat to the molten salt in the furnace tube in the form of thermal radiation to complete the heating process. The combustion system of the coal-fired heating molten salt furnace is composed of a grate, a combustion chamber, a ventilation device, an energy-saving device, a coal-serving mechanism, a slag discharge mechanism, a flue gas treatment device, etc. The coal-fired heating molten salt furnace currently used still has disadvantages, and there is still room for improvement in energy saving and low carbon goals;

[0003] Therefore, how to provide an energy-saving and low-carbon, actively adopt green innovative technology, and improve the energy efficiency of the device has become an important technical problem that technical personnel in this field urgently need to solve. Utility Model Content

[0004] The utility model aims to overcome the defects of the prior art and provide a melamine coal-fired molten salt furnace mixed combustion gas system.

[0005] In order to achieve the above purpose, the utility model provides the following technical solutions:

[0006] The utility model discloses a melamine coal-fired molten salt furnace mixed combustion gas system, comprising:

[0007] A furnace body, a combustion chamber arranged below the furnace body; and

[0008] A combustion system for supplying a heat source to the combustion chamber. The combustion system includes a grate disposed within the combustion chamber;

[0009] The combustion chamber is located above the grate and is provided with a gas inlet, which is connected to the burner so that the gas and coal can be mixed and burned in the combustion chamber.

[0010] Furthermore, the furnace body is a vertical square box structure.

[0011] Furthermore, a spiral salt tube is arranged in the furnace body, and a spiral small salt tube is arranged at one end of the furnace body.

[0012] Furthermore, the flue gas induced draft fan is connected to the flue gas exhaust port of the furnace body through a flue gas induced draft pipeline, and the flue gas induced draft pipeline is equipped with a waste heat recovery device.

[0013] Furthermore, it also includes a flame monitoring system, and the burner nozzle of the burner is equipped with the flame monitoring system.

[0014] In the above technical scheme, the utility model provides a melamine coal-fired molten salt furnace mixed combustion gas system, the beneficial effects are:

[0015] The utility model designs a gas-blended combustion system for a melamine coal-fired molten salt furnace in order to achieve energy conservation and low carbon emissions and improve the level of resource utilization of the three wastes. A gas inlet is provided above the grate in the combustion chamber, and the gas inlet is connected to the burner so that gas and coal can be mixed and burned in the combustion chamber, thereby reducing carbon dioxide emissions by 1,500 tons per year and reducing coal consumption by 25 kg per ton of melamine product. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present utility model. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.

[0017] Figure 1 This is a schematic diagram of the overall structure of a melamine coal-fired molten salt furnace mixed with gas system disclosed in the utility model;

[0018] Figure 2 This is a process flow chart of a melamine coal-fired molten salt furnace mixed with gas combustion system disclosed in the utility model;

[0019] Figure 3 The utility model discloses a gas burner flow diagram of a gas burner system of a melamine coal-fired molten salt furnace.

[0020] Description of reference numerals:

[0021] 1. Furnace body; 2. Combustion chamber; 3. Combustion system; 4. Grate; 5. Spiral salt pipe; 6. Spiral small salt pipe; 7. Burner; 8. Waste heat recovery device; 9. Flue gas induced draft fan; 10. Air blower; 11. Flue gas circulation fan; 12. Ceramic dust collector; 13. Denitrification dust collector; 14. Oxygen supply fan;

[0022] 21. Gas inlet;

[0023] 81. Nitrogen preheater; 82. Flue gas carrier gas preheater; 83. Deacidification reactor; 84. Waste heat boiler; 85. Air preheater. DETAILED DESCRIPTION

[0024] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below in conjunction with the accompanying drawings.

[0025] See also Figure 1 As shown;

[0026] The utility model discloses a melamine coal-fired molten salt furnace mixed combustion gas system, comprising: a furnace body 1, a combustion chamber 2, a combustion system 3, a grate 4, a spiral salt pipe 5, a spiral small salt pipe 6, and a burner 7;

[0027] The combustion chamber 2 is arranged below the furnace body 1, and a heat source is supplied to the combustion chamber 2 through a combustion system 3. The combustion system 3 includes a grate 4 arranged in the combustion chamber 2, wherein the combustion chamber 2 is provided with a gas inlet 21 above the grate 4, and the gas inlet 21 is connected to the burner 7 so that the gas and the coal are mixed and burned in the combustion chamber 2;

[0028] Preferably, the furnace body 1 is a vertical square box-shaped spiral coil structure, and its radiation heating surface is a double radiation section composed of a single-layer spiral coil. After the high-temperature flue gas passes through the coil for radiation heat exchange, it enters the independent convection heat exchange section from the upper flue for convection heat exchange, and is then discharged from the lower smoke exhaust port. The molten salt enters the furnace body 1 from the lower header, absorbs heat in the furnace, and is discharged from the upper header. A spiral salt tube 5 is arranged in the furnace body 1, and a spiral small salt tube 6 is arranged at one end of the furnace body 1.

[0029] The gas combustion method is as follows: the gas burner 7 is installed outside the furnace, the gas burns at the bottom of the furnace body 1, and the high-temperature flame burns upward. Figure 2 As shown, the oxygen supply blower 14 forces air for combustion, and the hot combustion gas flows from the center of the furnace body 1 to the channel between the two layers of heating spiral salt tubes 5, transferring heat to the molten salt in the spiral salt tubes 5;

[0030] Coal combustion method: The fuel is transported to the combustion chamber 2 through the fuel supply system, and burns on the grate 4 in the combustion system 3. The heat generated is transferred to the molten salt through the spiral salt tube 5 and the spiral small salt tube 6 in the form of radiation and convection.

[0031] See also Figure 2 As shown:

[0032] Preferably, the flue gas induced draft fan 9 is connected to the flue gas outlet of the furnace body 1 through a flue gas induced draft pipeline, and the flue gas induced draft pipeline is equipped with a waste heat recovery device 8, which includes a jacketed heat-insulated nitrogen preheater 81, a flue gas carrier preheater 82, a heat pipe waste heat boiler 83, and an air preheater 84 which are sequentially installed in the flue gas induced draft pipeline;

[0033] Specifically, after the gas combustion and the coal combustion are mixed, the flue gas is blown by the flue gas induced draft fan 9. Figure 2The flue gas induced draft pipeline and the waste heat recovery device 8 recover the waste heat and then cool it down. After the dust is removed by the dust collector, the flue gas induced draft fan 9 is discharged into the dust collector and desulfurized, and then introduced into the atmosphere;

[0034] Preferably, the air blower 10 is connected to the combustion chamber 2 through a combustion-supporting pipeline, the waste heat recovery device 8 has an air preheater 85, and the air preheater 85 is connected in series on the combustion-supporting pipeline. The air blower 8 sends cold air into the air preheater 85, and after absorbing the waste heat of the flue gas, the air is heated up and enters the combustion chamber to serve as combustion-supporting air for fuel combustion.

[0035] Preferably, the flue gas circulation fan 11 has one end connected to the combustion chamber 2 through a first circulation pipeline, and the other end connected to the pipeline at the air inlet end of the air preheater 85 through a second pipeline, and a ceramic dust collector 12 is installed on the second pipeline.

[0036] Preferably, the melamine coal-fired molten salt furnace mixed combustion gas system also includes a flame monitoring system, and the burner 7 burner is equipped with a flame monitoring system.

[0037] Specifically, the entire gas combustion process is controlled by a set of program controllers. In order to ensure the safety of the molten salt heating furnace and prevent accidents caused by burner flameout and flashback, a flame monitoring system is also installed. Once the flame monitor fails to detect the flame, the fuel solenoid valve of the main burner will be closed immediately to cut off the fuel entering the molten salt heating furnace. At the same time, in order to ensure the safety of combustion, the combustion air should be appropriately excessive, and a valve should be used to adjust its proportion. The main burner is crucial to the molten salt heating furnace. The fuel pipeline in the burner must not be blocked, otherwise it will cause the burner to fail to ignite or flame out. In addition, the installation position of the burner nozzle should be accurate and not skewed, otherwise the combustion flame will be skewed, causing the furnace tube surface to burn and crack, and the molten salt in the furnace tube to overheat. The steps of the burner ignition procedure are as follows: Figure 3 As shown:

[0038]

[0039] In the above technical scheme, the utility model provides a melamine coal-fired molten salt furnace mixed with gas system, which aims to achieve energy saving and low carbon, improve the level of resource utilization of three wastes, and achieve an annual reduction of carbon dioxide emissions by 1500t, and a reduction of coal consumption by 25kg per ton of melamine products;

[0040] The whole furnace is mainly composed of two parts: the furnace body and the combustion chamber. The structure of the furnace body 1 is a coil type, that is, the molten salt flows in the spiral coil surrounding the furnace body. The furnace body 1 is a square box-shaped furnace body 1, which is composed of a spiral salt tube and a shell. In order to make full use of the heat, the spiral salt tube is divided into a radiation heating surface and a convection heating surface. The tubes are densely arranged as a "partition wall" to control the flow direction of the high-temperature flue gas. The outer surface of the inner side of the inner circle of the spiral salt tube forms a radiation heat transfer surface to receive the radiant heat energy generated by the combustion system; and in the convection section of the spiral salt tube, the high-temperature flue gas transfers heat to the furnace tube during flow, thereby heating the molten salt in the furnace tube.

[0041] The combustion chamber requires that the flame cannot burn the spiral salt tube, and the most suitable heat intensity can be generated. The heat intensity has a great influence on the wall temperature of the spiral salt tube. If the heat intensity is too large, the service life will be shortened. The high-temperature combustion gas generated by the combustion chamber flows in the gap between the inner and outer spiral salt tubes without a fixed flow direction, and the heat is transferred by forced convection through the surface; the flow direction of the molten salt is opposite to the flow direction of the combustion gas. Through this forced convection, a larger logarithmic mean temperature difference can be obtained.

[0042] Compared with the prior art, the utility model has the following beneficial effects:

[0043] Oxygen-enriched combustion is to increase the oxygen content in the combustion aid, reduce the heat loss carried away by the flue gas by reducing the N2 content, increase the theoretical combustion temperature, increase the output of thermal equipment, and reduce the energy consumption of capturing CO2 in the flue gas by enriching it. Due to the soaring prices of energy such as oil, oxygen-enriched combustion has been valued for its high temperature and significant energy saving, and has been used in high-temperature industrial kilns and other equipment with good results. Due to the greenhouse effect, the global industry has aroused the attention to CO2 gas emission reduction, and oxygen-enriched combustion technology has once again become the focus of research by energy scientists from various countries. It has a great impact on the mass transfer and heat transfer processes inside the furnace.

[0044] Through the application of this technology in melamine molten salt furnace equipment, the annual carbon dioxide emissions can be reduced by 1,500 tons and the raw coal consumption can be reduced by 25 kg per ton of product.

[0045] The above only describes some exemplary embodiments of the present invention by way of illustration. It is undoubted that those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the above drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A melamine coal-fired molten salt furnace mixed combustion gas system, comprising: A furnace body (1), a combustion chamber (2) arranged below the furnace body (1); and A combustion system (3) for supplying a heat source to the combustion chamber (2). The combustion system (3) comprises a grate (4) arranged in the combustion chamber (2), characterized in that; The combustion chamber (2) is located above the grate (4) and is provided with a gas inlet (21), and the gas inlet (21) is connected to the burner (7) so that the gas and coal can be mixed and burned in the combustion chamber (2).

2. A melamine coal-fired molten salt furnace mixed combustion gas system according to claim 1, characterized in that ； The furnace body (1) is a vertical square box structure.

3. A melamine coal-fired molten salt furnace mixed combustion gas system according to claim 2, It is characterized by: A spiral salt tube (5) is arranged inside the furnace body (1), and a spiral small salt tube (6) is arranged at one end of the furnace body (1).

4. A melamine coal-fired molten salt furnace mixed combustion gas system according to any one of claims 1 to 3, characterized in that ； A flue gas induced draft fan (9) is connected to the flue gas exhaust port of the furnace body (1) via a flue gas induced draft pipeline, and the flue gas induced draft pipeline is provided with a waste heat recovery device (8).

5. A melamine coal-fired molten salt furnace mixed combustion gas system according to any one of claims 1 to 3, characterized in that ； It also comprises a flame monitoring system, and the burner nozzle of the burner (7) is equipped with the flame monitoring system.

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