Comprehensive utilization system for tablet vanadium calcining flue gas

Abstract

The utility model discloses a comprehensive utilization system for tablet vanadium calcining flue gas, which is characterized in that a first regulating valve is arranged on a flue gas pipeline between a chimney I and an induced draft fan I, a calcining flue gas return main pipe is arranged on the flue gas pipeline, and the calcining flue gas return main pipe is divided into four branch pipes. According to the comprehensive utilization system, the tablet vanadium three-step method calcination flue gas is led back to be supplied to the melting furnace and the calcination flue gas furnace for low-oxygen gas combustion and supplied to the calcination flue gas furnace and the flash evaporation drying machine for low-temperature flue gas mixing, and the purposes of saving energy of a production line and reducing the oxygen content of the system are achieved. In addition, after tablet vanadium is calcined through a three-step method, ammonia-containing flue gas is led back to be used as a low-oxygen combustion-supporting body for combustion of a melting furnace and a calcination flue gas furnace, ammonia gas is decomposed into hydrogen and nitrogen, and pollution-free water vapor is generated after hydrogen is combusted. The problems of ammonia emission pollution and treatment are successfully solved, the investment and operation cost of the whole system is reduced, and meanwhile fuel consumption is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of chemical industry, in particular to a comprehensive utilization system of tablet vanadium calcination flue gas. Background Art

[0002] The three-step process of producing vanadium pentoxide (V2O5) by vanadium tablets is currently the most commonly used process for vanadium pentoxide products. The main process is to add wet ammonium vanadate (usually 10-40% water content) into a flash dryer for dehydration, and then enter the calcining furnace (kiln) to decompose into powdered vanadium pentoxide and ammonia. The powdered vanadium pentoxide is then transported to a melting furnace to be melted, cast onto a sheet casting machine, and finally cooled into a finished vanadium pentoxide flake product.

[0003] The calcining furnace is heated by the flue gas provided by the flue gas furnace, which decomposes ammonium vanadate into vanadium pentoxide and ammonia. The flue gas (including ammonia) after calcination passes through the heat exchanger, dust collector, and induced draft fan and is directly discharged into the atmosphere from the chimney; or the flue gas after calcination is introduced into the ammonia recovery device and discharged after ammonia removal. Figure 2 shown.

[0004] At present, the three-step production of vanadium tablets has the following main problems: 1) The flue gas temperature after the heat exchanger and dust collector is about 150-180℃ and is directly discharged into the atmosphere without being used, resulting in energy waste. 2) The direct discharge of ammonia generated by the calcination and decomposition of ammonium vanadate will cause environmental pollution, or require the addition of an ammonia recovery device, thereby increasing investment and operating costs. Utility Model Content

[0005] The utility model aims to provide a comprehensive utilization system of tablet vanadium calcination flue gas, solve the ammonia emission and environmental management problems of tablet vanadium three-step production line, reduce the investment and operation cost of the whole system, and reduce fuel consumption.

[0006] In order to solve the above technical problems, the utility model adopts the following technical solutions:

[0007] The utility model provides a comprehensive utilization system of tablet vanadium calcining flue gas, comprising a dryer for dehydrating wet ammonium vanadate, a calcining furnace for decomposing dehydrated ammonium vanadate, a melting furnace for melting powdered vanadium pentoxide, and a tablet casting machine for casting; it also includes a flue gas furnace for supplying heat to the calcining furnace, a heat exchanger for conveying flue gas to chimney one, a dust collector one, and an induced draft fan one; wherein the flue gas generated by the dryer is conveyed to chimney two through dust collector two and induced draft fan two;

[0008] A first regulating valve is arranged on the flue gas pipeline between chimney 1 and induced draft fan 1, a calcination flue gas return main pipe is arranged on the flue gas pipeline and at an upstream position of the first regulating valve, and a main regulating valve is arranged on the calcination flue gas return main pipe, the calcination flue gas return main pipe is connected to the melting furnace through a first branch pipe, and is used to supply low-oxygen combustion-supporting gas for its burner;

[0009] The calcining flue gas return main pipe is also connected to the flue gas furnace through a second branch pipe, and the second branch pipe is used to supply low-oxygen combustion-supporting gas to its burner through a branch pipe, and is also led to the tail of the flue gas furnace through a branch pipe of the second branch pipe and used for mixing cold low-temperature flue gas;

[0010] The calcining flue gas return main pipe is also connected to the inlet pipe of the dryer through a third branch pipe, which is used to mix the high-temperature flue gas introduced from the melting furnace with the cold low-temperature flue gas;

[0011] An electric regulating valve is respectively arranged on each branch pipe.

[0012] Furthermore, a first branch regulating valve is provided on the first branch pipe;

[0013] A second branch regulating valve is arranged between the second branch pipe and the burner of the flue gas furnace, a second branch auxiliary regulating valve is arranged between the second branch pipe and the tail of the flue gas furnace; and a third branch regulating valve is arranged on the third branch pipe.

[0014] Compared with the prior art, the beneficial technical effects of the utility model are:

[0015] 1) By introducing the flue gas from the three-step calcination of vanadium tablets back to the melting furnace and calcination flue gas furnace as low-oxygen gas combustion and the calcination flue gas furnace and flash dryer as a comprehensive utilization system for mixing low-temperature flue gas, the purpose of energy saving in the production line and reducing the oxygen content in the system is achieved.

[0016] 2) By introducing the ammonia-containing flue gas after the three-step calcination of vanadium tablets back to the melting furnace and calcination flue gas furnace as a low-oxygen combustion-supporting body, the ammonia is decomposed into hydrogen and nitrogen, and the hydrogen is burned to generate pollution-free water vapor. The ammonia emission pollution and control problems are successfully solved, the investment and operation costs of the entire system are reduced, and the fuel consumption is reduced at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The utility model will be further described below in conjunction with the accompanying drawings.

[0018] Figure 1 This is a schematic diagram of the comprehensive utilization system of the calcination flue gas of vanadium tablets of the utility model;

[0019] Figure 2 The figure is a flow chart of the comprehensive utilization system of the existing vanadium tablet calcination flue gas. DETAILED DESCRIPTION

[0020] This embodiment discloses a comprehensive utilization system of flue gas from calcining vanadium tablets, comprising a dryer for dehydrating wet ammonium vanadate, a calcining furnace for decomposing dehydrated ammonium vanadate, a melting furnace for melting powdered vanadium pentoxide, and a tablet casting machine for casting; it also includes a flue gas furnace for supplying heat to the calcining furnace, a heat exchanger for conveying flue gas to chimney one, a dust collector one, and an induced draft fan one; wherein the flue gas generated by the dryer is conveyed to chimney two through dust collector two and induced draft fan two;

[0021] A first regulating valve 1 is installed on the flue gas pipeline between chimney 1 and induced draft fan 1, a calcination flue gas return main pipe is installed on the flue gas pipeline and at an upstream position of the first regulating valve 1, and a main regulating valve 2 is installed on the calcination flue gas return main pipe, and the calcination flue gas return main pipe is connected to the burner of the melting furnace through a first branch pipe;

[0022] The calcining flue gas return main pipe is also connected to the burner of the flue gas furnace through a second branch pipe, and is also led to the tail of the flue gas furnace through a branch pipe and used for mixing with cold low-temperature flue gas;

[0023] The calcining flue gas return main pipe is also connected to the inlet pipe of the dryer through a third branch pipe, which is used to mix the high-temperature flue gas introduced from the melting furnace with the cold low-temperature flue gas; electric regulating valves are installed on each branch pipe;

[0024] Specifically, a first branch regulating valve 3 is installed on the first branch pipe; a second branch regulating valve 4 is installed between the second branch pipe and the burner of the flue gas furnace, and a second branch auxiliary regulating valve 5 is installed between the second branch pipe and the tail of the flue gas furnace; and a third branch regulating valve 6 is installed on the third branch pipe.

[0025] The utility model is based on the original three-step production line of vanadium tablets (such as Figure 2 As shown in the figure, the exhaust flue gas in the calcining area is led out from the outlet pipe of the induced draft fan, and a first regulating valve 1 is added to the rear of the outlet pipe to adjust the amount of calcining flue gas returned.

[0026] A main regulating valve 2 is installed on the main pipe of the calcined flue gas led back, and the first branch is led to the melting furnace to supply low-oxygen combustion-supporting gas for its burner, and a first branch regulating valve 3 is installed on its branch pipeline; the second branch is led to the flue gas furnace, a part of which is supplied with low-oxygen combustion-supporting gas for its burner, and a second branch regulating valve 4 is installed on the pipeline, and the other part is led to the tail of the flue gas furnace for mixing with cold low-temperature flue gas, and a second branch auxiliary regulating valve 5 is installed on the pipeline; the third branch is led to the inlet pipeline of the flash dryer, and is used for mixing with cold low-temperature flue gas of the high-temperature flue gas introduced from the melting furnace, and a third branch regulating valve 6 is installed on its branch pipeline.

[0027] The diameter of the aforementioned pipeline is designed according to the required flue gas volume, and is supported by a steel bracket. The pipeline needs to be insulated. The control of the electric regulating valve can be automatically adjusted by a computer program compiled according to the system temperature, pressure and flow rate, and can also be manually adjusted according to actual conditions.

[0028] The low-temperature flue gas (containing ammonia, about 150-180℃) originally discharged after calcination is led back to the production line through the rear pipe of the induced draft fan for comprehensive utilization. The beneficial aspects of the system are: the first part is supplied to the melting furnace burner for low-oxygen combustion-supporting gas, which reduces the nitrogen oxide content of the system flue gas, increases the gas supply temperature, and reduces the oxygen content of the system flue gas; the second part is supplied to the calcining flue gas furnace burner for low-oxygen combustion-supporting gas and the furnace tail for mixing and temperature-adjusting gas, which reduces the nitrogen oxide content of the system flue gas, increases the gas supply temperature, and reduces the oxygen content of the system flue gas; the third part is supplied to the flash dryer system as mixed low-temperature flue gas. Compared with using normal temperature air as the mixed gas, the advantage is that the mixed gas temperature is increased and the oxygen content of the system flue gas is reduced.

[0029] By introducing the calcination flue gas back to the comprehensive utilization system, the purpose of energy saving of the three-step production line of vanadium tablets and reducing the oxygen content of the system can be achieved.

[0030] Another beneficial aspect of the system is that the low-temperature flue gas (containing ammonia) originally discharged after calcination is led back to the production line through the rear duct of the induced draft fan for comprehensive utilization: the flue gas after calcination contains a large amount of ammonia. These ammonia-containing flue gases are burned through the melting furnace and the calcination flue gas furnace burner, and the ammonia is decomposed into nitrogen and hydrogen. The hydrogen is ignited and burned to react with oxygen to generate water vapor, thereby achieving ammonia-free emission. The combustion of hydrogen produces a large amount of heat, which reduces the fuel consumption of the system and saves the investment and operating costs of the ammonia treatment system.

[0031] By introducing the calcination flue gas back to the combustion system, the ammonia emission and environmental management problems of the three-step production line of vanadium tablets are solved, the investment and operation costs of the entire system are reduced, and the fuel consumption is reduced.

[0032] The above embodiments are only descriptions of the preferred methods of the invention, and are not intended to limit the scope of the invention. Without departing from the design spirit of the invention, various modifications and improvements made to the technical solution of the invention by ordinary technicians in this field should fall within the protection scope of the claims of the invention.

Claims

1. A comprehensive utilization system of flue gas from calcination of vanadium tablets, comprising a dryer for dehydrating wet ammonium vanadate, a calcining furnace for decomposing dehydrated ammonium vanadate, a melting furnace for melting powdered vanadium pentoxide, and a tablet casting machine for casting; it also includes a flue gas furnace for supplying heat to the calcining furnace, a heat exchanger for conveying flue gas to chimney one, a dust collector one, and an induced draft fan one; wherein the flue gas generated by the dryer is conveyed to chimney two through a dust collector two and an induced draft fan two; Features: A first regulating valve (1) is arranged on the flue gas pipeline between chimney 1 and induced draft fan 1, a calcination flue gas return main pipe is arranged on the flue gas pipeline and upstream of the first regulating valve (1), and a main regulating valve (2) is arranged on the calcination flue gas return main pipe, and the calcination flue gas return main pipe is connected to the burner of the melting furnace through a first branch pipe; The calcining flue gas return main pipe is also connected to the burner of the flue gas furnace through a second branch pipe, and is also led to the tail of the flue gas furnace through the second branch pipe and used for mixing with cold low-temperature flue gas; The calcining flue gas return main pipe is also connected to the inlet pipe of the dryer through a third branch pipe, which is used to mix the high-temperature flue gas introduced from the melting furnace with the cold low-temperature flue gas; An electric regulating valve is respectively arranged on each branch pipe.

2. The comprehensive utilization system of tablet vanadium calcination flue gas according to claim 1, characterized in that: A first branch regulating valve (3) is provided on the first branch pipe; A second branch regulating valve (4) is provided between the second branch pipe and the burner of the flue gas furnace, and a second branch auxiliary regulating valve (5) is provided between the second branch pipe and the tail of the flue gas furnace; A third branch regulating valve (6) is arranged on the third branch pipe.

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