Energy-saving boiler capable of utilizing synthetic ammonia tail gas

Abstract

The utility model discloses an energy-saving boiler capable of utilizing synthetic ammonia tail gas, and belongs to the technical field of synthetic ammonia. Comprising a boiler, a primary air pipe, a secondary air pipe, a primary fan and a secondary fan, the primary fan is connected with the boiler through the primary air pipe, and the secondary fan is connected with the boiler through the secondary air pipe; the number of the secondary air pipes is four, and fuel gas inlets are formed in the secondary air pipes. The four fuel gas inlets are connected with a liquid nitrogen wash tail gas pipeline, a shift steam stripping pipeline, an ammonia washing tower tail gas pipeline and a Claus tail gas pipeline through pipelines with valves, pressure reducing valves and flame arresters correspondingly. The tail gas of the liquid nitrogen wash tail gas pipeline, the shift steam stripping pipeline, the ammonia washing tower tail gas pipeline and the Claus tail gas pipeline (specifically mixed into the secondary air of the boiler and respectively sent to the four secondary air pipes) is sent to the boiler for combustion, so that the coal consumption can be reduced, specifically, the coal consumption can be reduced by 3-4%. And meanwhile, normal operation of the boiler cannot be influenced by the introduced tail gas, and the risk of fire cannot occur.

Description

TECHNICAL FIELD

[0001] The utility model belongs to synthetic ammonia technical field, especially relate to a kind of energy-saving boiler capable of utilizing synthetic ammonia tail gas. BACKGROUND

[0002] Coal gasification is a thermochemical process. With coal or coal coke as raw material, oxygen (air, oxygen-enriched or pure oxygen), steam or hydrogen, etc. as gasification agent, the combustible part in coal or coal coke is converted into gaseous fuel or downstream raw material under high temperature conditions through chemical reaction.

[0003] In the synthetic ammonia production process, a large amount of tail gas is usually generated, which includes carbon monoxide, hydrogen, nitrogen, carbon dioxide or ammonia, etc. The liquid nitrogen washing tail gas pipeline, shift stripping steam pipeline, ammonia washing tower tail gas pipeline and Claus tail gas pipeline are all tail gas pipelines output by different processes. In the prior art, the tail gas is usually burned by a flare, i.e. the liquid nitrogen washing tail gas pipeline, shift stripping steam pipeline, ammonia washing tower tail gas pipeline and Claus tail gas pipeline are all connected with the flare.

[0004] The patent with application number CN202123353184.4 discloses a gas ammonia recycling system, which comprises an ammonia washing tower. The ammonia washing tower comprises a large tower body section and a small tower body section arranged in sequence from bottom to top. The small tower body section is provided with wire mesh packing therein, and the top thereof is connected with a flare through a pipeline. The upper part of the large tower body section is provided with a spray head. The upper part of the large tower body section and above the spray head are provided with a steam inlet. The middle part of the large tower body section is provided with a gas ammonia inlet. The lower part of the large tower body section and between the spray head are provided with a circulating pipe with a circulating pump. The steam inlet is connected with a low-pressure steam pipe network of a synthetic ammonia production system through a pipeline. The gas ammonia inlet is connected with a gas ammonia outlet of an ammonia separator, an exhaust port of a loading pump, an exhaust port of a loading crane pipe, a gas ammonia discharge port of an ammonia tank, a primary safety valve discharge port of the ammonia tank and a secondary safety valve discharge port of the ammonia tank through a pipeline. The lower part of the large tower body section or the circulating pipe is provided with an ammonia water outlet. The lower part of the large tower body section or the circulating pipe is provided with a water supplement port. The ammonia water outlet is connected with an ammonia water inlet of a boiler through a pipeline. The water supplement port is connected with a desalted water outlet of a desalted water supply structure of the boiler.

[0005] Patent with application number CN201922121564.1 discloses a kind of recovery and utilization device of non-condensable gas in slag water treatment system, including high-pressure flash tank, flash gas at the top of high-pressure flash tank is cooled after entering high-pressure flash separator by ash water heater and final cooler, non-condensable gas of high-pressure flash separator gas phase outlet is sent to shift stripper, the device also includes non-condensable gas water cooler and water washing tower;Wherein, the non-condensable gas water cooler inlet is connected by pipeline high-pressure flash separator gas phase outlet, outlet is connected by pipeline water washing tower lower non-condensable gas inlet, water washing tower upper feed port is connected by pipeline public engineering desalted water pipeline, water washing tower top discharge port is connected by pipeline purified pressure swing adsorption device desorption gas compressor inlet, water washing tower bottom discharge port is connected by pipeline coal grinding water supply pipeline.

[0006] Patent with application number CN202123349729.4 discloses a kind of collection and processing device of torch gas, including torch, cold box pipeline, cold torch gas collection pipeline, normal temperature torch gas collection pipeline, heat exchanger, buffer tank, nitrogen supply structure and spray heating structure, the initial end of the cold box pipeline, the initial end of the cold torch gas collection pipeline and the initial end of the normal temperature torch gas collection pipeline are all connected with the nitrogen supply structure, the terminal end of the cold box pipeline is connected with the buffer tank, the waste outlet of the liquid nitrogen washing cold box is connected with the cold box pipeline, the buffer tank is connected with the cold gas inlet of the heat exchanger through the first pipeline, the cold torch gas collection pipeline is used to collect cold torch gas and its terminal end is connected with the first pipeline, the hot gas outlet of the heat exchanger is connected with the torch through the second pipeline, the normal temperature torch gas collection pipeline is used to collect normal temperature torch gas and its terminal end is connected with the second pipeline, the cold gas inlet of the heat exchanger is connected with the low-pressure steam pipe network of the synthetic ammonia production system;The buffer tank includes a horizontal tank arranged along the front and back and two support foundations arranged side by side in front of and behind the bottom of the horizontal tank;The spray heating structure is located directly below the horizontal tank, it is located between the two support foundations, it is connected with the low-pressure steam pipe network, and it sprays steam to the bottom of the horizontal tank.

[0007] In the partial tail gas of synthetic ammonia, there are combustible carbon monoxide and hydrogen, etc., and direct torch combustion is a waste. SUMMARY

[0008] To solve the foregoing problems, the utility model embodiment provides an energy-saving boiler capable of utilizing synthetic ammonia tail gas, which sends tail gas from a liquid nitrogen washing tail gas pipeline, a shift stripping steam pipeline, an ammonia washing tower tail gas pipeline and a Claus tail gas pipeline to the boiler for combustion, thereby reducing coal consumption.The technical solution is as follows:

[0009] The utility model discloses an energy -conserving boiler can utilize synthetic ammonia tail gas, including boiler 14, primary air pipe, secondary air pipe, primary fan and secondary fan, the primary fan is connected with boiler 14 through primary air pipe, the secondary fan is connected with boiler 14 through secondary air pipe, the number of secondary air pipe is four and is equipped with gas import on it, four gas imports are connected with liquid nitrogen washing tail gas pipeline 9, shift stripping steam pipeline 10, ammonia washing tower tail gas pipeline 11 and claus tail gas pipeline 12 respectively through the pipeline of valve, pressure reducing valve and fire arrestor.

[0010] Wherein, the gas import of the first secondary air pipe in the utility model is connected with the liquid nitrogen washing tail gas pipeline 9 through the first bypass 1 with the first valve, the first pressure reducing valve and the first fire arrestor 5, the gas import of the second secondary air pipe is connected with the shift stripping steam pipeline 10 through the second bypass 2 with the second valve, the second pressure reducing valve and the second fire arrestor 6, the gas import of the third secondary air pipe is connected with the ammonia washing tower tail gas pipeline 11 through the third bypass 3 with the third valve, the third pressure reducing valve and the third fire arrestor 7, and the gas import of the fourth secondary air pipe is connected with the claus tail gas pipeline 12 through the fourth bypass 4 with the fourth valve, the fourth pressure reducing valve and the fourth fire arrestor 8.

[0011] Wherein, the first secondary air pipe, the second secondary air pipe, the third secondary air pipe and the fourth secondary air pipe in the utility model are arranged side by side in turn.

[0012] Wherein, the first pressure reducing valve in the utility model reduces the gas pressure from above 1000Kpa to below 10Kpa, the second pressure reducing valve reduces the gas pressure from above 120Kpa to below 10Kpa, the third pressure reducing valve reduces the gas pressure from above 400Kpa to below 10Kpa, and the fourth pressure reducing valve reduces the gas pressure from above 10Kpa to below 10Kpa.

[0013] Wherein, the pipe diameter of the gas import in the utility model is 1 / 8-2 / 3 of the pipe diameter of the corresponding secondary air pipe.

[0014] Specifically, the pipe diameter of the secondary air pipe in the utility model is 300mm, the pipe diameter of the first bypass 1 is 150mm, the pipe diameter of the second bypass 2 is 80mm, the pipe diameter of the third bypass 3 is 50mm, and the pipe diameter of the fourth bypass 4 is 150mm.

[0015] Further, the first bypass 1, the second bypass 2, the third bypass 3 and the fourth bypass 4 in the utility model are all provided with nitrogen gas purging bypass 13, the nitrogen gas purging bypass 13 is provided with a valve and is connected with a low-pressure nitrogen gas supply device.

[0016] Wherein, the other end of the liquid nitrogen washing tail gas pipeline 9 is connected with the cold box, the other end of the shift stripping steam pipeline 10 is connected with the shift stripping tower, the other end of the ammonia washing tower tail gas pipeline 11 is connected with the ammonia washing tower, and the other end of the Claus tail gas pipeline 12 is connected with the sulfur trap.

[0017] The technical scheme provided by the embodiment of the utility model has the beneficial effects that the embodiment of the utility model provides an energy-saving boiler capable of utilizing synthetic ammonia tail gas, tail gas (specifically mixed into secondary air of the boiler and sent into four secondary air pipes) of the liquid nitrogen washing tail gas pipeline, the shift stripping steam pipeline, the ammonia washing tower tail gas pipeline and the Claus tail gas pipeline is sent into the boiler for combustion, so that coal consumption can be reduced, specifically, coal consumption can be reduced by 3-4%. At the same time, the input tail gas will not affect the normal operation of the boiler, and there will be no fire risk; the investment of tail gas treatment equipment and the tail gas treatment amount can also be reduced. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 is the principle block diagram of the energy-saving boiler capable of utilizing synthetic ammonia tail gas provided by the embodiment of the utility model;

[0019] Figure 2 is the PID diagram of the energy-saving boiler capable of utilizing synthetic ammonia tail gas provided by the embodiment of the utility model;

[0020] Figure 3 is the principle block diagram of the nitrogen purging bypass.

[0021] In the figure: 1 first bypass, 2 second bypass, 3 third bypass, 4 fourth bypass, 5 first fire arrester, 6 second fire arrester, 7 third fire arrester, 8 fourth fire arrester, 9 liquid nitrogen washing tail gas pipeline, 10 shift stripping steam pipeline, 11 ammonia washing tower tail gas pipeline, 12 Claus tail gas pipeline, 13 nitrogen purging bypass, 14 boiler;

[0022] A from the cold box, B from the shift stripping tower, C from the ammonia washing tower, D from the sulfur trap, E from the low-pressure nitrogen supply device, F to another boiler. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical scheme and advantages of the utility model more clear, the utility model will be described in further detail below with reference to the drawings.

[0024] Embodiment 1

[0025] Referring to Figures 1-2, embodiment 1 provides an energy-saving boiler capable of utilizing synthetic ammonia tail gas, comprising a boiler 14, a primary air pipe, a secondary air pipe, a primary air fan and a secondary air fan. The boiler 14 uses coal as fuel to generate high-pressure steam; the high-pressure steam drives a steam turbine to generate electricity. The primary air fan is connected with the boiler 14 through the primary air pipe, and the secondary air fan is connected with the boiler 14 through the secondary air pipe. The number of the secondary air pipe is four, and a gas inlet is arranged on each of the four secondary air pipes. The four secondary air pipes are a first secondary air pipe, a second secondary air pipe, a third secondary air pipe and a fourth secondary air pipe. The first secondary air pipe, the second secondary air pipe, the third secondary air pipe and the fourth secondary air pipe are arranged side by side (at the front position of the boiler 14) in sequence, and are all connected with the same primary air fan. The gas inlet of the first secondary air pipe is connected with the liquid nitrogen washing tail gas pipe line 9 through the first bypass 1 provided with a first valve (including a safety valve, a manual valve and a interlocking valve, etc., to ensure the safety of the pipeline, and the other valves are the same), a first pressure reducing valve and a first flame arrester 5, the gas inlet of the second secondary air pipe is connected with the shift stripping steam pipe line 10 through the second bypass 2 provided with a second valve, a second pressure reducing valve and a second flame arrester 6, the gas inlet of the third secondary air pipe is connected with the ammonia washing tower tail gas pipe line 11 through the third bypass 3 provided with a third valve, a third pressure reducing valve and a third flame arrester 7, and the gas inlet of the fourth secondary air pipe is connected with the Claus tail gas pipe line 12 through the fourth bypass 4 provided with a fourth valve, a fourth pressure reducing valve and a fourth flame arrester 8. Among them, the first flame arrester 5, the second flame arrester 6, the third flame arrester 7 and the fourth flame arrester 8 are arranged close to the boiler 14 to ensure the safety of the pipeline.

[0026] Among them, the first pressure reducing valve in the embodiment of the utility model reduces the gas pressure from above 1000Kpa to below 10Kpa, the second pressure reducing valve reduces the gas pressure from above 120Kpa to below 10Kpa, the third pressure reducing valve reduces the gas pressure from above 400Kpa to below 10Kpa, and the fourth pressure reducing valve reduces the gas pressure from above 10Kpa to below 10Kpa. To ensure that the pressure of each tail gas matches the pressure in the boiler 14.

[0027] Among them, the pipe diameter of the gas inlet in the embodiment of the utility model is 1 / 8-2 / 3 of the pipe diameter of the secondary air pipe.

[0028] The other end of the liquid nitrogen washing tail gas pipeline 9 in the utility model is connected with a cold box (after being gasified by a corresponding structure, liquid nitrogen washing tail gas is output, which can be seen from the description of application No. CN202123349729.4), the other end of the shift stripping steam pipeline 10 is connected with a shift stripping tower (shift stripping steam is output, which can be seen from the description of application No. CN201922121564.1), the other end of the ammonia washing tower tail gas pipeline 11 is connected with an ammonia washing tower (ammonia washing tail gas is output, which can be seen from the description of application No. CN202123353184.4), and the other end of the claus tail gas pipeline 12 is connected with a sulfur trap (claus tail gas is output, which can be seen from the description of application No. CN202322896855.4).

[0029] Embodiment 2

[0030] Referring to Figures 2-3 Embodiment 2 provides an energy-saving boiler capable of utilizing synthetic ammonia tail gas, which has basically the same structure as that of embodiment 1, except that nitrogen purge bypasses 13 (located upstream of corresponding flame arresters) are arranged on the first bypass 1, the second bypass 2, the third bypass 3 and the fourth bypass 4 in the embodiment, and the nitrogen purge bypasses 13 are provided with valves (in a normally closed state) and are connected with low-pressure nitrogen supply devices (providing low-pressure nitrogen of about 0.4 MPa).

[0031] Embodiment 3

[0032] Embodiment 3 provides an energy-saving boiler capable of utilizing synthetic ammonia tail gas, which has basically the same structure as that of embodiment 1, except that the diameters of the first secondary air pipe, the second secondary air pipe, the third secondary air pipe and the fourth secondary air pipe in the embodiment are all 300 mm, the diameter of the first bypass 1 is 150 mm, the diameter of the second bypass 2 is 80 mm, the diameter of the third bypass 3 is 50 mm, and the diameter of the fourth bypass 4 is 150 mm. The first pressure reducing valve reduces the gas pressure from 1200 Kpa to 8-9 Kpa, the second pressure reducing valve reduces the gas pressure from 150 Kpa to 8-9 Kpa, the third pressure reducing valve reduces the gas pressure from 500 Kpa to 8-9 Kpa, and the fourth pressure reducing valve reduces the gas pressure from 12 Kpa to 8-9 Kpa; the air pressure of the secondary air fan is about 10 Kpa; and the furnace pressure of the boiler 14 is less than 10 Kpa.

[0033] Embodiment 4

[0034] Referring to Figure 2, the embodiment 4 provides an energy-saving boiler capable of utilizing synthetic ammonia tail gas, which has basically the same structure as the structure of the embodiment 1, and the difference is that the synthetic ammonia system in the embodiment is 300,000 tons in specification, the boiler is 75 tons in specification, and the number of the boilers is 2-3. Then the tail gas of the liquid nitrogen washing tail gas pipeline 9, the shift stripping steam pipeline 10, the ammonia washing tower tail gas pipeline 11 and the Claus tail gas pipeline 12 is simultaneously output to the multiple boilers.

[0035] The coal consumption of the existing boiler is 137 kg of standard coal per ton of steam, and after the improvement, the coal consumption can be reduced by about 5 kg of standard coal per ton of steam.

[0036] Among them, "first", "second", "third" and "fourth" in the patent only play a distinguishing role, and have no other special meaning.

[0037] The above only describes the preferred embodiments of the present application and is not intended to limit the present application, and any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. An energy-saving boiler capable of utilizing ammonia synthesis tail gas, comprising a boiler (14), a primary air duct, a secondary air duct, a primary air fan, and a secondary air fan, wherein the primary air fan is connected to the boiler (14) via the primary air duct, and the secondary air fan is connected to the boiler (14) via the secondary air duct; characterized in that, The number of secondary air ducts is four, and each of them is equipped with a gas inlet. The four gas inlets are connected to the liquid nitrogen washing tail gas pipeline (9), the shift stripping steam pipeline (10), the ammonia washing tower tail gas pipeline (11), and the Claus tail gas pipeline (12) respectively through pipelines equipped with valves, pressure reducing valves, and flame arresters.

2. The energy-saving boiler capable of utilizing ammonia synthesis tail gas according to claim 1, characterized in that, The gas inlet of the first and second secondary air ducts is connected to the liquid nitrogen scrubbing tail gas pipeline (9) via the first bypass (1) with the first valve, the first pressure reducing valve and the first flame arrester (5). The gas inlet of the second and second secondary air ducts is connected to the conversion stripping steam pipeline (10) via the second bypass (2) with the second valve, the second pressure reducing valve and the second flame arrester (6). The gas inlet of the third and second secondary air ducts is connected to the ammonia scrubbing tower tail gas pipeline (11) via the third bypass (3) with the third valve, the third pressure reducing valve and the third flame arrester (7). The gas inlet of the fourth and second secondary air ducts is connected to the Claus tail gas pipeline (12) via the fourth bypass (4) with the fourth valve, the fourth pressure reducing valve and the fourth flame arrester (8).

3. The energy-saving boiler capable of utilizing ammonia synthesis tail gas according to claim 2, characterized in that, The first secondary air duct, the second secondary air duct, the third secondary air duct, and the fourth secondary air duct are arranged side by side in sequence.

4. The energy-saving boiler capable of utilizing ammonia synthesis tail gas according to claim 2, characterized in that, The first pressure reducing valve reduces the gas pressure from above 1000 kPa to below 10 kPa, the second pressure reducing valve reduces the gas pressure from above 120 kPa to below 10 kPa, the third pressure reducing valve reduces the gas pressure from above 400 kPa to below 10 kPa, and the fourth pressure reducing valve reduces the gas pressure from above 10 kPa to below 10 kPa.

5. The energy-saving boiler capable of utilizing ammonia synthesis tail gas according to claim 2, characterized in that, The diameter of the gas inlet is 1 / 8 to 2 / 3 of the diameter of the corresponding secondary air duct.

6. The energy-saving boiler capable of utilizing ammonia synthesis tail gas according to claim 5, characterized in that, The diameter of the secondary air duct is 300mm, the diameter of the first bypass (1) is 150mm, the diameter of the second bypass (2) is 80mm, the diameter of the second bypass (3) is 50mm, and the diameter of the fourth bypass (4) is 150mm.

7. The energy-saving boiler capable of utilizing ammonia synthesis tail gas according to claim 2, characterized in that, The first bypass (1), the second bypass (2), the third bypass (3) and the fourth bypass (4) are all equipped with nitrogen purging bypass (13), and the nitrogen purging bypass (13) is equipped with a valve and is connected to a low-pressure nitrogen supply device.

8. The energy-saving boiler capable of utilizing ammonia synthesis tail gas according to claim 1, characterized in that, The other end of the liquid nitrogen wash tail gas pipeline (9) is connected to the cold box, the other end of the shift stripping steam pipeline (10) is connected to the shift stripping tower, the other end of the ammonia wash tower tail gas pipeline (11) is connected to the ammonia wash tower, and the other end of the Claus tail gas pipeline (12) is connected to the sulfur trap.

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