CN218810375U - Liquid ammonia production system for recycling pressure-relief replacement gas of molecular sieve washed by liquid nitrogen - Google Patents

Abstract

The utility model discloses a liquid ammonia production system for recycling pressure relief replacement gas of a molecular sieve washed by liquid nitrogen, which comprises a raw coal bunker, a BGL gasification furnace, a CO conversion system, a low-temperature methanol washing system, a liquid nitrogen washing system and an ammonia synthesis system which are connected in sequence; a coal lock is arranged between the raw coal bin and the gasification furnace; the gas holder, the liquid seal tank and the coal lock gas compressor are connected in sequence and then connected with the coal lock; the liquid nitrogen washing system comprises two molecular sieves and a cold box which are switched for use; the molecular sieve is communicated with the low-temperature methanol washing system through an air inlet pipe; the molecular sieve is communicated with the cold box through an air outlet pipe; the gas inlet pipe is connected with the torch gas inlet pipe through a regeneration exhaust pipe; the torch air inlet pipe is communicated with the liquid seal groove through a pipeline. The device has the advantages that the pressure relief and replacement gas of the molecular sieve in the liquid nitrogen washing system is delivered to the outlet of the gas holder, enters the BGL gasification furnace together with the coal lock gas, is delivered to the ammonia forming device for ammonia production through the original flow, and avoids the waste of torch delivery and combustion.

Description

Liquid ammonia production system for recycling pressure-relief replacement gas of molecular sieve washed by liquid nitrogen

The technical field is as follows:

the utility model relates to a molecular sieve pressure release replacement gas recycle's liquid ammonia production system is washed to liquid nitrogen belongs to coal chemical industry field.

Background art:

the synthetic ammonia is produced by gasifying coal as raw material and producing H ₂ And CO, and then adopting various purification methods to remove dust, H2S, organic sulfide, CO and CO in the gas ₂ And (3) obtaining clean 1.

Wherein, CO, CH4, C4H6 and AR gases in the coal gas are removed by adopting a liquid nitrogen molecular sieve to obtain pure H2; the molecular sieve is washed by liquid nitrogen for two switching uses, namely one is operated, the other is regenerated, and the switching period is 12 hours. The regeneration of the molecular sieve is the desorption process, and the molecular sieve is promoted under the conditions of low pressure and high temperature, so the molecular sieve is required to be decompressed to lower pressure before the regeneration of the molecular sieve, the components of the decompressed gas of the molecular sieve, namely hydrogen accounts for about 87%, methane accounts for about 3%, and carbon monoxide accounts for about 1.7%, and the decompressed gas is directly sent to a torch for combustion in the conventional treatment method, thereby causing waste.

The utility model has the following contents:

an object of the utility model is to provide a with the gaseous synthetic ammonia that generates of recycling of molecular sieve pressure release, avoid burning extravagant liquid nitrogen and wash molecular sieve pressure release replacement gas recycle's liquid ammonia production system.

The utility model discloses by following technical scheme implement: a liquid ammonia production system for recycling decompression replacement gas of a molecular sieve washed by liquid nitrogen comprises a raw coal bunker, a BGL gasifier, a CO conversion system, a low-temperature methanol washing system, a liquid nitrogen washing system and an ammonia synthesis system which are sequentially connected; wherein a coal lock is arranged between the raw coal bin and the gasification furnace; the gas holder, the liquid seal tank and the coal lock gas compressor are connected in sequence and then connected with the gas inlet of the coal lock; the liquid nitrogen washing system comprises two molecular sieves and a cold box which are switched for use; the air inlets of the two molecular sieves are communicated with the air outlet pipe of the low-temperature methanol washing system through an air inlet pipe; the air outlets of the two molecular sieves are communicated with the air inlet pipe of the cold box through an air outlet pipe; the gas outlet of the cold box is communicated with the hydrogen inlet of the ammonia synthesis system through a pipeline; an air inlet valve and an air outlet valve are correspondingly arranged on the air inlet pipe and the air outlet pipe of each molecular sieve respectively; the gas outlet pipe between each gas outlet valve and the corresponding molecular sieve is connected with a nitrogen gas source through a regeneration gas inlet pipe; each regeneration air inlet pipe is provided with a regeneration air inlet valve; the gas inlet pipe between each gas inlet valve and the corresponding molecular sieve is connected with a torch gas inlet pipe through a regeneration gas outlet pipe; each regeneration exhaust pipe is provided with a regeneration exhaust valve; a torch air inlet switching valve is arranged on the torch air inlet pipe; the flare gas inlet pipe between the regeneration exhaust valve and the flare gas inlet switching valve is communicated with the gas inlet of the liquid seal tank through a pipeline; a regeneration exhaust switching valve is arranged on a pipeline between the torch air inlet pipe and the air inlet of the liquid seal tank 72.

Preferably, the air inlet valve, the air outlet valve, the regeneration air inlet valve, the regeneration exhaust valve, the torch air inlet switching valve and the regeneration exhaust switching valve are all cut-off valves.

The utility model has the advantages that: compared with the prior art, the pressure relief and replacement gas of the molecular sieve in the liquid nitrogen washing system is sent to the outlet of the gas holder, enters the BGL gasification furnace together with the coal lock gas, is sent to the ammonia forming device for ammonia production through the original flow, and avoids the waste of torch feeding combustion; meanwhile, only one pipeline and two switch valves are needed to be added when the improvement is carried out in a system for conventionally using the BGL gasification furnace to generate liquid ammonia, the improvement workload is small, the improvement cost is low, the economic benefit is high, and the improvement investment cost recovery period is short.

Description of the drawings:

fig. 1 is a schematic diagram of the system connection of the present invention.

The specific implementation mode is as follows:

the embodiment is as follows: as shown in fig. 1, the liquid ammonia production system for recycling pressure-releasing replacement gas by using a liquid nitrogen-washed molecular sieve comprises a raw coal bin 1, a BGL gasifier 2, a CO shift system 3, a low-temperature methanol washing system 4, a liquid nitrogen washing system 5 and an ammonia synthesis system 6 which are connected in sequence, wherein raw coal in the raw coal bin 1 enters the BGL gasifier 2 for gasification, the CO shift system 3 converts carbon monoxide in crude gas generated by gasification of the BGL gasifier 2 into hydrogen, and the low-temperature methanol washing system 4 removes carbon monoxide and hydrogen sulfide in the crude gas by using a methanol solution; the liquid nitrogen washing system 5 removes other impurities in the coal gas to obtain pure hydrogen; the ammonia synthesis system 6 synthesizes hydrogen and nitrogen into synthetic ammonia and then prepares liquid ammonia;

a coal lock 7 is arranged between the raw coal bunker and the gasification furnace, and the coal lock 7 ensures the air tightness of the BGL gasification furnace 2 when the raw coal bunker 1 supplies coal to the BGL gasification furnace 2, and ensures the stable furnace pressure of the BGL gasification furnace 2; the gas holder 8, the liquid seal tank 9 and the coal lock gas compressor 10 are connected in sequence and then connected with the gas inlet of the coal lock 7 to provide a gas source for the coal lock device 18;

the liquid nitrogen washing system 5 comprises two molecular sieves 51 and a cold box 52 which are switched for use; the air inlets of the two molecular sieves 51 are communicated with the air outlet pipe 41 of the low-temperature methanol washing system 4 through an air inlet pipe 511; the air outlets of the two molecular sieves 51 are communicated with an air inlet pipe 521 of the cold box 52 through an air outlet pipe 512; the air outlet of the cold box 52 is communicated with the hydrogen inlet of the ammonia synthesis system 6 through a pipeline; an air inlet valve 513 and an air outlet valve 514 are correspondingly arranged on the air inlet pipe 511 and the air outlet pipe 512 of each molecular sieve 51 respectively; an air outlet pipe 512 between each air outlet valve 514 and the corresponding molecular sieve 51 is connected with a nitrogen gas source 11 through a regeneration air inlet pipe 515; a regeneration air inlet valve 516 is arranged on each regeneration air inlet pipe 515; the gas inlet pipe 511 between each gas inlet valve 513 and the corresponding molecular sieve 51 is connected with the torch gas inlet pipe 13 through a regeneration gas outlet pipe 517; a regeneration exhaust valve 518 is arranged on each regeneration exhaust pipe 517; one of the two molecular sieves 51 is operated, the other molecular sieve is regenerated and used by switching the air inlet valve 513, the air outlet valve 514, the regeneration air inlet valve 516 and the regeneration air outlet valve 518, and the switching period of the two molecular sieves 51 is 12 hours;

a torch air inlet switching valve 131 is arranged on the torch air inlet pipe 13; a flare gas inlet pipe 13 between the regeneration exhaust valve 518 and the flare gas inlet switching valve 131 is communicated with the gas inlet of the liquid seal tank 9 through a pipeline; a regeneration exhaust switching valve 519 is arranged on a pipeline between the torch air inlet pipe 13 and the air inlet of the liquid seal tank 9; by closing the torch gas inlet switching valve 131 and opening the regeneration exhaust switching valve 519, the nitrogen of the nitrogen gas source 11 is adopted to send the decompression gas with the components of about 87% of hydrogen, about 3% of methane and about 1.7% of carbon monoxide in the regeneration process of the molecular sieve 51 to the liquid seal tank 9 to be used as a gas source of a coal lock 7 to enter the BGL gasifier 2 again, the decompression gas and the crude gas generated by the BGL gasifier 2 are used together in the ammonia synthesis system 6 to generate synthetic ammonia, the decompression gas is prevented from being sent to the torch for combustion and wasted, taking the BGL gasifier 2 with 562 tons of daily production as an example, 0.54 ton of synthetic ammonia can be produced in each day, the synthetic ammonia operates for 330 days annually, the liquid ammonia does not contain the price of 4032.58 yuan/t, and the annual economic benefit is 71.86 ten thousand yuan; the nitrogen gas entering the BGL gasifier 2 can be used as protective gas during the gasification of the BGL gasifier 2; the air inlet valve 513, the air outlet valve 514, the regeneration air inlet valve 516, the regeneration exhaust valve 518, the torch air inlet switching valve 131 and the regeneration exhaust switching valve 519 are all shut-off valves.

Claims (2)

1. A liquid ammonia production system for recycling decompression replacement gas of a molecular sieve washed by liquid nitrogen comprises a raw coal bunker, a BGL gasifier, a CO conversion system, a low-temperature methanol washing system, a liquid nitrogen washing system and an ammonia synthesis system which are sequentially connected; wherein a coal lock is arranged between the raw coal bin and the gasification furnace; the gas holder, the liquid seal tank and the coal lock gas compressor are connected in sequence and then connected with the gas inlet of the coal lock; the liquid nitrogen washing system comprises two molecular sieves and a cold box which are switched for use; the air inlets of the two molecular sieves are communicated with the air outlet pipe of the low-temperature methanol washing system through an air inlet pipe; the air outlets of the two molecular sieves are communicated with the air inlet pipe of the cold box through an air outlet pipe; the gas outlet of the cold box is communicated with the hydrogen inlet of the ammonia synthesis system through a pipeline; an air inlet valve and an air outlet valve are correspondingly arranged on the air inlet pipe and the air outlet pipe of each molecular sieve respectively; the gas outlet pipe between each gas outlet valve and the corresponding molecular sieve is connected with a nitrogen gas source through a regeneration gas inlet pipe; each regeneration air inlet pipe is provided with a regeneration air inlet valve; the air inlet pipe between each air inlet valve and the corresponding molecular sieve is connected with the torch air inlet pipe through a regeneration exhaust pipe; each regeneration exhaust pipe is provided with a regeneration exhaust valve; the device is characterized in that a torch air inlet switching valve is arranged on the torch air inlet pipe; the flare gas inlet pipe between the regeneration exhaust valve and the flare gas inlet switching valve is communicated with the gas inlet of the liquid seal tank through a pipeline; and a regeneration exhaust switching valve is arranged on a pipeline between the torch air inlet pipe and the air inlet of the liquid seal tank.

2. The liquid ammonia production system of claim 1, wherein the gas inlet valve, the gas outlet valve, the regeneration gas inlet valve, the regeneration exhaust valve, the torch gas inlet switching valve and the regeneration exhaust switching valve are all shut-off valves.

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