CN-117663123-B - Ammonia gas low-nitrogen submerged combustion equipment and method

CN117663123BCN 117663123 BCN117663123 BCN 117663123BCN-117663123-B

Abstract

The invention discloses ammonia gas low-nitrogen submerged combustion equipment and a method. The submerged combustion equipment comprises a heating pool, an ammonia gas burner, a flue and a heat exchange tube bundle, wherein liquid is filled in the heating pool, the flue and the heat exchange tube bundle are submerged below the liquid level, the combustion equipment further comprises an ammonia gas regeneration tank, the middle lower part of the ammonia gas regeneration tank is located below the liquid level in the heating pool, the upper end of the ammonia gas regeneration tank stretches out of the top of the heating pool, two spraying facilities are arranged on the side wall of the ammonia gas regeneration tank, the spraying facility I at the upper end is used for introducing and spraying liquid higher than a liquid inlet into the ammonia gas regeneration tank, the spraying facility II at the lower end is connected with a liquid outlet of an aeration mixed liquid pump, and the ammonia gas burner is used for burning under an oxygen-deficient working condition. The low-nitrogen submerged combustion equipment can realize high-efficiency low-nitrogen combustion, and simplify the necessary denitration equipment of the traditional combustion system.

Inventors

ZENG XIANGYU
JIN PING
LIAO CHANGJIAN
LIU ZHIYU
MENG FANFEI

Assignees

中国石油化工股份有限公司
中石化（大连）石油化工研究院有限公司

Dates

Publication Date: 20260505
Application Date: 20220830

Claims (12)

1. The ammonia low-nitrogen submerged combustion equipment comprises a heating pool, an ammonia burner, a flue and a heat exchange tube bundle, wherein liquid is filled in the heating pool, the flue and the heat exchange tube bundle are submerged below the liquid level, and the equipment is characterized by further comprising an ammonia regeneration tank and an aeration mixed liquid pump, The upper end of the ammonia gas regeneration tank is provided with a gas injection device for injecting and taking out the regenerated gas at the top end of the ammonia gas regeneration tank; The side wall of the ammonia gas regeneration tank is provided with two spraying facilities, the spraying facility I at the upper end is used for introducing and spraying liquid higher than the liquid inlet into the ammonia gas regeneration tank, and the spraying facility II at the lower end is connected with the liquid outlet of the aeration mixed liquid pump; the bottom end of the ammonia gas regeneration tank is arranged at the tail end of the flue, and the waste heat of the flue gas is utilized to heat the liquid at the bottom of the ammonia gas regeneration tank, so that gas-liquid separation is realized; The downstream outlet of the ammonia gas burner is communicated with a flue, and a flue wall of the flue is provided with a flue gas distributor for discharging the burnt gas into the liquid of the heating pool; The gas phase inlet of the aeration mixed liquid pump is positioned at the outer end of a hollow transmission shaft of the mixed liquid pump and is communicated with a smoke exhaust pipe at the upper part of the heating tank; the ammonia solution is separated and regenerated after being heated at the bottom of the ammonia regeneration tank, and the regenerated ammonia is sucked by the combustion-supporting air flow through the gas injection device at the top end of the ammonia regeneration tank and returns to the burner along with the combustion-supporting air flow for repeated combustion.
2. The ammonia low nitrogen submerged combustion apparatus of claim 1, wherein the ammonia regeneration tank has a drain port at the bottom and is connected to a liquid pump for draining liquid at the bottom of the ammonia regeneration tank and directing it back to the heating tank or for draining.
3. The ammonia gas low-nitrogen submerged combustion equipment according to claim 1 is characterized in that the aeration mixed liquid pump comprises a shell, a motor, a transmission shaft, a cam disc, a telescopic rod and a spring one-way valve, wherein a partition blocking body is arranged in the shell, the upper stream of the partition blocking body is an aeration mixed area, the lower stream of the partition blocking body is a liquid outlet area, a cylindrical groove is formed in the center of the partition blocking body and is used for fixing the transmission shaft, a plurality of channels are formed in the position, corresponding to the telescopic rod, of the partition blocking body and are used for fixing the telescopic rod, a closed cavity is formed by the telescopic rod and a hollow structure in the telescopic rod together, one end of the telescopic rod is in non-fixed contact with the cam disc, the other end of the telescopic rod is connected with the spring one-way valve, a reverse spring one-way valve is arranged at each liquid outlet of the spring one-way valve and is used for liquid check, a through hole is formed in the part, located in the shell, a liquid inlet is formed in the middle section of the telescopic rod, and the right side of the telescopic rod is of a hollow structure.
4. An ammonia low nitrogen submerged combustion apparatus according to claim 3 wherein the motor is located outside the housing and is fixedly connected to a cam disc located inside the housing by a drive shaft.
5. The ammonia gas low-nitrogen submerged combustion device of claim 1, wherein the heating tank is of a closed structure, and an upper cover is arranged at the upper end of the heating tank.
6. An ammonia low nitrogen submerged combustion apparatus according to claim 1 wherein the inlet and outlet of the heat exchange tube bundle are a liquefied natural gas inlet and a natural gas outlet, respectively.
7. The ammonia gas low-nitrogen submerged combustion apparatus of claim 1, wherein the ammonia gas burner comprises a burner outer shell and a burner nozzle sleeved on the inner layer, wherein the top end of the burner outer shell is connected with a fuel ammonia gas pipeline; The burner nozzle is provided with an inner layer structure and an outer layer structure, wherein the inner layer is provided with a thermal storage catalytic cracking body around a vertical axis, the thermal storage catalytic cracking body is of an inverted round platform structure which gradually contracts from a top end inlet to a middle section, a middle section is of a cylindrical structure to a bottom end outlet, the burner nozzle is internally provided with an outer layer structure around the inner layer thermal storage catalytic cracking body, the upper half part of the outer layer structure is of the cylindrical structure, the middle section is gradually contracted from the middle section to the bottom end outlet, and the side surface of the outer layer of the nozzle is provided with a combustion-supporting air inlet and is communicated with a combustion-supporting air pipe line.
8. The ammonia gas low-nitrogen submerged combustion device of claim 7, wherein the thermal storage catalytic cracking body is filled by uniformly mixing ceramic thermal storage balls and an ammonia gas cracking catalyst, and the periphery of the thermal storage catalytic cracking body is wrapped by a metal fiber net.
9. The ammonia low nitrogen submerged combustion apparatus of claim 7, wherein a flue gas recirculation path is provided between the inside of the outer housing of the burner and the outside of the burner nozzle for recirculating high temperature flue gas to the burner nozzle for heating the regenerative catalytic cracking.
10. An ammonia low nitrogen submerged combustion method, wherein the ammonia low nitrogen submerged combustion apparatus according to any one of claims 1 to 9 is applied.
11. The ammonia low nitrogen submerged combustion method of claim 10, characterized by comprising the following: (1) The ammonia gas burner continuously burns in an oxygen-deficient state, high-temperature flue gas generated by combustion forms a reflux zone in a flaring section, part of the high-temperature flue gas flows into a heat accumulating catalytic cracking body through a flue gas reflux channel to heat an internal heat accumulator, and the ammonia gas cracking catalyst cracks part of the passing ammonia gas into nitrogen and hydrogen; (2) The high-temperature flue gas generated by the combustion in the step (1) is discharged into a heating pool through a flue gas distributor, and most of the heat of the flue gas heats substances in a heat exchange tube bundle; (3) Part of the excessive unburned ammonia reduces NOx generated by combustion into N 2 in the flow process of a high-temperature flue, and part of the unreacted ammonia is dissolved in water in the heating tank, and the other part of the unreacted ammonia exists at the upper end of the heating tank in a gas phase form; (4) The liquid and the gas in the heating pool are respectively input into an aeration mixed liquid pump through a liquid outlet pipe and a smoke exhaust pipe and are fully mixed in the liquid pump, and nitrogen is discharged through a pressure relief opening; (5) Ammonia solution respectively from the heating tank and the aeration mixed liquid pump is injected into the ammonia regeneration tank through a side inlet of the ammonia regeneration tank, the ammonia solution is separated and regenerated after being heated at the bottom of the ammonia regeneration tank, and the regenerated ammonia is sucked by a combustion-supporting air flow through an ejector at the top end of the ammonia regeneration tank and returns to the combustor along with the combustion-supporting air flow for repeated combustion.
12. The ammonia gas low nitrogen submerged combustion method of claim 11, wherein the ammonia gas burner has an equivalence ratio of 1.05-1.2.

Description

Ammonia gas low-nitrogen submerged combustion equipment and method Technical Field The invention belongs to the technical field of heat energy engineering, and particularly relates to ammonia low-nitrogen submerged combustion equipment and method. Background The demand for energy saving, emission reduction and carbon reduction technologies is urgent in industrial production, and the adoption of novel environment-friendly fuel to replace the traditional fossil raw materials is one important measure. Ammonia energy is recognized as a 2.0 version of hydrogen energy, not only inherits excellent characteristics of hydrogen energy in terms of environmental protection property and high heat value, but also can be liquefied at-33 ℃ or at normal temperature of 7-8 atmospheres in the aspect of energy storage and transportation, and breaks through the difficulty that hydrogen energy is difficult to store and transport, so that ammonia can be regarded as a novel energy with the current most application potential. In terms of combustion technology, submerged combustion technology is widely focused due to its extremely high combustion efficiency, and has found some typical applications in the fields of LNG gasification and "three-waste" treatment. For example, patent CN 108178214A discloses a two-stage submerged combustion evaporation integrated treatment method for organic waste liquid, and the patent divides an evaporation tank into two evaporation chambers, thereby realizing two-stage staged submerged combustion evaporation. The method can improve the evaporation concentration efficiency, save energy and simplify equipment and treatment flow. However, although the submerged combustion technology has higher combustion efficiency and lower temperature of generated flue gas, the difficulty in removing nitrogen oxides in low-temperature flue gas is higher, and even if a denitration catalyst is adopted for assisting in removing NOx, the temperature requirement cannot be met. For example, patent CN112963857a discloses an ultralow NOx emission submerged combustion gasification system and a tail gas denitration waste heat recovery process, the patent contains a hot blast stove, the heat required by flue gas denitration is generated by a burner arranged in the hot blast stove, and the flue gas is finally discharged after denitration by liquid flow heat exchange in a water tank. Although the equipment can realize flue gas denitration, the equipment is complex and the maintenance difficulty is high. And when the submerged burner is using nitrogen as fuel, flue gas denitration will consume more additional energy due to the higher NOx concentration in the flue gas. Disclosure of Invention Aiming at the problems in the prior art, the invention aims to provide ammonia gas low-nitrogen submerged combustion equipment and a combustion method. According to a first aspect of the invention, there is provided an ammonia low nitrogen submerged combustion apparatus. The ammonia low-nitrogen submerged combustion device comprises a heating pool, an ammonia burner, a flue and a heat exchange tube bundle, wherein liquid is filled in the heating pool, and the flue and the heat exchange tube bundle are submerged below the liquid level; The combustion equipment is characterized by further comprising an ammonia gas regeneration tank, wherein the middle lower part of the ammonia gas regeneration tank is positioned below the liquid level in the heating tank, and the upper end of the ammonia gas regeneration tank extends out of the top of the heating tank; The bottom end of the ammonia gas regeneration tank is positioned at the tail end of the flue, and the liquid at the bottom of the ammonia gas regeneration tank is heated by utilizing the waste heat of the flue gas, so that gas-liquid separation is realized. Further, the upper end of the ammonia gas regeneration tank is provided with a gas injection device for injecting and taking out the regenerated gas at the top end of the ammonia gas regeneration tank. The gas injection device may be of conventional construction in the art. A typical injection device comprises a nozzle and an injection throat, wherein the outlet of the nozzle extends into the injection throat. The inlet of the ejector nozzle is connected with the combustion-supporting air inlet, the outlet of the ejector throat pipe is communicated with the booster fan, and the booster fan is pressurized and then is communicated with the combustion-supporting air inlet of the ammonia combustor. Further, the bottom end of the ammonia gas regeneration tank is provided with a water outlet and is connected with a liquid pump, and the water outlet is used for discharging the liquid at the bottom end of the ammonia gas regeneration tank and leading the liquid back to the heating tank or discharging the liquid. The ammonia gas burner takes ammonia gas as fuel and burns under the condition of oxygen deficiency. The downstream outlet of the ammonia gas bu