A process device for coupling the incineration of ammonia-containing waste gas and waste liquid from coal-to-ethylene glycol production.

Abstract

This utility model relates to the field of coal-to-ethylene glycol waste gas and waste liquid incineration technology, specifically to a process device coupling the incineration of ammonia-containing waste gas and waste liquid in coal-to-ethylene glycol. This utility model, by setting an ammonia-containing waste gas combustion port on the waste gas and waste liquid incinerator in the coal-to-ethylene glycol process, incinerates the ammonia-containing waste gas generated from the coal-water slurry gasification to ethylene glycol process. The ammonia in the ammonia-containing waste gas acts as a denitrification reducing agent, replacing traditional urea or purchased ammonia water. The combustible components are burned to generate heat, which is recovered as steam, reducing operating costs. Simultaneously, it co-treats nitrogen oxides, sulfur oxides, and odorous substances, eliminating the pollution risk of direct discharge of waste gas.

Description

Technical Field

[0001] This utility model relates to the field of coal-to-ethylene glycol waste gas and waste liquid incineration technology, specifically to a process device for coupling the incineration of ammonia-containing waste gas and waste gas and waste liquid from coal-to-ethylene glycol production. Background Technology

[0002] Under high temperature and pressure, coal-water slurry reacts with oxygen to produce crude syngas (containing CO, H2, CO2, H2S, etc.). Nitrogen in the coal is mainly converted into NH3 and HCN (hydrogen cyanide). Subsequent processes generate ammonia-containing waste gases, which are wasted through flare incineration. Based on the process flow, the following three processes will generate ammonia-containing waste gases: Gasification section: (1) Crude syngas scrubbing tower: The crude syngas is cooled and dust removed (coal dust and ash) by the scrubbing tower. Some NH3 dissolves in the scrubbing water (ash water), but the undissolved NH3 enters the next section with the purified crude syngas. At the same time, the venting gas at the top of the scrubbing tower (gas discharged to balance the pressure) will directly carry out NH3, forming ammonia-containing waste gas. (2) Black water flash evaporation system: The black water (containing ash, dissolved NH3, CO2, etc.) produced by gasification enters the flash tank for depressurized flash evaporation, releasing flash vapor (containing NH3, CO2, H2S, etc.). This part of the gas is an important source of ammonia-containing waste gas.

[0003] Shift section: The shift section uses a catalyst (such as iron-based or copper-based) to react CO and H2O in the crude synthesis gas to produce CO2 and H2 (CO + H2O → CO2 + H2). The NH3 carried in the raw gas does not participate in the main reaction, but will be enriched or released in the system. (1) Shift furnace outlet separator: The gas after the shift reaction (containing unreacted NH3, CO2, H2S, etc.) is separated by the separator to remove condensate. The uncondensed NH3 enters the subsequent purification section with the shift gas; the purge gas at the top of the separator (used for pressure balance) will directly discharge ammonia-containing gas. (2) Condensate flash tank: The condensate (containing dissolved NH3, NH4) generated by the shift system is used to evaporate the gas from the shift system. + (etc.) are introduced into a flash tank for depressurized flash evaporation, releasing flash vapor containing NH3, which needs to be collected and treated.

[0004] Purification section: The core of the purification section is to remove impurities such as H2S and CO2 from the synthesis gas (e.g., low-temperature methanol washing). NH3 in the raw material gas will be absorbed by the methanol solvent and released with the impurity gas during regeneration. (1) Low-temperature methanol washing tower: Methanol absorbs H2S, CO2 and NH3 at low temperature. The tail gas of the absorption tower (trace amount of unabsorbed gas) contains a small amount of NH3. (2) Methanol regeneration tower: The methanol solvent that has absorbed the impurities is heated / reduced in the regeneration tower to release acidic gas (H2S, CO2). At the same time, the absorbed NH3 will escape with the acidic gas to form ammonia-containing waste gas. Utility Model Content

[0005] The purpose of this utility model is to provide a process device that couples the combustion of ammonia-containing waste gas from coal-to-ethylene glycol production with the incineration of waste gas and waste liquid, so as to recover and utilize the ammonia-containing waste gas described in the background art, thereby enabling the ammonia-containing waste gas to be utilized as a resource.

[0006] To achieve the above objectives, this utility model provides the following technical solution: A process apparatus for coupling the incineration of ammonia-containing waste gas and waste liquid in coal-to-ethylene glycol production includes an ammonia-containing waste gas collection unit, a pretreatment unit, an incinerator unit, and a desulfurization unit. The incinerator unit includes an incinerator body, a high-temperature superheater, a selective catalytic reduction unit, a medium-temperature superheater, a low-temperature superheater, a preheating boiler unit, and an air preheating unit connected in sequence. The incinerator body is provided with waste gas and waste liquid combustion ports for the combustion of waste gas and waste liquid in the coal-to-ethylene glycol process.

[0007] Ammonia-containing waste gas collection unit: It is connected to ammonia-containing waste gas sources through pipelines with flow regulating valves. The delivery volume of each pipeline can be adjusted according to the waste gas concentration to ensure a stable total amount of ammonia entering the incinerator.

[0008] Pretreatment unit: It is equipped with a liquid separator, demister, particulate filter, buffer tank and pressure stabilizing tank connected in sequence to remove impurities such as water mist and coal dust from the exhaust gas and prevent clogging of subsequent equipment.

[0009] Incinerator body: The incinerator is also equipped with an ammonia-containing waste gas combustion port connected to the output end of the pretreatment unit to receive the pretreated ammonia-containing waste gas. The combustible components (such as H2 and CO) in the ammonia-containing waste gas are used as auxiliary fuel to reduce external fuel consumption. High-temperature combustion (850℃~1100℃) can decompose toxic substances such as HCN.

[0010] Selective non-catalytic reduction method: Utilizing NH3 in ammonia-containing waste gas as a reducing agent, it reacts with NO produced during incineration at high temperature. X A selective non-catalytic reduction reaction occurs (4NH3+4NO+O2→4N2+6H2O), removing some nitrogen oxides.

[0011] Desulfurization unit: The desulfurization unit is located after the air preheating unit and uses the ammonia method or limestone-gypsum method to remove SO2 from the flue gas, ensuring that the SO2 concentration in the emitted flue gas is ≤35mg / m³. 3 . Furthermore, the ammonia-containing waste gas source includes a syngas scrubbing tower in the gasification section, a black water flash evaporation system, a converter outlet separator, a converter condensate flash evaporation tank, a methanol regeneration tower, and an absorption tower tail gas outlet.

[0012] Furthermore, the buffer tank and the pressure stabilizing tank are equipped with an online ammonia concentration detector to detect the concentration of ammonia in the ammonia-containing waste gas; the buffer tank is also connected to a nitrogen pipeline, and when the ammonia concentration is higher than 5%, nitrogen is introduced to dilute the ammonia and control the concentration of ammonia in the ammonia-containing waste gas to be less than or equal to 5%.

[0013] Compared with the prior art, the beneficial effects of this utility model are: Resource utilization: Ammonia in the ammonia-containing waste gas generated from the coal-water slurry gasification to ethylene glycol process is used as a denitrification reducing agent to replace traditional urea or purchased ammonia water. The combustible components are burned to generate heat and recover steam, which reduces operating costs.

[0014] Environmental compliance: It co-processes nitrogen oxides, sulfur oxides and odorous substances, and the emission indicators meet national standards, eliminating the pollution risk of direct discharge of waste gas.

[0015] System integration: The integrated design of waste gas collection, pretreatment, incineration, denitrification, desulfurization and energy recovery simplifies the process flow. Attached image description:

[0016] Figure 1 This is a schematic diagram of the structure of this utility model; In the diagram: 1-demister; 2-particulate filter; 3-liquid separator; 4-buffer tank; 5-pressure stabilizer; 6-incinerator unit. Detailed Implementation Example 1

[0017] refer to Figure 1 To enable the resource utilization of ammonia-containing waste gas generated in the coal-water slurry to ethylene glycol process, this utility model provides a process device coupling the combustion of ammonia-containing waste gas and waste liquid in coal-to-ethylene glycol production. The device includes an ammonia-containing waste gas collection unit, a pretreatment unit, an incinerator unit, and a desulfurization unit. The incinerator unit comprises, in sequence, an incinerator body, a high-temperature superheater, a selective catalytic reduction unit, a medium-temperature superheater, a low-temperature superheater, a preheating boiler unit, and an air preheating unit. The incinerator body is equipped with waste gas and waste liquid combustion ports for the combustion of waste gas and waste liquid in the coal-to-ethylene glycol process. Multiple pipelines of the waste gas collection unit are respectively connected to the syngas scrubbing tower of the coal-water slurry gasification section, the black water flash evaporation system, the converter outlet separator, the converter condensate flash evaporation tank, the methanol regeneration tower, and the absorber tail gas outlet. Flow regulating valves on each pipeline adjust the delivery volume according to the ammonia concentration in the waste gas (detected in real-time by an online monitoring instrument) to stabilize the ammonia volume fraction in the mixed waste gas at 5% or below.

[0018] The pretreatment unit is equipped with a liquid separator 1, a demister 2, a particulate filter 3, a buffer tank 4, and a pressure stabilizing tank 5 connected in sequence. When ammonia-containing waste gas enters the pretreatment unit, it first separates the liquid water in the liquid separator, and then passes through the demister 1 and the particulate filter to remove particles with a diameter ≥10μm, removing impurities such as water mist and coal dust from the waste gas to avoid clogging of subsequent equipment. Then it enters the buffer tank 4 and the pressure stabilizing tank 5. The pretreated ammonia-containing waste gas is sent to the main body of the incinerator of the incinerator unit 6.

[0019] The incinerator body is equipped with exhaust gas and waste liquid combustion ports for the combustion of exhaust gas and waste liquid from the coal-to-ethylene glycol process. The combustion chamber temperature is controlled at 850℃~1100℃. The combustion of exhaust gas and waste liquid generates heat. At the same time, ammonia-containing exhaust gas is also sent to the incinerator for combustion. The combustible components (such as H2 and CO) in the ammonia-containing exhaust gas release heat through combustion. The auxiliary fuel inlet only supplements a small amount of natural gas when the calorific value of the exhaust gas is insufficient. The ammonia in the ammonia-containing exhaust gas undergoes a selective non-catalytic reduction reaction with the nitrogen oxides produced by combustion at high temperature, converting some of the nitrogen oxides into nitrogen. The remaining unconverted nitrogen oxides enter the subsequent selective catalytic reduction unit (SCR unit), where they react with the ammonia produced by ammonia water (the ammonia amount is supplemented and adjusted through an ammonia injection grid) under the action of a catalyst layer to remove the remaining nitrogen oxides. The denitrified flue gas enters the desulfurization unit, where SO2 is removed from the flue gas using the ammonia method or the limestone-gypsum method, ensuring that the SO2 in the emitted flue gas meets emission standards.

[0020] In the incinerator unit, the waste gas, waste liquid, and ammonia-containing waste gas generated in the coal-to-ethylene glycol process are burned in the incinerator to produce high-temperature flue gas. This flue gas then flows sequentially through a high-temperature superheater, a medium-temperature superheater, a low-temperature superheater, a preheating boiler unit, and an air preheating unit to recover heat from the flue gas and produce steam and preheated air. The cooled flue gas then enters the desulfurization unit, where SO2 is removed before being discharged through a chimney. The NO in the emitted flue gas is also removed. X ≤50mg / m 3 SO2 ≤ 35 mg / m³ 3 It meets national emission standards.

[0021] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A process apparatus for coupling the incineration of ammonia-containing waste gas from coal-to-ethylene glycol production with waste gas and waste liquid, characterized in that: The system includes an ammonia-containing waste gas collection unit, a pretreatment unit, an incinerator, and a desulfurization unit. The incinerator includes, in sequence, an incinerator body, a high-temperature superheater, a selective catalytic reduction unit, a medium-temperature superheater, a low-temperature superheater, a preheating boiler, and an air preheating unit. The incinerator body is equipped with waste gas and waste liquid combustion ports for combustion of waste gas and waste liquid in the coal-to-ethylene glycol process. The ammonia-containing waste gas collection unit is connected to an ammonia-containing waste gas source via pipelines with flow regulating valves. The pretreatment unit is equipped with, in sequence, a separator, a demister, a particulate filter, a buffer tank, and a pressure stabilizing tank. The incinerator body is also equipped with an ammonia-containing waste gas combustion port connected to the output end of the pretreatment unit. The desulfurization unit is located after the air preheating unit.

2. The process device of claim 1, wherein the process device is characterized in that: The ammonia-containing waste gas sources include the syngas scrubbing tower of the gasification section, the black water flash evaporation system, the converter outlet separator, the converter condensate flash evaporation tank, the methanol regeneration tower, and the absorber tail gas outlet.

3. The process device of claim 1, wherein the process device is characterized in that: The buffer tank and the pressure stabilizing tank are equipped with online ammonia concentration detectors; the buffer tank is also connected to a nitrogen pipeline.

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