A method for purifying and decolorizing liquid ammonia product

Abstract

The present invention discloses a method for purifying and decolorizing a liquid ammonia product, comprising the following steps: S1, transporting sulfur-containing wastewater discharged from an oil refinery to a sulfur-containing wastewater pressure stripping unit for treatment via a feedstock pump; S2, extracting condensed crude ammonia gas from the sulfur-containing wastewater pressure stripping unit and introducing it into a gas-liquid mixer; S3, injecting a decolorizing agent into the gas-liquid mixer, and separating the mixed material after injection of the decolorizing agent into a gas-liquid separator. The separated liquid phase is transported via a pipeline to the feedstock pump inlet, and the separated gas phase is transported via a pipeline to an ammonia refining tower; S4, the gas phase separated by the gas-liquid separator is circulated and washed with ammonia water within a temperature range of -10-0°C in the ammonia refining tower. The method of the present invention can solve the problem of reddish color and low purity of the liquid ammonia product produced by the sulfur-containing wastewater pressure stripping unit in oil refineries, thereby obtaining a high-purity, colorless liquid ammonia product that meets national standards.

Description

Technical Field

[0001] The present invention relates to the technical field of liquid ammonia refining, and in particular to a method for purifying and decolorizing a liquid ammonia product. Background Art

[0002] The refinery's sulfur-containing wastewater pressurized stripping unit treats sulfur-containing wastewater discharged from the refinery, recovering nitrogen resources. Crude ammonia is extracted from the center of the stripping tower via pressurized side-stream stripping. After cooling and dehydration, high-purity enriched ammonia is obtained. Sulfur-containing wastewater contains impurities such as hydrogen sulfide, ammonia, phenol, cyanide, and hydrocarbons. After stripping, a small amount of impurities remains in the stripping tower along with the crude ammonia and enters the liquid ammonia product. This results in a reddish color and low purity of the liquid ammonia, impacting the product's quality and making it difficult to meet the quality standards for anhydrous liquid ammonia. Summary of the Invention

[0003] In order to solve the problems of the prior art, the present invention provides a system and method for decolorizing and purifying a liquid ammonia product using a pressurized stripping device for sulfur-containing wastewater, which solves the problem of red color and low purity of the liquid ammonia product produced by a pressurized stripping device for sulfur-containing wastewater in refineries, and obtains high-purity colorless liquid ammonia that meets national standards.

[0004] A method for purifying and decolorizing a liquid ammonia product comprises the following steps:

[0005] S1. The sulfur-containing wastewater discharged from the oil refining unit is transported to the sulfur-containing wastewater pressure stripping unit for treatment through the raw material pump;

[0006] S2, the sulfur-containing wastewater pressure stripping device extracts the condensed crude ammonia gas into the gas-liquid mixer;

[0007] S3, injecting decolorant into the gas-liquid mixer, the mixed material after injection of the decolorant enters the gas-liquid separator for separation, the separated liquid phase is transported to the raw material pump inlet through a pipeline, and the separated gas phase is transported to the ammonia refining tower through a pipeline;

[0008] S4. The gas phase after gas phase separation in the gas-liquid separator is washed and purified with ammonia water in a cycle within the temperature range of -10-0℃ in the ammonia refining tower.

[0009] Preferably, the sulfur-containing wastewater pressure stripping device is a stripping tower with a central extraction outlet.

[0010] Preferably, the decolorizing agent is an alkaline solution.

[0011] A method for purifying and decolorizing a liquid ammonia product, using a pressurized steam stripping device to purify and decolorize the system, which includes a raw material feed pipe, a raw material pump, a sulfur-containing wastewater pressurized steam stripping device, a gas-liquid mixer, a gas-liquid separator, an ammonia refining tower, and a gas pipeline arranged in sequence;

[0012] The outlet end of the raw material feed pipe is connected to the raw material pump, the outlet of the raw material pump is connected to the sulfur-containing wastewater pressurized stripping device through a pipeline, the side line gas outlet of the sulfur-containing wastewater pressurized stripping device is connected to the gas-liquid mixer through a pipeline, the gas-liquid mixer is also connected to a decolorant pipeline, the outlet of the gas-liquid mixer is connected to the gas-liquid separator through a pipeline, the liquid phase outlet of the gas-liquid separator is connected to the raw material feed pipe through a liquid phase pipeline, the gas phase outlet of the gas-liquid separator is connected to the ammonia refining tower through a pipeline, a circulation pump and a circulation pipeline are provided next to the ammonia refining tower to circulate and wash the inside of the ammonia refining tower, and the top of the ammonia refining tower is connected to a gas pipeline for outputting the high-purity gas therein.

[0013] Preferably, the high-purity gas after the circulation wash is transported to the subsequent process through the gas pipeline.

[0014] Preferably, the circulation pump is a centrifugal pump.

[0015] Advantages of the present invention: The method of the present invention can solve the problem of red color and low purity of the liquid ammonia product of the sulfur-containing wastewater pressure stripping device in the refinery, and obtain a high-purity colorless liquid ammonia product that meets national standards. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a schematic diagram of the structure of the pressure stripping device purification and decolorization system. DETAILED DESCRIPTION

[0017] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations.

[0018] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention as claimed, but rather merely represents selected embodiments of the present invention. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort are intended to fall within the scope of protection of the present invention.

[0019] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings.

[0020] In the description of the embodiments of the present invention, it should be noted that if the terms "upper," "lower," "inner," "outer," etc. appear, the orientation or positional relationship indicated is based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of the invention is usually placed when in use. These terms are only used to facilitate the description of the present invention and simplify the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, they should not be understood as limitations on the present invention. In addition, if the terms "first," "second," etc. appear in the description of the present invention, they are only used to distinguish the description and should not be understood as indicating or implying relative importance.

[0021] In the description of the embodiments of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "disposed" and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; mechanical connections, electrical connections; direct connections, indirect connections through an intermediate medium, and internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention in specific circumstances.

[0022] <Example 1>

[0023] As shown in the accompanying drawings, a method for purifying and decolorizing a liquid ammonia product adopts a sulfur-containing wastewater pressure stripping device to purify and decolorize the system, which includes a raw material feed pipe 1, a raw material pump 3, a sulfur-containing wastewater pressure stripping device 4, a gas-liquid mixer 5, a gas-liquid separator 7, an ammonia refining tower 8, and a gas pipeline 10 arranged in sequence;

[0024] The outlet end of the raw material feed pipe 1 is connected to the raw material pump 3, the outlet of the raw material pump 3 is connected to the sulfur-containing wastewater pressurized stripping device 4 through a pipeline, the side line gas outlet of the sulfur-containing wastewater pressurized stripping device 4 is connected to the gas-liquid mixer 5 through a pipeline, the gas-liquid mixer 5 is also connected to the decolorant pipeline 6, the outlet of the gas-liquid mixer 5 is connected to the gas-liquid separator 7 through a pipeline, the liquid phase outlet of the gas-liquid separator 7 is connected to the raw material feed pipe 1 through the liquid phase pipeline 2, the gas phase outlet of the gas-liquid separator 7 is connected to the ammonia refining tower 8 through a pipeline, a circulation pump 9 and a circulation pipeline are provided next to the ammonia refining tower 8 to circulate and wash the ammonia refining tower 8, and the top of the ammonia refining tower 8 is connected to a gas pipeline 10 for outputting the high-purity gas therein.

[0025] The high-purity gas after the circulation wash is transported to the subsequent process through the gas pipeline 10, and the circulation pump 9 is a centrifugal pump.

[0026] The sulfur-containing wastewater from the raw material feed pipe 1 enters the sulfur-containing wastewater pressurized stripping device 4 for treatment through the raw material pump 3, and the gas extracted from the side line enters the gas-liquid mixer 5, and after mixing with the decolorizer, enters the gas-liquid separator 7 together. The liquid phase of the gas-liquid separator 7 enters the raw material feed pipe 1 through the liquid phase pipeline 2 and is mixed with the raw material. The gas phase at the top of the gas-liquid separator 7 enters the ammonia refining tower 8. A circulation pipeline is set at the bottom of the ammonia refining tower 8, and the gas phase is circulated and washed by the circulation pump 9. The high-purity gas after washing is transported to the subsequent process through the gas pipeline 10.

[0027] <Example 2>

[0028] A method for purifying and decolorizing a liquid ammonia product comprises the following steps:

[0029] S1. The sulfur-containing wastewater discharged from the oil refining unit is transported to the sulfur-containing wastewater pressure stripping unit for treatment through the raw material pump;

[0030] S2, the sulfur-containing wastewater pressure stripping device extracts the condensed crude ammonia gas into the gas-liquid mixer;

[0031] S3, injecting decolorant into the gas-liquid mixer, the mixed material after injection of the decolorant enters the gas-liquid separator for separation, the separated liquid phase is transported to the raw material pump inlet through a pipeline, and the separated gas phase is transported to the ammonia refining tower through a pipeline;

[0032] S4. The gas phase after gas phase separation in the gas-liquid separator is washed and purified with ammonia water in a cycle within the temperature range of -10-0℃ in the ammonia refining tower.

[0033] The sulfur-containing wastewater pressure stripping device is a stripping tower with a central extraction outlet.

[0034] The decolorizing agent is an alkaline solution.

[0035] The above implementation cases are only for illustrating the technical solutions and features of the present invention, and their purpose is to enable people familiar with the technology to implement them better. They cannot be used to limit the scope of protection of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention are within the scope of protection of the present invention. The ones not described in detail are prior art.

Claims

1. A method for purifying and decolorizing a liquid ammonia product, characterized in that It includes the following steps: S1. The sulfur-containing wastewater discharged from the oil refining unit is transported to the sulfur-containing wastewater pressure stripping unit for treatment through the raw material pump; S2, the sulfur-containing wastewater pressure stripping device extracts the condensed crude ammonia gas into the gas-liquid mixer; S3, injecting decolorant into the gas-liquid mixer, the mixed material after injection of the decolorant enters the gas-liquid separator for separation, the separated liquid phase is transported to the raw material pump inlet through a pipeline, and the separated gas phase is transported to the ammonia refining tower through a pipeline; S4. The gas phase after gas phase separation in the gas-liquid separator is circulated and washed with ammonia water in the ammonia refining tower within the temperature range of -10-0°C; the sulfur-containing wastewater pressurized stripping device is a stripping tower with a central extraction port; the decolorizing agent is an alkaline solution.

2. The method for purifying and decolorizing a liquid ammonia product according to claim 1, characterized in that: A pressure stripping device is used for purification and decolorization, which comprises a raw material feed pipe (1), a raw material pump (3), a sulfur-containing wastewater pressure stripping device (4), a gas-liquid mixer (5), a gas-liquid separator (7), an ammonia refining tower (8) and a gas pipeline (10) which are arranged in sequence; The outlet end of the raw material feed pipe (1) is connected to a raw material pump (3), the outlet of the raw material pump (3) is connected to a sulfur-containing wastewater pressurized stripping device (4) through a pipeline, the side gas outlet of the sulfur-containing wastewater pressurized stripping device (4) is connected to a gas-liquid mixer (5) through a pipeline, the gas-liquid mixer (5) is also connected to a decolorant pipeline (6), the outlet of the gas-liquid mixer (5) is connected to a gas-liquid separator (7) through a pipeline, the liquid phase outlet of the gas-liquid separator (7) is connected to the raw material feed pipe (1) through a liquid phase pipeline (2), the gas phase outlet of the gas-liquid separator (7) is connected to an ammonia refining tower (8) through a pipeline, a circulating pump (9) and a circulating pipeline are provided next to the ammonia refining tower (8) to circulate and wash the inside of the ammonia refining tower (8), and the top of the ammonia refining tower (8) is connected to a gas pipeline (10) for outputting the high-purity gas therein.

3. The method for purifying and decolorizing a liquid ammonia product according to claim 2, characterized in that The high-purity gas after the circulation wash is transported to the subsequent process via the gas pipeline (10).

4. The method for purifying and decolorizing a liquid ammonia product according to claim 2, characterized in that The circulating pump (9) is a centrifugal pump.

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