阅读说明：本技术 一种煤化工变换低温冷凝液汽提工艺 (Steam stripping process for low-temperature condensate in coal chemical conversion ) 是由 李颖 林明丽 蔡国斌 穆荣哲 胡文生 于 2020-07-30 设计创作，主要内容包括：本发明公开一种煤化工变换低温冷凝液汽提工艺,S1：获取变换分离器分离出的低温变换冷凝液,并对变换冷凝液进行预热；S2：将预热后的变换冷凝液从中部通入汽提塔,同时将低压蒸汽从底部通入汽提塔；S3：变换冷凝液与低压蒸汽在提馏段的填料或塔盘内逆向接触汽提,提馏后的汽提气在精馏段的填料或塔盘内与塔顶冷凝回流液逆向接触,将回流液精馏；S4：精馏后的汽提气通过塔顶冷凝器冷凝,冷凝分离后的汽提气送至下游装置,分离后的回流液回流至精馏段；通过改变变换低温冷凝液进料位置,改变塔顶换热器冷却介质,优化换热器的操作温度,能够有效解决塔顶冷凝器、管道和阀门腐蚀问题以及塔顶冷凝器下部区域和酸水汽提出口气相管道铵盐结晶的问题。(The invention discloses a coal chemical conversion low-temperature condensate steam stripping process, which comprises the following steps of S1: obtaining low-temperature conversion condensate separated by the conversion separator, and preheating the conversion condensate; s2: introducing preheated conversion condensate into a stripping tower from the middle part, and simultaneously introducing low-pressure steam into the stripping tower from the bottom; s3: the conversion condensate and low-pressure steam are in reverse contact steam stripping in a packing or a tray of a stripping section, stripped steam is in reverse contact with condensed reflux liquid at the top of the tower in the packing or the tray of a rectifying section, and the reflux liquid is rectified; s4: condensing the rectified stripping gas through a tower top condenser, sending the condensed and separated stripping gas to a downstream device, and refluxing the separated reflux liquid to a rectification section; by changing the feeding position of the low-temperature condensate, the cooling medium of the tower top heat exchanger is changed, the operating temperature of the heat exchanger is optimized, and the problems of corrosion of a tower top condenser, a pipeline and a valve, and crystallization of ammonium salt in a gas phase pipeline at the lower part of the tower top condenser and an acid water stripping outlet can be effectively solved.)

1. The steam stripping process for low-temperature condensate in coal chemical transformation is characterized by comprising the following steps of: the process comprises the following steps of:

s1: obtaining low-temperature conversion condensate separated by the conversion separator, and preheating the conversion condensate;

s2: introducing preheated conversion condensate into a stripping tower from the middle part, and simultaneously introducing low-pressure steam into the stripping tower from the bottom;

s3: the conversion condensate and low-pressure steam are in reverse contact steam stripping in a packing or a tray of a stripping section, stripped steam is in reverse contact with condensed reflux liquid at the top of the tower in the packing or the tray of a rectifying section, and the reflux liquid is rectified;

s4: condensing the rectified stripping gas through a tower top condenser, sending the condensed and separated stripping gas to a downstream device, and refluxing the separated reflux liquid to a rectification section;

s5: and sending qualified stripping condensate after the stripping of the stripping tower kettle out of the stripping tower.

2. Stripping process according to claim 1, characterized in that: the cooling medium of the condenser adopts desalted water.

3. The stripping process according to claim 1, wherein in step S4, the stripping gas temperature after condensation separation is 100-120 ℃.

4. Stripping process according to claim 1, characterized in that: the stripper operating pressure is less than 0.4 MPaG.

Technical Field

The invention belongs to the technical field of coal chemical conversion sections, and particularly relates to a low-temperature condensate steam stripping process for coal chemical conversion.

Background

The function of the steam stripping of the transformation low-temperature condensate is mainly to strip the low-temperature condensate (generally the temperature is lower than 150 ℃) acid water separated by the transformation separator out the impurity ions such as NH3, H2S, CO2 and the like in the condensate acid water from the condensate by a low-pressure steam heating steam stripping mode, thereby achieving the purpose of purifying the transformation condensate. Meanwhile, the tail gas containing impurity ions such as NH3, H2S, CO2 and the like which is stripped out is sent to a downstream device for further treatment.

At present, the steam stripping for treating the conversion low-temperature condensate in China mainly comprises the following processes:

(1) single-tower open type steam stripping process

(2) Single-tower closed steam stripping process

(3) Double-tower steam stripping process

(4) Single column side stripping NH 3.

The above stripping processes each have advantages and disadvantages. But all have the problems of crystallization and blockage of ammonium salt in the gas pipeline at the acid water stripping outlet, and corrosion of equipment (a condenser, a separator and the like), pipelines and valves at the top of the stripping tower.

Disclosure of Invention

The invention provides a coal chemical industry transformation low-temperature condensate steam stripping process, which uses a unique steam stripping process, changes the cooling medium of a tower top heat exchanger and optimizes the operating temperature of the heat exchanger by changing the feeding position of the transformation low-temperature condensate, and can effectively solve the problems of corrosion of a tower top condenser, a pipeline and a valve, and crystallization of ammonium salt in a gas phase pipeline at the lower area of the tower top condenser and a steam stripping outlet of acid water.

The invention is realized in this way, a coal chemical industry transform low-temperature condensate stripping process, including the stripping tower that adopts two sections of fillers or trays, the top of the stripping tower is provided with a condenser, the upper part in the stripping tower is set as the rectifying section, the lower part in the stripping tower is set as the stripping section, the rectifying section or the stripping section is respectively provided with a filler or a tray, the process for transforming low-temperature condensate stripping includes the following steps:

s1: obtaining low-temperature conversion condensate separated by the conversion separator, and preheating the conversion condensate;

s2: introducing preheated conversion condensate into a stripping tower from the middle part, and simultaneously introducing low-pressure steam into the stripping tower from the bottom;

s3: the conversion condensate and low-pressure steam are in reverse contact steam stripping in a packing or a tray of a stripping section, stripped steam is in reverse contact with condensed reflux liquid at the top of the tower in the packing or the tray of a rectifying section, and the reflux liquid is rectified;

s4: condensing the rectified stripping gas through a tower top condenser, sending the condensed and separated stripping gas to a downstream device, and refluxing the separated reflux liquid to a rectification section;

s5: and sending qualified stripping condensate after the stripping of the stripping tower kettle out of the stripping tower.

Preferably, the condenser cooling medium is desalted water.

Preferably, in step S4, the stripping gas temperature after condensation and separation is 100 to 120 ℃.

Preferably, the stripper operating pressure is less than 0.4 MPaG.

Compared with the prior art, the invention has the beneficial effects that:

(1) compared with the traditional tower top feeding, the feeding position of the low-temperature transformation condensate entering the stripping tower is the middle upper part of the tower, and the condensate is further concentrated by the operation of the upper packing or the rectifying section of the tray, so that substances such as NH3, H2S, CO2 and the like in the exhaust gas at the tower top are further concentrated, impurity ions in the condensate are stripped more thoroughly, and the stripping effect is obviously improved.

(2) According to the invention, the cooling medium of the overhead condenser is changed from traditional circulating water to desalted water, and the operation temperature of the desalted water is much higher than that of the circulating water, so that the average wall temperature of tube pass metal of the overhead condenser can be greatly increased, and the problem of ammonium salt crystallization in the lower area of the tube pass of the overhead condenser is effectively solved; meanwhile, due to the fact that the cleanliness of desalted water is higher than that of circulating water, the cleaning frequency of the tower top condenser is reduced, and the maintenance burden of a factory on equipment can be reduced.

(3) The temperature of the gas at the outlet of the tower top is controlled to be 100-120 ℃, and the problem that the pipeline is blocked by ammonium salt crystals due to low temperature of a gas conveying pipeline at the outlet of the tower top can be effectively solved under the condition that the gas discharge amount at the tower top is not remarkably increased.

Drawings

FIG. 1 is a schematic view of the structure of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

In the description of the present invention, it is to be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like, indicate orientations or positional relationships based on the orientations or positional relationships illustrated in the drawings, and are used merely for convenience in describing the present invention and for simplicity in description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed in a particular orientation, and be operated, and thus, are not to be construed as limiting the present invention. Further, in the description of the present invention, "a plurality" means two or more unless specifically defined otherwise.

Referring to fig. 1, the present invention provides a technical solution:

the utility model provides a coal chemical industry transform low temperature condensate strip technology, includes the strip tower that adopts two sections packings or tower tray, the strip tower top is provided with the condenser, and upper portion sets up to the rectifying section in the strip tower, and the lower part sets up to the stripping section in the strip tower, rectifying section or stripping section are provided with packings or tower tray respectively, and the technology of changing the strip of low temperature condensate includes following step:

s1: obtaining low-temperature conversion condensate separated by the conversion separator, and preheating the conversion condensate;

s2: introducing preheated conversion condensate into a stripping tower from the middle part, and simultaneously introducing low-pressure steam into the stripping tower from the bottom;

s3: the conversion condensate and low-pressure steam are in reverse contact steam stripping in a packing or a tray of a stripping section, stripped steam is in reverse contact with condensed reflux liquid at the top of the tower in the packing or the tray of a rectifying section, and the reflux liquid is rectified;

s4: condensing the rectified stripping gas through a tower top condenser, sending the condensed and separated stripping gas to a downstream device, and refluxing the separated reflux liquid to a rectification section;

s5: and sending qualified stripping condensate after the stripping of the stripping tower kettle out of the stripping tower.

The invention adopts a single stripping tower process, the low-temperature conversion condensate liquid is heated and then enters the middle part of the tower, and the bottom of the tower is heated and stripped by low-pressure steam. Tail gas containing NH3, H2S, CO2 and the like generated at the top is cooled and separated by a vertical condenser at the top of the tower, and the tail gas at the top of the tower is sent to a downstream device for further treatment; because the tower top condenser adopts a vertical structure, condensed condensate can naturally flow back into the stripping tower. The overhead condenser of the process is vertical and is arranged at the top of the stripping tower, so that a reflux pipeline, a valve and a reflux pump at the top of the stripping tower can be saved, the investment and the operating cost of the device can be reduced, and the corrosion problem of the pipeline, the valve and the reflux pump of a reflux system can be effectively avoided.

The preheated low-temperature conversion condensate enters the middle part of a stripping tower, low-pressure steam is introduced from the bottom of the stripping tower, the conversion condensate and the low-pressure steam are reversely contacted and stripped in a packing or a tray at the lower part of the stripping tower, stripping steam containing non-condensable gases such as NH3, H2S and CO2 extracted by stripping section steam is reversely contacted with a condensed reflux liquid at the top of the tower through a packing or a tray at the upper part of a rectifying section, the reflux liquid is rectified, the rectified stripping gas is condensed to 100-120 ℃ through a condenser at the top of the tower, the condensed and separated stripping tail gas is sent to a downstream device for further treatment, and qualified condensate after stripping at the bottom of the stripping tower is sent out of the device. The operation pressure of the stripping tower is controlled below 0.4 MPaG, and desalted water is used as a cooling medium of the overhead condenser.

Compared with the traditional tower top feeding, the feeding position of the low-temperature conversion condensate into the stripping tower is the middle-upper part of the tower, and the condensate is further concentrated by the operation of the upper packing or the rectifying section of a tray, so that substances such as NH3, H2S, CO2 and the like in the tower top exhaust gas are stripped more thoroughly, and the stripping effect is obviously improved.

The cooling medium of the overhead condenser is changed from traditional circulating water into desalted water, and the operation temperature of the desalted water is much higher than that of the circulating water, so that the average wall temperature of tube pass metal of the overhead condenser can be greatly improved, and the problem of ammonium salt crystallization in the lower area of the tube pass of the overhead condenser is effectively solved; meanwhile, due to the fact that the cleanliness of desalted water is higher than that of circulating water, the cleaning frequency of the tower top condenser is reduced, and the maintenance burden of a factory on equipment can be reduced.

The temperature of the gas at the outlet of the tower top is controlled to be 100-120 ℃, and the problem that the pipeline is blocked by ammonium salt crystals due to low temperature of a gas conveying pipeline at the outlet of the tower top can be effectively solved under the condition that the gas discharge amount at the tower top is not remarkably increased.

The present invention is not limited to the above preferred embodiments, and any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention should be included in the protection scope of the present invention.