Alcohol-containing chemical tank field VOC (volatile organic compound) tail gas three-stage condensation system

Abstract

The invention discloses an alcohol-containing chemical tank field VOC tail gas three-stage condensation system, and relates to the technical field of oil gas treatment, the alcohol-containing chemical tank field VOC tail gas three-stage condensation system specifically comprises a precooler, the precooler is used for conducting heat exchange on VOC tail gas entering the system and purified VOC tail gas coming out of the system, the VOC tail gas entering the system is precooled to 15-20 DEG C, and the cooling capacity is recycled; the first-stage shallow condenser is arranged on one side of the precooler and is used for cooling the VOC tail gas to 2-4 DEG C, so that most water vapor and part of components in the VOC tail gas are condensed; the second-stage middle condenser is arranged on one side of the first-stage shallow condenser and is used for cooling the VOC tail gas to-20 DEG C to-28 DEG C, so that most of residual water vapor and most of VOC components in the VOC tail gas are condensed; by means of the three-stage condensation system, gradient utilization of cooling capacity is achieved, and the good energy-saving effect is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of oil and gas processing, and in particular to a three-stage condensation system for VOC tail gas in a tank area containing alcohol chemicals. Background Art

[0002] In petrochemical plants, chemical tank areas are an important part. In the process of chemical storage and transportation, VOC tail gas will inevitably be generated due to the respiration of storage tanks and chemical loading, causing great economic losses and environmental pollution. In addition, my country's standards and specifications also clearly stipulate the concentration requirements for VOC emissions. Therefore, VOC tail gas must be treated and recycled. Summary of the invention

[0003] The purpose of the present invention is to provide a three-stage condensation system for VOC tail gas in a tank area containing alcohol chemicals. According to the different boiling points of various alcohols in the VOC tail gas, a three-stage condensation system for VOC tail gas in a tank area containing alcohol chemicals is provided. Different components in the VOC tail gas are graded and recovered at different temperatures, thereby increasing the recovery effect and reducing the consumption of cooling capacity.

[0004] The purpose of the present invention can be achieved through the following technical solutions:

[0005] A three-stage condensation system for VOC tail gas in a tank area containing alcohol chemicals, comprising:

[0006] A precooler, which is used for heat exchange between the VOC tail gas entering the system and the purified VOC tail gas leaving the system, precooling the VOC tail gas entering the system to 15 to 20 degrees and recovering the cold energy;

[0007] The first-stage shallow condenser is set on one side of the precooler to cool the VOC tail gas to 2-4°C, so that 70-80% of the water vapor and 15-20% of the components in the VOC tail gas are condensed;

[0008] The secondary middle condenser is arranged on one side of the primary shallow condenser and is used to cool the VOC tail gas to -20°C to -28°C, so that the remaining water vapor and 70-80% of the VOC components in the VOC tail gas are condensed;

[0009] The third-stage deep condenser is arranged on one side of the second-stage middle condenser and is used to cool the VOC tail gas to -65 to -75°C so that the remaining hydrocarbon components in the VOC tail gas are condensed.

[0010] As a further solution of the present invention: the three-stage deep condenser is connected to the precooler through a cold return pipe to recover cold energy and cool the VOC tail gas.

[0011] As a further solution of the present invention: the bottoms of the precooler, the first-stage shallow condenser, the second-stage medium condenser, and the third-stage deep condenser are all connected to the waste liquid tank through a return pipe.

[0012] As a further solution of the present invention: the waste liquid tank is connected to the waste liquid pump through a waste liquid drainage pipe.

[0013] As a further solution of the present invention: the precooler is also connected to the spray tower via a cooling capacity discharge pipe.

[0014] As a further solution of the present invention: the spray tower comprises a tower body, an air intake connecting pipe is installed on the tower body, the air intake connecting pipe extends into the tower body and is arranged in an L shape, a large gear is sleeved on the air intake connecting pipe, a rotating disk is fixedly installed on the top of the large gear, the rotating disk is a hollow structure, a plurality of reverse arc-shaped sheets are arranged in an array on the inner wall of the rotating disk, and a plurality of air holes are opened on the outer peripheral surface of the rotating disk;

[0015] A rotating motor is fixedly installed inside the tower body, a small gear is fixedly installed on the output shaft of the rotating motor, and the small gear is meshed and connected with the large gear;

[0016] The tower body is provided with a water inlet pipe, on which a transmission water pipe is vertically arranged. The transmission water pipe penetrates the sealing cover plate and extends into the rotating disk. A plurality of water spray pipes are arranged in an array on the transmission water pipe.

[0017] As a further solution of the present invention: the water spray pipe is provided with a plurality of inclined water spray holes.

[0018] As a further solution of the present invention: the end array of the transmission water pipe is provided with a plurality of positive arc-shaped pieces.

[0019] As a further solution of the present invention: a placement tray is sleeved on the transmission water pipe and located above the water spray pipe, and an adsorption filler is placed inside the placement tray.

[0020] As a further solution of the present invention: a rotating cover is rotatably connected to the placement plate, the rotating cover is fixedly connected to the transmission water pipe, through holes are provided on the rotating cover and the placement plate, a plurality of driving rods are arranged in an array at the bottom of the rotating cover, and a plurality of stirring rods are installed on the driving rods.

[0021] Beneficial effects of the present invention:

[0022] The present invention sets up a three-stage condensation system to condense and liquefy water vapor and most of the VOC components in the VOC tail gas and recycle them; effectively realizes the cascade utilization of cold energy, and has great energy-saving and environmental protection significance and economic value for the recovery of VOC containing alcohol chemicals;

[0023] The present invention can purify the condensed gas again by setting up a spray tower. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The present invention will be further described below in conjunction with the accompanying drawings.

[0025] Figure 1 It is a schematic diagram of the overall connection structure of the present invention;

[0026] Figure 2 It is a schematic diagram of the overall structure of the spray tower of the present invention;

[0027] Figure 3 It is a schematic diagram of the internal structure of the spray tower of the present invention;

[0028] Figure 4 It is a schematic diagram of the internal structure of the placing disk and the rotating disk of the present invention.

[0029] In the figure: 1, air inlet pipe; 2, precooler; 3, first-stage shallow condenser; 4, second-stage medium condenser; 5, third-stage deep condenser; 6, first water return pipe; 7, second water return pipe; 8, third water return pipe; 9, fourth water return pipe; 10, waste liquid tank; 11, waste liquid drain pipe; 12, waste liquid pump; 13, cold return pipe; 14, cold drain pipe; 15, spray tower; 151, tower body; 152, air inlet connecting pipe; 153, water inlet Tube; 154, exhaust pipe; 155, rotating motor; 156, small gear; 157, large gear; 158, rotating disk; 159, air hole; 160, sealing cover plate; 161, water spray pipe; 162, water spray hole; 163, placement plate; 164, rotating cover; 165, transmission water pipe; 166, forward arc sheet; 167, reverse arc sheet; 168, stirring rod; 169, driving rod; 170, through hole. DETAILED DESCRIPTION

[0030] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in 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. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] See also Figure 1 As shown, the present invention is a three-stage condensation system for VOC tail gas in a tank area containing alcohol chemicals, comprising a precooler 2, one side of which is provided with an air inlet pipe 1, and the precooler 2 is used for heat exchange between the VOC tail gas entering the system and the purified VOC tail gas leaving the system, precooling the VOC tail gas entering the system to 15 to 20 degrees, and recovering a portion of the cooling capacity;

[0032] The primary shallow condenser 3 is arranged on one side of the precooler 2 and is used to cool the VOC tail gas to about 3°C, so that most of the water vapor and some components in the VOC tail gas are condensed;

[0033] The secondary middle condenser 4 is arranged on one side of the primary shallow condenser 3 and is used to cool the VOC tail gas to about -25°C, so that most of the remaining water vapor and most of the VOC components in the VOC tail gas are condensed;

[0034] The third-stage deep condenser 5 is arranged on one side of the second-stage middle condenser 4 and is used to cool the VOC tail gas to about -70°C so that almost all the remaining hydrocarbon components in the VOC tail gas are condensed.

[0035] The three-stage deep condenser 5 is connected to the precooler 2 via a cold return pipe 13 for recovering cold energy and cooling the VOC tail gas.

[0036] The bottoms of the precooler 2, the first-stage shallow condenser 3, the second-stage medium condenser 4, and the third-stage deep condenser 5 are all connected to the waste liquid tank 10 through a return pipe.

[0037] The waste liquid tank 10 is connected to a waste liquid pump 12 via a waste liquid drain pipe 11 .

[0038] The precooler 2 is also connected to the spray tower 15 via a cooling capacity discharge pipe 14 .

[0039] In the precooler 2, the treated VOC tail gas is heat exchanged, and part of the condensed water vapor and other media enter the waste liquid tank 10. The VOC tail gas from the precooler 2 enters the primary shallow cooler 3, the secondary intercooler 4, and the tertiary deep cooler 5, respectively, and its temperature is reduced to 3°C, -25°C, and -70°C, respectively. In the primary shallow cooler 3, the condensed water vapor and part of the VOC components enter the waste liquid tank 18, and the first refrigerant (R404A) comes and returns to the primary compression; in the secondary intercooler 4, almost all the condensed water vapor and most of the VOC components enter the waste liquid tank 10, and the second refrigerant (R404A) comes and returns to the secondary compression; in the tertiary deep cooler 5, almost all the condensed hydrocarbons enter the waste liquid tank 10, and the third refrigerant (R23) comes and returns to the tertiary compression; after the treated VOC gas from the tertiary deep cooler 5 returns to the precooler 2 to recover the cold, the final VOC gas enters the next process.

[0040] See also Figure 2-4As shown, the spray tower 15 includes a tower body 151, an air inlet connecting pipe 152 is installed on the tower body 151, and an air outlet pipe 154 is installed on the top of the tower body 151; a drain pipe is installed at the bottom for draining water, the air inlet connecting pipe 152 extends into the tower body 151 and is arranged in an L shape, a large gear 157 is sleeved on the air inlet connecting pipe 152, a rotating disk 158 is fixedly installed on the top of the large gear 157, the air inlet connecting pipe 152 is inserted into the rotating disk 158, the rotating disk 158 is a hollow structure, and a plurality of reverse arc-shaped sheets 167 are arranged in an array on the inner wall of the rotating disk 158, and a plurality of air holes 159 are opened on the outer peripheral surface of the rotating disk 158;

[0041] A rotating motor 155 is fixedly installed inside the tower body 151, and a small gear 156 is fixedly installed on the output shaft of the rotating motor 155, and the small gear 156 is meshed and connected with a large gear 157;

[0042] The tower body 151 is provided with a water inlet pipe 153 , and a transmission water pipe 165 is vertically provided on the water inlet pipe 153 . The transmission water pipe 165 penetrates the sealing cover plate 160 and extends into the rotating disk 158 . A plurality of water spray pipes 161 are arranged in an array on the transmission water pipe 165 .

[0043] The water spray pipe 161 is provided with a plurality of inclined water spray holes 162. The end array of the transmission water pipe 165 is provided with a plurality of positive arc-shaped pieces 166.

[0044] The final VOC gas enters the spray tower 15 and enters the rotating disk 158 through the air intake connecting pipe 152, starts the rotating motor 155, drives the small gear 156 to rotate, drives the rotating disk 158 to rotate through the large gear 157, and drives the reverse arc piece 167 to rotate; at the same time, water enters the water spray pipe 161 through the transmission water pipe 165, and drives the water spray pipe 161 and the transmission water pipe 165 to rotate under the setting of the inclined water spray hole 162, thereby realizing rotary spraying, and the spraying range is wider. In the case of the transmission water pipe 165, the forward arc piece 166 will be driven to rotate. In the case where the forward arc piece 166 and the reverse arc piece 167 rotate in opposite directions, the time of the gas inside the rotating disk 158 will be increased, the effect of slow flow will be achieved, and it will be dispersed from all sides so that it is fully in contact with the sprayed water, and the impurity removal effect is better; and the rotation of the water spray pipe 161 reduces the rising speed of the gas, which will also increase its retention time inside the spray tower 15.

[0045] A placement plate 163 is sleeved on the transmission water pipe 165 and located above the water spray pipe 161, and an adsorption filler is placed inside the placement plate 163. A rotating cover 164 is rotatably connected to the placement plate 163, and the rotating cover 164 is fixedly connected to the transmission water pipe 165. Through holes 170 are provided on the rotating cover 164 and the placement plate 163. A plurality of driving rods 169 are arranged in an array at the bottom of the rotating cover 164, and a plurality of stirring rods 168 are installed on the driving rods 169.

[0046] During the rotation of the transmission water pipe 165 , the rotating cover 164 is driven to rotate, and then the stirring rod 168 is driven to rotate, so as to turn over the adsorption filler and increase its adsorption capacity.

[0047] The above is a detailed description of an embodiment of the present invention, but the content is only a preferred embodiment of the present invention and cannot be considered to limit the scope of implementation of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the patent coverage of the present invention.

Claims

1. A three-stage condensation system for VOC tail gas in an alcohol-containing chemical tank area, characterized in that: include, A precooler (2), wherein the precooler (2) is used for heat exchange between the VOC tail gas entering the system and the purified VOC tail gas leaving the system, precooling the VOC tail gas entering the system to 15 to 20 degrees, and recovering the cold energy; A primary shallow condenser (3) is arranged on one side of the precooler (2) and is used to cool the VOC tail gas to 2-4°C, so that 70-80% of the water vapor and 15-20% of the components in the VOC tail gas are condensed; The secondary medium condenser (4) is arranged on one side of the primary shallow condenser (3) and is used to cool the VOC tail gas to -20°C to -28°C, so that the remaining water vapor and 70-80% of the VOC components in the VOC tail gas are condensed; The third-stage deep condenser (5) is arranged on one side of the second-stage middle condenser (4) and is used to cool the VOC tail gas to -65 to -75°C, so that the remaining hydrocarbon components in the VOC tail gas are condensed.

2. A three-stage condensation system for VOC tail gas in an alcohol-containing chemical tank area according to claim 1, characterized in that: The three-stage deep condenser (5) is connected to the precooler (2) via a cold return pipe (13) and is used to recover cold energy and cool the VOC tail gas.

3. A three-stage condensation system for VOC tail gas in an alcohol-containing chemical tank area according to claim 2, characterized in that: The bottoms of the precooler (2), the first-stage shallow condenser (3), the second-stage medium condenser (4), and the third-stage deep condenser (5) are all connected to the waste liquid tank (10) via a return pipe.

4. A three-stage condensation system for VOC tail gas in an alcohol-containing chemical tank area according to claim 3, characterized in that: The waste liquid tank (10) is connected to the waste liquid pump (12) via a waste liquid drainage pipe (11).

5. The three-stage condensation system for VOC tail gas in the tank area of ​​alcohol-containing chemicals according to claim 1 is characterized in that: The precooler (2) is also connected to the spray tower (15) via a cooling capacity discharge pipe (14).

6. The three-stage condensation system for VOC tail gas in the tank area of ​​alcohol-containing chemicals according to claim 5 is characterized in that: The spray tower (15) comprises a tower body (151), an air intake connecting pipe (152) is installed on the tower body (151), the air intake connecting pipe (152) extends into the tower body (151) and is arranged in an L shape, a large gear (157) is sleeved on the air intake connecting pipe (152), a rotating disk (158) is fixedly installed on the top of the large gear (157), the rotating disk (158) is a hollow structure, a plurality of reverse arc-shaped sheets (167) are arranged in an array on the inner wall of the rotating disk (158), and a plurality of air holes (159) are opened on the outer peripheral surface of the rotating disk (158); A rotating motor (155) is fixedly installed inside the tower body (151), a small gear (156) is fixedly installed on the output shaft of the rotating motor (155), and the small gear (156) is meshingly connected with a large gear (157); The tower body (151) is provided with a water inlet pipe (153), and a transmission water pipe (165) is vertically provided on the water inlet pipe (153). The transmission water pipe (165) penetrates the sealing cover plate (160) and extends into the rotating disk (158). A plurality of water spray pipes (161) are arranged in an array on the transmission water pipe (165).

7. A three-stage condensation system for VOC tail gas in an alcohol-containing chemical tank area according to claim 6, characterized in that: The water spray pipe (161) is provided with a plurality of water spray holes (162) which are arranged obliquely.

8. The three-stage condensation system for VOC tail gas in the tank area of ​​alcohol-containing chemicals according to claim 6 is characterized in that: The end array of the transmission water pipe (165) is provided with a plurality of positive arc-shaped pieces (166).

9. The three-stage condensation system for VOC tail gas in the tank area of ​​alcohol-containing chemicals according to claim 6 is characterized in that: A placement plate (163) is sleeved on the transmission water pipe (165) and located above the water spray pipe (161), and an adsorption filler is placed inside the placement plate (163).

10. A three-stage condensation system for VOC tail gas in an alcohol-containing chemical tank area according to claim 9, characterized in that: The placement plate (163) is rotatably connected to a rotating cover (164), the rotating cover (164) is fixedly connected to a transmission water pipe (165), through holes (170) are provided on the rotating cover (164) and the placement plate (163), a plurality of driving rods (169) are arranged in an array at the bottom of the rotating cover (164), and a plurality of stirring rods (168) are mounted on the driving rods (169).

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