Skid-mounted system for preparing sodium bisulfite from tail gas containing sulfur dioxide

Abstract

The utility model discloses a skid-mounted system for preparing sodium bisulfite from tail gas containing sulfur dioxide, belonging to the technical field of tail gas recycling. The technical scheme comprises a circulation tank and a controller. The circulation tank is divided into chamber one, chamber two and chamber three by baffles one and two. The circulation tank is provided with a primary falling film absorber, a secondary falling film absorber and a primary absorption tower connected by pipelines. The primary falling film absorber is provided with a SO 2 The tail gas inlet pipeline, the first-level absorption tower is provided with a sodium hydroxide solution inlet pipeline and a tail gas outlet pipeline, and the sodium hydroxide solution inlet pipeline is provided with an inlet control valve; the bottom of the circulation tank is provided with a finished product extraction pipeline, and the finished product extraction pipeline is provided with an extraction control valve, and the chamber is provided with a conductivity meter and a liquid level sensor. The utility model integrates the relevant equipment of tail gas absorption, saves investment and reduces the floor space, and realizes a high degree of automation of the tail gas absorption process.

Description

Technical Field

[0001] The utility model belongs to the technical field of tail gas recycling, and specifically relates to a skid-mounted system for preparing sodium bisulfite from tail gas containing sulfur dioxide. Background Art

[0002] Sodium bisulfite is widely used in the bleaching of cotton fabrics and organic matter, as a reducing agent in the dye, papermaking, leather making, and chemical synthesis industries, and in the pharmaceutical industry for the production of intermediate food-grade products as bleaching agents, preservatives, and antioxidants. In recent years, it has begun to be used in biology to improve photosynthesis and increase production. There are three main process technologies for the production of sodium bisulfite in China: the preparation method using sodium pyrosulfite and water; the preparation method using sulfur dioxide and sodium bicarbonate; and the preparation method using sulfur dioxide and sodium hydroxide. The main raw materials for the preparation method using sulfur dioxide and sodium hydroxide are sodium hydroxide solution and sulfur dioxide, and the reaction equation is: SO2+NaOH→NaHSO3. The existing preparation device requires the multi-stage falling film absorber and absorption tower to be set up separately, the equipment is arranged in a dispersed manner, there are many connecting pipes, and the risk of leakage is high; the realization of automation requires the investment of more automatic control instruments, which occupies a large area and has high investment and operating costs. Utility Model Content

[0003] The utility model provides a skid-mounted system for preparing sodium bisulfite from tail gas containing sulfur dioxide, which integrates a falling film absorber, a primary absorption tower and a circulation tank into one, and two baffles of different heights are arranged in the circulation tank to divide the inside of the circulation tank into three chambers. A water seal device is arranged at the bottom of the falling film absorber to prevent the tail gas from being mixed. The skid-mounted system integrates the relevant equipment for tail gas absorption, saves investment and reduces the floor space, and realizes a high degree of automation of the tail gas absorption process.

[0004] The technical solution of the utility model is:

[0005] A skid-mounted system for preparing sodium bisulfite from tail gas containing sulfur dioxide comprises a circulation tank and a controller. The circulation tank is configured into chamber one, chamber two and chamber three by baffles one and two inside the circulation tank. A primary falling film absorber, a secondary falling film absorber and a primary absorption tower connected by pipelines are arranged on the circulation tank. The primary falling film absorber is provided with an inlet pipeline for tail gas containing SO2. The primary absorption tower is provided with an inlet pipeline for sodium hydroxide solution and an outlet pipeline for tail gas. An inlet control valve is arranged on the inlet pipeline for sodium hydroxide solution. A finished product production pipeline is arranged at the bottom of the circulation tank. The finished product production pipeline is provided with a production control valve. A conductivity meter and a liquid level sensor are arranged in chamber one. The production control valve, the liquid level sensor, the inlet control valve and the conductivity meter are all electrically connected to the controller.

[0006] Preferably, the height of baffle plate 1 is smaller than the height of baffle plate 2, and the overflow transfers mass between adjacent chambers.

[0007] Preferably, a water seal device is provided at the bottom of both the primary falling film absorber and the secondary falling film absorber.

[0008] Preferably, the water sealing device comprises a liquid collecting conical tube and a liquid collecting tray, and the bottom of the liquid collecting conical tube is lower than the opening of the liquid collecting tray.

[0009] Preferably, both the primary falling film absorber and the secondary falling film absorber are provided with a cooling water inlet pipeline and a cooling water outlet pipeline.

[0010] Preferably, the primary falling film absorber, the secondary falling film absorber and the primary absorption tower are all connected to a circulation pump.

[0011] Compared with the prior art, the utility model has the following beneficial effects:

[0012] 1. The skid-mounted system of the utility model integrates the relevant equipment of exhaust gas absorption, which saves investment and reduces the floor space, and realizes high automation of the exhaust gas absorption process.

[0013] 2. The primary falling film absorber, the secondary falling film absorber, the primary absorption tower and the circulation tank are integrated into one. Two baffles of different heights are arranged in the circulation tank to divide the interior of the circulation tank into three chambers, which correspond to the primary falling film absorber, the secondary falling film absorber and the primary absorption tower respectively. The height of the baffles increases step by step, and the overflow is used to transfer mass between adjacent chambers, which saves more energy and reduces the operation cost.

[0014] 3. A water seal device is set at the bottom of the falling film absorber, and the gas phase is extracted from the side of the water seal device to prevent the gas from flowing between stages.

[0015] 4. The production control valve is controlled by the conductivity meter installed in chamber 1, and the liquid level sensor and liquid inlet control valve set in chamber 1 form liquid level control to realize automatic liquid replenishment of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a structural schematic diagram of the utility model.

[0017] Figure 2 This utility model Figure 1 Magnified view of area A.

[0018] In the figure, 1, circulation tank; 2, baffle 1; 3, baffle 2; 4, chamber 1; 401, conductivity meter; 5, chamber 2; 6, chamber 3; 7, primary falling film absorber; 8, secondary falling film absorber; 9, primary absorption tower; 10, SO2-containing tail gas inlet pipeline; 11, sodium hydroxide solution inlet pipeline; 1101, liquid inlet control valve; 12, tail gas outlet pipeline; 13, finished product production pipeline; 1301, production control valve; 14, water seal device; 1401, liquid collection cone tube; 1402, liquid collecting tray; 15, cooling water inlet pipeline; 16, cooling water outlet pipeline; 17, circulation pump. DETAILED DESCRIPTION

[0019] In order to enable those skilled in the art to better understand the technical solutions in the present invention, 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 them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0020] Example

[0021] like Figure 1 and 2 As shown, this embodiment provides a skid-mounted system for preparing sodium bisulfite from tail gas containing sulfur dioxide, including a circulation tank 1 and a controller. The circulation tank 1 is configured into a chamber 1 4, a chamber 2 5 and a chamber 3 6 by baffle 1 2 and baffle 2 3. The height of baffle 1 2 is less than that of baffle 2 3. Overflow is used to transfer mass between adjacent chambers.

[0022] The circulation tank 1 is provided with a primary falling film absorber 7, a secondary falling film absorber 8 and a primary absorption tower 9 which are connected by pipelines. The primary falling film absorber 7, the secondary falling film absorber 8 and the primary absorption tower 9 are all connected with a circulation pump 17; the primary falling film absorber 7 and the secondary falling film absorber 8 are both provided with a water seal device 14 at the bottom, and the water seal device 14 comprises a liquid collecting conical tube 1401 and a liquid collecting tray 1402. The bottom of the liquid collecting conical tube 1401 is lower than the dish opening of the liquid collecting tray 1402, and a gas phase port is opened above the liquid seal liquid level of the liquid collecting conical tube to achieve gas-liquid separation; the primary falling film absorber 7 and the secondary falling film absorber 8 are both provided with a cooling water inlet pipeline 15 and a cooling water outlet pipeline 16;

[0023] The first-stage falling film absorber 7 is provided with a SO2-containing tail gas inlet pipeline 10, the first-stage absorption tower 9 is provided with a sodium hydroxide solution inlet pipeline 11 and a tail gas outlet pipeline 12, and the sodium hydroxide solution inlet pipeline 11 is provided with an inlet control valve 1101; a finished product production pipeline 13 is provided at the bottom of the circulation tank 1, and the finished product production pipeline 13 is provided with a production control valve 1301, and a conductivity meter 401 and a liquid level sensor are provided in the chamber 4, and the production control valve 1301, the liquid level sensor, the inlet control valve 1101 and the conductivity meter 401 are all electrically connected to the controller.

[0024] The usage process is:

[0025] 1) Preparation before starting: add sodium hydroxide solution to the primary absorption tower 9 through the sodium hydroxide solution inlet pipeline 11, and then let the sodium hydroxide solution enter the circulation tank 1, the liquid level in the chamber three 6 is consistent with the height of the baffle two 3, the liquid level in the chamber two 5 is consistent with the height of the baffle one 2, the liquid level in the chamber one 4 is lower than the height of the baffle one 2, and the valves of the cooling water inlet pipeline 15 and the cooling water outlet pipeline 16 are opened;

[0026] 2) Absorption process: start the circulation pump 17 corresponding to the first-stage falling film absorber 7, the second-stage falling film absorber 8 and the first-stage absorption tower 9, open the valve on the SO2-containing tail gas inlet pipeline 10, and start the sulfur dioxide absorption operation. After the tail gas passes through the first-stage falling film absorber 7, the second-stage falling film absorber 8 and the first-stage absorption tower 9 in sequence, it enters the tail gas treatment system through the tail gas outlet pipeline 12. Specifically, the sodium hydroxide solution in the chamber 1 4 first reacts with the sulfur dioxide in the tail gas in the first-stage falling film absorber 7, and the remaining tail gas after absorption enters the second-stage falling film absorber 8, and the sodium hydroxide solution in the chamber 2 5 reacts with the sulfur dioxide in the second-stage falling film absorber 8, and the remaining tail gas enters the first absorption tower, and the sodium hydroxide solution in the chamber 3 reacts with the remaining sulfur dioxide. In the whole process, the sodium bisulfite material concentration in the chamber 1> the chamber 2> the chamber 3.

[0027] When the detection value of the conductivity meter 401AIC-101 reaches the set production value, the production control valve 1301 starts to be controlled to produce the finished product; at the same time, the liquid level sensor of the circulation tank 1 controls the sodium hydroxide inlet pipeline inlet control valve 1101 to replenish the liquid, and the replenished sodium hydroxide solution first enters chamber three 6, overflows to chamber two 5 through the left baffle, and then overflows to chamber one 4 through the baffle on the left side of chamber two 5, and concentrates step by step.

[0028] Although the present invention is described in detail by referring to the accompanying drawings and in combination with the preferred embodiments, the present invention is not limited thereto. Without departing from the spirit and essence of the present invention, a person skilled in the art may make various equivalent modifications or substitutions to the embodiments of the present invention, and these modifications or substitutions shall be within the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A skid-mounted system for preparing sodium bisulfite from sulfur dioxide-containing tail gas, characterized in that: The invention comprises a circulation tank (1) and a controller. The circulation tank (1) is configured into a chamber (4), a chamber (5) and a chamber (6) by means of a baffle plate (2) and a baffle plate (3). The circulation tank (1) is provided with a first falling film absorber (7), a second falling film absorber (8) and a first absorption tower (9) which are connected by pipelines. The first falling film absorber (7) is provided with an SO2-containing tail gas inlet pipeline (10). The first absorption tower (9) is provided with a sodium hydroxide solution inlet pipeline (11). 1) and an exhaust gas outlet pipeline (12), a liquid inlet control valve (1101) is arranged on the sodium hydroxide solution liquid inlet pipeline (11); a finished product extraction pipeline (13) is arranged at the bottom of the circulation tank (1), and the finished product extraction pipeline (13) is provided with an extraction control valve (1301); a conductivity meter (401) and a liquid level sensor are arranged in the chamber one (4), and the extraction control valve (1301), the liquid level sensor, the liquid inlet control valve (1101) and the conductivity meter (401) are all electrically connected to the controller.

2. The skid-mounted system for preparing sodium bisulfite from sulfur dioxide-containing tail gas according to claim 1, characterized in that: The height of baffle plate 1 (2) is smaller than the height of baffle plate 2 (3), and the adjacent chambers are connected by overflow for mass transfer.

3. The skid-mounted system for preparing sodium bisulfite from sulfur dioxide-containing tail gas according to claim 1, characterized in that: A water seal device (14) is provided at the bottom of each of the first-stage falling film absorber (7) and the second-stage falling film absorber (8).

4. The skid-mounted system for preparing sodium bisulfite from sulfur dioxide-containing tail gas according to claim 3, characterized in that: The water sealing device (14) comprises a liquid collecting conical tube (1401) and a liquid collecting tray (1402), wherein the bottom of the liquid collecting conical tube (1401) is lower than the opening of the liquid collecting tray (1402).

5. The skid-mounted system for preparing sodium bisulfite from sulfur dioxide-containing tail gas according to claim 1, characterized in that: The first-stage falling film absorber (7) and the second-stage falling film absorber (8) are both provided with a cooling water inlet pipeline (15) and a cooling water outlet pipeline (16).

6. The skid-mounted system for preparing sodium bisulfite from sulfur dioxide-containing tail gas according to claim 1, characterized in that: The first falling film absorber (7), the second falling film absorber (8) and the first absorption tower (9) are respectively connected to a circulation pump (17).

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