VOC waste gas treatment system in waste storage pretreatment process

Abstract

The invention discloses a VOC waste gas treatment system in a waste storage pretreatment process. The VOC waste gas treatment system comprises a high-concentration waste gas treatment device and a low-concentration waste gas treatment device. The high-concentration waste gas treatment device comprises a waste gas filter, an adsorption tank, a nitrogen heater, a condenser and a cooler; a gas inlet of the waste gas filter is connected with an outlet of the waste gas collecting device; a waste gas outlet of the adsorption tank is respectively connected with a gas outlet of the waste gas filter and a discharge chimney; a gas inlet and a gas outlet of the nitrogen heater are respectively connected with a nitrogen source and a nitrogen inlet of the adsorption tank; an inlet and an outlet of the condenser are respectively connected with a nitrogen outlet of the adsorption tank and a liquid inlet of the waste liquid tank; a gas inlet and a gas outlet of the cooler are respectively connected with a nitrogen outlet and a nitrogen inlet of the adsorption tank; an outlet of the waste liquid tank and a nitrogen outlet of the adsorption tank are both connected with a hazardous waste incineration line; and the low-concentration waste gas treatment device comprises a washing tower connected between the waste gas collection device and the discharge chimney. The VOC waste gas treatment efficiency can be effectively improved.

Description

Technical Field

[0001] The invention relates to a VOC waste gas disposal system in a waste storage pretreatment process. Background Art

[0002] For hazardous waste disposal companies, among the hazardous wastes disposed of, the incoming amount of volatile organic waste accounts for a relatively high proportion of the total disposal amount. During the daily storage and disposal process, a large amount of organic waste gas will escape. These gases are collected by the exhaust system in the hazardous waste temporary storage warehouse and pre-treatment workshop and need to be disposed of before discharge to reduce air pollution.

[0003] Although appropriate storage containers and facilities should be selected to ensure that waste materials will not leak or volatilize during storage. Secondly, in the pretreatment process, refined operations are adopted to reduce the release of VOC (volatile organic compounds), but a small amount of VOC is still released into the ambient air, affecting the environment in the factory. At present, VOC absorption and treatment facilities are installed in the factory and workshop to prevent it from entering the atmosphere and causing harm to the environment and human body.

[0004] Commonly used VOC absorption technologies include: adsorption, liquid absorption, condensation, membrane separation, etc. VOC disposal methods include: catalytic combustion, photocatalytic oxidation technology, biological disposal, etc. Each method has its own advantages and disadvantages, and several technologies are often combined in series to achieve the purpose of VOC safe disposal.

[0005] However, compared with other enterprises, hazardous waste disposal enterprises have characteristics such as large size, high ventilation requirements, and high pollutant concentration in their storage and disposal workshops, which leads to large overall air volume in the system. Therefore, the disposal equipment needs to have large capacity and high disposal efficiency. Summary of the invention

[0006] The purpose of the present invention is to overcome the defects of the prior art and provide a VOC waste gas treatment system in the waste storage pretreatment process, which can adjust the waste gas treatment process according to the VOC concentration in the waste gas and the production load, thereby effectively improving the efficiency of waste gas treatment.

[0007] The object of the present invention is achieved as follows: A VOC waste gas treatment system in a waste storage pretreatment process comprises a high-concentration waste gas treatment device and a low-concentration waste gas treatment device; characterized in that:

[0008] The high-concentration waste gas treatment device includes a waste gas filter, an adsorption tank, a nitrogen heater, a cooler, a condenser, a waste liquid tank, a hazardous waste incineration line and an emission chimney; wherein,

[0009] The air inlet of the exhaust gas filter is connected to the outlet of the exhaust gas collecting device;

[0010] The exhaust gas inlet of the adsorption tank is connected to the exhaust gas outlet of the exhaust gas filter, and an activated carbon filler is installed in the adsorption tank; the purified gas outlet of the adsorption tank is connected to the inlet of the exhaust chimney;

[0011] The air inlet of the nitrogen heater is connected to the nitrogen source, and the air outlet of the nitrogen heater is connected to the nitrogen inlet of the adsorption tank;

[0012] The inlet of the condenser is connected to the nitrogen outlet of the adsorption tank, and the outlet of the condenser is connected to the liquid inlet of the waste liquid tank;

[0013] The air inlet of the cooler is connected to the nitrogen outlet of the adsorption tank, and the air outlet of the cooler is connected to the nitrogen inlet of the adsorption tank;

[0014] The hazardous waste incineration line is connected to the outlet of the waste liquid tank and the nitrogen outlet of the adsorption tank respectively;

[0015] The low-concentration waste gas treatment device includes a washing tower and a common exhaust chimney with the high-concentration waste gas treatment device;

[0016] The air inlet of the washing tower is connected to the exhaust gas collecting device; the air outlet of the washing tower is connected to the exhaust chimney.

[0017] In the above-mentioned VOC waste gas treatment system during the waste storage pretreatment process, the waste gas in the waste gas collection device is collected from the hazardous waste storage warehouse or the pretreatment workshop through an air suction system.

[0018] In the above-mentioned VOC waste gas treatment system during the waste storage pretreatment process, there are at least two adsorption tanks, which are arranged in parallel.

[0019] The above-mentioned VOC waste gas treatment system in the waste storage pretreatment process, wherein the waste gas treatment system also includes four fans installed one by one at the outlet of the waste gas collection device, the nitrogen outlet of the adsorption tank, the purified gas outlet of the adsorption tank and the air outlet of the washing tower; the waste gas treatment system also includes a waste liquid pump installed at the outlet of the waste liquid tank.

[0020] The VOC waste gas treatment system in the waste storage pretreatment process of the present invention is characterized by:

[0021] 1. By setting up high-concentration waste gas treatment devices and low-concentration waste gas treatment devices, the waste gas treatment process can be adjusted according to the VOC concentration in the waste gas and the production load, effectively improving the efficiency of waste gas treatment;

[0022] 2. The desorption process is an oxygen-free environment with low safety risks; it achieves pollution-free emissions and is suitable for large-scale waste gas VOC disposal. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a principle structure diagram of the VOC waste gas treatment system in the waste storage pretreatment process of the present invention. DETAILED DESCRIPTION

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

[0025] See also Figure 1 The VOC waste gas treatment system in the waste storage pretreatment process of the present invention includes a high-concentration waste gas treatment device and a low-concentration waste gas treatment device.

[0026] The high-concentration waste gas treatment device includes a waste gas filter 2, an adsorption tank 3, a nitrogen heater 4, a condenser 5, a cooler 6, a waste liquid tank 7, a hazardous waste incineration line 8, an emission chimney 9, a first fan 11 to a third fan 13 and a waste liquid pump 14; wherein,

[0027] The air inlet of the exhaust filter 2 is connected to the outlet of the exhaust collection device 1; the exhaust gas in the exhaust collection device 1 is collected from the hazardous waste storage warehouse or the pretreatment workshop through the suction system;

[0028] The exhaust gas inlet of the adsorption tank 3 is connected to the exhaust gas outlet of the exhaust gas filter 2, and the purified gas outlet of the adsorption tank 3 is connected to the inlet of the exhaust chimney 9; there are at least two adsorption tanks 3, which are arranged in parallel, and each adsorption tank 3 is installed with activated carbon filler; under the condition that the adsorption is not affected, the two adsorption tanks 3 are desorbed in turn;

[0029] The air inlet of the nitrogen heater 4 is connected to the nitrogen source 40, and the air outlet of the nitrogen heater 4 is connected to the nitrogen inlet of the adsorption tank 3; the nitrogen heater 4 is electrically heated or steam heated;

[0030] The inlet of the condenser 5 is connected to the nitrogen outlet of the adsorption tank 3, and the outlet of the condenser 5 is connected to the liquid inlet of the waste liquid tank 7;

[0031] The air inlet of the cooler 6 is connected to the nitrogen outlet of the adsorption tank 3, and the air outlet of the cooler 6 is connected to the nitrogen inlet of the adsorption tank 3;

[0032] The hazardous waste incineration line 8 is connected to the outlet of the waste liquid tank 7 and the nitrogen outlet of the adsorption tank 3 respectively;

[0033] The first fan 11 is installed at the outlet of the exhaust gas collecting device 1; the second fan 12 is installed at the nitrogen outlet of the adsorption tank 3; and the third fan 13 is installed at the purified gas outlet of the adsorption tank 3.

[0034] The waste liquid pump 14 is installed at the outlet of the waste liquid tank 7 .

[0035] The low-concentration waste gas treatment device includes a washing tower 10, a fourth fan 15 and an emission chimney 9 shared with the high-concentration waste gas treatment device; the air inlet of the washing tower 10 is connected to the waste gas collection device 1, and the air outlet of the washing tower 10 is connected to the emission chimney 9 through the fourth fan 15.

[0036] The VOC waste gas treatment system in the waste storage pretreatment process of the present invention includes the following stages in the process of treating high-concentration waste gas:

[0037] 1. Organic matter adsorption stage. This high-concentration waste gas is generated in the pretreatment of hazardous waste in the workshop and in places and working conditions where VOC emissions are large, such as the storage of hazardous waste. After the high-concentration waste gas is collected by the suction system in the workshop, it is sent to the disposal system of the present invention through the pipeline by the first fan 11. It first passes through the exhaust gas filter 2, which removes particulate matter and dust in the exhaust gas, and then is sent to the adsorption tank 3. The adsorption tank 3 is equipped with activated carbon fillers to adsorb and purify organic matter in the exhaust gas; the exhaust gas that meets the purification standards is sent to the exhaust chimney 9 through the third fan 13 installed at the purified gas outlet of the adsorption tank 3 and discharged into the atmosphere.

[0038] 2. In the organic matter desorption stage, when the adsorption tank 3 is saturated with adsorption, the exhaust gas inlet and the purified gas outlet of the adsorption tank 3 are closed, and nitrogen is introduced from the nitrogen inlet of the adsorption tank 3 to replace the nitrogen with the oxygen in the adsorption tank 3; when the oxygen in the adsorption tank 3 is exhausted, the nitrogen heater 4 is turned on to heat the nitrogen to 160-200°C; during the heating period, the nitrogen circulates between the nitrogen heater 4 and the adsorption tank 3 until the target temperature; the hot nitrogen desorbs the organic matter through the activated carbon filler in the adsorption tank 3; the oxygen concentration in the nitrogen is monitored throughout the desorption process to prevent it from reaching the explosion limit;

[0039] 3. After the desorption of organic matter, the nitrogen gas with organic matter is disposed of in the following ways: a) directly sent to the hazardous waste incineration line 8 through one pipeline for incineration; b) sent to the condenser 5 through another pipeline to cool down to below 10°C, condensing the organic matter carried in the nitrogen gas into liquid, and the condensed liquid is collected by the waste liquid tank 7, and then sent to the hazardous waste incineration line 8 for incineration through the waste liquid pump 14; the cooled nitrogen gas can be sent to other adsorption tanks through pipelines to be adsorbed together with the waste gas and then discharged into the atmosphere, or re-enter the nitrogen heater 4 for cyclic desorption;

[0040] The disposal method a) or b) of nitrogen containing organic matter can be selected based on factors such as the load of the main business of the hazardous waste disposal enterprise and the concentration of VOC (volatile organic compounds) in the nitrogen.

[0041] When the desorption of organic matter is completed, nitrogen circulates between the cooler 6 and the adsorption tank 3 to reduce the temperature of the activated carbon filler in the adsorption tank 3 to room temperature.

[0042] In the VOC waste gas treatment system in the waste storage pretreatment process of the present invention, when the production load of hazardous waste pretreatment is low or the VOC concentration in the waste gas is low, the low-concentration waste gas is sent to the washing tower 10 through a pipeline, and after being washed by the washing tower 10, it is sent to the emission chimney 9 through the fourth fan 15 for discharge; the washing tower 10 uses water as a washing liquid, and a small amount of sodium hydroxide (NaOH) is added to the water to maintain the weak alkalinity of the washing liquid (pH 9-11); the washing wastewater from the washing tower 10 is sent to the organic wastewater treatment system for treatment.

[0043] The above embodiments are only used to illustrate the present invention, rather than to limit the present invention. Those skilled in the relevant technical field may make various changes or modifications without departing from the spirit and scope of the present invention. Therefore, all equivalent technical solutions should also belong to the scope of the present invention and should be defined by the claims.

Claims

1. A VOC waste gas treatment system in a waste storage pretreatment process, comprising a high-concentration waste gas treatment device and a low-concentration waste gas treatment device; characterized in that: The high-concentration waste gas treatment device includes a waste gas filter, an adsorption tank, a nitrogen heater, a cooler, a condenser, a waste liquid tank, a hazardous waste incineration line and an emission chimney; wherein, The air inlet of the exhaust gas filter is connected to the outlet of the exhaust gas collecting device; The exhaust gas inlet of the adsorption tank is connected to the exhaust gas outlet of the exhaust gas filter, and an activated carbon filler is installed in the adsorption tank; the purified gas outlet of the adsorption tank is connected to the inlet of the exhaust chimney; The air inlet of the nitrogen heater is connected to the nitrogen source, and the air outlet of the nitrogen heater is connected to the nitrogen inlet of the adsorption tank; The inlet of the condenser is connected to the nitrogen outlet of the adsorption tank, and the outlet of the condenser is connected to the liquid inlet of the waste liquid tank; The air inlet of the cooler is connected to the nitrogen outlet of the adsorption tank, and the air outlet of the cooler is connected to the nitrogen inlet of the adsorption tank; The hazardous waste incineration line is connected to the outlet of the waste liquid tank and the nitrogen outlet of the adsorption tank respectively; The low-concentration waste gas treatment device includes a washing tower and a common exhaust chimney with the high-concentration waste gas treatment device; The air inlet of the washing tower is connected to the exhaust gas collecting device; the air outlet of the washing tower is connected to the exhaust chimney.

2. The VOC waste gas treatment system in the waste storage pretreatment process according to claim 1, characterized in that: The waste gas in the waste gas collection device is collected from a hazardous waste storage warehouse or a pretreatment workshop through an air suction system.

3. The VOC waste gas treatment system in the waste storage pretreatment process according to claim 1, characterized in that: There are at least two adsorption tanks, which are arranged in parallel.

4. The VOC waste gas treatment system in the waste storage pretreatment process according to claim 1, characterized in that: The waste gas treatment system also includes four fans installed one by one at the outlet of the waste gas collection device, the nitrogen outlet of the adsorption tank, the purified gas outlet of the adsorption tank, and the gas outlet of the washing tower; the waste gas treatment system also includes a waste liquid pump installed at the outlet of the waste liquid tank.

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