Hebei Province, Henan Province, Shandong Province, Jiangsu Province and other provinces have issued documents on comprehensively strengthening the control of volatile organic compounds pollution, in-depth assistance for volatile organic compounds treatment, and on the basis of enterprise self-inspection, carrying out sampling tests on VOCs waste gas collection and investigation of potential safety hazards in treatment facilities. During the inspection, it was found that the enterprises generally had problems such as incomplete ledger collection, low exhaust gas collection rate and removal rate of treatment facilities, non-standard setting of hazardous waste storage sites, lack of sampling ports or non-standard sampling port settings, as follows:
In terms of VOCs material ledger, enterprises generally do not summarize all the information that needs to be sorted out on a ledger as required, and the record format is not standardized.
According to HJ 944-2018 "General Provisions of Technical Specifications for Environmental Management Ledger and Pollutant Discharge Permit Implementation Report of Pollutant Discharging Units (Trial)", enterprises should establish a ledger of raw and auxiliary materials containing VOCs, including the name, amount used, ** amount, amount of waste, whereabouts and VOCs content of raw and auxiliary materials.
In terms of the operation ledger of treatment facilities, enterprises lack systematic information records, especially incomplete information records such as operation time, waste gas treatment capacity and residence time.
According to GB37822-2019 "Volatile Organic Compounds Fugitive Emission Control Standard", enterprises should establish a ledger to record the main operation and maintenance information of waste gas collection systems and VOCs treatment facilities, such as operation time, exhaust gas treatment capacity, residence time, adsorbent regeneration replacement cycle and replacement amount, catalyst replacement cycle and replacement amount, absorption liquid pH value and other key operating parameters. The retention period of the ledger shall not be less than 3 years.
In the process of on-site inspection, due to the influence of the production workshop is too large or the production equipment is too large, and the production line is too long, the processes with low exhaust gas collection efficiency are, and the production workshop of injection molding, film blowing, mixing, calendering and other processes in the plastic products industry is difficult to seal.
Some enterprises collect the organic waste gas generated in the molten state of plastic by setting up a local gas collection hood in the workshop, but due to the large movement of the production equipment, the distance between the gas collection hood mouth and the control point is far, and the collection effect is poor. The post-press finishing process of the printing industry, the gluing process is carried out directly in the printing workshop, because the printing equipment comes with a collection port, the waste gas generated is easy to collect, and the adhesive waste gas is discharged unorganized in the workshop, and the waste gas of the edge sealing process of the furniture products industry is also easy to be ignored and discharged in an unorganized form.
In the process of on-site inspection, it was found that the number of UV lamps installed in some enterprises did not match the processing capacity, or the particles generated by the process did not enter the UV photolysis device directly after pretreatment, and the particles settled on the UV lamps, and the photolysis effect was minimalThe amount of activated carbon filled does not match the amount of volatile organic compounds produced to be treated, or the activated carbon is in a state of failure because the activated carbon is not replaced for a long time.
According to the provisions of HJ 2026-2013 "Technical Specification for Industrial Organic Waste Gas Treatment Engineering by Adsorption Method", the gas flow rate of the adsorption layer of the fixed bed adsorption device should be determined according to the form of the adsorbent. When using granular adsorbents, the gas flow rate should be less than 06 m/s；When using fibrous adsorbents (activated carbon fiber felts), the gas flow rate should be less than 015m/s；When using honeycomb adsorbents, the gas flow rate should be less than 12 m/s。The flow rate of the exhaust gas in the adsorption device is too fast and the residence time is insufficient, resulting in the emission of volatile organic compounds in the exhaust gas without being adsorbed or achieving the desired treatment effect.
The secondary pollutants generated during the operation of enterprise governance facilities, such as spray waste liquid, adsorption saturated waste activated carbon or filter cotton, and the outer packaging of raw materials contaminated with organic solvents used in the production process, are all hazardous wastes and contain volatile organic compounds. During the on-site inspection, it was found that the enterprise had waste paint buckets that were not covered for storage, or that the hazardous waste was not put in the designated hazardous waste storage site. In some enterprises, there are no standardized signs in the hazardous waste room, and the ground is not treated with anti-seepage.
In order to calculate the removal rate of the treatment facility, the enterprise shall set up a permanent standard sampling port at the appropriate position of the air duct before and after the exhaust gas treatment facility, and the location of the sampling port shall comply with the provisions of HJ T 397-2007 "Technical Specification for Waste Gas Monitoring from Fixed Sources" and GB T 16157-1996 "Sampling Method for Particulate Matter and Gaseous Pollutants in the Exhaust of Fixed Pollution Sources", and the sampling position shall be set at a diameter of not less than 6 times the diameter from the downstream direction of the elbow, valve and reducer and not less than 3 times the diameter from the upstream direction of the above components. In order to facilitate sampling, the exhaust port sampling port is mostly set up in a place less than 1 times the diameter downstream of the elbow, and the sampling data is inaccurate and the disposal rate of the treatment facility cannot be calculated.
* |Qinghui environmental protection.
Edit |Small fish.
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