Why is there any peculiar smell when the solvent recovery device meets the emission standard? How to further control the exhaust gas? Direct answer: reaching the standard and being odorless are two different things-the emission limit is set according to the concentration caliber, and the instrument measures the numerical value, while the human smell threshold for many solvents is much lower than the instrument detection limit, the concentration at the emission port is completely compliant, and the smell may still be smelled in the downwind direction; Odor may also come from unorganized emission. A small amount of gas escaping from the device flange, breather valve and waste liquid storage tank do not enter the discharge port, and the detection report, the nose is not fooled. In the order of governance, first block the unorganized emissions, and then talk about the depth of the discharge, the order reversal will spend money in the wrong place. This article clearly explains the sources of odors and the sequence for their control.
Two reasons. First, the olfactory threshold difference: the olfactory threshold of sulfur-containing solvents, aldehydes and ketones and some aromatic hydrocarbons is very low, and the odor can be sensed when the concentration is far below the limit value, which is the natural difference between the sensing caliber and the assessment caliber; Second, unorganized escape: sampling and measuring are the discharge ports, flange sealing, tank top breathing, and instantaneous escape during loading and unloading are not in this caliber, and on-site odor often comes from these "undetectable channels" undetectable channels ". The two reasons often exist at the same time, and the investigation must be carried out once. It is easy to do nothing but look at the discharge outlet.
The cost performance of unorganized discharge treatment is higher than that of discharge port modification: flange and valve packing are tightened and replaced periodically, waste liquid and recovery solvent storage tank are balanced with nitrogen seal or breather valve, closed joints are used in loading, unloading and feeding links, and all open containers are removed. These actions are not invested much, and the smell of the scene is usually lowered by one gear. The position of ventilation and discharge outlets in the workshop should also be reviewed to avoid the exhaust being brought back to the operation area by the airflow, thus forming a "standard but uncomfortable" situation. It is suggested to list the unorganized points one by one according to the area. It is easy to leak by feeling. The dense area of pump and valve is the key point.
When the odor at the discharge port cannot be pressed down, the players will be divided into stages according to the concentration: if the concentration is acceptable, the first-stage adsorption check will be given priority after membrane separation or condensation, with small investment and direct effect; If the concentration is very low but the odor is sensitive, consider introducing the exhaust gas into the boiler or thermal oxidation system to burn it, so that the solvent value cannot be returned but the odor can be cut off. If the process allows, the recovery efficiency of the front section. The selection of the three routes is based on concentration, gas volume and site, not whose equipment is advanced-the three data are measured clearly before selection, and the scheme naturally floats out.
| means | Applicable concentration | Features |
|---|---|---|
| cascade adsorption check | medium low concentration | Small investment, consumables need to be replaced regularly |
| introduction of thermal oxidation | Low concentration odor sensitive | Odor broken roots, running has fuel costs |
| Improve the recovery rate of the front section | Each concentration section | Decrease the load of the check section |
| Nitrogen sealing and closed feeding | disorganized escape | Invest small, do it first |
| Seal Cycle Management | Flange and pump valve | Periodicity to prevent recurrence |
| Ventilation review | Workshop feeling improved | Avoid exhaust backflow in operating area |
Don't take the report hardtop. First do unorganized emission investigation and management, then point detection in the downwind direction, and respond to complaints with comparative data before and after management; most complaints stem from unorganized dispersion and perceived differences.
Look at the trend of export concentration without looking at the calendar, penetrate forward and change; Record the emission data before and after replacement, and the cost of consumables and the effect of treatment are clearly set out.
Yes. Therefore, it is the last option: first improve the efficiency of the recovery section, and then apply thermal oxidation when there is only a small amount of tail gas left in the closing section, so as to minimize the amount of "burning.
This article by LuoyangWohong PetrochemicalEquipment Co., Ltd. arranges that the company provides design, manufacturing and operation and maintenance services for condensation recovery, membrane separation recovery and complete solvent recovery devices for chemical and pharmaceutical enterprises. If you need process evaluation or scheme configuration, please contact and exchange.
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