Most of the condensate in the condensation recovery unit carries water: if the water is not properly treated, the quality of the recovered liquid cannot be improved, and there are many disputes in the reuse process. The stratification tank is dry-the condensate is left standing in the tank, the solvent phase and the water phase are naturally separated by density difference, the solvent phase is transferred to storage for reuse, and the water phase is measured and processed. The stratified tank looks like a static tank, which is not well managed, and the problems of recycling liquid with water and water phase with solvent will occur at both ends.
The three grips of stratified tank management are standing time, interface control and quality inspection: time is not enough for stratification and is not complete, interface control is not allowed to entrap the two phases with each other, and the detection vacancy problem is exposed only when it flows to the reuse end. All three things have been done in place, and the layered tank is really under control.
The standing time is not determined by patting the head: the greater the density difference between solvent and water, the faster the separation will be, and the interface of aromatic condensate will be clear when it is standing for half an hour to one hour. Condensate containing more mutually soluble components such as alcohol ketone has limited parts that can be divided, and the function of standing is mainly to sink free water. Time shall be measured by batch-sampling and observing the interface regularly after the condensate is fed into the tank. The time required for the stability of the interface is the static time benchmark of the device, which shall be written into the operation procedures and implemented by batch. For devices with tight production rhythm, two tanks are used to rotate and stand still, giving consideration to both time and output.
The influence of the feeding method on the stratification is often ignored: the feeding directly rushes to the bottom of the tank, which will stir up the already divided layers, and the static efforts in front are all in vain. The way of feeding and buffering allows the condensate to flow into the tank slowly, the disturbance is small, and the stability of stratification is obviously improved.
The operation core of interface control is water discharge: water phase is discharged from the bottom of the tank, and when it is placed near the discharge port, it will stop, and the solvent will run off. The interface shall be observed by sight glass or liquid level gauge, and shall be recorded by water discharge step by step; if conditions permit, the interface instrument shall be provided with high and low limit alarm, and manual observation shall be conducted to check each other with the instrument. The released aqueous phase is not released in one go: the solvent content in the aqueous phase is measured, and the high content is separated or refluxed for two times, and the account is not leaked.
The detection before the solvent phase is transferred is the last pass: moisture is the first item, and most reuse scenarios have window requirements for moisture; Purity or distillation range is determined by downstream use. The qualified inspection is transferred to storage, the unqualified return processing, the transfer and return are recorded, and the quality management falls on the batch ledger.
| Management item | Key operational points | Disposal of common problems |
|---|---|---|
| Standing time | According to the batch actual determination benchmark | If it is not enough, rotate the two cans. |
| Feeding mode | Upper feed slow-flow non-flushing layer | Change of punching layer to buffer feeding |
| interface observation | The sight glass level gauge checks each other | Alarm High and Low Limit Settings |
| Bottom drain | Put it near the interface and stop | If the solvent is over-released, the solvent will be lost. |
| water phase treatment | Transfer after detection and metering | secondary separation with high content |
| Quality inspection | Moisture purity batch by batch | Unqualified return processing |
Check the operation first and then look at the design: whether the standing time is enough and the feeding method does not flush the tank are all common reasons-the feeding directly to the bottom will stir up the divided layers, and most of them can be improved by changing the feeding and buffer plate. Evaluate the structure of the tank after the operation is eliminated, and modify it if necessary.
Moisture is the first item, most reuse scenarios have window requirements for moisture. There are records of qualified transfer storage, unqualified return processing, transfer and return.
Low temperature makes viscosity rise and stratification slow, and the standing time is appropriately lengthened. The tank body is kept warm or heated to keep the temperature, and the condensate does not freeze or stratify. Before winter, check the heat preservation of the tank again, and do the antifreeze of the drain pipe together.
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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