Talking about the Application of Solvent Recovery Device in Production of Flexible Packaging

Solvents are currently used in many aspects of flexible packaging production. For example, production equipment, plate cylinders, and work tools are mostly cleaned with flammable organic solvents. After cleaning, these heavily polluted solvent wastes will volatilize during storage. On the one hand, they will seriously pollute the environment; on the other hand, direct or indirect contact with solvents by the human body will also affect physiological health in varying degrees, and even severely endanger life. Therefore, these waste solvents must be drained in time, but the cost is often high. In recent years, a number of companies have begun to develop equipment for the recovery and utilization of waste solvents. So far, a more mature treatment method is a self-purification treatment method using the distillation principle to separate the solvent from the waste liquid.

Common solvent waste treatment

In the actual process, there are three main waste treatment methods.

1. Through a professional sewage company to regulate the sewage

The waste removal regulations clearly regulate the standard waste removal. Such work can only be entrusted to waste removal agencies approved by the government. In Germany, if the amount of waste removed is not large, the cost of removal is generally above 0.55 marks/litre.

The waste disposal method is usually incineration, and the cost of incineration mainly depends on the heat of combustion and the content of H2O.

2. Recycling by the supplier at each delivery

Some suppliers have stated that they are willing to recycle used waste solvents when they purchase new solvents. In this case, the recovery will depend on the desire of the supplier. In addition, due to the high cost of sewage, the purchase price of new solvents is getting higher and higher. Therefore, this method is costly.

3. Distillation purification and recycling through professional service companies

If the amount of solvent to be removed is large, it is necessary to rely on specialized service companies to carry out distillation purification treatment, and the purified solvent is then delivered to the original company for continued use. The disadvantage of this approach is the quality of the solvent purification process, instability, and low recovery.

Self-purification of solvent waste

In general, when the solvent is used for cleaning, the content of the contaminants dissolved in the solvent can reach 30%, and the purification effect is often unsatisfactory by simple filtration and membrane technology. If the solids content in the wash solution exceeds 50%, the most effective solvent recovery method is high temperature distillation, which separates the solids from the liquid. For example, OFRU Resource Recycling Co., Ltd. has been engaged in the research and development of this technology for 20 years and has developed a “self-circulation operation” solvent waste liquid purification treatment device. The solvent after recycling is clean and pure, and it can be used again. For washing operations, solvent purchase costs and solvent storage and discharge costs can be drastically reduced.

Advantages of self-purification treatment 1 High recovery rate, valuable raw materials can be recovered;
2 no longer rely on other companies;
3 can handle high quality solvents as needed;
4 Low input costs, and can reduce processing costs up to 90%;
5 Very short cost recovery period, usually less than 1 year;
6 Reduced solvent storage, thereby reducing operating funds;
7 Reducing environmental pollution will help the company meet SO environmental standards.

Self-cleaning treatment technology

Solvent waste or contaminated solvents (organic solvents or aqueous solvents) can be purified by evaporating and then condensing. In this regard, OFRU can provide a range of models of distillation equipment. According to different uses, the distillation unit provided has a capacity of 2 to 2000 liters/hour, and if the distillation purification apparatus can be used in combination with the existing washing system, the effect is most satisfactory.

First, the contaminated solvent is pumped or manually discharged into an evaporation vessel. A heat-conducting medium is arranged on the jacket of the evaporation container to heat the liquid solvent. The heat-conducting medium may be steam, hot water, or hot oil. When the solvent reaches its boiling point, it begins to evaporate, changing from a liquid to a gas. After passing through the condenser, the solvent vapor will return to its liquid state. As a result, the contaminated solvent becomes a clean, clear regenerated solvent.

In the distiller, dirt is trapped. Since the temperature in the evaporator is still high, the residual dirt can easily be drained away in the liquid state. Distillation bags are recommended if the solids require evaporation to dryness. Distillation bags are placed in distillation boilers prior to distillation. Distillation bags contain the contaminated solvent. After distillation, the distillation bag can simply be removed from the distillation equipment. Since the squeegee and other appliances are omitted, the entire purification cost is reduced. After the residue is solidified, it is recommended to collect it in an old container, which can be used to achieve a standardized disposal of waste on an ordinary dumping site.

Reuse of purified solvents

The solvent recovered by the distillation purification process can be reused. When used repeatedly, the distillation mixture loses its "intensity" because its low-boiling substances are lost over time. In order to achieve the original quality, you can add some fresh solvent to balance.

Investment Analysis

Several major factors of cost accounting

The impact factors for the assessment of purchased solvent recovery equipment are summarized. Need several weights

1 How much is the purchased equipment and how much is the price?

2 Whether it is to remove or transport waste or to take it away from the supplier free of charge, it will incur a certain cost, while the latter will have to bear obligations for a long time.

3 What is the required storage room? What is the task of storing new solvents and waste solvents?

From the point of view of self-cleaning treatment, there are several points that are very important.

1 Evaporation of solvent required electricity consumption (recovery of 100 liters of solvent waste power consumption of about 15kW/h
2 Is the condensation water-cooled or air-cooled?
3 Personnel to be put in (processing cost for inspection and cleaning 4 distillation residues (RMB/ton). Period of installment payment According to experience, equipment for solvent recovery, regardless of its size, installment payment period of up to 3 years. Payments can be paid within a few months, which is closely related to each recovery cost (reuse) and the purchase price of the solvent. If it is a small batch of solvent recovery, add it; Cost-effective.

Installation and purification of recycling equipment conditions

In Germany, installation of small-scale purification and recycling equipment is not required to apply for approval, as long as the production of notices. Due to geographical differences, the respective competent authorities are not the same and generally need to notify the industry security inspection department.

OFRU's solvent recovery equipment is explosion-proof, so it can be used for the distillation of combustible solvents. The equipment is installed in an explosion-proof and fireproof place. It can also be installed in the open air. It only needs a roof.

Conclusion

Self-cleaning treatment of contaminated washing solvents is worthy of promotion. Its investment can be recovered in the short and medium term. Especially when used in combination with existing washing and purifying facilities, the use of purification and recycling equipment can greatly reduce the waste solvent discharge. And the cost of new solvent purchases. Every day, fresh solvents are present, which is no longer a desire today. By the self-circulating treatment of dirt, a very low production cost can be achieved.

Shanghai Zhipu Printing Technology Co., Ltd. Zhang Isaac

Source: Printing Technology