The new cleaning process brings new life to heat exchangers

Thread Content

New cleaning process revives heat exchangers Author/Source: Sinochem New Network Date: 2020-03-27 Clicks: 115 Recently, good news came from the Second Chemical Production Workshop of Shanxi Coking Company: the temperature of the ammonia vaporization wastewater dropped from 55°C to 37°C! This indicates that the heat exchangers for this wastewater have achieved the desired results as a result of the technical upgrades and cleaning processes. 　　It is understood that the ammonia vaporization unit is primarily responsible for processing the excess ammonia water from the coking system; on one hand, it produces concentrated ammonia water of economic value, and on the other hand, it ensures that the wastewater meets the temperature requirements for biological treatment. For a long time, due to the tar present in the ammonia vaporization wastewater and scaling on the cooling water side, the heat exchangers used for this wastewater have been prone to blockage, which has resulted in a **reduction in their heat exchange efficiency and service life**. Although multiple attempts were made previously, the results were not satisfactory; the replaced heat exchangers had to be discarded, resulting in a significant reduction in economic benefits. 　　The Second Chemical Production Workshop of Shanxi Coking Company carried out bold innovations in the cleaning process for used heat exchangers, based on the physical and chemical properties of the dirt inside those heat exchangers. In accordance with the cleaning plan, technicians clean the wastewater side of the heat exchanger. After connecting the heat exchanger to the crude benzene system, it is cleaned using oil at 170°C. The heavy tar attached to the inside of the heat exchanger dissolves completely in the cleaning oil due to the heating, and then it is removed from the system through a regenerator; this process does not affect the normal operation of crude benzene production. They carry out chemical cleaning of the cooling water side using acid wash solutions prepared on their own; amino sulfonic acid, which has stable chemical properties, low corrosivity, and excellent cleaning efficacy, is used as the main cleaning agent, along with surfactants and strippers, to thoroughly remove the dirt from the cooling water side. After 48 hours of continuous cleaning, the cleaning task was completed successfully. During the cleaning process, this workshop conducted repeated tests and inspections, exercising strict control over various aspects such as the design and construction of cleaning pipelines, the management of cleaning process parameters, and the adjustment of operations in the crude benzene system, to ensure flawless cleaning results. 　　“After the cleaned heat exchanger is put into use, it not only ensures the temperature of the biochemical feedwater but also extends the service life of the wastewater heat exchanger; this alone saves the company over 200,000 yuan per year. ”Zhang Peng, the main person in charge of the project, said.