EuroWire January 2024

Technology News

By-product separator: operating CV lines responsibly

and environment and sustainability (cleaner exhaust nitrogen gas from CV line to atmosphere; less waste water; better controlled by-product collection). Maillefer has developed the by-product removal process as an integral part of CV line development, and offers several individual components for by-product removal as a part of an overall approach. The goal is to secure and maximise production potential and to minimise the scrap cable produced. The BPS and the gas reheater (GRH) component are the most effective parts of a by-product extraction system. The BPS separates the decomposed crosslinking by-products by condensing associated particles found in the nitrogen flow. The condensate is collected at the bottom of the unit. The BPS is equipped with a time-controlled valve that purges the liquid waste collected towards holding tanks. The GRH continues by increasing the temperature of the gas returning from the BPS. It is located in the same gas circulation loop as the BPS, and the heated gas is injected into the second to-last curing tube, at the same temperature as the nitrogen within the curing tube. Both BPS and GRH are available as upgrades, ready to integrate into any existing CV line. Maillefer can provide three main upgrade types for existing CV lines in order to improve by product extraction – complete, partial and selective. Complete: if the CV line is not equipped with a by-product removal system, a complete BPS system with GRH is proposed. By studying the by-product removal process for the CV in place, a full system is engineered accordingly. Partial: if the line is already equipped with BPS but without a GRH, it is possible to improve by-product separation by integrating the new component into the existing circulation loop and BPS. Selective: if the existing CV line is equipped with a by-product removal system that gives undesired results, selected elements are replaced, which may include Maillefer’s BPS and GRH. Maillefer Extrusion Oy www.maillefer.net

By-product formation during the continuous vulcanising process has been primarily a cable quality issue, but has equally become an environmental one. Maillefer offers a modern by product separation (BPS) system that couples to extrusion lines seamlessly. Medium voltage, high voltage and extra-high voltage cables are largely XLPE insulated and produced on CV lines. The crosslinking method employed on horizontal (HVC), vertical (VCV) or catenary (CCV) CV lines is peroxide based. If the unwanted by-products that result from this process are insufficiently extracted, they will cause cable quality issues. Improved by-product separation and collection during the CV process has multiple benefits directly on the product and also on the environment: maintaining optimal production conditions (stable cooling and heating capacity; cleaner cooling water and cooling gas; fewer quality issues with produced cables and scrapped cables); reduced maintenance work (less curing tube and heat exchanger cleaning needed; increased reliability of vulcanising equipment A clean BPS unit before by-product extraction

and instruments in operation; decreased maintenance costs);

The same unit showing successful residue collection

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January 2024