WCA March 2024

Technology News

By-product separator: operating CV lines responsibly 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. in operation); 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 individual components for by-product removal as a part of an overall approach. The goal is to 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. A time-controlled valve 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. BPS and GRH are available as upgrades, to integrate into any existing CV line. Maillefer can provide three upgrade types for existing CV lines – 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

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); reduced maintenance work (less cleaning needed; increased reliability of vulcanising equipment and instruments

A clean BPS unit before by-product extraction

The same unit showing successful residue collection

Invented in 1952.

Fit for the future.

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March 2024