Ship unloading into the silo
Approximately five ships per month dock at the Cementa terminal. When ships arrive, they are either pneumatically or mechanically discharged. The mechanical unloading screw can unload up to 1100 tph from the ship and the material is then fed via a flexible chute towards an AUMUND bucket elevator. The cement is lifted by the bucket elevator approximately 15 m high and a 35 m long fluidslide sends the material from the jetty to two 80 m high bucket elevators with a 550 tph silo feeding capacity. The elevators run 14 hr/week.
Depending on the type of vessel that is docked, pneumatic unloading is carried out either via a pressure vessel or via a pump system. Material is discharged into a collecting bin that is located inside the stair tower – with a discharging capacity of up to 400 tph. The material is then transferred from the bin to one of the two silo feeding bucket elevators.
No mechanical conveying equipment is used at the facility; instead only fluidslides are used. Lennart Björkering at the Cementa silo explained: “If we were to use screws to get the cement out, we would need four screws with each one needing 200 kW power (800 kW altogether). We have two bucket elevators with a 200 kW motor each.” By using 200 kW bucket elevators rather than 800 kW, Cementa has a 75% lower energy consumption. The facility has been using the elevators for four years without needing to carry out any major maintenance.
Cement loading from the silo
The silo has three truck lanes for bulk loading from the silo. Trucks enter the lanes underneath the silo via a road entrance. There are two IBAU HAMBURG Simplex Loaders, each with a loading capacity of 250 tph. Each lane can accommodate different heights of various trucks and has a travel mechanism that enables the mobile loader to be positioned precisely above the blow tank filling socket.
Through the use of a chip-card system supplied by Haver & Boecker, the truck driver is able to complete the loading of cement independently, i.e. no further supervisory silo personnel is required, enabling a safe, reliable and efficient loading of cement. Once the loading process is completed, the truck will contain no more than 40 t of cement. Typically, the cement is then distributed locally across Sweden but Cementa also distributes to Germany and Denmark.
Dust controlThe facility has been open for several years now and questions may arise regarding dust buildup. However, the facility has good dust control measures to minimise buildup and reduce dust. Dust control is very important, according to Lennart Björkering. He explained the facility has 14 filters that control the levels of dust during loading and unloading.
All point sources that have dust emissions potential are equipped with Scheuch dust filters. The measurement is carried out by an accredited company every two years. The measurement includes all dust collectors and is made according to EN 13284-1.
The silo facility is committed to continually providing cement to the market. It currently is storing Bascement, Anläggningscement and flygaska (flyash). With the silo’s various storage compartments, it is fully equipped to efficiently handle various types of cement throughout the year and with an independently functioning unloading system, it facilitates proficient distribution across Sweden.
This is part two of a two-part article written for World Cement’s Ports and Terminals Supplement and abridged for the website. Subscribers can read the full April issue by signing in, and can also catch up on-the-go via our new app for Apple and Android. Non-subscribers can access a preview of the April 2016 issue here.
Written by Harleigh Hobbs
Read the article online at: https://www.worldcement.com/special-reports/28032016/port-visit-cementa-part-two/