Bulk Cement Shipping
Bulk Cement (Powdered Cement) in bulk is fluid enough to be pumped and, as a result, there exist cement-tankers which have tanks rather than holds and which rely on pneumatic pumps to discharge their cargoes.
Some such ships supplement or substitute this facility by using shipboard mechanical equipment, such as Siwertell handling systems to discharge, whereby cement is lifted by Archimedean screw out of cargo compartments and carried overside by conveyor-belt or bucket-line. Such ships are usually too specialised for tramping and will be employed on and built for long-term contracts, serving the cement industry.
Bulk Cement can be quite readily transported in conventional bulk carriers, though, cargo-handling in these cases being effected by one or more of a variety of methods. The simplest, perhaps, is to use grabs fitted either to shoreside apparatus or to the ships’ own gear for both loading and discharging, the problem with such a system being the amount of dust created.
Consequently, some bulkers are loaded by pneumatic means, small holes (cement holes) being cut into the closed hatch-cover of cargo compartments, and pipelines connected to each; one or more through which to load cement, and one or more others via which to extract dust and air from the compartment. Upon completion of loading, the pipelines are disconnected and the small holes (cement holes) made good to the Ship Master’s and/or Classification Society’s approval as to seaworthiness, a typical charterparty clause covering such a loading method being:
“In order to facilitate the loading operation, Charterers to have the option to burn up to three holes of approximately 100 centimetres diameter in the hatch of each hold which is to be loaded, such burning to be performed under supervision of Master and class surveyor. The holds are to be rewelded to class surveyor’s satisfaction prior to departing from last load port. It is agreed that all such work shall be carried out in Charterers’ time and at their expense.”
After Bulk Cement Shipping, to avoid dust pollution at the cargo receiving end, discharge may be effected by shore-based pneumatic or mechanical means or, in the case of ships involved on only short distances and thus discharging before the cargo has had a chance to compact, by vacuvator.
Where these facilities do not exist, however, a further alternative is to discharge into a Cement Mothership anchored off-shore, where atmospheric pollution will be less obnoxious to the local environment. Such Cement Mothership may be fitted with mechanical equipment to help them to unload bulk carriers secured alongside, storing product on board and thereafter discharging cement over side into smaller coastal craft, or proceeding into port to discharge via a sealed unloading system into silo, lorries or railway wagons.
In case of need, cargo can be stored onboard for some time, and certain, sophisticated Cement Motherships incorporate even a bagging plant, by which method bulk cement can be converted prior to discharge by conveyor belt for onward distribution.
Bulk Cement is thus a perfectly feasible cargo for conventional bulk carriers, although it is important that before loading cargo compartments are scrupulously clean and odour-free.
The slightest amount of sugar residue from a previous cargo, for example, can ruin Bulk Cement by destroying its binding properties, whilst ammonia fumes create quick-setting tendencies in the cargo.
Bulk Cement loaded direct from factory kilns, incidentally, may sometimes be as warm as 75°C.
The angle of repose of Bulk Cement can vary widely, and mechanical trimming equipment may be employed to obtain a reasonable cargo level, a ship occasionally being required to remain alongside the loading berth for twelve hours or so, to enable trapped air to exit from the cargo and for a stow to settle.
Ship’s cargo compartments should be thoroughly swept and cleaned following the discharge of bulk cement, although this operation may be hindered if dampness or water ingress into the hold has caused portions of the cargo to adhere to hold sides, necessitating the laborious task of chipping away solidified pieces.
Bulk Cement Stowage Factor:
- Bulk Cement Stowage Factor 22/27
The carriage of cement at sea has grown steadily in volume until today it provides a major source of merchant ship employment. There are various types of cement requiring a variety of ingredients based on supplies of chalk or limestone, clay, ores, gypsum and flyash, (once a waste product from coal-burning power stations). But from a seaborne trade perspective, the product can be divided into bagged and bulk, the latter being capable of sub-division into finished cement and clinker. Whether for bagged or for bulk, nearly all carriage terms are negotiated on adapted versions of the GENCON Charterparty Form. Many nations possess cement factories, and thus the business takes the form of a complex trade of criss-crossing shipments of raw materials to these factories; partly refined cement (clinker) transported between cement works perhaps hundreds of miles apart; and the final, vital product for construction projects being delivered around the world in bags or in bulk. This final product is a fine grey powder which contracts as much as 12% from an aerated condition following handling, to a non-aerated state once it has settled, and which can be very dusty. Obviously it should be kept scrupulously dry so as to avoid solidifying, and conventional, non-sealed cargo-handling work cannot be conducted in rainy conditions.
As with many commodities, certain regions lack both the infrastructure and the port facilities to handle bulk commodities and, as a result, there is demand in these areas for cement imports to be bagged (Bagged Cement), preferably in single, manageable sacks.
The sacks utilized are usually of the paper type in several ply strength which, although requiring more handling than units of sacks grouped together on pallets, are easier to shift by a surplus of labour and in the absence of fork-lift trucks and other mechanized assistance, as is often the case in developing regions.
Bagged Cement Shipping
At the loading end, however, many cement factories employ sophisticated apparatus enabling speedy loading of single or palletized sacks on ships adjacent to the works, although a careful check will need to be made of hatch opening sizes and of tween-deck clearances to ensure that the loading apparatus, fork-lift trucks and any pallets themselves will fit into available spaces.
In addition to the loaded Cement Bags (Bagged Cement), a quantity of empty bags, usually around 3% of the number filled, are usually included by shippers to replace paper bags split open during discharge handling.
Shippers often prefer to load sacked cement into tween-deck general cargo ships or into multi-purpose ship types having the facility of reducing the height of stow which, in the case of excessive tier heights in single-deck ships, may cause splitting of lower stowed bags.
To assist the speed of handling in inclement weather conditions, some manufacturers are able to cover cement in paper sacks by an outer plastic sheeting, shrink-wrapped for added security.
What is Jumbo Bag (Big-Bag)?
Jumbo Bags (Big-Bags) are made from such as polypropylene or PVC-coated polyester are a modern alternative to carrying cement in paper sacks, each bag of around 1 to 1.5 metric tonnes capacity (with heavy-duty bags of up to 3 tonnes capacity) lifted by plastic straps.
The cheaper polypropylene versions of these sacks are often split at the discharging ports or thereafter and destroyed, but the latest generation of heavy-duty PVC-coated polyester jumbo-bags are virtually climate-proof, can be utilized for storage purposes, and are re-usable for up to several years and for many trips.
Paper Bagged Cement
Additionally, cement in conventional Paper Sacks (Bagged Cement) may be palletized, shrink-wrapped, in units of between 1.5 and 2.5 tonnes each, providing facilities exist at each end to manoeuvre and to handle such cargo.
Bulk Cement Shipping
Bulk cement shipping involves the transportation of large quantities of cement in specialized ships designed to handle powdered or granular materials. Cement is an essential construction material used worldwide, and the ability to transport it efficiently and safely is crucial to support infrastructure development and maintenance.
Key aspects of bulk cement shipping include:
- Bulk Cement Ship Type: Bulk cement is typically transported using specialized ships known as cement carriers or pneumatic cement carriers. These ships have specialized cargo holds and equipment designed to handle the movement and storage of powdered materials like cement. Some of these ships are equipped with self-discharging systems, such as mechanical or pneumatic systems, that facilitate the unloading process at the destination port.
- Bulk Cement Loading: Loading bulk cement onto a ship requires specialized equipment, such as blowers or air compressors, which pump the cement into the cargo holds through a system of pipes and hoses. The cement is typically loaded in a powdered or granular form and requires careful handling to minimize dust generation and contamination.
- Bulk Cement Stowage: Bulk cement is a high-density cargo with a relatively low stowage factor, typically ranging from 0.95 to 1.05 m3/MT (33.5 to 37 ft3/LT). This means that it takes up less space in the cargo hold compared to other bulk materials, allowing for efficient use of the ship’s capacity.
- Bulk Cement Shipping Safety: The transportation of bulk cement presents several safety considerations, including the risk of dust explosion and the potential for cargo shift. Proper ventilation and dust suppression systems are essential to minimize these risks. Additionally, the crew must follow safety procedures and guidelines for handling powdered cargos to ensure the safe transportation of bulk cement.
- Bulk Cement Unloading: At the destination port, the cement is typically unloaded using specialized equipment, such as mechanical or pneumatic systems, which transfer the cement from the ship’s cargo holds to storage facilities or directly to trucks or railcars for further distribution. The unloading process must be carefully managed to prevent dust generation and contamination of the environment.
Bulk cement shipping is an essential component of the global cement trade, enabling the efficient and safe transportation of large quantities of this vital construction material to support infrastructure projects worldwide.
Pneumatic Cement Carriers
Pneumatic cement carriers are specialized ships designed for the transportation of cement and other powdered materials in bulk. They are equipped with advanced systems that facilitate the efficient loading, stowage, and unloading of cement, ensuring the safe and effective delivery of this essential construction material. Some key features and aspects of pneumatic cement carriers include:
- Pneumatic Cement Carriers’ Cargo Holds: Pneumatic cement carriers have specially designed cargo holds that are constructed to store and transport powdered materials like cement. These holds are often coated or lined with materials that minimize friction, prevent contamination, and facilitate the flow of cement during loading and unloading.
- Pneumatic Cement Carriers’ Pneumatic Conveying System: One of the defining features of a pneumatic cement carrier is its pneumatic conveying system. This system uses air compressors or blowers to create a flow of air that carries the cement through a network of pipes and hoses. The pneumatic conveying system enables the efficient loading and unloading of cement, reducing the need for manual labor and minimizing the risk of dust generation and environmental contamination.
- Pneumatic Cement Carriers’ Self-Discharging Capabilities: Many pneumatic cement carriers are equipped with self-discharging systems that allow the ship to unload its cargo without the need for additional equipment or infrastructure at the destination port. These systems can include mechanical or pneumatic equipment, such as screw conveyors, air slides, or fluidized discharge systems, which facilitate the transfer of cement from the ship’s cargo holds to storage facilities or directly to trucks or railcars for further distribution.
- Pneumatic Cement Carriers’ Dust Control and Ventilation: The transportation of cement in bulk can generate significant amounts of dust, posing safety and environmental risks. Pneumatic cement carriers are equipped with dust control and ventilation systems that help minimize dust generation during loading, stowage, and unloading. These systems may include dust collectors, filters, and air-sealing devices to ensure a clean and safe working environment.
- Pneumatic Cement Carriers’ Safety Considerations: The operation of pneumatic cement carriers involves several safety considerations, including the risk of dust explosions and the potential for cargo shift. Crew members must follow strict safety procedures and guidelines for handling powdered cargos, and the ship must be equipped with appropriate safety equipment, such as fire suppression systems and gas detection devices.
Pneumatic cement carriers play a crucial role in the global cement trade, enabling the efficient and safe transportation of large quantities of cement to support infrastructure development and maintenance worldwide. These specialized ships are designed to optimize the handling of powdered materials, ensuring their safe and effective delivery to their intended destinations.
Types of Cement
Some of the most common cement types include:
- Ordinary Portland Cement (OPC): OPC is the most widely used type of cement in the construction industry. It is made from limestone, clay, and other raw materials, which are heated at high temperatures to form clinker. The clinker is then ground with gypsum to produce OPC. OPC is available in different grades, such as 33, 43, and 53, which indicate the cement’s compressive strength in megapascals (MPa) after 28 days of curing.
- Portland Pozzolana Cement (PPC): PPC is a type of blended cement that includes pozzolanic materials, such as fly ash, rice husk ash, or volcanic ash, in addition to the usual cement clinker and gypsum. The addition of pozzolanic materials improves the cement’s long-term strength, durability, and resistance to chemical attack. PPC is commonly used in hydraulic structures, marine structures, and masonry applications.
- Rapid Hardening Cement: Rapid hardening cement, also known as high early strength cement, is designed to achieve high strength in a short period. It is made by finely grinding cement clinker and gypsum, resulting in a higher specific surface area and faster hydration. Rapid hardening cement is used in situations where quick strength development is required, such as repair works, precast concrete, and cold weather concreting.
- Low Heat Cement: Low heat cement is formulated to produce less heat during hydration, reducing the risk of thermal cracking in large concrete structures. It contains a lower proportion of tricalcium aluminate (C3A) and dicalcium silicate (C2S) in the clinker, resulting in slower hydration and lower heat generation. Low heat cement is commonly used in mass concrete structures, such as dams, bridge piers, and thick concrete slabs.
- Sulphate Resisting Cement: Sulphate resisting cement is designed to resist the harmful effects of sulphates, which can cause concrete deterioration and loss of strength. It contains a lower proportion of tricalcium aluminate (C3A) in the clinker, making it less susceptible to sulphate attack. This type of cement is used in structures exposed to high levels of sulphates, such as sewer systems, foundations, and coastal constructions.
- White Cement: White cement is made from raw materials with low iron content, resulting in a white-colored cement with similar properties to OPC. It is often used for architectural and decorative purposes, such as precast concrete, terrazzo, and stucco, as well as in applications requiring a high aesthetic appeal.
- Masonry Cement: Masonry cement is a specially formulated blend of Portland cement, limestone, and other additives, designed for use in mortar applications. It provides improved workability, adhesion, and water retention, making it suitable for masonry work, such as bricklaying, stone masonry, and plastering.
Bulk Cement Ocean Transportation
Ocean transportation of bulk cement involves several key considerations and steps to ensure the safe and efficient movement of the cargo from the loading port to the destination port. Here is an overview of the process:
- Selection of the Appropriate Ship: Based on the quantity and specifications of the cement cargo, a suitable ship must be chosen. Common types of ships used for bulk cement transportation include specialized cement carriers, self-discharging bulk carriers, and pneumatic cement carriers.
- Bulk Cement Cargo Handling Equipment: The selected ship should be equipped with suitable cargo handling equipment, such as pneumatic conveying systems or mechanical discharge systems, for efficient loading and unloading of the cement.
- Bulk Cement Loading Port Preparation: Prior to loading, the loading port should ensure that the cement cargo is adequately prepared, free from contaminants, and that the loading equipment is in good working condition.
- Bulk Cement Stowage Planning: A stowage plan should be developed, taking into account the stowage factor of the cement, the ship’s cargo capacity, and any specific requirements related to the cargo or ship. The stowage plan should aim to maximize space utilization and ensure the safe and efficient handling of the cargo.
- Bulk Cement Loading Process: The loading process should be carefully monitored and supervised, ensuring that the cargo is loaded in accordance with the stowage plan and any applicable regulations or guidelines.
- Securing the Bulk Cement Cargo: Once loaded, the cement cargo should be properly secured to prevent shifting or damage during the voyage. This may involve using additional securing measures, or adjusting the ship’s ballast and trim.
- Bulk Cement Ship Voyage Planning: The ship’s route should be planned, taking into account weather conditions, navigational hazards, and any other factors that may affect the safety and efficiency of the transportation.
- Bulk Cement Unloading Process: Upon arrival at the destination port, the unloading process should be carefully managed and supervised to ensure the safe and efficient discharge of the cement cargo. Special care must be taken to prevent exposure of the cement to moisture during unloading, as this can lead to cement solidification and damage to the cargo.
- Bulk Cement Shipping Compliance with Regulations: Throughout the entire ocean transportation process, all parties involved must ensure compliance with applicable international and local regulations, such as the International Maritime Solid Bulk Cargoes (IMSBC) Code, which provides guidelines for the safe handling and transportation of bulk cargoes, including cement.
By considering these factors and following best practices for the ocean transportation of bulk cement, shipping companies can ensure the safe, efficient, and cost-effective delivery of the cargo to its final destination.
Top Cement Exporting Countries
Currently, the following countries are among the top cement exporters:
- China: China is the world’s largest cement producer and exporter, driven by its vast population, rapid urbanization, and extensive infrastructure development projects. The country is home to numerous cement manufacturers and has a significant production capacity.
- Turkey: Turkey is another significant player in the global cement trade, with a well-developed cement industry and favorable geographical location. The country exports cement to various regions, including Europe, Africa, and the Middle East.
- Vietnam: Vietnam has emerged as a major cement exporter in recent years, thanks to its rapidly growing cement industry, which is supported by abundant limestone reserves and government initiatives to modernize the sector. The country exports cement to various destinations, including Southeast Asia, East Asia, and the Pacific region.
- Japan: Japan is a notable cement exporter, with a well-developed cement industry and advanced production technologies. The country exports cement to various markets, including East Asia and the Pacific region.
- Germany: Germany is a leading cement exporter within the European Union, with a well-developed cement industry and advanced production technologies. The country exports cement to various European and global markets.
- Spain: Spain is another significant cement exporter within the European Union, with a strong cement industry and extensive production capacity. The country exports cement to various markets, including Europe, Africa, and the Middle East.
- India: India is a major cement exporter, with a large domestic cement industry and vast limestone reserves. The country exports cement to various destinations, including South Asia, the Middle East, and Africa.
- Thailand: Thailand is a notable cement exporter in Southeast Asia, with a strong cement industry and abundant limestone reserves. The country exports cement to various regional and global markets.
- Iran: Iran is a significant cement exporter in the Middle East, with a well-developed cement industry and extensive production capacity. The country exports cement to various markets, including the Middle East, Central Asia, and Africa.
- Pakistan: Pakistan is a major cement exporter in South Asia, with a growing cement industry and vast limestone reserves. The country exports cement to various destinations, including South Asia, the Middle East, and Africa.
These countries play a crucial role in the global cement trade, ensuring the availability of cement for construction projects worldwide. Their well-developed cement industries and infrastructure enable them to produce and export large quantities of cement to meet global demand.