The transfer of bulk fluids and solids from storage to transport is one of the few areas where the output of a factory is exposed to atmosphere and human presence during its lifetime. This fluid/powder has been crafted using science and engineering. In some cases this takes minutes, but most likely is the summation of many hours of consumed energy, craft and valuable ingredients.
The point at which the product is transferred from site storage to transport storage (drums or road, rail and marine tankers), creates a number of very real risks for both the integrity of the finished product, the operators handling it and the environment.
In the fertiliser industry the volumes of fresh and waste liquids that can be classified as highly dangerous is abnormally high when compared to many other industries. In particular acids, ammonia and other noxious chemicals that need to be handled with great care, are transferred on an hourly basis to provide feedstock.
In general these are top loaded into tankers and bottom unloaded. The operators need to be able to connect the transport container to the plant system with ease and without risk of injury through burns, inhalation or falls from height. The solution for safe handling can only arise from a multi-faceted approach to the problem as detailed below:
- Falls from height
- Fluid handling
Each of these depends heavily on the design and ability of the other facets to allow the other to function effectively within its environs. In 2015, bulk fluid handling problems simply cannot be resolved by attempting to tackle a single facet of the problem. Understanding that is key to making systems future-proof and capable of being operated by untrained or unfamiliar personnel, while at the same time providing a level of safety that meets corporate, local and national guidelines.
Take a look at these two recent projects Carbis Loadtec Group have worked on.
A Large Fertiliser Conglomerate, Finland
The first is carried out in Finland for a large fertiliser conglomerate.
The site receives railcars in two configurations for import of ammonia. The position of the tanker connections is such that, they can only use three of the four unloading spots, due to the working range of the existing arms. Changing the arms in isolation would provide the increased range necessary to unload four tankers simultaneously.
But the prevention of falls from heights meant that the only viable arrangement was to equip the bay with harnesses and wires. This being a 24/7 operation in a country where temperatures reach -40oC the client considered that a safer method of accessing the tankers was needed.
Carbis Loadtec developed a unique safety cage system which would enable the client’s operators to have unrestricted access to the whole of each tanker, with no risk from falls. These have special flooring that allows the rail tank cars ladders to pass through without obstruction, while the gap that may be between the cage and tanker is minimised or eliminated. The operator can access the full length of the rail car and position the liquid unloading and vapour return arm anywhere within the cage structure.
The connections are made using high pressure couplings and the design of the loading arms means that all that is required is simple and efficient guidance of the arms to working and parking positions. Each and every facet is covered and dealt with using a long term viability approach. The system is capable of dealing with constant traffic for long periods of time and will remain ahead of any foreseeable legislation tightening on all facets.
CF Industries, USA
The second is also rather unique. CF Industries in Port Neal, Iowa, are building a state-of-the-art facility to manufacture urea which is then shipped in powder form to a processing plant on the Gulf Coast.
In this case the rail cars are loaded continuously. The compartments are sealed using “coffin lid” style closures and filled from overhead hoppers using bellows systems. The solution for the quickest, safest and cleanest operator access and filling is to provide a safety cage that is almost 43 metres (140 foot) long.
The operators access the cage from standard gangways fixed to a permanent platform. They can travel the length of the cage using the built in and full enclosed walkway. When they reach the area need to gain access to the compartment opening, they can step through the spring shut gate onto the tanker, open the compartment lid in cage one, operate the bellows in cage two and close the lid in cage three.
The whole system elevates to allow clearance from the rail car. This is a unique and very exciting development as the urea market in the USA begins to expand rapidly and clients are looking for fool-proof, efficient and durable systems.