Gypsum Transportation

Power Station to Plasterboard Factory

Problem

A plasterboard manufacturer had secured a new source of gypsum and approached Best-Chem to look at the dust issues that would arise from the handling and transportation of this dusty material.

Gypsum is a sustainable and environmentally-friendly material that is a key raw material in the construction industry.  Synthetic gypsum is produced as a by-product of the Flue Gas Desulphurisation (FGD) process at a coal-fired power station, which removes harmful sulphur dioxide that would otherwise be released into the atmosphere.  Furthermore the re-use of this gypsum diverts it from landfill and also reduces the need to mine natural gypsum and the associated environmental impact this creates.

At the power station, gypsum is transported via series of conveyors, from the storage shed to the rail load out facility.  A shuttle conveyor with a telescopic chute attached then moves along the length of the rail wagon loading gypsum to the required height.  Once a wagon is loaded, the train moves along and the next wagon is positioned under the shuttle conveyor.  Each train may have up to 25 wagons.

At this point, the level of moisture in the product is such that dust is not an issue.  The problem arises during the journey to the plasterboard factory, because as the gypsum dries, it will release dust, creating an environmental issue and also a loss of material.

A requirement was therefore imposed stating that the gypsum must be coated with a dust control sealant.

The client and the power station had previous experience of chemical spray bars, however there were a number of shortcomings in previous designs, and they wanted a robust solution.

With experience of similar applications, Best-Chem was able to provide references and was subsequently invited to design a solution.

Solution

Best-Chem engineers designed a pump set that would accurately mix the chemical and water and supply a spray bar mounted to a gantry above the rail tracks.

The spray bar needed to be close to the material, to prevent overspray and ensure complete and even coating of sealant.  However the open box wagons being used were lower than the height of the locomotive and also the trucks, which would occasionally be loaded from the same point.  To overcome this problem, the spray bar was fitted to a custom built, remote-controlled hoist that would lower the spray bar to the required height at the start of each loading process.  The spray bar could also be lowered further, to ground level, to allow safe access for maintenance.

The equipment and chemical is stored in a modified 10ft container, fitted with bund, lights, insulation and heating.  The incoming water supply and outgoing solution line are also trace heated to ensure availability throughout the winter months.  The system also features a flush facility, which is activated at the end of each loading cycle to clear the solution line and spray nozzles of any chemical.

Best-Chem had only a short window to install the equipment and the System had to work right first time, from the first wagon that was loaded under the contract.  We are pleased to say that we were successful and the system has treated 100% of trains to date. 

The chemical, DustBind, has performed well and you will see from the photos below that the ‘crust’ created on the surface of the gypsum remains intact after the rail journey.