Storage hoppers for bulk and sometimes only apparently bulk materials are a symbiotic part of pulse nozzle installations. Blocking, overhang formation, bridging – many types of hoppers and materials, and problems everywhere almost identical. In the case described here, we are dealing with a coal hopper in a thermal power plant. The quality of coal and added products such as biomass differ not only in composition but also in moisture content. The amount of material combined with the poor properties of the bulk, but also with the change in geometry, makes the bunker useless without mechanical intervention. Here, the installation of pulse nozzles comes to the rescue, allowing for maintenance-free de-thatching, improving the transfer and, above all, not having to hit the hopper.
Lead time
Before installation
The main tasks prior to the physical implementation of the activity were the prefabrication of the control cabinet and the preparation of the pulse nozzles with mounting components.
Important elements as semi-prefabricated were the compressed air manifolds. The pre-welded ones were prepared in the workshop.
Assembly
The assembly of the complete pulse nozzle system consisted of several stages. First, boreholes were drilled into the walls of the trays and mounting components were assembled. At the same time, the control cabinet was hung. Then the installation of pulse nozzles in the mounting elements. This stage allowed the installation of compressed air manifolds. Slinging and making holes for the stubs for the valves and the billets of the pulse nozzles were done at the facility. Once the entire installation was completed, it was time for corrosion protection and the distribution of control cables from the cabinet to the pulse nozzles.
The next step was to commission the installation, test, connect the pressure switch and train the operators.
Customer problem
Notorious blockage of coal – the only and serious problem. With changes in the quality and moisture content of the fed coal, coal hoppers become an obstacle to further transport of fuel. The formation of overhangs and bridges that cannot be removed even by air cannons. The constant need for the operator to hit the hammer as a thwarting not only causes low work efficiency, but also affects safety.
All attempts to date to solve the problem have proved ineffective. Vibration, cannons, hammers all failed to produce positive results.
So the customer decided to perform a test installation of pulsenozzles on one of the coal hoppers just to see that our flow guarantee is real and backed by references and experience.
Challenges
The limited time the storage tank was set aside meant that all the work involved in installing the pulse nozzle system and, above all, the mounting components had to be done very precisely and without slippage.
Installed earlier attempts to improve the flow of material in the form of air cannons meant that the amount of space both on the walls themselves and around them was greatly reduced. Navigating the manifold pipes between the air cannon tanks required several geometric compromises.
- Site inspection, discussions with the staff as well as determination of the installation locations of pulse nozzles
- Installation of pulse nozzles placed in the silo cone (13 nozzles VA-51C)
- Commissioning and adjustment of the nozzles’ operating algorithm to the prevailing conditions while reducing compressed air consumption
- Pulse nozzles VA-51C
- Fitting elements of the MPS-51C-TK2 series – elements with wear-resistant steel plate
- Control cabinet using Siemens LOGO PLC controller
What did we do as a part of the project?
Site inspection and discussion with the customer of the problems encountered
Using our extensive experience in coal transportation projects, we presented a concept for the arrangement of pulse nozzles,
We carried out the entire installation including the installation of nozzles, manifolds, and the automation that controls the equipment.
The control system within the test installation operates locally.