VLP invests to increase process safety
03 Nov 2016
VLP has invested £240,000 in new equipment at its Wythenshawe site to improve process safety.
VLP’s Vitabond process involves the manufacture of adhesives formulated with flammable solvents such as MEK, Toluene, Acetone as well as non flammable solvents such as methylene chloride. Manufacture involves mixing solids such as resins, rubber and other additives to the liquid being mixed under high shear conditions.
There is a degree of risk from fire or explosion associated with adding materials to the tanks and therefore over the last ten years VLP has undertaken technical evaluations and trials with many systems. These have used proprietary equipment for handling such materials, however none exactly met the needs of the business. The best solution was devised by the team at VLP with supportfrom Process Safety Manager and Chemical Engineer Dr. Mike Rowley. They designed a simple double door loading hopper ‘dropbox’ that would allow for a closed system to be operated with nitrogen purging and just about any size, shape, density solid material to be loaded.
Working with an external mechanical engineer and fabrication contractor a prototype unit was built and tested in 2015. This proved successful during the trials and gave the business sufficient confidence to apply for capital to adopt this solution, combined with Nitrogen inerting, for all Vitabond manufacturing tanks, along with additional safety and operating improvements to modernise the process.
During the Spring, the first dropbox was successfully commissioned along with a new PLC based control system and solvent batching system. This first unit was operated for a while to finalise the control parameters used. In early Summer, the remaining tanks were fitted with similar units and commissioned and equipment had been operating reliably since installation.
Due to the high profile and high risk nature of the project, safety has always been to the fore and rigorous evaluation of the concept initially, mechanical design and process operations have been completed by leading experts from DEKRA (formerly Chilworth Technology world leading experts in flammable atmospheres/static risk control), RSA as well as VLP’s team, Mike Rowley and Vitafoam’s Iain Spence.
In conclusion, Business Manager John Hannah said ‘We required investment of £240k to deliver the project. The team managed to keep costs down to such a reasonable level through great work by VLP engineering department and the patience of the operating team during the change process, as well as Mike
Rowley’s significant contribution. Well done to the whole team.’
The team at VLP who designed and installed the ‘dropbox’ solution (from left to right) Matt Draper, Dave Leach, Mark Lomax, Alan Denby, Mike Rowley and Ronnie Quinlan.
New nitrogen installation at VLP
Schematic of the VLP/Vita designed ‘dropbox’
Speaking about the project, Mike Rowley said ‘Due to the complexity and practical difficulty in controlling static discharges in all circumstances, particularly when making additions of high risk insulating materials such as resins to tanks, the avoidance of ignition sources has always posed a low but credible risk of causing a fire and explosion.
For additions of such materials, which are likely to become highly charged by simply pouring them into the mix tank, ideally the basis of safety should be avoidance of flammable atmosphere by removing
oxygen from the tank when adding the materials. This is usually done by nitrogen inerting (displacing air from the tank by adding nitrogen) to control oxygen levels well below the “Limiting Oxygen Concentration” of the solvent being used. This requires the tanks to be sealed and therefore solids additions to be made through a closed system.
Many closed systems for adding solids exist however the difficulty at VLP arose from the range of materials used in the process and their wide physical form. Materials range from very light and fine powders such as fume silica to very large lumps of resin and rubber.’