The chemical dosing system developed by LEADA offers clear advantages to users who conduct maintenance activities on chemical dosing systems. It is said to occupy a fraction of the space required by conventional mobile units of similar capabilities and utilises built-in solar panels, which eliminate the need for diesel generators, associated refuelling costs and environmental impacts. Additionally, the dosing system offers remote access functionalities, allowing users to monitor and adjust operations remotely, from anywhere, at any time, reducing the need and frequency of site visits.
Ben Paxman, associate director at LEADA, explains: “We know that industries who undertake chemical dosing activities are hampered by the lack of redundancy built into their systems. This also affects their ability to refurbish existing equipment. Our team developed a mobile chemical dosing system that can keep process critical operations going during refurbishment. We have provided mechanical and electrical engineering services to the water industry for over 20 years, so when Severn Trent Services contacted us to further develop our existing mobile chemical dosing system for an off-grid solution for their client, The Coal Authority, we were able to quickly develop an advanced, efficient and reliable solution.”
The LEADA design comprises a self-contained trailer, equipped with tank, pumps, a control panel, a 5.12kW lithium-ion battery powered by solar PV panels and a PLC with a back-up uninterruptible power supply. Having developed the initial concept, LEADA’s team turned to Mitsubishi Electric to help realise its vision of a compact, off-grid design and turn this into an efficient, robust and highly reliable system.
The control solution developed for this project relies on the Q-Series PLC to communicate with the system’s pumps and instruments to adjust key process parameters using a number of option control philosophies and dosing algorithms.
Stewart Lea explains: “The Q-series PLC was ideal because of its compact footprint and ability to perform complex operations at high-speed. It also allowed us to take advantage of the Ethernet port it features, to provide visibility on SCADA systems, which minimised the need for on-site visits by operators. The PLC communicates with a GOT 2000 HMI to visualise key metrics, flag anomalies and enable end users to interact with the system.”
Ben Paxman adds: “The dosing unit we developed needed an easy-to-use interface that provided end users with a clear overview of system status and available functions. Mitsubishi Electric’s HMI delivers this and offers a ‘sleep mode’ that can further reduce energy consumption on the trailer. In addition, the system provides remote-controlled access to users. This means they can have full control and operate the HMI from remote locations via an app-based solution.”
Finally, communications are enabled by CC-Link open fieldbus technology. This technology supports multi-vendor devices, enhancing compatibility and providing a basis for future upgrades.
The first operational chemical dosing trailer was successfully completed and delivered to the Coal Authority within three months. While the upgrade of this mobile dosing system includes a self-sufficient power supply to address specific customer requirements, similar solutions are available for any customer, or as part of a hire agreement on a short-term basis.