A Swedish company has developed a new system for optimising pellet production. Results from the first installation, at Swedish energy utility Falu Energi & Vatten AB, suggest that the system enables a better and more consistent pellet quality.
Developed by Uny Konsult AB the first Pellmess fvt 4260 system was installed in spring 2014 at Falu Energi’s 46 000 tonne per annum pellet plant. The system is based on an automated measurement of density, moisture content and temperature of the pellets produced. The measurement data is analysed and processed by a software programme. Any corrective adjustments needed in the production process to achieve the desired level of quality in the finished pellets are relayed directly and carried out automatically.
According to Ulf Nygren, CEO for UNY Konsult AB and inventor of the patented Pellmess system, it is the first pellet production “measure and optimise” process system of its kind. It is less dependent on personnel because the measurements are done automatically providing both more consistent measurement results and lower measuring costs compared to conventional manual systems used to measure and optimise the pellet production process. In addition measurements can be made at more frequent intervals, which reduces variations in the quality of the finished pellet product.
– Moisture measurement is done with microwave technology and we have developed communication using mobile broadband so that the system can send the data. This means we can monitor and control the system remotely, explained Ulf Nygren.
After installation in spring 2014, it was run in parallel with the old manual method in order to demonstrate that the new automated system was reliable. The second step was to put data into the process control system. This was done in April 2015 and the system has been operational ever since. According to Nygren it has functioned flawlessly with minimum stand deviation on measurements and Falu Energi has exercised its option to purchase the equipment.
– Step number three is to measure the capacity, the quantity of pellets produced. The aim is to make the pellet plant fully automatic in so far that it does not require on-site personnel to take measurements and make adjustments to the production process itself. Instead daily routine inspection and maintenance work can be scheduled during normal working hours as operational staff do not need to take measurements during nights and weekends since this is handled automatically, said Nygren.
According to Nygren an investment in the system is in the region of SEK 1 million (≈ EUR 105 000) with the payback time being a function of labour cost savings.
– The real value lies in being able to produce a high quality pellet consistently. This reduces the risk of quality inconsistency issues turning up at the end-user, concluded Ulf Nygren.
Brief description of Pellmess FVT 4260
A microwave sensor automatically measures the moisture content of the finished pellets. Measurement of the volume weight of the finished pellets occurs when an automatic sample cylinder is filled with pellets from processing. The test cylinder rests on weighing cells that register the weight of the sample. An output signal is transmitted and used, for example to adjust the parameters for dosing screw to the pellet press. By automatic sampling of temperature, moisture content and density of the final product, the process is operator independent. The optimisation system can be remotely controlled. The system uses a computer programme to control the sampling, collection and analysis of test results, which are compared with reference values for density, moisture content and temperature and to adjust the control parameters.