Put Some Wood in Your Tank!
Through a new, patented method, wood chips can be converted into fuel. This is carried out in a multistage process. In the first stage of the gasifier, the wood chips - at temperatures up to 932°F (500°C) and pressures up to 72.5 psig (5 bar) - are decomposed into biomass cokes and tarladen gas. The biomass cokes are carried out on conveying equipment and fed to the grinding process through a system of locks. To allow this process to run continuously, automatic discharge via lock hoppers is necessary. For this purpose, the lock hoppers are equipped with sensors to measure level, limit, and pressure.
Level Measurement in the Lock Hoppers with the VEGAFLEX 61
The lock hopper is filled with biomass cokes. A guided microwave VEGAFLEX 61 sensor in cable version measures the level continuously. When the lock hopper is full, the filling process is stopped and the valve is closed. The special advantage of the VEGAFLEX 61 is its reliable measurement performance even under unfavorable conditions, such as low DK (dielectric constant) value of the biomass cokes, and strong dust generation during filling.
Backup Detection with the VEGAVIB 61
When the lock valve closes, no cokes should be in the chute - otherwise the valve would not close completely. Backup detection is provided by a VEGAVIB 61 vibrating level switch. Its patented rod design, in contrast to a tuning fork, has been optimized for use in bulk solids. It avoids material getting wedged in the instrument and provides maximum functional reliability.
Pressure Measurement with the VEGABAR 64
Before the cokes can be transferred to the grinding process, the pressure of approximately 72.5 psig (5 bar) in the lock hopper must be released. Vessel discharge can only take place after pressure equalization. For that reason, the pressure is measured by the VEGABAR 64. With its tube extension, it sits perfectly flush with the vessel wall. The robust ceramic diaphragm is highly resistant against abrasion.
