What makes a LiCl solution challenging to measure
In their systems, lithium chloride solutions usually operate close to a limit: concentrated enough for sorption, electrolysis, or evaporation to run economically, while still far enough from saturation to prevent crystallization. There is often only a narrow window between these two points, and the concentration constantly shifts during operation due to absorbed water, evaporation, and replenishment.
LiquiSonic®: the brine measures itself
An ultrasonic pulse travels through the salt solution between the two prongs of the measuring fork. The measuring path is known, and the transit time is recorded at high resolution. This yields the speed of sound and, together with the measured temperature, the concentration.
Clear solution or turbid brine: same measured value
Sound propagates independently of color, transparency, and electrical conductivity. What interferes with optical and conductivity-based devices plays no role here.
Temperature is part of the measurement
Each sensor also records the process temperature and directly compensates for its influence on the speed of sound. Changes between absorber and regenerator are therefore covered.
Material selected for the medium
Chloride-containing solutions attack standard stainless steel. We therefore also manufacture the wetted parts from titanium or Hastelloy, or alternatively with a coating.
Sensor and analysis unit can be installed separately
The connection to the controller is digital and interference-free up to 1,000 m. The display location does not have to be the measurement location.
The measured value at the process
The LiquiSonic® The controller displays the current value locally and simultaneously transmits it to the control system. Up to four sensors can be connected to one device, for example lean and rich brine in the same circuit.
The main value takes center stage
Concentration is shown large and readable from a distance, with unit, along with the temperature.
Limits visibly highlighted
The bars show where the value lies within the permissible window and how far it is from the warning limit.
Trend instead of snapshot
The trend view shows whether the brine is drifting and in which direction, long before a limit is reached.
Technical background
Dissolved lithium chloride changes the density and compressibility of the water and thus the speed at which sound propagates through it. Transmitter and receiver are arranged in a fixed geometry relative to each other, so the transit time produces an absolute value. This does not drift and does not need regular readjustment. We store the correlation of speed of sound and temperature to concentration as a product data set for your specific solution.
In regenerators, at pumps, and after depressurization stages, the brine often carries gas with it. Ultrasonic measurement tolerates significantly more of this than density-based methods, but it also has an upper limit. Bubbles characteristically alter the received signal: the sensor detects this to a certain extent and reports it instead of silently outputting an incorrect value.
Pure LiCl-water systems are the simple case. If accompanying salts from raw brine or recycle remain within known, narrow limits, this is taken into account in the design. If a second component fluctuates more strongly, the content of two dissolved substances in the same carrier medium can also be determined separately using an additional measured variable. We clarify in advance whether this is necessary in your case based on your analyses.
What inline measurement delivers
- Routine samples and titrations are needed less often
- Replenishment is based on measured values instead of experience
- No personnel at the open vessel for sampling
- Run evaporation and regeneration only as far as necessary
- Safety margins on the target density can be reduced
- Fewer discarded batches, less lithium loss
- Approach to saturation becomes visible early
- Fewer flushing and cleaning shutdowns at heat exchangers
- Seamless recording for quality verification and audit