Loading Cryogenic Liquids

Avoid flashing issues while loading cryogenic liquids with safe, reliable, and accurate density fluid measurements utilizing Yokogawa’s industry-leading Coriolis flowmeter to eliminate measurement issues and increase the accuracy of inventory. 

 

Introduction

During the loading of truck tanks with cryogenic liquids, measurement of product flowing through the lines must be accurate and safe. 

In order to maintain proper loading and invoicing, operators need to know if the material changes state, or flashes, from liquid to gas or solid.

A successful loading process shows three measurements in balance: the tank inventory, the flow totalizer in the out-loading area, and the truck-tank scale. When flashing occurs and the process is not adjusted, the key measurements are out of balance.

 

Challenges

A facility in Mexico produces, distributes, and markets industrial gases (like Nitrogen, Oxygen, and Argon) to industrial facilities and to hospitals. Their truck loading setup included orifice plates to measure material as it flowed. Problems arose when flashing occurred — the orifice plates were not able to alert operators to the state change. 

The orifice plates could not provide state information to help operators accurately start/stop a batch. Also, during the cleaning of the line after filling, orifice plates could not indicate when the cleansing Nitrogen was in/out of the pipe, indicating start/finish of cleaning.

 

Solution

As part of continuous improvements to the process, the company sought to eliminate measurement issues and increase the accuracy of inventory and invoicing. The operators recognized that the RotaMASS TI Coriolis flowmeter from Yokogawa would solve the problem.

In measuring cryogenic fluids, it is important to maintain a consistent temperature through the meter. Fluid properties change dramatically and affect the process performance. To solve the problem, the RotaMASS is designed with an option where the sensor and heat tracing are located side-by-side with the internal Coriolis tubes and are contained in a two-part enclosure. Insulation wool is added to fill the void and the two halves are then riveted together. The terminal box is mounted externally to allow for easy access in the field.

The RotaMASS meter reads the density of the fluid and detects if the material flashes into gas. Operators can be alerted to the state change and can adjust valves. Density measurements help prepare the out-loading batch by assuring them that the line is fully packed with the liquid product.

Other benefits include more informed line cleaning — RotaMASS accurately detects when the procedure has started and finished. In the near future, the facility plans to use data logging to further optimize the batches.

 

Key Benefits

• No matter the temperature, improved accuracy for tons of product per load.
• More efficient use of cleaning time and materials.
• Improved accuracy in invoicing and storage.