Summary

Sanwei New Materials, a Chinese chemical producer, manufactures 1,4-butanediol (BDO) – a key raw material for biodegradable plastics – using the Reppe process. In this process, hydrogen gas reacts with a copper-based catalyst to form 2-butyne-1,4-diol (BYD), which is then hydrogenated into BDO. Precisely controlling the hydrogen gas flow throughout the reaction is essential both for reaction efficiency and for keeping the finished BDO within specification. The plant operates several high-pressure hydrogen gas lines that needed a dependable flow measurement solution.

Application

Fig. 1: Panametrics clamp-on transducers installed on a high-pressure hydrogen gas line.

Solution

Clamp-on ultrasonic flow meters have measured hydrogen gas for almost 30 years, but clamp-on technology is rarely used at such extreme pressures: hydrogen’s low density combined with very thick, high-pressure pipe walls creates acoustic conditions that typical clamp-on gas transducers cannot handle. Panametrics tested transducers at 200 kHz, 500 kHz and 1 MHz, and found that the C-RS-402 sensor operating at 1 MHz delivered accurate, reliable results. Applying damping material around the clamping fixture and polishing the pipe surface beneath the sensors further improved signal quality. The team installed a triple-traverse configuration and configured the Panametrics XMT1000LC clamp-on flow meter (part of the PanaFlow LC platform) for high-voltage operation, raising the signal-to-noise ratio to between 5:1 and 8:1. With stable readings established, the plant’s DCS could base its process control directly on the flow-meter data. Close cooperation between the Panametrics technology and local service teams delivered a solution that now gives Sanwei New Materials more accurate, reliable hydrogen gas measurement – improving both safety and productivity.