Remote FTIR Monitoring of Batch Chemical Solvent Emissions

Challenge 

A batch chemical manufacturing facility in North East England required temporary continuous emissions monitoring capability while permanent monitoring infrastructure was being developed and installed. The facility itself needed to ensure emissions continued to be monitored during this interim period. 

Traditional short-term stack testing was not able to capture the highly variable nature of emissions generated by the batch production process. The episodic nature of solvent releases, with large concentration spikes associated with specific stages of the batch manufacturing cycle, meant that periodic spot testing would miss critical emission events. 

The facility required a solution that could provide continuous visibility of emission behaviour across full production cycles without requiring constant on-site attendance, while maintaining monitoring capability during the transition to permanent systems. 

Project Description and Background 

SOCOTEC UK & Ireland deployed an FTIR analyser at a fine chemical manufacturing facility for approximately 13 months of continuous monitoring.  

The facility operated batch chemical processes that generated variable solvent emissions throughout different production stages. The monitoring targeted several solvent species associated with the manufacturing process, including MTBE, methanol, toluene, methyl acetate and carbon dioxide used as a process indicator. The facility did not operate a thermal oxidiser, meaning emissions reflected direct process behaviour rather than combustion-treated exhaust. 

Through SOCOTEC’s continuous monitoring, it was revealed that emissions were highly episodic, with characteristic features including short-duration solvent spikes, background solvent concentrations between batch events and a correlation between solvent releases and CO₂ process signals.  

The monitoring was located at the process vent, in order to capture direct emissions from production operations. 

Solution 

SOCOTEC’s long-term FTIR analyser solution operated in a remote configuration. The system was designed to minimise on-site intervention requirements while maintaining comprehensive monitoring capability. Some of the key highlights of the deployment include:  

• Long-term FTIR analyser deployment on-site 
• System operated in remote configuration 
• Instrument health and analyser performance checked remotely 
• Weekly site visits only required for routine checks 
• Continuous data capture across process operating cycles 

The FTIR analysis provided a wide measurement dynamic range, allowing solvent concentrations from low ppm levels through to several thousand ppm to be measured within the same measurement system, typically without the need for dilution.  

During deployment, the analyser successfully captured low-level background solvent concentrations, short duration solvent spikes reaching several thousand ppm and rapid concentration changes across batch production cycles. 

This wide measurement range allowed continuous monitoring to capture both background emissions and peak release events without requiring analyser range switching or dilution systems. This made it particularly valuable for batch chemical manufacturing processes to take place – it is here that emissions vary significantly during different stages of production. 

Conclusion 

The project successfully delivered comprehensive emissions monitoring over the 13-month deployment period. This included a long-term emissions profile captured across full production cycles, the identification of solvent release patterns linked to process operations, reduced site attendance requirements through remote analyser monitoring, as well as an improved level of understanding of plant emission behaviour.  

The project helped demonstrate the value of continuous monitoring when compared with periodic testing, as well as reducing the overall operational cost, due to not having to fully attend the site to monitor.  

The deployment demonstrated SOCOTEC's capability to transition from traditional attended monitoring to an unmanned operation, significantly reducing site attendance requirements and associated operational costs. The continuous monitoring approach provided visibility of emission behaviour that would be difficult to detect using conventional short-duration testing approaches, including identification of intermittent solvent release events and improved understanding of process-related emission patterns. 

The data collected supported operational troubleshooting, environmental compliance investigations, and the design and optimisation of abatement systems through improved understanding of emission profiles. This case study demonstrates SOCOTEC's ability to provide standby and long-term FTIR deployment services for facilities requiring improved understanding of emission behaviour, process troubleshooting, or temporary monitoring during plant changes.