Overcoming the Toxic Gas Threat in Pulp and Paper Plants | Automation.com

Overcoming the Toxic Gas Threat in Pulp and Paper Plants

Overcoming the Toxic Gas Threat in Pulp and Paper Plants

By Joshua Hernandez, Global Product Manager, Rosemount flame & gas detection products, Emerson Automation Solutions

All processing facilities have goals to operate their facilities safely, in compliance with regulations, and profitably. Safety is paramount among these objectives; thus, it is important to measure, alert when abnormal, and understand the hazards that could negatively impact the facility or personnel. One potential danger is toxic gas. Tragically, there are still toxic gas-related fatalities in the pulp and paper industry1.

A wide range of applications have the potential for toxic gas exposure. This sounds like a straightforward industrial safety concern until you see what toxic gas exposure, in this case hydrogen sulfide, really means:

  • 5 - 10 ppm:  Relatively minor metabolic changes
  • 100 ppm:  Immediately dangerous to life and health (IDLH)
  • 100 - 1,000 ppm:  Serious respiratory, central nervous, and cardiovascular system effect
  • 1,000 - 2,000 ppm:  Loss of consciousness and possible death

Obviously, toxic gas is a critical problem, not only threatening life, but also property, since it is flammable. One of the industries that must account for a high potential for hydrogen sulfide release is pulp and paper manufacturing. Equipment associated with the kraft process where hydrogen sulfide can be a significant safety risk includes digesters, the recovery boiler and steam power production units. Hydrogen sulfide is generated from the chemical processes to delignify wood material in batch or continuous digesters, and hydrogen sulfide may become entrained in steam lines that run throughout the plant, threatening personnel and plant safety.

Monitoring for toxic gas is not only an issue of safety, but also one of operational efficiency. A spike in hydrogen sulfide concentration is one indication that something has gone wrong with the process. In addition, aborted maintenance trips due to unreported gas leaks can be costly and time consuming.

It is critical to monitor for toxic gas releases, but like many industries, pulp and paper manufacturing is cost sensitive. In some plants, it can be cost prohibitive to install and operate conventional gas detection systems at the necessary sites due to geography and infrastructure. The installation, wiring, and commissioning costs for each additional wired device can add tens of thousands of dollars to the instrument’s total installed cost. As a result, operators have been forced to rely on portable gas detection devices, or even worse, carry on with no gas detection at all.

This is why the advent of wireless toxic gas monitoring that is supported and fully compliant with the International Electrotechnical Commission 62591 safety standard (which covers WirelessHART devices) is so significant – it offers a more cost-effective solution. New advancements in wireless toxic gas monitoring technology are substantial, as the comparison in Figure 1 shows.

Figure 1

When considering a wireless toxic gas monitor, it is important to select one that is fully integrated and battery-powered. These combined features improve toxic gas leak coverage to keep personnel safe and protect critical assets. Today’s wireless technology delivers reliable readings, enabling remote collection of field data as frequently as once per minute. The instrument should offer quick and easy installation, so the system can be up and running in a matter of minutes. Accurate wireless readings keep operators updated on changing conditions remotely, reducing manual operator rounds and improving safety by keeping personnel out of hazardous areas and safeguarding against catastrophic events. In pulp and paper plants, wireless gas monitors should be installed near recovery boilers where “black liquor” is burned.

Wireless toxic gas monitors put protection against hydrogen sulfide within reach of every plant. It can be implemented at a fraction of the cost of conventional monitoring and provide far more flexibility – a win/win for the pulp and paper industry.

Figure 2: Rosemount 928 Wireless Toxic Gas Monitor from Emerson

About the Author

Joshua Hernandez is global product manager for Rosemount flame and gas detection products at Emerson Automation Solutions in Shakopee, MN. Email him at [email protected].

 

https://www.sia.org.au/news-and-publications/news/two-fatalities-in-suspected-hydrogen-sulfide-gas-leak-paper-mill

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