Excellent question, Al - I may have to update the article to answer your question!
The hydrogen mentioned in the PHMSA docket comes from cathodic protection (CP) on the pipelines (it appears this can happen on any kind of pipeline using CP). From some quick research:
Cathodic protection (CP) is used to prevent corrosion in pipelines by making them the cathode of an electrochemical cell, where a more reactive metal (the anode) corrodes instead. However, under certain conditions, especially when the CP system operates at excessively negative potentials, hydrogen can form hard spots in pipelines through a process known as hydrogen embrittlement.
There's also some good scientific explanations here and on the website in general:
Interesting physics and chemistry. When I was a factory rep for 3M, we had 2 products for protecting pipelines from corrosion: one was a powder coating applied electrostatically at the pipe factory. We convinced Northwest Natural Gas in Portland to have their engineers specify it on all their pipe orders. the coating was a lime green color. For welds, where the coating would be burnt off, we had a product called “scotchwrap”, somewhat like duct tape but thicker (10 mils) and non-dialectric.
The coated pipe was expensive, so I assume that CP is a cheaper way to go. I’m familiar with cathodic protection - when I owned a little parts and service company for commercial kitchen equipment, we installed and serviced 15 PSI Market Forge boilers for steam cooking. They had a “descaler” hung inside the boiler to prevent corrosion. It was also called a cathode. They would often be dissolved in about a year, and we would replace them as part of annual maintenance.
Interesting. Why, how are they exposed to hydrogen? Are they water lines or natural gas?
Excellent question, Al - I may have to update the article to answer your question!
The hydrogen mentioned in the PHMSA docket comes from cathodic protection (CP) on the pipelines (it appears this can happen on any kind of pipeline using CP). From some quick research:
Cathodic protection (CP) is used to prevent corrosion in pipelines by making them the cathode of an electrochemical cell, where a more reactive metal (the anode) corrodes instead. However, under certain conditions, especially when the CP system operates at excessively negative potentials, hydrogen can form hard spots in pipelines through a process known as hydrogen embrittlement.
There's also some good scientific explanations here and on the website in general:
https://www.corrosionpedia.com/definition/649/hydrogen-induced-cracking-hic
Interesting physics and chemistry. When I was a factory rep for 3M, we had 2 products for protecting pipelines from corrosion: one was a powder coating applied electrostatically at the pipe factory. We convinced Northwest Natural Gas in Portland to have their engineers specify it on all their pipe orders. the coating was a lime green color. For welds, where the coating would be burnt off, we had a product called “scotchwrap”, somewhat like duct tape but thicker (10 mils) and non-dialectric.
The coated pipe was expensive, so I assume that CP is a cheaper way to go. I’m familiar with cathodic protection - when I owned a little parts and service company for commercial kitchen equipment, we installed and serviced 15 PSI Market Forge boilers for steam cooking. They had a “descaler” hung inside the boiler to prevent corrosion. It was also called a cathode. They would often be dissolved in about a year, and we would replace them as part of annual maintenance.