An alternative to toxic alcohols, methanol, and mono-ethylene glycol, which are traditionally used as hydrate inhibitors, has been proposed.
On Monday, September 27, it became known that scientists of the Gubkin Russian State University of Oil and Gas suggested using carbonic acid diamide (urea) to prevent hydrate formation in gas pipelines and equipment of oil and gas production companies. The research was conducted jointly with the Qilu University of Technology in China, the university’s press service reports.
Hydrates form when the various components that make up the natural gas combine with water. These crystalline formations stick together to form clogs which can block gas transmission lines, causing accidents and stopping the gas flow.
Methanol and mono-ethylene glycol are now used as hydrate inhibitors in the oil and gas industry. However, these alcohols have significant drawbacks. First of all, they are toxic. In addition, methanol is highly volatile, which leads to losses from its evaporation and dissolution in compressed gas.
The main advantage of urea is its environmental friendliness. At the same time, it is comparable to mono-ethylene glycol in its inhibiting ability. Methanol urea loses to it about twice, but it has no volatility. Researchers have conducted a preliminary assessment of the use of urea as an inhibitor and concluded that its safety to the environment, coupled with sufficient functional and economic efficiency creates a good prospect for widespread industrial use.
Today urea is mainly used as a nitrogen fertilizer and in the production of wood-fibre boards. About 100 million tons of urea are produced in the world annually.
Let us remind that last May, Gubkin University researchers offered another alternative to methanol and mono-ethylene glycol as a gas hydrate inhibitor - dimethyl sulfoxide. It is not as environmentally friendly as urea, but still less toxic than traditional inhibitors and combines high activity as a solvent for crystalline deposits in wells and pipelines with low volatility.