Researchers at Lawrence Livermore National Laboratory in California have developed the world’s first reactor that can continuously convert methane to methanol at room temperature and pressure. With a technique that uses 3D printing and enzymes taken from methane consuming bacteria called methanotrophs, the team claim to have solved a key problem of natural gas production efficiency. Meanwhile, chemical traders are also studying the impact the discovery will have on methanol prices, as the product is a key chemical feedstock in polymer and paint manufacturing.
At present companies extracting natural gas, which often has a high methane content, have trouble storing and transporting the gas. As a result, much of it leaks into the atmosphere or is flared off. Estimates by the BBC calculate that as much as 20% of ‘the enhanced greenhouse effect’ is caused by methane emissions, converting waste methane to methanol could help combat climate change and aid the energy and chemical industries.
To make use of the methane, producers convert the gas to methanol, a more manageable liquid. However none of the conversion processes, such as steam reformation, are very efficient as they require high temperatures or pressure. As a result, many smaller gas drilling facilities make no effort to recoup excess methane.
But now a breakthrough has been made that may allow for cost-effective conversion on site at even the smallest, so called ’stranded‘, gas production facilities.
Explaining how the new process works, the online journal Phys.org, reports that, “The only known catalyst (industrial or biological) to convert methane to methanol under ambient conditions with high efficiency is the enzyme methane monooxygenase (MMO), which converts methane to methanol. The reaction can be carried out by methanotrophs that contain the enzyme, but this approach inevitably requires energy for upkeep and metabolism of the organisms. Instead, the team [at LLNL] separated the enzymes from the organism and used the enzymes directly.” By doing this, the team found that, “…isolated enzymes offer the promise of highly controlled reactions at ambient conditions with higher conversion efficiency and greater flexibility.”
The researchers published their results in the journal Nature Communications to explain how the conversion was made by, “Using particulate methane monooxygenase (pMMO), to create a biocatalytic polymer material that converts methane to methanol, [and by then] embedding the material within a silicone lattice to create mechanically robust, gas-permeable membranes, and direct printing of micron-scale structures with controlled geometry.”
Sarah Baker, project lead and chemist at LLNL, was shocked at the results, saying, “Remarkably, the enzymes retain up to 100 percent activity in the polymer.”
The significance of the discovery was made clearer by Joshuah Stolaroff, an environmental scientist on the team, who explained that, “Up to now, most industrial bioreactors are stirred tanks, which are inefficient for gas-liquid reactions. [Whereas] The concept of printing enzymes into a robust polymer structure opens the door for new kinds of reactors with much higher throughput and lower energy use.”
Baker adds that, “The printed enzyme-embedded polymer is highly flexible for future development and should be useful in a wide range of applications, especially those involving gas-liquid reactions.”
So it seems that the full implication of the research has yet to be seen, but already some industry experts are predicting that such an efficient and easily reproducible and practical solution could find its way not only into gas fields, but also landfill sites. The efficiency of the process has yet to be independently tested, but the research team are confident of their study, and even claim that, “The 3-D-printed polymer could be reused over many cycles and used in higher concentrations than possible with the conventional approach of the enzyme dispersed in solution.”
Whilst scientists everywhere hope that the process can soon be adopted by industry to lower human impact on climate, many in the gas drilling and exploration industry hope that it will make smaller gas reserves more efficient to tap as well as increase their profits in larger fields. The 3D printing industry is also due to take note, whilst chemical traders everywhere are already looking for the discovery’s impact on methanol prices.