It is currently estimated that natural gas resources will be exhausted in 130 years; however, those reserves where extraction is cost-effective will only flow for another 60 years or so. Scientists at the Max Planck Institute for Coal Research and at the Max Planck Institute of Colloids and Interfaces might be helping to make it worthwhile to tap into previously unused resources. They have developed a catalyst that converts methane to methanol in a simple and efficient process. Methanol can be transported from locations where it is not economical to build a pipeline. (Angewandte Chemie Int. Ed., September 1, 2009)
It is not cost-effective to lay pipelines to remote or small natural gas fields; nor is it worthwhile accessing the methane in coal seams or in gas sand, or which is burned off as a by-product of oil production, although the methane burned off throughout the world could more than satisfy Germany’s requirement for natural gas. It is also too expensive to liquefy the gas and transport it on trains or in tankers – and even chemistry has so far been unable to offer a solution. Although there are chemical ways to convert methane to methanol, which is easy to transport and which is suitable as a raw material for the chemical industry, “the processes commonly used up to now for producing diesel fuel – steam reforming followed by methanol synthesis or Fischer-Tropsch synthesis – are not economical,” says Ferdi Schüth, Director at the Max Planck Institute for Coal Research in Mülheim an der Ruhr. He and his colleagues have been working with Markus Antonietti and his team at the Max Planck Institute of Colloids and Interfaces in Potsdam to develop a catalyst that might change all this.
The catalyst consists of a nitrogenous material, a covalent, triazine-based network (CTF) synthesized by the chemists in Potsdam. “This solid is so porous that the surface of a gram is approximately equivalent in size to a fifth of a football field,” says Markus Antonietti. The researchers in Mülheim insert platinum atoms into the voluminous lattice of the CTF. Thanks to the large surface area, the catalyst oxidizes the methane efficiently to methanol, as it offers the methane a large area in which to react when the chemists immerse it in oxidizing sulphuric acid, force methane into the acid and heat the mixture to 215° Celsius under pressure. Methanol is created from more than three-quarters of the converted gas.
A catalyst manufactured by the American chemist Roy Periana more than ten years ago from platinum and simple nitrogenous bipyrimidine also effectively creates methanol, but only supports the reaction in a soluble form. This means that the catalyst – which chemists refer to as a homogenous catalyst – subsequently needs to be separated off in a laborious and somewhat wasteful process. “It’s much easier with our heterogeneous catalyst,” says Ferdi Schüth. The chemists in Mülheim filter out the powdery platinum and CTF catalyst, and then separate the acid and methanol in a simple distillation.
The catalyst developed by the Max Planck chemists probably uses the same mechanism as the Periana catalyst and was indeed inspired by it. “When I saw the structure of CTF, I noticed the elements which correspond to its bipyrimidine ligands,” says Schüth. “That’s when I had the idea of manufacturing the solid catalyst.”
via Energy-saving powder.
The predicted end of natural gas in 60 years is worth noting. Here are some facts about natural gas:
Natural gas is a major source of electricity generation through the use of gas turbines and steam turbines. Most grid peaking power plants and some off-grid engine-generators use natural gas. Particularly high efficiencies can be achieved through combining gas turbines with a steam turbine in combined cycle mode. Natural gas burns more cleanly than other fossil fuels, such as oil and coal, and produces less carbon dioxide per unit energy released. For an equivalent amount of heat, burning natural gas produces about 30% less carbon dioxide than burning petroleum and about 45% less than burning coal. Combined cycle power generation using natural gas is thus the cleanest source of power available using fossil fuels, and this technology is widely used wherever gas can be obtained at a reasonable cost. Fuel cell technology may eventually provide cleaner options for converting natural gas into electricity, but as yet it is not price-competitive. …
Natural gas is often described as the cleanest fossil fuel, producing less carbon dioxide per joule delivered than either coal or oil., and far fewer pollutants than other fossil fuels. However, in absolute terms it does contribute substantially to global carbon emissions, and this contribution is projected to grow. According to the IPCC Fourth Assessment Report (Working Group III Report, Chapter 4), in 2004 natural gas produced about 5,300 Mt/yr of CO2 emissions, while coal and oil produced 10,600 and 10,200 respectively (Figure 4.4); but by 2030, according to an updated version of the SRES B2 emissions scenario, natural gas would be the source of 11,000 Mt/yr, with coal and oil now 8,400 and 17,200 respectively. (Total global emissions for 2004 were estimated at over 27,200 Mt.)
In addition, natural gas itself is a greenhouse gas (methane) far more potent than carbon dioxide when released into the atmosphere, although released in much smaller quantities. Natural gas is mainly composed of methane, which has a radiative forcing twenty times greater than carbon dioxide. This means a ton of methane in the atmosphere traps in as much radiation as 20 tons of carbon dioxide. Carbon dioxide still receives the lion’s share of attention over greenhouse gases because it is in much higher concentrations. Still, it is inevitable in using natural gas on a large scale that some of it will leak into the atmosphere. Current USEPA estimates place global emmissions of methane at 3 trillion cubic feet annually, or 3.2% of global production. Methane represented 14.3% of all global anthropogenic greenhouse gas emissions in 2004 . …
A pipeline odorant injection station
In any form, a minute amount of odorant such as t-butyl mercaptan, with a rotting-cabbage-like smell, is added to the otherwise colorless and almost odorless gas, so that leaks can be detected before a fire or explosion occurs. Sometimes a related compound, thiophane is used, with a rotten-egg smell. Adding odorant to natural gas began in the United States after the 1937 New London School explosion. The buildup of gas in the school went unnoticed, killing three hundred students and faculty when it ignited. Odorants are considered non-toxic in the extremely low concentrations occurring in natural gas delivered to the end user.