Natural gas the major gain from the drilling

BUSINESSWEEKLY

THE firming up of the gas and oil condensate discoveries in the Muzarabani area by Geo Associates, with some very good news from the latest samples, will make a lot of things possible that were not really possible before.

While Minister of Mines and Mining Development Zhemu Soda, and remember he also has a background in energy from his previous portfolio, could not give a lot of detail, the critical confirmation of the finding was important.

Equally important was the fact that the natural gas strike is of a sweet and very pure gas, that is without hydrogen sulphide, a serious contaminant that costs a lot to remove and is a major corrosion chemical and pollutant if left in the gas supply. Carbon dioxide and water are the other two less desirable contaminants, but it appears like that there is little carbon dioxide and the water is easy to remove.

Minister Soda said helium had been found in the gas samples. This is common and can be left in the gas as it is totally inert, although if it is more than one percent there is good money to be made by extracting it and selling it. Nitrogen is the other inert gas frequently found in natural gas, and again no one really bothers removing it.

The samples seem to be confirming that the heavier hydrocarbons, those that have more than four carbon atoms in a molecule, are still very light hydrocarbons, what are frequently described as condensates since they form minute droplets rather than large liquid masses. Here a lot more detail will be needed, but as Minister Soda noted they are the building blocks, and contain some of the needed ingredients, of blended fuels, petrol, diesel and Jet A1.

Many people will be far more excited over these oil condensates than the natural gas, but are probably mistaken at least in the near future, like the next decade. It will take time to build the sort of refinery that processes the condensates, to produce fuel from the raw material mix that will actually come out of the ground.

And even then it might be more cost effective to be able to mix what the condensates are extracted from our basin with those extracted in say Mozambique to get a wider range of raw materials to make up the fuels.

Modern petrols need, for example, a very wide range of chain and ring hydrocarbons to cope with the ban on lead tetraethyl being added and the mixture and type of hydrocarbons, with between fur and 12 carbon atoms in each molecule, with most of them being in the middle of that range, means that care needs to be taken to ensure that the processed fuel will not be too expensive by having to have too many of the components made up in earlier processing stages.

A second factor is the decision by the global community to switch over the next decade to electric vehicles. By 2035 there should be no internal combustion engines being made for motor vehicles.

There will still obviously be a dimin

need petroleum fuels after that date, but new electric vehicles are likely to start dominating the markets well before 2035.

This is likely to see the demand for petroleum fuels continuing to rise, especially in countries like Zimbabwe, for a few years, then start levelling off and then start diminishing as the percentage of electric vehicles rises.

We need to be careful that we do not commit to building a fancy refinery that will be commissioned as the demand for fuels starts falling, and that would probably see the prices start falling.

The heavier molecules will not be wasted if fuel demand falls fast. They will be ideal, along with some of the gas components of the natural gas, as the stock for plastics and other industrial materials and will be able to earn far more value by building Zimbabwe’s chemical industry.

The natural gas is a different proposition when it comes to energy. If, as the samples now suggest, our natural gas is disassociated from the heavier fractions and contains minimal amounts of the undesirable contaminants we will have a very usable natural gas very early in the commercialisation process.

This tends to fit in with our energy demands. We need more electricity all the time, and even the switch-over to electric vehicles will add to our electricity demand.

Natural gas is a major source of generating electric power and with modern systems and equipment can be commissioned fairly quickly, is cheaper than coal-generated power, and has around half the carbon footprint of coal. While climate talks concentrate on dumping coal, natural gas is largely unaffected by the changes proposed, possibly because it supplies over half of Europe’s energy after that continent largely converted from coal to gas.

The core of a natural gas power station is a gas turbine driving a generator. Gas turbines are better known as jet engines, although the turbines in a power station, while derived from aircraft technology, are the pure turbine, 1950s style, rather than the turbofans now under aircraft wings that move vast quantities of air. In a power station you want to spin the axle with maximum torque, not move air around. A gas turbine and generator unit can be commissioned in less than a year.

However, the efficiency of a power station designed for 24/7 generation, which is what Zimbabwe needs since it has Kariba for peak demand, is doubled if the waste heat from the gas turbine, which very conveniently is almost all in the exhaust, is used in a heat-exchanger to generate steam that in turn drives a steam turbine that drives the generator.

Modern designers and manufacturers reckon that by combining the two sources, often in the ratio of two gas turbines to one steam turbine, they can get energy efficiencies of over 60 percent. That is high in combustion engines, roughly twice for example what you get in a petrol engine. This means you get a lot more power for every cubic metre of gas.

Mozambique has already found investors to build power stations in its southern gas field, one small station and one a lot larger, and these are now fuelling Mozambique’s fairly dramatic economic growth and providing some useful exports.

Zimbabwe has been a customer. The point is that investors are willing to move into gas power generation in Southern Africa and the final price of the power is affordable in a developing country.

The actual gas, if it is clean, will be mostly methane, one carbon atom with four hydrogen atoms. Most of the rest with be ethane, two carbon atoms.

There will be some propane, three carbon atoms, and the four carbon atom molecules, butane and what are normally called the branched or iso-butanes although the real name would be methyl propane.

Adding to the initial processing would be to take those propanes and butanes out of the mix, and sell them as liquid petroleum gas.

It is not vital, as the power station will easily cope with the small traces in the natural gas, but we can become self-sufficient relatively easily in this

Methane is also a primary raw material for making ammonia, which is used to make the ammonium fertilisers and so natural gas, which remember might require modest processing, but nothing like what liquid fuels need, could start making us self-sufficient in that range of fertilisers to add to our already growing production in phosphates. If we could find deposits of potassium compounds we would be totally self-sufficient but two out of three is a good start.

We have noted before that Zimbabwean industry has been built up in the secondary industries. We now have the opening we need to move into the primary chemical industries.

The natural gas from our strike can be mobilised first, for power, for liquid petroleum gas and for fertiliser, while we are exploring how gas and the actual mix of condensates can be further used.

We might well want to produce fuels and be able to do so cost effectively.

But we will almost certainly want a wider range of products, and as the world retreats from liquid fuels might well be able to make more money from the greater range.