Natural Gas helps Increase Global Food Supply
Natural gas has played a major role in increasing the global food supply. A major feedstock in the fertilizer industry, natural gas is an important input for the creation of nitrogen based fertilizers. According to the International Fertilizer Industry Association, 97 percent of the world’s supply of nitrogen fertilizer uses natural gas as the energy source.
Before the availability of artificially created nitrogen, food shortages were chronic in several parts of the globe. But the idea of creating ammonia artificially using natural gas and then converting ammonia to nitrates and nitrites to develop plant food (fertilizers) led to a rapid increase in crop yields across the world. In fact, there has been a doubling of agriculture production across the world from 1950 to 1990, thanks to the availability of nitrogen fertilizers. Today, the world produces 87 million tonnes of nitrogen fertilizer and is credited with helping grow at least 40 percent of the world’s food production.
Creating Ammonia-based Fertilizer from Natural Gas: The first step in creating ammonia from natural gas is called primary-reforming or gas vapour conversion. After the sulphur is removed from natural gas, it is mixed with heated water vapour and supplied to the reactor, where it passes through catalyst beds. The result is a mixture of hydrogen, methane, carbon dioxide (СО2), and carbon oxides. This mixture is sent to the secondary reforming (gas-vapour conversion), where it is mixed with atmospheric oxygen, vapour, and nitrogen in proper proportions. The Carbon oxides and dioxides are removed from the mixture. Then, a mixture of hydrogen and nitrogen is sent to ammonia synthesis.
This mass produced fertilizer has revolutionised global agriculture and made life easier for farmers as it frees them from using slow, time-consuming and painstaking methods to replenish nitrogen in the soil.
Why is Natural Gas the Better Alternative? Ammonia based fertilizers can also be manufactured using coal and heavy oils. China, which has a shortage of natural gas, depends heavily on coal. However, coal is detrimental in terms of both environment and economic efficiency. Similarly, heavy oils – used by some Indian fertilizer manufacturers too – are not as efficient as natural gas.
The following estimates made by the International Energy Agency gives a clear picture on the benefits of using natural gas for production of fertilizers.
The table states that the energy consumption of heavy oil and coal in the production of fertilizers are 1.3 and 1.7 times more than that of natural gas. Similarly investment and production costs are also higher for heavy oil and coal.
Coal is inexpensive and plentiful as compared to natural gas. But the International Energy Agency recommends a shift from heavy oil or coal based processes to natural gas to reduce energy use as well as emissions. Using coal based plants (including those with clean coal technology) results in excessive carbon di oxide, airborne mercury and other pollutants being released into the environment. These are ultimately responsible for global warming and the subsequent climate change.
Natural Gas – Assuring Food Security: Natural gas has thus played a vital role in ensuring food security to the global population. Reports by world bodies indicate that the world food production will have to double by 2050 in order to feed an increasingly large population. Once again, ammonia based nitrogen fertilizers created from natural gas will hold the key to attaining this goal.