In China, use cleaner techniques of coal burning to cut smog

Smog from coal is one of the major problems facing Chinese Premier Li Keqiang as he tries to wage a "war on pollution". Already, smog in Beijing and Shanghai has become untenable, mostly due to pollution from old factories, coal and cement plants and steel mills in Hebei, Shanxi and other provinces. This pollution is exacerbated by inefficient cook stoves, dilapidated and poorly maintained vehicles and the like.

Pollution is often exacerbated by socio-political factors such as poverty and corruption. From a technical perspective, the cause of smog is incomplete and improper combustion of fossil fuels such as diesel, coal and bunker oil. In China's case, a lot of the smog is caused by the burning of coal.

Contrary to what some people may think, coal is not just used for power generation. If that were the case, a lot of coal usage could be replaced by renewable energy sources such as solar and wind.

The problem is that many industrial processes need heat, which often comes from burning fuel. Heat can be used to create steam for power generation, for melting steel and other materials, for brewing beer and cooking food and for drying, cleaning and sterilising products and containers, which is typically done with steam.

Remember how you sterilised your infant's baby bottles with a steamer?

In the food industry, many processes, such as the dehydration of liquid milk to make the powdered variety, cleaning beer bottles and brewing, require a lot of heat.

A plant can try using electric heating, but this requires a large amount of electricity, which may end up being sourced from fossil fuels anyway.

So if there is no choice but to burn fuel to create heat, how can one do it in a cleaner way and use less of it? The answers range from the simple and immediately doable to those that require significant amounts of capital spending.

The first and simplest way is to ensure that the pollution control equipment is in place, working and actually switched on. There are many stories from all over the region where factories try to save electricity by switching off their anti-pollution equipment. Sometimes the devices are only turned on when inspectors are on the premises. Sometimes they are not turned on at all because the inspectors have been paid off to look the other way.

Another way to control pollution is to buy the waste excess heat from another factory nearby. Instead of each factory trying to generate its own heat, the excess heat from another factory can be bought as steam by the other.

Another simple technique recommended by the US Department of Energy's National Renewable Energy Laboratory is to replace a portion (roughly 20 per cent) of the coal used with dried agricultural biomass such as nut shells or wood chips. This reduces the greenhouse gas output normally received from burning coal.

More advanced upgrades include the use of fluidised bed burners, which swirl coal particles in jets of air to ensure each is fully burned, much like a popcorn-making machine pops kernels into the air.

Gasifying and liquefying coal, which converts the coal into a gas or liquid before burning, is another option, while some prefer to switch their boilers to natural gas or biomass waste.

The more complicated options, such as carbon capture and sequestration systems, are now not commercially viable.

The best way to limit pollution is still to do away with coal in applications where it can be replaced. But if Chinese industry continues to insist on burning coal, then it must use the cleaner techniques already available. All that is needed is the will to actually implement them.

Dennis Posadas is a clean tech consultant and the author of Greenergized. He is working on a corporate sustainability fable