Novosibirsk scientists' technology of fuel-free ignition of pulverized coal boilers is included in the list of modern technologies of the Russian Federation

In May 2020, engineers of the Faculty of Power Engineering, NSTU NETI and the team of COTES Engineering conducted the first open hot tests of a new technology for igniting pulverized coal boilers without the use of fuel oil, which will allow abandoning the use of fuel oil for ignition. The new technology will reduce the energy companies expenses as well as the amount of harmful emissions into the atmosphere during the fuel combustion.

Today in Russia, fuel oil is used as an ignition and backup fuel for the thermal power plants operation. The substance works like a conventional liquid for igniting coal. Coal is a low-reaction fuel that is difficult to ignite without additional help, such as gas or fuel oil. Almost all Russian thermal power plants still use fuel oil as a backup fuel in the event of the coal supply interruptions.

The fuel oil combustion emits many dangerous substances into the atmosphere: carbon dioxide, nitrogen oxides, sulfur and sulfur anhydrides, vanadium compounds, carbon monoxide and methane. These substances leaving the chimney during the boilers ignition can cause respiratory diseases, poisoning, irritation of the mucous membranes and other health problems.

Scientists all over the world are trying to find fuel oil replacement not only because of the environmental problems, but also because of the high cost of maintaining fuel oil facilities and the annual decline in its quality which directly depends on the depth of oil refining.

At one time in the USSR, and later in China, they found a fuel oil substitution: a plasmatron. However, the technology has become widespread only in China, where today more than 700 power boilers are equipped with a plasma ignition system using electric arc plasmatrons. The technology used in China has a fairly high percentage of incomplete combustion of the pulverized coal mixture, as well as the high energy consumption of the equipment. In this regard, the issue was not only the efficiency of the technology (service life, economic indicators), but also the safety of its use on a number of coals.

Specialists of COTES Engineering and NSTU NETI managed to develop a new analog of the plasma fuel-free technology based on electroionization ignition in a cyclone burner without the use of an electric arc plasmatron. Engineers and scientists were able to find an effective and safe solution to the technology of plasma fuel-free ignition not only at a lower cost, but also with an increase in the equipment service life. The continuous operation time of the Novosibirsk developers' burner is more than 2000 hours, while the burner with an electric arc plasmatron can work for about 200 hours.

The development is a complex consisting of a burner device, a power source, a monitoring and control system. Pulverized coal fuel (a mixture of air and coal dust) is used to ignite the boiler instead of fuel oil during the operation of this complex at the power plant. Technical solutions of Novosibirsk inventors are protected by patents of the Russian Federation.

The ignition process occurs owing to the complex composition of the ions. The electric field energy emerging from the power source is converted into the energy of chemical reactions of combustion at ambient temperatures. Low fuel ignition temperature reduces the amount of emissions of hazardous substances into the atmosphere.

Open tests of the new technology of fuel-free ignition of pulverized coal boilers were held at the 5 MW firing stand at the site of Kutateladze Institute of Thermophysics SB RAS. Representatives of several Novosibirsk enterprises attended the testing site to get acquainted with the new technology.

According to the developers, the technology will reduce emissions of hazardous substances and increase the economic efficiency of thermal power plants boilers. "The installation will save resources. The payback period of this technology implementation is 2 to 5 years. Unlike coal, fuel oil is a more expensive fuel, which increases in price every year. In addition, fuel oil is also subject to an additional tax. The price will increase even more. An additional excise tax on fuel oil has been introduced since April 1, 2021. The use of fuel oil is several times more expensive than the use of coal. The price growth trend will continue. This is due to the fact that the depth of oil refining increases, and fuel oil, in turn, is a heavy fraction, that is, the residue of the processing. Because of this, the quality of fuel oil decreases, and its price also increases, " said Denis Sinelnikov, an assistant at the Department of Thermal Power Plants at NSTU NETI.

"Fuel oil is a dirtier fuel than coal. It leads to the eventual failure of electric filters used to clean the flue gases. In ignition modes, the same electric filters are turned off when burning fuel oil due to the formation of viscous ash. We have reason to believe that our team invention will minimize hazardous emissions to the environment. This is what we plan to find out together with COTES Engineering, " says Denis Sinelnikov.

The first variants of the technology implementation were tested at thethermal power plants of Irkutskenergo and Krasnoyarsk GRES-2. These places saw the successful closed tests of fuel-free ignition of pulverized coal at the BKZ-420 boiler with a steam capacity of 420 t/h and the PK-24 boiler with a steam capacity of 270 t/h.

Currently, COTES Engineering offers full implementation of fuel-free ignition of pulverized coal boiler technology including upgrading the design of the burner, the supply of the power source, and connection of the device own monitoring system to the embedded TPP control system.