Apart from diesel, gas and recently also alternative fuels such as rapeseed oil and sewage off-gas, heavy fuel oil (HFO) is one of the fuels that can be used to fire boilers and engines. Just like the other fuels, the combustion of heavy fuel oil also produces nitrogen oxides (NOx) which have to be kept below legally specified emissions limits. A highly efficient and reliable process for reducing these emissions that has been well established for many years is selective catalytic reduction (SCR).

• SINOx for stationary applications
  
  

With its SINOx® system, Siemens has been making a valuable contribution to this field of technology. In addition to supplying complete turnkey exhaust-gas cleaning systems for industrial sources of NOx emissions (e. g. waste gases from chemical industrial production processes of refuse incineration plants), Siemens turned its attention very early on to boiler and engine combustion systems that are fired using wood, diesel, gas and, particularly, heavy fuel oil.

• Heavy Fuel-Oil Combustion Systems
  
  

Heavy fuel oil is a refinery by-product that is cheap to obtain. Depending on its origin and composition, it can contain a variety of chemical elements and compounds that are sometimes hard to identify. The exhaust gases produced by heavy oil-fired combustion systems often contain substances that are potentially hazardous for catalytic materials. These can be expected to include, for example, high concentration of alkali, alkaline earth and heavy metals which can have an adverse effect on the service lives of the catalysts. On the other hand, some of the constituents in the exhaust from heavy-fuel-oil-fired boilers and engines can in fact enhance catalyst activity.
This highly complex interaction between constituents that degrade and promote catalyst activity is what finally determines the anticipated service life of a catalytic reactor. However, Siemens' many years of experience in cleaning boiler and engine exhaust gases and our successful development work in connection with raising the resistance of our SINOx® catalysts to poisoning allow us to guarantee long component service lives, even in heavy fuel oil-fired systems. Furthermore, we are always ready to help you out with inexpensive catalyst replacement strategies, and also take back spent material for efficient recycling at no extra cost.