The heat power needed for the production of soda ash is produced in Deven AD. The combustion installation of Thermo-electric power plant Deven is a system for combined production of heat and electrical power (cogeneration system), which is defined as the most important option in the best available techniques for reduction of the emissions of green-house gases, but it is as per old Russian design from 1964. The production is done by burning of three types of fuels (imported coal, natural gas and black oil) in 7 steam-boilers (5 coals and 2 gases). Thermo-electric power plant Devnya EAD was privatized in August 2000 by Solvay Sodi AD. After the privatization the company is renamed to Deven AD. In 2006, in order to meet the new European legislation in the field of preservation of the environment, as well as to cover the requirements, underlying in Chapter 22 from the Memorandum for incorporation of Bulgaria to the European community, Solvay Sodi decided to undertake the renovation of some of the existing boilers and the replacement of these, which are morally outdated with a new big boiler from the type „circulating fluidized bed”. The characteristic for this new type of boiler is that the fuel constantly circulates through the furnace and the separators in order to increase the residence time of the particles in the furnace, which allows burning at lower temperature than the usual one. The result is a favorable for the environment installation with very low emissions of nitric oxides (< 200 mg/nm3), of sulphur oxides (< 200 mg/nm3) thanks to the addition of limestone, very low emissions of dust (< 30 mg/nm3), with a simple construction, reliability, excellent efficiency, with freedom and possibilities for the burning of various range of solid fuels, which allows the primary power resources to be used better. The total budget for this project, including the additional improvements, having the designed to contribute to environment improvements in the existing installations, amounts to 150 million BGN. The boiler of circulating fluidized bed in Thermo-electric power plant Deven is part of the investment project for increasing the production capacity of Solvay Sodi with 25% up to 1.5 million tons of soda ash annually. It was officially opened on 27 April 2010.
