Ecotube System - A European Alternative to SNCR and SCR NOx Reduction Systems

摘要

This work presents the main features, advantages and evaluation of applications of the novel Ecotube system, an advanced and effective tool for combustion improvement and emission reduction. The Ecotube system was invented by the Swedish company ECOMB AB in the early 90's and has until now been installed in over 25 units worldwide. The Ecotube system represents an innovative cost-effective optimisation tool for all combustion processes and principally comprises retractable lances -^sEcotubes - that are equipped with injection nozzles.The main application for this technique is air-staging, whereby high velocity air is injected through the nozzles - an advanced Over-Fire Air system. Water can be injected for Gas Temperature Control and various agents, such as Ammonia, Urea and Limestone, can also be mixed into the air jets for additional NOx reduction as well as reduction of SOx, HCI etc in the furnace. The Ecotubes are strategically positioned within the furnace enabling injected air and other agents to create a radically improved mixing of the combustion products, resulting in destruction of laminar gas columns and the formation of completely mixed turbulent flow patterns. CFD and a special in-furnace camera technique are used to examine and confirm the right position of the Ecotubes, injection angels etc as well as to verify the improvements after the system is installed. A major step in the world market was taken in 2005, when four Ecotubes were installed in the two (two in each unit) Waste To Energy units in Bessieres, outside Toulouse in south France. This was the first large order from France and the election of ECOMB AB as Turn-key supplier to Econotre, a subsidiary to giants SUEZ, was a big challenge for ECOMB. In strong competition from SNCR and SCR suppliers ECOMB got the vote, because of economics and environmental friendly solutions -^sNO agents, such as ammonia or urea are used for NOx-reduction, just air-staging with pure air. The combustion process improvements in those units -^sWITH PURE AIR injected via the Ecotubes - can be summarized as; # over 60% Reduction of NOx #11,7% Increased Waste Throughput over a 6 months period # 4,6% Increased Power Output over a 6 months period # Very Efficient Control of Flame Temperatures with optional Water Injection from the Ecotubes, an important step for Reducing Fire-side Erosion and Corrosion# Minimum 10% Reduction of Fly-Ash (not verified yet) Trials with injection of NOx reduction agents, such as ammonia and urea, will be tested as a development phase of this project - in order to achieve Ultra Low NOx emissions. This techniques has now been brought to the WTE Market in US, being marketed by Synterprise from Chattanooga, TN.