Technology of mercury removal from exhaust from coal fired boilers

For the Polish power industry, the basic fuel is hard coal and lignite, which contains significant amounts of mercury. Current emission standards in the European Union (IED directive and in the near future BAT conclusions) create conditions for investment in flue gas cleaning installations for coal-fired power plants. During the combustion of coal, mainly metallic mercury (Hg0) is produced, which is difficult to remove from the flue gas in dedusting installations (electrostatic precipitators and fabric filters) and wet flue gas desulphurization plants. In these installations, oxidized mercury (Hg2+) and ash bound mercury (Hg(p)) are removed. In order to reduce the mercury concentration in flue gases, the DEMERTEC technology was created, which is based on the oxidation of metallic mercury to an oxidized form and its removal from flue gas in an existing flue gas de-dusting or de-sulphurization installations. The article presents the results of field tests of the DEMERTEC technology for flue gas from hard coal and lignite. This technology was tested on a ~ 400 MWe unit fed with lignite and on an FGD absorber in which flue gas was purified from two units with a capacity of 195 and 220 MWe fed with hard coal. In both cases, mercury emissions were reduced below the levels required by the BAT conclusions.

Waste Gas End-of-Pipe Treatment Techniques in Italian IPPC Chemical Plants

Due to more stringent emission regulations, very efficient emission control technologies are required adopting national IPPC permits based on BAT conclusions. Some abatement techniques are operating inside IPPC plants based in Italy. This chapter includes the results of a screening of Italian IPPC plants, trying to highlight operating conditions of abatement devices and possible already existing improvements for several compounds removal. The abatement techniques analyzed operate mainly on VOC content reduction or on inorganic compounds abatement. ISPRA experience has allowed to analyze different operative conditions, related with abatement techniques and their application in IPPC permitted plants. The results of this analysis suggest a possible reconsideration and new assessment for some end-of-pipe devices in order to find other, better-defined operational contexts, different from Italian provisions and an evaluation of current operational performances of the devices, in order to improve their environmental conditions consistently with BAT application.

Waste Gas End-of-Pipe Treatment Techniques in Italian IPPC Chemical Plants

Due to more stringent emission regulations, very efficient emission control technologies are required adopting National IPPC Permits based on BAT Conclusions. Some abatement techniques are operating inside IPPC plants based in Italy. This paper include the results of a screening of Italian IPPC Plants up to day, trying to highlight operating conditions of abatement devices and possible already existing improvements for several compounds removal. The abatement techniques analyzed operate mainly on VOC content reduction or on inorganic compounds abatement. ISPRA experience has allowed to analyze different operative conditions, related with abatement techniques and their application in IPPC permitted plants. The results of this analysis allow to suggest a possible reconsideration and new assessment for some end-of-pipe devices, in order to find other better defined operational contexts, different from actually Italian provisions and an evaluation of current operational performances of the devices, in order to improve their environmental conditions, consistently with BAT application.

Dust emission from wet, low-emission coke quenching process

Coke plants, which produce various types of coke (metallurgical, foundry or heating), at temperatures between 600 and 1200°C, with limited access to oxygen, are major emitters of particulates and gaseous pollutants to air, water and soils. Primarily, the process of wet quenching should be mentioned, as one of the most cumbersome. Atmospheric pollutants include particulates, tar substances, organic pollutants including B(a)P and many others. Pollutants are also formed from the decomposition of water used to quench coke (CO, phenol, HCN, H2S, NH3, cresol) and decomposition of hot coke in the first phase of quenching (CO, H2S, SO2) [1]. The development of the coke oven technology has resulted in the changes made to different types of technological installations, such as the use of baffles in quench towers, the removal of nitrogen oxides by selective NOx reduction, and the introduction of fabric filters for particulates removal. The BAT conclusions for coke plants [2] provide a methodology for the measurement of particulate emission from a wet, low-emission technology using Mohrhauer probes. The conclusions define the emission level for wet quenching process as 25 g/Mgcoke. The conducted research was aimed at verification of the presented method. For two of three quench towers (A and C) the requirements included in the BAT conclusions are not met and emissions amount to 87.34 and 61.35 g/Mgcoke respectively. The lowest particulates emission was recorded on the quench tower B and amounted to 22.5 g/Mgcoke, therefore not exceeding the requirements.