USE AND DISPOSAL OF ACIDIC WATER CONDENSATE FROM GAS-FIRED BOILER UNITS
Array
Keywords:
heat-recovery technologies, exhaust-gases, deep cooling, decarbonization.Abstract
During operation in boiler units of modern condensing boilers or modernization of old-style boilers, water condensate is formed due to heat-recovery equipment in the mode of cooling exhaust-gases below the dew point of water vapor. At natural gas is burned in equipment, the range of values of the pH value of the condensate is within the range of 3 ÷ 6. In this connection, the problem arises of the useful use of this condensate or its safe drainage into the sewer network. At useful use, the resulting condensate can be used for the needs of the boiler units (for washing boilers, in chemical water-purification systems) or outside the boiler house (for laundries, greenhouses, swimming pools, etc.). In the case of condensate drainage into the city sewer network, as a rule, its preliminary decarbonization is required. This is a necessary environmental measure and operational standard to protect the sewer network and related equipment, including treatment facilities, from premature wear.
Among the directions of condensate decarbonization known in Ukraine, the most common are:
- decarbonization by degassing by the contact method, which consists in removing CO2 from the heated solution by blowing air in the nozzle layer (ceramic or plastic), through which condensate flows. Degassing occurs due to the instability of the H2CO3 compound, which, when heated, easily decomposes into H2O and CO2;
- chemical decarbonization, by combining carbon dioxide in an insoluble compound with various reagents, which are added to the container using a dispenser;
- decarbonization by passing the condensate through a granular filter containing calcium carbonate, such as marble chips or lime.
Removal of carbonic acid from condensate during filtration in a layer of marble chips is seen as the simplest method of decarbonization of water condensate from those considered. On the basis of this method of decarbonization, the authors propose a technical solution for the developed neutralizer with a description of its design and operating principle.
The paper presents the results of calculated studies of the volumes of formed condensate and an example of its safe use in the case of modernization of a gas-fired water-heating boiler with a nominal thermal power of 1 MW by a heat-recovery system with simple or complex use of heat.
It is shown that when using modern heat-recovery technologies in gas-fired boiler houses, there are different circuit and technical solutions for possible useful use or safe evacuation of acidic condensate formed during the implementation of these technologies. In cases where it is advisable to neutralize this condensate, there are effective methods for its decarbonization and appropriate equipment.
References
2. Fialko, N.M., Gnedash, G.O., Navrodska, R.O., Presich, G.O., & Shevchuk, S.I. (2019). Improving the efficiency of complex heat-recovery systems for gas-fired boiler installations. Scientific Bulletin of UNFU, 29(6), 79–82. https://doi.org/10.15421/40290616
3. Balzamov, D.S., Sabitov, L.S., Timershin, B.F., & Balzamova, E.Y. (2018). Increase of efficiency of heat sources work due to application of condensation economizers on an example of a boiler PTVM-180. In IOP Conference Series: Materials Science and Engineering, 412(1), 012007. https://doi.org/10.1088/1757-899X/412/1/012007
4. Levy, Edward, Bilirgen, Harun, Jeong, Kwangkook, Kessen, Michael, Samuelson, Christopher, & Whitcombe, Christopher. Recovery of Water from Boiler Flue Gas. United States. https://doi.org/10.2172/952467
5. Wei, M., Zhao, X., Fu, L., & Zhang, S. (2017). Performance study and application of new coal-fired boiler flue gas heat recovery system. Applied energy, 188, 121–129. https://doi.org/10.1016/j.apenergy.2016.11.132
6. Fialko, N., Navrodska, R., Ulewicz, M., Gnedash, G., Alioshko, S., & Shevcuk, S. (2019). Environmental aspects of heat recovery systems of boiler plants. In E3S Web of Conferences, Vol. 100, p. 00015. EDP Sciences. https://doi.org/10.1051/e3sconf/201910000015
7. Novakivskii, M. Kompleksni teploutylizatsiyni systemy dlya kotliv maloyi ta serednoyi potuzhnosti z pidvyshchenym volohovmistom vidkhidnykh haziv [Complex heat-utilization systems for low and middle power boilers with increased moisture content of waste gases]. The thesis for a Degree of “Candidate of Technical Science”, specialty 05.14.06 / NAS of Ukraine, Kyiv, 2017, 21.
8. Navrodska, R., Fialko, N., Presich, G., Gnedash, G., Alioshko, S., & Shevcuk, S. (2019). Reducing nitrogen oxide emissions in boilers at moistening of blowing air in heat recovery systems. In E3S Web of Conferences, Vol. 100, p. 00055). EDP Sciences. https://doi.org/10.1051/e3sconf/201910000055
9. Burger, H., & Boehle, W. (2000). Specification sheet ATV-A 251: Energy-saving high-efficiency boiler systems and condensation water removal; Arbeitsblatt ATV-A 251 schafft Klarheit: Energiesparende Brennwertanlagen und Kondenswasserableitung. Waermetechnik-Versorgungstechnik, 45. https://www.osti.gov/etdeweb/biblio/20087888
10. Katkov, D.S. (2015). Kompleksnaya ekologicheskaya otsenka raboty gazovykh kondensatsionnykh kotlov. Agrarnyy nauchnyy zhurnal, (2), 42–44.
11. On approval of the rules of sewage reception to centralized drainage systems and the procedure for determining the size of the charge for over-discharge wastewater to centralized drainage systems : оrder of the Ministry of Regional Development of Ukraine from 01.12.2017, аvailable at:
https://zakon.rada.gov.ua/go/z0056-18
12. Efimov, A.V., Goncharenko, A.L., Goncharenko, L.V., & Esipenko, T.A. (2017). Sovremennye tekhnologii glubokogo okhlazhdeniia produktov sgoraniia topliva v kotelnykh ustanovkakh, ikh problemy i puti resheniia. Kharkiv Polytechnic Institute, Kharkiv. http://repository.kpi.kharkov.ua/handle/KhPI-Press/32826
Downloads
Published
How to Cite
Issue
Section
License
The authors who publish in this collection agree with the following terms:
• The authors reserve the right to authorship of their work and give the magazine the right to first publish this work under the terms of license CC BY-NC-ND 4.0 (with the Designation of Authorship - Non-Commercial - Without Derivatives 4.0 International), which allows others to freely distribute the published work with a mandatory reference to the authors of the original work and the first publication of the work in this magazine.
• Authors have the right to make independent extra-exclusive work agreements in the form in which they were published by this magazine (for example, posting work in an electronic repository of an institution or publishing as part of a monograph), provided that the link to the first publication of the work in this journal is maintained. .
• Journal policy allows and encourages the publication of manuscripts on the Internet (for example, in institutions' repositories or on personal websites), both before the publication of this manuscript and during its editorial work, as it contributes to the emergence of productive scientific discussion and positively affects the efficiency and dynamics of the citation of the published work (see The Effect of Open Access).
