The reduction of mercury emissions in currently existing coal-based power plant solutions by each method i.e. preliminary, primary and secondary (consisting of introducing coal into the combustion chamber and then removing mercury from the combustion gases arising from the combustion process) does not solve the problem of achieving the required limits by power plants. Therefore, the need has arisen to look for new, effective solutions.
The results presented in the work concern the analysis of environmental benefits for the use of zeolites obtained from by-products of coal combustion such as fly ash (from hard coal and lignite) in technologies for removing gaseous forms of mercury. The tested zeolites were silver-modified X-type structures. The reference material in the considerations was active carbon impregnated with bromine – a commercially available sorbent on the market.
The article considers environmental benefits resulting from the use of tested zeolites taking the product life cycle, sorbent efficiency and the possibility of its regeneration compared to activated carbon (AC/Br) into account. The LCA analysis was performed taking the estimated material and energy balances of the manufacturing processes into account. When comparing the production process of type X zeolite materials on the processing line and activated carbons in the amount necessary to capture 375 g Hg from exhaust gases, the LCA analysis showed that zeolites contribute to a lower potential impact on the environment. The advantage is that 5 times less zeolite sorbent than activated carbons is needed to capture the same amount of mercury. In addition, zeolite materials can be regenerated, which extends their life time
CCS (Carbon Capture and Storage) technology is one of the methods that limit the release of carbon dioxide into the atmosphere. However, the high cost of capturing CO2 in this technology is a major obstacle to the implementation of this solution by power plants. The reduction of costs is expected primarily on the side of the capture and separation of CO2 from flue/ industrial gas. The article presents the financial performance of the most popular amine technology (MEA) against mesoporous material about MCM-41 structure obtained from fly ash, impregnated with polyethyleneimine (PEI), for CCS installations. The study was conducted for an investment comprising three key components that provide a full value chain in CCS validation (capture, transport and storage). The mineralogical studies and determination of the physicochemical properties of mesoporous material produced from waste materials such as fly ash allowed us to identify the best class sorbents of MCM-41, which can be used in CO2 capture technologies. Developing an innovative relationship not only allows 100% of CO2 to be removed but also reduces operating costs (OPEX), primarily including energy by 40% and multiple material costs relative to amine mixtures such as MEA.
Mercury emissions have become one of the problems in the energy sector in recent years. The currently used mercury removal techniques include: primary, secondary and preliminary methods. However, due to the large variation in the mercury content in hard and brown coal and the different characteristics of power plants, these methods are often not effective enough to meet the new requirements set by BREF/BAT which requires a search for new, high-efficiency solutions. The proposal for a new technology has been developed in the project “Hybrid Adsorption Systems to Reduce Mercury Emissions Using Highly Effective Polymer Components” (HYBREM). The project was implemented by the consortium of SBB Energy SA and ZEPAK Pątnów II Power Plant. An innovative, high-efficiency hybrid technology for purifying exhaust gases from mercury was developed. GORE polymer modules were used as a technology base where, in combination with the injection of solid sorbents, a hybrid technology was developed. To assess the economic efficiency of the similar case as in the HYBREM project model based on OPEX and CAPEX, each method was selected separately. The article focused on the substitution of solid sorbents used in the HYBREM project by zeolite based materials. Modified zeolite X, applied in the project, was derived from fly ash. Preliminary analysis shows that the system of proposed technologies is very cost-competitive compared only to GORE technology. The basic factors are the possibility of recovering zeolites from ash, combined with low investment outlays.
The paper presents an application of Life Cycle Assessment (LCA) method for the environmental evaluation of the technologies for the fertilizers production. LCA has been used because it enables the most comprehensive identifi cation, documentation and quantifi cation of the potential impacts on the environment and the evaluation and comparison of all signifi cant environmental aspects. The main objective of the study was to assess and compare two technologies for the production of phosphorus (P) fertilizers coming from primary and secondary sources. In order to calculate the potential environmental impact the IMPACT 2002+ method was used. The fi rst part of the LCA included an inventory of all the materials used and emissions released by the system under investigation. In the following step, the inventory data were analyzed and aggregated in order to calculate one index representing the total environmental burden. In the scenario 1, fertilizers were produced with use of an integrated technology for the phosphorus recovery from sewage sludge ash (SSA) and P fertilizer production. Samples of SSA collected from two Polish mono-incineration plants were evaluated (Scenario 1a and Scenario 1b). In the scenario 2, P-based fertilizer (reference fertilizer – triple superphosphate) was produced from primary sources – phosphate rock.
The results of the LCA showed that both processes contribute to a potential environmental impact. The overall results showed that the production process of P-based fertilizer aff ects the environment primarily through the use of the P raw materials. The specifi c results showed that the highest impact on the environment was obtained for the Scenario 2 (1.94899 Pt). Scenario 1a and 1b showed the environmental benefi ts associated with the avoiding of SSA storage and its emissions, reaching -1.3475 Pt and -3.82062 Pt, respectively. Comparing results of LCA of P-based fertilizer production from diff erent waste streams, it was indicated that the better environmental performance was achieved in the scenario 1b, in which SSA had the higher content of P (52.5%) in the precipitate. In this case the lower amount of the energy and materials, including phosphoric acid, was needed for the production of fertilizer, calculated as 1 Mg P2O5. The results of the LCA may play a strategic role for the decision-makers in the aspect of searching and selection of the production and recovery technologies. By the environmental evaluation of diff erent alternatives of P-based fertilizers it is possible to recognize and implement the most sustainable solutions.
en
pl
