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Determinations of design parameters and investigation on operation performance of a tar removal system for gas cleaning of biomass producer gas have been undertaken. The presence of the tars in the producer gas has been the major hindrance for the commercialisation of the biomass gasification technology for power generation, hydrogen production, Fischer Tropsch (FT) synthesis, chemical synthesis and synthetic natural gas (SNG) synthesis. The characteristic of the tars to condense at reduced temperatures cause problems in the downstream processing as the tars can block and foul the downstream process equipment such as gas engines reactor channels, fuel cells, etc. Considerable efforts have been directed at the removal of tars from the producer gas where the tars can be either chemically converted into lighter molecular weight molecules or physically transferred from gas phase to liquid or solid phase. In the former, the tars have been removed in a scrubber by transferring them from the producer gas to a scrubbing liquid and then removed from the liquid to air in a stripper and finally recycled them into air to a gasifier to recover their energy. A tar removal test system involving a scrubber and stripper has been designed based on the predicted tar solubility in canola methyl ester (CME) as the scrubbing liquid and its measured properties (CME is a type of methyl ester biodiesel). The tar solubility has been predicted to decrease with increasing temperatures and thus its value increases at lower temperatures. In designing the test system, the design parameters are needed including equilibrium coefficients of the gas-liquid system, molar transfer coefficient and the optimum liquid to gas flow rate ratio. The equilibrium coefficients have been predicted based on thermodynamic theories where the required data are determined from CME composition and known properties of each component of the CME as well as the properties of the model tar (naphthalene). The molar transfer coefficients are then experimentally determined and the correlations as a function of liquid and gas flow rates are proposed which are consistent with literature. The optimum liquid to gas flow rate ratios have been found to be 21.4±0.1 for the scrubber and 5.7±0.1 for the stripper. Using these optimum ratios, the tar removal efficiencies in the scrubber and the stripper are 77 and 74%, respectively. The analysis of the system performance has been achieved after an innovative method of determining tar concentrations in both the liquid and gas phase had been developed based on the concept of the density of liquid mixtures. However, these tar removal efficiencies are low due to the fact that the targeted tar concentration in the scrubber’s off-gas was large. As a result the system has been redesigned based on the determined design parameters and its operation performance retested. In the redesigned system, the tar removal efficiency in the scrubber and stripper is 99%. The redesigned system would be integrated with the UC gasifier for downstream gas cleaning. Since 1% of tars are not removed, a makeup tar free CME of 0.0375 litres per hour for the 100kW UC gasifier has been introduced in the recycle stream between the scrubber and stripper to avoid tar accumulation in the system.

The aluminosilicate materials kaolinite, calcium montmorillonite and emathlite have been tested as solid sorbents for alkali vapour in controlled gaseous environments, in order to study their sorption characteristics. The study used pan pelletised and extruded pellets in single pellet and fixed bed reactor systems under gaseous environmental conditions containing water vapour, hydrogen chloride and nitrogen at a temperature of 850°C. The means of producing the pellets and the composition of the gaseous environment were shown to determine the sorption performance of the sorbent pellets. The physical properties of the pellet (particle size, total pore volume, surface area, crush strength) significantly affect the sorption effectiveness, while the formation of reaction products is dependent upon the sorbents' chemical composition and on the sorption conditions. Reaction products identified under the various sorption conditions indicated possible pathways for alkali capture. Hydrogen chloride mixtures were shown to cause a reverse of the sorption process for some sorbents. A leaching method for extracting sodium from treated pellets enabled the type of bonding to be determined but not necessarily the prime sorption mechanism. With the introduction of water vapour, some evidence was presented that the alkali sorption rate can change significantly. The previously reported effect of hydrogen chloride upon alkali capture by the sorbent material, calcium montmorillonite; shown by McLaughlin (1990) was confirmed and the effect was also investigated for emathlite and kaolinite. Reversibility depended upon the presence or absence of hydrogen chloride. Both water vapour and hydrogen chloride determine sorption activity and capacity. Likewise the structural characteristics of the pellet influences the sorption activity and capacity. The sorption process is not due to aluminosilicate reaction alone but also due to replacement mechanisms. Conclusions are drawn regarding mechanism and theoretical model proposed.

The Diploma’s work deals with design to use new methods of cleaning the combustion products for the incinerator of biomass, which guarantees removal of dioxins from the combustion products. Thesis depicts methods of cleaning the combustion products, like ADIOX, using ceramic filters, catalytically filters and methods REMEDIA. Thesis compares constituent methods in terms of effectiveness and according to economic analysis applicable to incinerator of biomass-power output 1 MW. Thesis acquaints with the conception of biomass and with thermic processing, which produces dioxins. Thesis processes using biomass in Czech Republic and plan for using in the future. Thesis processes detailed model of filter using the fabric filters REMEDIA. Suggestion of position of the filter and it is connection to original products line of cleaning the combustion products. Increased pressure loss of the new pipework way and increased consumption of ventilator incinerator is calculated for the new connection. In quest of decreasing the thermal loss of combustion products and in quest of increasing safety of operation is calculated and in quest of increasing safety of operation is calculated proposal of isolation for the filter and pipework. In the end of the thesis is depicted using the technology for decreased amount of dioxins from the fly ash from dioxin filter.

The thesis is focused on analyzing the current status of the technology used for cleaning flue gas from persistent organic pollutants, especially PCDD/F. For the three most commonly used methods of solution operational and energy efficiency comparison was made, where achievable energy export and the impact of the change in working conditions on the efficiency indicators of energy production and use of the energy was evaluated. In conditions we considered an alternative machine-technological solutions used for the final disposal of persistent organic pollutants resulting from the waste combustion in terms of additional operating costs and energy efficiency.

<p>År 2000 startades ett samarbete mellan Wuhan i Kina och Borlänge Energi i Sverige. De två parterna bestämde år 2005 tillsammans med IVL, Svenska Miljöinstitutet, att samarbeta inom följande områden; hållbar energiproduktion, hållbar avfallsproduktion samt grundandet av ett miljöteknikcentrum i Wuhan. Miljöteknikcentrumet är till för att vara en plattform för svensk miljöteknik och expertis. Som ett första steg inför grundandet av ett miljöteknikcentrum gjordes en undersökning för att se inom vilka sektorer svensk miljöteknik kan etableras.</p><p>Undersökningen var inriktat på industriell avloppsvattenrening i Wuhan; bedömning av vilka typer av industrier/företag som har problem med avloppsvattenreningen och i vilken utsträckning det finns svenska tekniklösningar på problemen. Undersökningen genomfördes genom intervjuer med myndigheter och en del utvalda företag. Det var svårt att få fram information om vilka företag som inte följer de kinesiska gränsvärdena, varför en del besök gjordes till företag som lever upp till gränsvärdena. På grund av detta togs även andra problem med miljön som företagen hade upp. Några kommunala reningsverk besöktes och intervjuades också för att få en bättre bild av den kommunala vattenreningssituationen. En generell beskrivning av Wuhans miljösituation utfördes också samt en beskrivning av de viktigaste miljömyndigheterna och institutionerna.</p><p>Wuhans största utmaning är att konstruera reningsverk till alla de 3.5 miljoner som fortfarande släpper sitt avloppsvatten rätt ut till sjöar och floder, snarare än att ytterligare rena det industriella avloppsvattnet. Behandlingsgraden av det industriella avloppsvattnet har nått 97 % medan behandlingsgraden av det kommunala avloppsvattnet endast nått 70 %.</p><p>Besök vid de utvalda företagen och kommunala reningsverk ledde till slutsatsen att svensk teknik och expertis kan införas i följande områden: hantering av slam från reningsverk, byggandet av förbränningsanläggningar för sopor och hur man löser problemet med att rena luften från gaser som SO2 och dioxiner. De flesta företagen kunde följa de kinesiska gränsvärdena för utsläpp av avloppsvatten men mycket kan göras för att förbättra företagens tekniker ytterligare. Detta utförs dock nästan aldrig eftersom det är en ekonomisk fråga. Det är möjligt för Wuhan att sätta lokala, hårdare gränsvärlden för att tvinga företagen att förbättra sina reningstekniker ytterligare.</p> / <p>In 2000 a co-operation between Wuhan in China and Borlänge Energi in Sweden started. The two parts decided in 2005 together with IVL, the Swedish Research Institute, to co-operate in the fields of sustainable energy production, sustainable waste management and the establishment of an Environmental Technology Centre, supplying Swedish environmental expertise to companies in Wuhan. As a first step for the establishment of an Environmental Technology Centre in Wuhan, an investigation was made to find out in which sectors Swedish environmental technology could be established.</p><p>The investigation took aim at observing the industrial wastewater treatment in Wuhan and to see which types of companies that have problems with the wastewater treatment and if there existed Swedish technology that could solve the problems. The investigation was performed through interviews with the authorities and some selected companies. It was difficult to get information about companies that did not comply with the National Chinese wastewater standards. This meant that some of the visits were made to companies that comply with the standards, also taking into consideration other problems with the environment that the companies might have. Visits were also paid to municipal wastewater treatment plants to get an overview over the municipal wastewater treatment situation. An overall survey of the environmental situation in Wuhan was also made and a presentation of the most important environmental departments and institutions is given.</p><p>The greatest challenge for Wuhan is to construct wastewater treatment plants for the around 3.5 million people that still discharge their wastewater directly to rivers and lakes, rather than to improve the industrial wastewater treatment further. The treatment rate of the industrial wastewater has reached 97%, but the municipal wastewater treatment rate has only reached 70%.</p><p>After the visits to the selected companies and municipal wastewater treatment plants the conclusion was made that Swedish technologies and expertise can be applied to the following areas; handling sludge from the wastewater treatment plants, construction of waste incineration plants and handling flue gas and dioxins. Most of the visited companies could follow the wastewater standards. Although much can be done to improve their technologies further, this is not done since it is too expensive. It is possible for Wuhan to apply stricter local wastewater treatment standards. This could be used as a tool to make companies invest more money in improvements of their technologies.</p>