This study investigates the partial combustion technique for tar conversion using a modified experimental set up comprising a packed bed reactor with bed-inside probe for air supply. Simulated producer gas (SPG) and benzene were selected as a real producer gas alternative and model tar component respectively. The benzene conversion was investigated under different experimental conditions such as reactor temperature (650–900 °C), packed bed height (0–12 cm), residence time (1.2–1.9 s), air fuel ratio (0.2 and 0.3) and SPG composition. The results showed insignificant effect of temperature over benzene conversion while air fuel ratio of 0.3 caused high benzene conversion than at 0.2. Absence of packed bed lead high benzene conversion of 90% to polyaromatic hydrocarbons (PAHs) compared to similar low PAHs free benzene conversion of 32% achieved at both packed heights. In SPG composition effect, H2 and CH4 had a substantial inverse effect on benzene conversion. An increase in H2 concentration from 12 to 24 vol% increased the benzene conversion from 26 to 45% while an increase in CH4 concentration from 7 to 14 vol% reduced the benzene conversion from 28 to 4%. However, other SPG components had insignificant impacts on benzene conversion.

This study investigates the conversion of benzene in a novel highly non-porous ɣ-Al₂O₃ packed bed reactor at 1000–1100 °C. The influences of packed bed presence, reforming medium (steam and CO₂), gas flow rate and benzene concentration on steady state benzene conversion are examined. In presence of packed bed, benzene conversions of 52, 75, and 84% were achieved with combined steam and CO₂ reforming at 1000, 1050, and 1100 °C, respectively. Whereas, benzene conversion of 65% without the packed bed at 1000 °C experienced a continuous increase in differential upstream pressure (DUP) of high temperature (HT) filter at reactor downstream due to deposition of in situ generated coke. High concentrations of generated CO and H₂ of 2.3 and 6 vol% with packed bed than 1.4 and 4.7 vol% without the packed respectively, were achieved. CO₂ reforming achieved high benzene conversions of 68–98% than 42–80% achieved with stream reforming at packed bed reactor temperatures of 1000–1100 °C. The results indicated that presence of ɣ-Al₂O₃ packed bed with possible surface reactions directed the conversion of benzene to combustible gases instead of coke. Hence, ɣ-Al₂O₃ packed bed reactor could be a suitable choice for coke-free conversion of tar of gasifier producer gas.

The use of green heterogeneous catalysts that are obtained from waste agricultural biomass can make the production of biodiesel more economical. In this research, three solid base heterogeneous catalysts (Catalyst A, B, and C) were synthesized from kola nut pod husks, and the synergistic effects of the elemental composition on catalytic activities for biodiesel production were studied. The results revealed a high surface area of Catalysts A, B, and C at 419.90 m²/g, 430.54 m²/g, and 432.57 m²/g, respectively. Their corresponding pore diameters are 3.53 nm, 3.48 nm, and 3.32 nm, showing that the catalysts are mesoporous in nature. The X-ray Fluorescence (XRF) results revealed the presence of a variety of alkaline earth metals and their corresponding metal oxides in substantial amounts. Catalyst A was produced with the highest concentration of calcium at 40.84 wt.% and calcium oxide at 68.02 mole%. The substantial concentration of other elements, such as potassium, magnesium, and aluminum, and their corresponding metal oxides are the proof of high catalytic activity of the produced green catalysts. The high CaO contents of all three produced catalysts and their high surface areas indicate their strong potential for good catalytic activities applied to the synthesis of biodiesel.

Gasification is generally acknowledged as one of the technologies that will enable the large-scale production of biofuels and chemicals from biomass and waste. One of the main technical challenges associated to the deployment of biomass gasification as a commercial technology is the cleaning and upgrading of the product gas. The contaminants of product gas from biomass/waste gasification include dust, tars, alkali metals, BTX, sulphur-, nitrogen- and chlorine compounds, and heavy metals. Proper measurement of the components and contaminants of the product gas is essential for the monitoring of gasification-based plants (efficiency, product quality, by-products), as well as for the proper design of the downstream gas cleaning train (for example, scrubbers, sorbents, etc.). In practice, a trade-off between reliability, accuracy and cost has to be reached when selecting the proper analysis technique for a specific application. The deployment and implementation of inexpensive yet accurate gas analysis techniques to monitor the fate of gas contaminants might play an important role in the commercialization of biomass and waste gasification processes.

This special report commissioned by the IEA Bioenergy Task 33 group compiles a representative part of the extensive work developed in the last years by relevant actors in the field of gas analysis applied to(biomass and waste) gasification. The approach of this report has been based on the creation of a team of contributing partners who have supplied material to the report. This networking approach has been complemented with a literature review. The report is composed of a set of 2 documents. Document 1(the present report) describes the available analysis techniques (both commercial and underdevelopment) for the measurement of different compounds of interest present in gasification gas. The objective is to help the reader to properly select the analysis technique most suitable to the target compounds and the intended application. Document 1 also describes some examples of application of gas analysis at commercial-, pilot- and research gasification plants, as well as examples of recent and current joint research activities in the field. The information contained in Document 1 is complemented with a book of factsheets on gas analysis techniques in Document 2, and a collection of video blogs which illustrate some of the analysis techniques described in Documents 1 and 2.

This guideline report would like to become a platform for the reinforcement of the network of partners working on the development and application of gas analysis, thus fostering collaboration and exchange of knowledge. As such, this report should become a living document which incorporates in future coming progress and developments in the field.

Gasification is generally acknowledged as one of the technologies that will enable the large-scale production of biofuels and chemicals from biomass and waste. One of the main technical challenges associated to the deployment of biomass gasification as a commercial technology is the cleaning and upgrading of the product gas. The contaminants of product gas from biomass/waste gasification include dust, tars, alkali metals, BTX, sulphur-, nitrogen- and chlorine compounds, and heavy metals. Proper measurement of the components and contaminants of the product gas is essential for the monitoring of gasification-based plants (efficiency, product quality, by-products), as well as for the proper design of the downstream gas cleaning train (for example, scrubbers, sorbents, etc.). The deployment and implementation of inexpensive yet accurate gas analysis techniques to monitor the fate of gas contaminants might play an important role in the commercialization of biomass and waste gasification processes.

This special report commissioned by the IEA Bioenergy Task 33 group compiles a representative part of the extensive work developed in the last years by relevant actors in the field of gas analysis applied to (biomass and waste) gasification. The approach of this report has been based on the creation of a team of contributing partners who have supplied material to the report. This networking approach has been complemented with a literature review. This guideline report would like to become a platform for the reinforcement of the network of partners working on the development and application of gas analysis, thus fostering collaboration and exchange of knowledge. As such, this report should become a living document which incorporates in future coming progress and developments in the field.

In this report, the technical and economical feasibility to produce higher alkanes from bioglycerol has been investigated. The main purpose of producing this kind of chemicals would be to replace the fossil LPG used in upgraded biogas production. When producing biogas and exporting it to the natural gas grid, the Wobbe index and heating value does not match the existing natural gas. Therefore, the upgraded biogas that is put into the natural gas grid in Sweden today contains 8-10 vol-% of LPG. The experimental work performed in association to this report has shown that it is possible to produce propane from glycerol. However, the production of ethane from glycerol may be even more advantageous. The experimental work has included developing and testing catalysts for several intermediate reactions. The work was performed using different micro-scale reactors with a liquid feed rate of 18 g/h. The first reaction, independent on if propane or ethane is to be produced, is dehydration of glycerol to acrolein. This was showed during 60 h on an acidic catalyst with a yield of 90%. The production of propanol, the second intermediate to producing propane, was shown as well. Propanol was produced both using acrolein as the starting material as well as glycerol (combining the first and second step) with yields of 70-80% in the first case and 65-70% in the second case. The propanol produced was investigated for its dehydration to propene, witha yield of 70-75%. By using a proprietary, purposely developed catalyst the propene was hydrogenated to propane, with a yield of 85% from propanol. The formation of propane from glycerol was finally investigated, with an overall yield of 55%.

The second part of the experimental work performed investigated the possibilities of decarbonylating acrolein to form ethane. This was made possible by the development of a proprietary catalyst which combines decarbonylation and water-gas shift functionality. By combining these two functionalities, no hydrogen have to be externally produced which is the case of the propane produced. The production of ethane from acrolein was shown with a yield of 75%, while starting from glycerol yielded 65-70% ethane using the purposely developed catalyst. However, in light of this there are still work to be performed with optimizing catalyst compositions and process conditions to further improve the process yield. The economic feasibility and the glycerol supply side of the proposed process have been investigated as well within the scope of the report. After an initial overview of the glycerol supply, it is apparent that at least the addition of alkanes to biogas can be saturated by glycerol for the Swedish market situation at the moment and for a foreseeable future. The current domestic glycerol production would sustain the upgraded biogas industry for quite some time, if necessary. However, from a cost standpoint a lower grade glycerol should perhaps be considered.

In Sweden, biofuels have come into substantial use, in an extent that are claimed to be bigger than use of fossil oil. One driving force for this have been the CO2-tax that was introduced in 1991 (1). According to SVEBIO:s calculations (2) based on the Swedish Energy Agency´s prognosis, the total energy consumption in Sweden 2012 was 404 TWh. If the figure is broken down on the different energy sources (figure 1) one can see that the consumption roughly distribute in three different, equally sized, blocks, Biofuels, fossil fuels and water & nuclear power. The major use of the fossil fuels is for transport and the water & nuclear power is used as electric power. The main use of the biofuels is for heating in the industrial sector and as district heating. In 2009 the consumption from those two segments was 85 TWh, and 10 TWh of bio power was co-produced giving an average biomass to electricity efficiency of 12%. This indicates a substantial conversion potential from hot water production to combined heat and power (CHP) production. in Sweden 2013 broken down on the different energy sources. In 2006 the pulp, paper and sawmill industry accounted for 95% of the bio energy consumption in the industrial sector, and the major biofuel consumed was black liquor (5). However, the pulp and paper industries also produced the black liquor in their own processes. The major energy source (58%) for district heating during 2006 was woody biomass (chips, pellets etc.) followed by waste (24%), peat (6%) and others (12%) (5). The use of peat has probably decreased since 2006 since peat is no longer regarded as a renewable energy source. While the use of biofuel for heating purpose is well developed and the bio-power is expected to grow, the use in the transport sector is small, 9 TWh or 7% in 2011. The main consumption there is due to the mandatory addition (5%) of ethanol to gasoline and FAME to diesel (6). The Swedish authorities have announced plans to increase the renewable content to 7.5 % in 2015 on the way to fulfill the EU’s goal of 10 % renewable transportation fuels in 2020. However the new proposed fuel directive in EU says that a maximum of 5% renewable fuel may be produced from food sources like sugars and vegetable oils. Another bothersome fact is that, in principle, all rape seed oil produced in Sweden is consumed (95-97%) in the food sector, and consequently all FAME used (in principle) in Sweden is imported as FAME, rape seed oil or seed (6). In Sweden a new source of biodiesel have emerged, tall oil diesel. Tall oil is extracted from black liquor and refined into a diesel fraction (not FAME) and can be mixed into fossil diesel, i.e. Preem Evolution diesel. The SUNPINE plant in Piteå have a capacity of 100 000 metric tons of tall oil diesel per annum, while the total potential in all of Sweden is claimed to be 200 000 tons (7). 100 000 tons of tall oil corresponds to 1% of the total diesel consumption in Sweden. in Sweden for 2010 and a prognosis for 2014. (6). Accordingly, the profoundest task is to decrease the fossil fuel dependency in the transport sector, and clearly, the first generation biofuels can´t do this on its own. Biogas is a fuel gas with high methane content that can be used in a similar way to natural gas; for instance for cooking, heating and as transportation fuel. Today biogas is produced by fermentation of waste (municipal waste, sludge, manure), but can be produced by gasification of biomass, for instance from forest residues such as branches and rots (GROT in Swedish). To get high efficiency in the production, the lower hydrocarbons, mainly methane, in the producer gas, should not be converted into synthesis gas. Instead a synthesis gas with high methane content is sought. This limits the drainage of chemically bonded energy, due to the exothermic reaction in the synthesis step (so called methanisation). In 2011 0.7 TWh of biogas was produced in Sweden by fermentation of waste (6) and there were no production by gasification, at least not of economic importance. The potential seems to be large, though. In 2008 the total potential for biogas production, in Sweden, from waste by fermentation and gasification was estimated to 70 TWh (10 TWh fermentation and 60 TWh gasification) (8). This figure includes only different types of waste and no dedicated agricultural crops or dedicated forest harvest. Activities in the biogas sector, by gasification, in Sweden are the Göteborgs energi´s Gobigas project in Gothenburg and Eon´s Bio2G-project, now pending, in south of Sweden. If the producer gas is cleaned and upgraded into synthesis gas also other fuels could be produced. In Sweden methanol and DME productions are planned for in the Värmlands metanol-project and at Chemrecs DME production plant in Piteå.

During the last three years Biofuel-Solution, a privately held Swedish entity, has developed an IP-portfolio around gas-phase glycerol conversion into medium-value chemicals. The targeted chemicals have large to very large markets, to allow for use by more than a fraction of the glycerol available today without impacting the cost of the product. The reason behind is that glycerol is a by-product from the biofuel industry, including biodiesel and bioethanol. This indicates large production volumes, even though the glycerol is a fraction of the fuel produced. A by-product from any fuel process will be vast and therefore any chemical produced from this side-product will have to have a large market to offset it to. In order to avoid changing the fundamental market behavior, similar to what the biodiesel industry has done to the glycerol market.

In the course of this work, several end-products have been targeted. These include plastic monomers, mono-alcohols and energy gases; using acrolein as a common starting point. To produce chemicals with high purity and efficiency, selective and active catalysts are required. For instance, a process for producing propionaldehyde and n-propanol has been developed to the point of demonstration and commercialization building on the gas-phase platform.

By developing multi-function catalysts which perform more than one task simultaneously, synergies can be reached that cannot be achieved with traditional catalysts. For instance, by combining catalyst functionalities, reactions that are both endothermic and exothermic can be performed simultaneously.

This mean lower inlet reactor temperatures (in this particular case) and a more even temperature distribution. By performing the dehydration of glycerol to acrolein in combination with another, exothermal reaction by-products can be suppressed and yields increased.

It also means that new reaction pathways can be achieved, allowing for new ways to produce chemicals and fuels from glycerol. As in the case of ethane production from acrolein, where a catalyst surface has been devised where acrolein is first adsorbed. The actual mechanism is unknown but in speculation, the adsorbed acrolein is decarbonyled into ethylene and carbon monoxide on a first reaction site. The formed carbon monoxide diffuses to another active site, where it reacts with water through the so called water-gas shift reaction to carbon dioxide and hydrogen. Said carbon dioxide leaves as an end-product, and the hydrogen diffuses to another active site where it reacts with ethylene to form ethane. This gives a way of producing energy gases from glycerol in a very compact reactor set-up, effectively reducing footprint and capital cost and increasing productivity of an installation.

This study investigates several commercial selective catalytic reduction (SCR) catalysts (A–E) for application in a high-temperature (approximately 525 °C) and high-concentration (5000 ppm NO) system in combination with CO₂ capture. The suggested process for removing high concentrations of NO_x seems plausible and autothermal operation is possible for very high NO concentrations. A key property of the catalyst in this system is its thermal stability. This was tested and modelled with the general power law model using second-order decay of the BET surface area with time. Most of the materials did not have very high thermal stability. The zeolite-based materials could likely be used, but they too need improved stability. The SCR activity and the possible formation of the by-product N₂O were determined by measurement in a fixed-bed reactor at 300–525 °C. All materials displayed sufficiently high activity for a designed 96% conversion in the twin-bed SCR reactor system proposed. The amount of catalyst needed varied considerably and was much higher for the zeolithic materials. The formation of N₂O increased with temperature for almost all materials except the zeolithic ones. The selectivity to N₂ production at 525 °C was 98.6% for the best material and 95.7% for the worst with 1000 ppm NO_x in the inlet; at 5000 ppm NO_x, the values were much better, i.e., 98.3 and 99.9%, respectively.

A commercial vanadia, tungsta on titania SCRcatalyst was poisoned in a side stream in a waste incinerationplant. The effect of especially alkali metal poisoning was observed resulting in a decreased activity at long times of exposure. The deactivation after 2311 h was 36% whilet he decrease in surface area was only 7.6%. Thus the major cause for deactivation was a chemical blocking of acidic sites by alkali metals. The activation–deactivation model showed excellent agreement with experimental data. The model suggests that the original adsorption sites, from the preparation of the catalyst, are rapidly deactivated but are replaced by a new population of adsorption sites due to activation of the catalyst surface by sulphur compounds (SO₂, SO₃) in the flue gas.

In a joint project, Linnaeus University in Växjö (LNU) and the Faculty of Engineering at Lund University (LTH) were commissioned by the Swedish Energy Agency to make an inventory of the techniques and systems for small scale gasifier-gas engine combined heat and power (CHP) production and to evaluate the technology. Small scale is defined here as plants up to 10 MW_th, and the fuel used in the gasifier is some kind of biofuel, usually woody biofuel in the form of chips, pellets, or sawdust. The study is presented in this report.

The report has been compiled by searching the literature, participating in seminars, visiting plants, interviewing contact people, and following up contacts by e-mail and phone.

The first, descriptive part of the report, examines the state-of-the-art technology for gasification, gas cleaning, and gas engines. The second part presents case studies of the selected plants:

• Meva Innovation’s VIPP-VORTEX CHP plant
• DTU’s VIKING CHP plant
• Güssing bio-power station
• Harboøre CHP plant
• Skive CHP plant

The case studies examine the features of the plants and the included unit operations, the kinds of fuels used and the net electricity and overall efficiencies obtained. The investment and operating costs are presented when available as are figures on plant availability. In addition we survey the international situation, mainly covering developing countries.

Generally, the technology is sufficiently mature for commercialization, though some unit operations, for example catalytic tar reforming, still needs further development. Further development and optimization will probably streamline the performance of the various plants so that their biofuel-to-electricity efficiency reaches 30-40 % and overall performance efficiency in the range of 90 %.

The Harboøre, Skive, and Güssing plant types are considered appropriate for municipal CHP systems, while the Viking and VIPP-VORTEX plants are smaller and considered appropriate for replacing hot water plants in district heating network. The Danish Technical University (DTU) Biomass Gasification Group and Meva International have identified a potentially large market in the developing countries of Asia.

Areas for suggested further research and development include:

• Gas      cleaning/upgrading
• Utilization      of produced heat
• System      integration/optimization
• Small scale      oxygen production
• Gas engine      developments

A mechanistic understanding of potassium release is essential to mitigate the potassium-induced ash problems during biomass combustion. This work studies the effects of operational condition on the potassium release and transition during the combustion of wheat straw, and elucidate the release potential of potassium associated with the structural change of biomass particles. The combustion tests were carried out in a laboratory-scale reactor, working in a wide range of temperatures and heating rates. It was found that the combustion of biomass sample at a temperature up to 1000 °C results in a release of over 60% of its initial potassium content. Raising the heating rate from 8 °C/min to 25 °C/min could lead to an additional release of up to 20% of the initial amount of potassium. A three-stage potassium release mechanism has been concluded from this work: the initial-step release stage (below 400 °C), the holding stage (400–700 °C) and the second-step release stage (above 700 °C). Comprehensive morphology analysis with elemental (i.e. K, S, O, Si) distribution was carried out; the results further confirmed that potassium is likely to exist inside the stem-like tunnel of biomass particles, mainly in forms of inorganic salts. During the heating-up process, the breakdown and collapse of biomass particle structure could expose the internally located potassium and thus accelerate the release of potassium and the transform of its existing forms. Lastly, a detailed temperature-dependent release mechanism of potassium was proposed, which could be used as the guidance to mitigate the release of detrimental potassium compounds by optimising the combustion process.

Ahead of heat exchanger network (HEN) design, setting an optimal pinch temperature difference for pinch analysis depends vitally on the capital cost target. Conventional methods based on the spaghetti (SPA) structure ignoring matching optimization might result in calculated cost targets of large deviations. This work evolved the SPA structure via four stages by shifting energy towards low-cost matching. The fourth structure evolved from the SPA structure (ESPA-IV structure) with the lowest-cost matching after loops elimination forms the base to establish the ESPA method. It is validated by numerical experiment and applied to a case reported in literature, meanwhile comparisons are always made to the SPA method. The numerical experiment proves that the ESPA method can obtain capital cost targets with higher accuracy than the SPA method. The target deviations (often within ±5%) given by the ESPA method are much lower than those (well above 10%) derived by the SPA method. In the case study, the given HEN is further optimized as hinted by ESPA method results. Of two target methods, the cost target indicated by ESPA method is closer to the optimum capital cost newly derived after optimization. The high accuracy of the ESPA method is further verified.

A 20%Co/0.5%Re/γAl₂O₃ Fischer-Tropsch catalyst was poisoned by four potassium salts (KNO₃, K₂SO₄, KCl, K₂CO₃) using the aerosol deposition technique, depositing up to 3500 ppm K as solid particles. Standard characterization techniques (H₂ Chemisorption, BET, TPR) showed no difference between treated samples and their unpoisoned counterpart. The Fischer-Tropsch activity was investigated at industrially relevant conditions (210 °C, H₂:CO = 2:1, 20 bar). The catalytic activity was significantly reduced for samples exposed to potassium, and the loss of activity was more severe with higher potassium loadings, regardless of the potassium salt used. A possible dual deactivation effect by potassium and the counter-ion (chloride, sulfate) is observed with the samples poisoned by KCl and K₂SO₄. The selectivity towards heavier hydrocarbons (C₅₊) was slightly increased with increasing potassium loading, while the CH₄ selectivity was reduced for all the treated samples. The results support the idea that potassium is mobile under FT conditions. The loss of activity was described by simple deactivation models which imply a strong non-selective poisoning by the potassium species.

The influence of potassium species on a Co based Fischer-Tropsch catalyst was investigated using an aerosol deposition technique. This way of poisoning the catalyst was chosen to simulate the actual potassium behaviour during the biomass to liquid (BTL) process utilizing gasification followed by fuel synthesis. A reference catalyst was poisoned with three levels of potassium and the samples were characterized and tested for the Fischer-Tropsch reaction under industrially relevant conditions. None of the conventional characterization techniques applied (H2 Chemisorption, BET, TPR) divulged any difference between poisoned and unpoisoned samples, whereas the activity measurements showed a dramatic drop in activity following potassium deposition. The results are compared to previous results where incipient wetness impregnation was used as the method of potassium deposition. The effect of potassium is quite similar in the two cases, indicating that irrespective of how potassium is introduced it will end up in the same form and on the same location on the active surface. This indicates that potassium is mobile under FTS conditions, and that potassium species are able to migrate to sites of particular relevance for the FT reaction.

The effect of ash salts on Co-based Fisher–Tropsch catalysts was studied using an aerosol deposition technique. The major elements in the ash were found to be K, S and Cl. The ash was deposited on a calcined catalyst as dry particles with an average diameter of approx. 350 nm. The loading of ash particles was varied by varying the time of exposure to the particles in a gas stream. Catalyst characterization did not reveal significant differences in cobalt dispersion, reducibility, surface area, pore size, or pore volume between the reference and the catalysts with ash particles deposited. Activity measurements showed that following a short exposure to the mixed ash salts (30 min), there were no significant loss of activity, but a minor change in selectivity of the catalyst . Extended exposure (60 min) led to some activity loss and changes in selectivity. However, extending the exposure time and thus the amount deposited as evidenced by elemental analysis did not lead to a further drop in activity. This behavior is different from that observed with pure potassium salts, and is suggested to be related to the larger size of the aerosol particles deposited. The large aerosol particles used here were probably not penetrating the catalyst bed, and to some extent formed an external layer on the catalyst bed. The ash salts are therefore not able to penetrate to the pore structure and reach the Co active centers, but are mixed with the catalyst and detected in the elemental analysis.

Pore condensation followed by polymerizationis proposed as an explanatory model of several observationsreported in the literature regarding the dehydration ofglycerol to acrolein. The major conclusion is that glycerolpore condensation in the micro- and mesopores, followedby polymerization in the pores, play a role in catalystdeactivation.

Pore condensation has been suggested as an initiator of deactivation in the dehydration of glycerol to acrolein. To avoid potential pore condensation of the glycerol, a series of WO3supported on ZrO2 catalysts have been prepared through thermal sintering, with modified pore systems. It was shown that catalysts heat treated at temperatures above 800 °C yielded suitable pore system and the catalyst also showed a substantial increase in acrolein yield. The longevity of the heat-treated catalysts was also improved, indeed a catalyst heat treated at 850 °C displayed significantly higher yields and lower pressure-drop build up over the 600 h of testing. Further, the catalyst characterisation work gave evidence for a transition from monoclinic to triclinic tungsten oxide between 850 and 900 °C. There is also an increase in acid-site concentration of the heat-treated catalysts. Given the improved catalyst performance after heat-treatment, it is not unlikely that pore condensation is a significant contributing factor in catalyst deactivation for WO3 supported on ZrO2 catalysts in the glycerol dehydration reaction.

Filtration failure occurs when filter media is blocked by accumulated solid particles. Suitable operating conditions were investigated for cake cleaning by partial oxidation of filter-cake particles (FCP) during biomass gasification. The mechanism of the FCP partial oxidation was investigated in a ceramic filter and by using thermo-gravimetric analysis through a temperature-programmed route in a 2 vol.% O2–N2 environment. Partial oxidation of the FCP in the simulated product gas environment was examined at 300–600°C in a ceramic filter that was set and heated in a laboratory-scale fixed reactor. Four reaction stages, namely drying, pre-oxidation, complex oxidation and non-oxidation, occurred in the FCP partial oxidation when the temperature increased from 30°C to 800°C in a 2 vol.% O2–N2 environment. Partial oxidation was more effective for FCP mass loss from 275 to 725°C. Experimental results obtained in a ceramic filter indicated that the best operating temperature and FCP loading occurred at 400°C and 1.59 g/cm2, respectively. The FCP were characterized by Fourier-transform infrared spectroscopy, scanning electron microscopy and Brunaeur–Emmett–Teller before and after partial oxidation. Fourier-transform infrared spectroscopy analysis revealed that partial oxidation of the FCP can result in a significant decrease in C–Hn (alkyl and aromatic) groups and an increase in C=O (carboxylic acids) groups. The scanning electron microscopy and Brunaeur–Emmett–Teller analysis suggests that during partial oxidation, the FCP underwent pore or pit formation, expansion, amalgamation and destruction.

Biomass combustion is a carbon–neutral method to generate heat and power and is integral to combating climate change. The wet scrubber is a promising device for recovering heat and reducing particle emissions from flue gas, under the driving force of new European Union legislation. Here, the heat recovery of a wet scrubber was investigated using process data and computer simulations. The process data showed that the scrubber could continuously recover heat corresponding to 10–20% of the energy input. The simulation model consists of two interlinked modules: Module 1 simulates droplet movement in the scrubber, while Module 2 uses the output of Module 1 to predict the heat recovery. The model was validated against process data, showing a mean error of 5.6%. Further optimization was based on the validated model by varying different process parameters, including nozzle position and moisture addition to the flue gas. Moisture addition was shown to be a feasible strategy for potentially increasing heat recovery by up to 3.3%. These results indicate that heat recovery in wet scrubbers is a feasible way to make particle removal cost effective in medium-scale combustion facilities, and that the developed simulation model can play an important role in optimizing these processes.

The deactivation of a commercial Selective Catalytic Reduction (SCR) catalyst, of V2O5-WO3/TiO2 type, has been studied through comparisons with results from a full-scale biomass combustion plant to that with laboratory experiments. In the latter, the catalyst was exposed to KCl and K2SO4 by both wet impregnation with diluted salt solutions and deposition of generated submicrometer aerosol particles by means of an electrostatic field. The reactivity of fresh and deactivated samples was examined in the SCR reaction. Chemical and physical characterizations were focusing on internal structures and chemical composition. Deposition of submicrometer sized particles on the monolithic SCR catalyst was shown to induce deactivation with characteristics resembling those obtained in a commercial biomass combustion plant.

The deactivation of a commercial selective catalytic reduction (SCR) catalyst of type V2O5−WO3/TiO2 has been studied in this work through comparisons of results from a full-scale biomass combustion plant with those from laboratory experiments. In the latter, the catalyst was exposed to KCl, K2SO4, and ZnCl2 by both wet impregnation with diluted salt solutions and deposition of generated submicrometer aerosol particles by means of an electrostatic field. The reactivity of freshly prepared and deactivated catalyst samples was examined in the SCR reaction, for which the influence of the different salts and the method of exposure were explored. Chemical and physical characterizations of the catalyst samples were carried out focusing on surface area, pore volume, pore size, chemical composition, and the penetration profiles of potassium and zinc. Particle-deposition deactivation as well as commercially exposed catalyst samples were shown to impact surface area and catalyst activity similarly and to have penetration profiles with pronounced peaks. Salt impregnation influenced pore sizes and catalyst activity more strongly and showed flat penetration profiles. Deposition of submicrometer-sized particles on the monolithic SCR catalyst has been shown to induce deactivation of the catalyst with characteristics resembling those obtained in a commercial biomass combustion plant; the laboratory process can be used to further assess the deactivation mechanism by biomass combustion.

The study on the use of multi-holed orifice plate for measuring flow rate is a growing area of research. As compared to standard orifice plate, multi-holed orifice plates (MO) have number of advantages, such as, these plates require minimum straight piping at the upstream without compromising the pressure losses and provide better accuracy in the measurement of flow rates. In this study, a systematic methodology is adopted for investigating the effect of different geometrical parameters on pressure loss coefficient and values of parameters under investigation varied using central composite design. The geometrical parameters chosen for the study are: (a) Number of holes; (b) Multi-hole Diameter ratio and (c) Compactness of holes. Commercial computational fluid dynamics code (ANSYS Fluent) is employed to perform simulations for 15 different settings of these parameters to analyze their effect on pressure loss coefficient and flow development length at downstream of multi-holed orifice plates. It is found that values of pressure loss coefficient is a strong function of multi-hole diameter ratio, whereas, the flow conditioning properties are strongly affected by the number of holes.

Detta arbete är en delstudie i projektet

Seafarm. Syftet med denna studie är att utreda om algen Laminaria Digitata och vassen Phragmites Australis är lämpliga substrat i en samrötningsprocess för biogasproduktion. Metoden som användes är experimentell och utfördes under 35 dagar med en tvåstegsreaktor bestående av en lakbädd och en UASB-reaktor. Under försökets gång upptäcktes vissa fel och brister hos apparatuppställningen vilka orsakade läckage och andra brister. Detta resulterade i ett systemförslag med skiss till en ny lakbädd samt optimering av driftparametrar om försöket ska återupprepas.

Efter 35 dagar avslutades försöket och utifrån den data som sammanställts uppvisar processen en bra metanpotential på 589 liter CH

4/kg COD. Processen uppvisade en låg alkalinitet med ett sjunkande pH som till följd av inmatning. Detta var grunden för den låga belastningen som processen klarade av. För framtida försök för just dessa substrat så rekommenderas en tillförsel av buffert så att alkaliniteten ökar och även möjligheterna för en högre belastning.

Synthesis gas consists of a mixture between hydrogen, carbon monoxide, carbon dioxide and water. This gas is normally generated by gasification of a carbon containing fuel, to be used as a feedstock for various synthesis processes. The actual composition of the gas depends on many different factors such as type of fuel, type of gasifier, mode of operation of the gasifier etc. The producer gas, i.e. the gas after the gasification step, usually need upgrading since it contains lower hydrocarbons and tars that needs to be converted. This upgrading, from producer gas into synthesis gas is done in the reformer step. The resulting synthesis gas is not necessarily suited for the subsequent synthesis step; it might need to be processed further. For instance the carbon dioxide level might need to be decreased and/or the hydrogen-carbon dioxide ratio to be adjusted. The water gas shift (WGS) process is the process where the ratio between hydrogen and carbon monoxide in the synthesis gas can be tuned.

This deliverable contains both laboratory experiments and experiments where the watergas-shift catalyst has been exposed to gas and particles generated by biomass gasification.The gasification experiments took place in the 100 kWth CFB gasifier at Delft University of Technology in Delft in July 2008 and in February and August 2009.

This work investigates the long-term performance of Ba-Ni-hexaaluminate, BaNixAl12-xO19 as a catalyst in reforming of 1-methyl naphthalene and/or methane in a model-gas simulating that from a circulating fluidized bed (CFB) gasifier during 23-29 h in a lab scale set-up, as well as the tendency for coke formation, sintering and sulphur poisoning. 1-Methyl naphthalene is used as a tar model substance. The Ba-Ni-hexaaluminate induces a high conversion of both compounds in the temperatures investigated (850 and 950 degrees C) under sulphur-free conditions. In sulphur-containing gas, the methane conversion stops at 20 ppm H2S and the reforming of 1-MNP at 850 degrees C is slightly reduced at 100 ppm.

This article reports results from measurements of mainly submicrometer particles at the inlet and outlet of a newly designed industrial wet electrostatic precipitator (WESP) in a combined heat and power plant fueled with municipal solid waste. The measurements were carried out with dual electric low-pressure impactors in parallel at the precipitator inlet and outlet. In addition, measurements were carried out with traditional total dust filters, low-pressure impactors, a scanning mobility particle sizer, and an aerodynamic particle sizer. The measurements aimed to characterize the aerosol particles and measure the efficiency of the WESP with special attention to fine and ultrafine particles. In general, the WESP performance and response to varying conditions was found to be in line with predictions made for the design. The WESP featured a cooled collector surface, but based on the limited results, no conclusion could be drawn regarding any possible improvement from collector cooling. The characterization of the aerosol particulate matter was challenging because of fast fluctuations in particle concentration. Methodological considerations are pointed out, mainly regarding the SMPS and ELPI measuring systems.

This study focuses on multi-holed orifice plates, which have superior flow measuring characteristics as comparedto their conventional counterparts. However, literature is scant on quantitative parametric investigations. In thisexperimental study, the performance of a multi-holed orifice plate is evaluated for variable number of holes (n),equivalent diameter ratio (EDR), compactness ratio (C), plate thickness ratio (s/d) and upstream developinglength (L/D) in developing flow regimes for the Reynolds number range of 24,500–55,500 by using CentralComposite Design. A total number of 324 experiments were performed. It was found that EDR has the mostsignificant effect on pressure loss coefficient, followed by ‘n’ and ‘C’. Moreover, it was found out that singleorifice (SO) and multi-holed orifice (MO) have almost the same pressure losses for the same value of EDR/β.However, flow develops quickly for MOs. Higher values of coefficient of discharge were observed in the case ofMOs as compared to the SOs with little effect of upstream disturbances. The effect of developing length is significanton the accuracy of orifice meter. However, when the multi-holed orifice plates are installed at 2D upstreamlength, the effect of upstream disturbances are diminished. This result provides the flexibility ofinstallation, which means that multi-holed orifices can be installed at 2D. The experimental data is in goodagreement with literature. Finally, an optimum orifice plate (5,0.4,0.7) was selected for flow developing regionwith minimum pressure loss coefficient based upon the experimental results.

Multi-holed Orifices (MOs) are widely used in swirling, cavitating and developing flows to reduce pressurelosses. This study focuses on analysis of MOs for developing turbulent flows. A large number of experimentswere performed, exploring the number of holes (n), Equivalent Diameter Ratio (EDR), compactness ratio (C),plate thickness ratio (s/d) and upstream developing length (L/D) in the Reynolds number (ReD) range of24,500-55,500. An empirical correlation of pressure loss coefficient and flow rate is formulated. It isobserved that pressure loss coefficient decays with the fourth power of EDR. A comparative study of theexperimental data with the literature is presented to ensure consistency and reliability.

This thesis project investigates the granular flow of wood pellets inside a pilot-scale rotary kiln and its impact on the pyrolysis process. The study focuses on two key factors that must be determined to evaluate their effects on pyrolysis: the mass flow rate delivered by the feeding system at different motor frequencies and the mean residence time (MRT) of the wood pellets. The research is divided into two parts: the first characterizes granular flow without heat application, while the second examines the system behavior under high-temperature pyrolysis conditions.

For the first part, the mass flow rate was assessed by measuring the emptying time of the feeding silo at different screw velocities. In contrast, the MRT was determinedwith two scenarios: (1) batches of different masses of wood pellets and (2) continuousfeed until a stable solid bed was formed that allowed tracer particle tracking.

In the second part of the study, the drum’s rotational speed and fed mass flow rate were varied. Results indicated a direct proportionality between the mass flow rate delivered by the feeding systems and the screw motor frequency. Additionally, the MRT was found to follow an inverse relation with the drum’s rotational speed if the process was done in batches. In contrast, the MRT was 20 minutes at a feeding rate of 51 kg h^-1 and a drum’s rotational speed of 0.36 rad s ^-1 with a continuous feeding process.

Finally, the study concludes that the wood pellet feed rate and drum rotational speed significantly influence the pyrolysis process in the rotary kiln. The system remained stable for wood pellets inside the rotary drum, starting with a feeding rate of 8 kg h^-1 and scaling up until a maximum of 21 kg h^-1. This behavior is evidenced by the direct proportionality between the evolution of flue gas and pyrolysis gas temperatures over time and the necessity to adjust air supply to maintain system stability.

In this project, we have explored RuO2 and Ru nanoparticles (∼ ∼10 and ∼ ∼5 nm, respectively, estimated from XRD data) to be used as gate material in field effect sensor devices. The particles were synthesized by wet chemical procedure. The capacitance versus voltage characteristics of the studied capacitance shifts to a lower voltage while exposed to reducing gases. The main objectives are to improve the selectivity of the FET sensors by tailoring the dimension and surface chemistry of the nanoparticles and to improve the high temperature stability. The sensors were characterized using capacitance versus voltage measurements, at different frequencies, 500 Hz to 1 MHz, and temperatures at 100–400°C. The sensor response patterns have been found to depend on operating temperature. X-ray photoelectron spectroscopy (XPS) analyses were performed to investigate the oxidation state due to gas exposure. Quantum-chemical computations suggest that heterolytic dissociative adsorption is favored and preliminary computations regarding water formation from adsorbed hydrogen and oxygen was also performed

Wide band gap materials such as SiC, AlN, GaN, ZnO, and diamond have excellent properties such as high operation temperature when

used as field effect devices and a high resonating frequency of the substrate materials used in piezoelectric resonator devices. Integration of FET

and resonating sensors on the same chip enables powerful miniaturized devices, which can deliver increased information about a gas mixture or

complex liquid. Examples of sensor devices based on different wide band gap materials will be given.

This study focuses on the hygroscopic properties of submicrometer

aerosol particles emitted from two small-scale district heating

combustion plants (1 and 1.5 MW) burning two types of biomass

fuels (moist forest residue and pellets). The hygroscopic particle

diameter growth factor (Gf ) was measured when taken from a dehydrated

to a humidified state for particle diameters between 30–

350 nm (dry size) using a Hygroscopic Tandem Differential Mobility

Analyzer (H-TDMA). Particles of a certain dry size all showed

similar diameter growth and the Gf at RH = 90% for 110/100 nm

particles was 1.68 in the 1MWboiler, and 1.5 in the 1.5MWboiler.

These growth factors are considerably higher in comparison to

other combustion aerosol particles such as diesel exhaust, and are

the result of the efficient combustion and the high concentration of

alkali species in the fuel. The observed water uptake could be explained

using the Zdanovski-Stokes-Robinson (ZSR) mixing rule

and a chemical composition of potassium salts only, taken from

ion chromatography analysis of filter and impactor samples (KCl,

K2SO4, andK2CO3). Agglomerated particles collapsed and became

more spherical when initially exposed to a moderately high relative

humidity. When diluted with hot particle-free air, the fractallike

structures remained intact until humidified in the H-TDMA.

A method to estimate the fractal dimension of the agglomerated

combustion aerosol and to convert the measured mobility diameter

hygroscopic growth to the more useful property volume diameter

growth is presented. The fractal dimension was estimated to be

∼2.5.

Biomass gasification followed by fuel synthesis is one of the alternatives for producing liquid fuels and chemicalsfrom biomass feedstocks. The gas produced by gasification contains CO, H2, H2O, CO2, light hydrocarbons and tars. Thelight hydrocarbons can account for as much as 50% of the total energy content of the gas, depending on the type of gasifier,operating conditions and feedstock. The gas also contains catalyst poisons such as sulphur, in the form of H2S and COS. Thispaper presents simulations of a reverse-flow partial-oxidation reformer that converts the light hydrocarbons into more synthesisgas, while achieving efficiencies approaching that of conventional catalytic processes. Variations in parameters such as pressure,amount of oxidant and steam-to-carbon ratio were also investigated. Simulations of the reforming of natural gas were includedfor comparison. The results show the benefits of using reverse-flow operation with lean gases such as gasifier product gas.

A stepwise microwave synergistic pyrolysis (SMSP) approach is proposed as a new way to relieve disposal problems of the sewage sludge. Here the sludge is first pre-pyrolyzed by a conventional heating stage, and then rapidly pyrolyzed by a microwave-induced heating stage without any extra microwave absorbers or blending needed. Under simulated process pyrolysis conditions, the dried sludge, intermediate and final sludge-based biochar samples were prepared in the laboratory. Their chemical composition, microstructure and morphology, and leaching toxicity of heavy metals were carefully characterized and analyzed by various techniques such as proximate and ultimate analysis, X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, Brunauer-Emmett-Teller (BET), and scanning electron microscope equipped with energy-dispersive x-ray spectroscopy (SEM-EDX). Results showed that the pre-pyrolytic biochar can be rapidly heated up to 1100 °C within 5 min under microwave irradiation. The pre-pyrolytic stage increased the carbonization and ash enrichment degree of the sludge which itself acted as a good microwave absorber while achieving a quick temperature rise under microwave irradiation. The ash remaining ratio and the specific surface area of the biochar derived from the SMSP approach (labelled as SBC2) are increased by 6.46% and 16.17% respectively, compared with the conventional biochar sample (SBC1). And SBC2 still had diverse surface functional groups kept after SMSP. The residual ratios of Ni, Cu, Zn, Pb, Cr and Cd in SBC2 was more noticeable than in SBC1 but the leaching ratios quite the contrary. Vitrification is also well proved by the increment of quartz peak detected by XRD tests, and the formation of melted glassy spheres with elemental composition of Si, Ca, Al observed by SEM-EDX. It can favorably increase solidification level and decrease leaching toxicity of heavy metals in the SBC2. The feasibility of this proposed SMSP concept has been positively supported by our experimental results. The properties of the sludge-based biochar produced from the SMSP approach also show great potential to be utilized as precursors to produce various adsorbents.

The effects of varying fuel mixtures and using a lime additive were studied in a 125-MWth circulating fluidized bed boiler. A high-temperature aerosol measurement method using a hot-dilution probe was used to characterize the particles and condensing inorganic vapors upstream from the superheater. The particle size distributions of the extracted samples indicate that when high-sulfur rubber waste, waste wood, and forest fuel were cocombusted, the hot flue gas contained no substantial amount of particulate matter in the fine (<0.3 mu m) particle size range, although the SO2 concentration exceeded 70 ppm. Only a nucleation mode was observed, which was presumably formed from inorganic vapors that condensed in the sampling probe. The size-segregated elemental analysis of the extracted samples indicated that when lime was added, the nucleation mode mainly comprised condensed alkali chlorides, while the sulfates dominated the mode when no lime was added. The presumed explanation for the sulfates in the nucleation mode was the sulfation of the alkali chlorides inside the sampling system. When only the wood fuels and no rubber fuel were cocombusted, the SO2 concentration in the gas was approximately 5 ppm. In this case, an alkali sulfate particle mode formed at approximately 70 nm in the hot flue gas. In addition, vapors of alkali chlorides and lead formed particulate matter inside the sampling probe when using low dilution ratios.

Growing customer demands and more stringent regulations to reduce harmful air emissions from ships have resulted in an increased interest for the installation of shipboard abatement technologies. Specifically, the selective catalytic reduction (SCR) technology to reduce emissions of nitrogen oxides (NOx) was early adopted by several Swedish shipping companies. The potential NOx reduction efficiency of the SCR is well established, but the practical experiences of shipboard installations have been less documented. This paper reviews from a systems perspective the practical experiences of marine SCR installations in Swedish shipping. The aim is to identify important not only technical but also human and organizational conditions necessary for safe, efficient, and sustainable SCR operations at sea. Further, to investigate to what extent the capabilities and limitations of human operators and maintainers are taken into account in the design and installation phase of the systems. Two focus group interviews (n010) and five individual interviews were held with relevant stakeholders in the industry, following a semi-structured schedule on the themes installation, operation, maintenance, and training. The results show that deficiencies in the overall system design—with a combination of technical issues, maintenance access problems, and untrained operators with inadequate understanding of the SCR process—have led to inefficient, costly, and unsafe operations. It is concluded that installations and operations of marine SCR systems, and possibly other forthcoming abatement technologies, would benefit from the use of traditional ergonomic principles and methods. This would in turn contribute towards increased sustainability and a reduced environmental impact from shipping.