Syngas

Selective partial oxidation of methane to syngas over LaNiO 3 , La 0.8 Ca(or Sr) 0.2 NiO 3 and LaNi 1−x Co x O 3 (where x = 0.2-1) perovskites at extremely short contact time ( ≈0.8 ms) has been investigated. Also, simultaneous oxidative conversion and steam and CO 2 reforming of methane to syngas over LaNiO 3 at short contact time ( ≈9 ms) has been studied at different temperatures and CH 4 /O 2 feed ratios. The catalysts, before and after reaction, were characterized by XRD and SEM. LaNiO 3 perovskite shows high activity and selectivity in the oxidative conversion of methane to syngas. However, the partial substitution of its La by Ca or Sr and also the partial or complete substitution of its Ni by Co causes a large decrease in both its activity and its selectivity. LaNiO 3 is transformed to its catalytically active form, Ni 0 /La 2 O 3 , during the initial period of the process. This catalyst shows very good performance in the simultaneous oxidative conversion (which is exothermic) and steam and CO 2 reforming reactions (which are endothermic) of methane to syngas, at short contact time, operating in a most energy efficient manner and also requiring only a little or no external energy.

A controllable composition and morphology AuAg/ZnO catalyst, prepared by an easily scalable method, was, for the first time, explored for the electrocatalytic reduction of CO 2. It was found that the composition of the bimetallic alloy contributes to the overall CO 2 reduction performance. In particular, as also demonstrated by density functional theory calculations, CO production increases, decreasing the Au content in the catalyst alloy. The experimental investigation reveals that the products are H 2 and CO, which production rate increases in the presence of ZnO, up to a Faradic efficiency of 94.7 % at 0.4 V. On the other hand, controlling the oleic acid covering it is possible to modulate the surface properties allowing to obtain, at 0.6 V, H 2 /CO ratios equal to 1.1 and 1.9 for nanocatalysts thermally treated for 2 and 5 h, respectively.

This paper focuses on the comparison of different glycerol reforming technologies aimed to hydrogen and syngas production. The reactions of steam reforming, partial oxidation, autothermal reforming, dry reforming and supercritical water gasification were analyzed. For this, the Gibbs energy minimization approach was used in combination with the virial equation of state. The validation of the model was made between the simulations of the proposed model and both, simulated and experimental data obtained in the literature. The effects of modifications in the operational temperature, operational pressure and reactants composition were analyzed with regard to composition of the products. The effect of coke formation was discussed too. Generally, higher temperatures and lower pressures resulted in higher hydrogen and syngas production. All reforming technologies demonstrated to be feasible for use in hydrogen or synthesis gas production in respect of the products composition. The proposed model showed good predictive ability and low computational time (close to 1 s) to perform the calculation of the combined chemical and phase equilibrium for all systems analyzed.

Sentez gazından (CO ve H2) dimetil eter (DME) üretimindeki asıl amaç bu kimyasalın yakıt olarak kullanımının avantajlı görülmesidir. Yapısında kükürt ve azot bulunmaz ve atmosferdeki bozunabilirliği 3 ile 30 saat arasında değişim gösterir. Bu da DME’nin çevre dostu bir yakıt olmasını sağlar. Ancak prosesin fazla maliyetli olması ve talebin düşüklüğünden günümüzde yakıttan ziyade itici gaz olarak kullanılır.
DME endüstride çoğunlukla metanol dehidrasyonuyla üretilir. DME üretimi ‘kademeli DME üretimi’ ve ‘doğrudan DME üretimi’ olmak üzere iki çeşittir. Kademeli DME üretiminde ilk reaktörde sentez gazından metanol üretilip ikinci reaktörde bu metonol saflaştırılıp DME’ye dönüştürülür. Doğrudan DME üretiminde ise metanol üretimi ve dehidrasyonu tek bir reaktörde gerçekleşir. Bu sebepten maliyet düşse de endüstride metanol üretimi yaygınlığından, doğrudan DME üretim prosesi tercih edilmemektedir.
Kademeli DME üretimi de denemesini yaptığımız doğrudan DME üretimi de katalitik reaksiyonlardır. Katalizör karışımlarının uygulanması için denememizde sabit yataklı reaktör (fixed bed) kullanılır.

Steam Reforming  Practical Operations
Contents
Reaction Chemistry
Typical Reformer Configurations
Catalyst Design Criteria
Carbon Formation and Prevention
Catalyst Deactivation
Steaming Reforming Catalysts
Monitoring Reforming Catalysts
Catalyst Loading
Reduction & Start-Up
Tube Wall Temperature Measurement

Thermochemical equilibrium modeling is the basis of the numerical method implemented in this study to predict the performance of a biomass gasifier. To validate the model, a close agreement is shown between numerical and experimental results. The model is then used in order to optimize the selection procedure of a specific biomass for a certain application. For this purpose, the minimum and maximum amount of carbon, hydrogen, and oxygen for 55 different biomass materials are extracted to calculate the range of variation of oxygen content and carbon/hydrogen ratio. The influences of such variations on syngas characteristics are then studied. Syngas characteristics are comprised of syngas calorific value, outlet gas temperature, gasification efficiency, and the volume of syngas obtained. The results are plotted in a generalized format that may be used for a wide range of biomass materials. These plots can be used for the selection of a biomass material based on desired conditions. Therefore, the developed model in this study provides a tool for design optimization of a biomass downdraft gasifier.

HYDROGENATION REACTOR DESIGN - Fixed Bed Reactor Internals
The following is designed to give an overview on and some insight in the general design features of hydrogenation reactors and the impact of the various reactor internals on performance.

Ammonia CO2 Removal Systems
Why Remove CO2 ?
Poisons Synthesis catalyst
Can be used downstream in Urea production
If allowed into the loop would
Also act as inert in loop
Increase the compression costs
Used as a product in its own right
Carbonated drinks
Refrigeration units
Can be exported to methanol plant

Dry reforming of methane (DRM) is one of the attractive methods for the utilisation of greenhouse gases (e.g., CH4 , CO2) to produce valuable fuels. In the quest for an efficient development in DRM, several technologies have been practised, while dielectric barrier discharge (DBD) cold plasma technology garners special attention in the utilisation of CO 2 and CH 4 through DRM process due to easy upscaling opportunities and mild operating conditions. However, the low energy efficiency (EE) of DBD plasma is a distinct challenge and it offers an in-depth insight into its basic operational understandings. This review presents the overall status and current developments in DBD plasma for DRM. In the mainstream, challenges in DBD plasma technology, catalyst-plasma interactions and developments in plasma catalysts to improve the yield and selectivity of DRM have been discussed. The current status and developments in DBD reactor configuration based on reactor geometry, such as the electrode morphology, discharge gap (D gap), discharge volume (V D) and material packing to maximise the productivity of DRM are specifically investigated. The effects of the operating parameters, such as gas hourly space velocity (GHSV), specific input energy (SIE) and feed ratio are critical for product distribution. The current status of reaction kinetics and prospects in fluid modelling of catalytic DBD plasma DRM reactor is reviewed to understand the underlying reaction mechanism. Finally, further advancements in the catalytic DBD plasma DRM has become a requisite to make it commercially viable for the successful production of valuable fuels.

This work presents a pilot-scale investigation aimed at assessing the feasibility and reliability of biomass pellet gasification. Wood sawdust and sunflower seeds pellets were tested in a 200 kW downdraft gasifier operating with air as gasifying agent. The gasification of pelletized biomass led to rather high and unstable pressure drops, reducing the gasifier productivity and stability. Furthermore the generation of fine residues compromised the operation of wet ash removal systems. On the other hand, good syngas compositions (H 2 17.2%, N 2 46.0%, CH 4 2.5%, CO 21.2%, CO 2 12.6%, and C 2 H 4 0.4%), specific gas production (2.2-2.4 N m 3 kg À1 ) and cold gas efficiency (67.7-70.0%) were achieved. For these reasons pelletized biomass should be considered only as complementary fuel in co-gasification with other feedstock.

Coal is the most important energy source for our country, which is dependent on foreign
energy sources. Moreover, it has reserve of about 200 years. Nevertheless, direct
utilization of coals brings about some challenges such as air pollution and higher emissions
of greenhouse gas which impact upon on health. For this reason, coal is gasified, and
cleaner, higher calorific synthetic fuels are obtained. In this thesis, coal gases (blast
furnace gas and generator gas) which are obtained by gasification or by product of coking
of coal have burned with pure oxygen, combustion and emission characteristics were
investigated experimentally and numerically. Furthermore, it is also aimed to ensure
dissemination of usage of local coal, as gaseous fuel, for different industries and the
integration of these gases with metal and glass industry, cutting, welding and so on
processes. For this purpose, low calorific coal gases have been properly oxy-combusted
experimentally by burner and combustion performances and emission values have been
measured in the first part of the work. The experimental results for existing burner have
shown that the burner wall was overheated due to the very high flame temperature (about
2000 K) in the flame holder zone. This undesirable situation has required the improvement
of the oxidizer inlet section of the existing burner for pure oxygen flow. Hence, the
oxidizer inlet section of the burner has been reduced approximately four times as
volumetric flow rate of oxygen is lower about 4 times than the air. The oxy-combustion
burner has been obtained by this modification. In the second part of study, the effect of this
improvement on the combustion characteristics of coal gases was investigated numerically
by a computational fluid dynamics software. The predicted temperature profiles have been
compared with the experimental data and it has been demonstrated that there is consistency
between the predicted and the measured results adequately. Studies have shown that low
calorific coal can be used effectively in our country.

An application for biomass is the synthesis of liquid fuels such as dimethyl ether, and methanol etc. our effort is intended to explore the syngas production technology from biomass using catalytic gasification process and the various process and technologies involved in the purification of biomass derived syngas. In this context, the characteristic of syngas such as yield, the H2/CO ratio and the different factors affecting H2/CO ration have been studied. This ratio is an important parameter which has an upper effect on our process. The reactors employ are fluidized bed, gasifier and the fixed bed reactor. H2/CO ratio lies between 1.87 & 4.45. Further, text of this report involves the purification of syngas. Three technologies are there for syngas cleanup and are classified according to the temperature of the gas which is leaving clean up device. The Hot Gas Cleanup technology has been discussed in details because of energy efficiency and prevention of reheating and cooling of the gas. Wet scrubbers cyclones, absorbers with varying sorbents are discussed regarding Hot Gas Clean up with new approaches for Chlorine and Tar removal.

Site Safety Awareness
Process Safety Training
Confined Space Entry
Hazardous Substances In Refineries
Hazards of Air and Oxygen
Hazards of Electricity and Static Electricity
Hazards of Nitrogen and Catalyst Handling
Hazards of Steam
Hazards of Trapped Pressure and Vacuum
Hazards of Water
Hotel Fire Safety
Liquid Hydrocarbon Tank Fires
Safe Handling of Light Ends
Safe Furnace and Boiler Firing
Safe Tank Farms and (Un)loading Operations
Safe Ups and Downs for Process Units
Control of Work

A review was conducted on the use of thermochemical biomass gasification for producing biofuels, biopower and chemicals. The upstream processes for gasification are similar to other biomass processing methods. However, challenges remain in the gasification and downstream processing for viable commercial applications. The challenges with gasification are to understand the effects of operating conditions on gasification reactions for reliably predicting and optimizing the product compositions, and for obtaining maximal efficiencies. Product gases can be converted to biofuels and chemicals such as Fischer-Tropsch fuels, green gasoline, hydrogen, dimethyl ether, ethanol, methanol, and higher alcohols. Processes and challenges for these conversions are also summarized.

The gasification of the sugar cane bagasse produces synthesis gas (syngas) in which CO and H 2 are the essential components. The composition of producer gas depends on the types of gasifier and the gasification conditions among others. This work is developed by using the model of biomass gasification in a circulating fluidized bed gasifier using the ASPEN PLUS simulator. The Gibbs free energy minimization method was used to predict the composition of the produced gas. The influence of operating conditions as temperature, equivalence ratio (ER), and steam injection on gasifier performance are investigated. The model predicts syngas composition, heating values and conversion efficiency in good agreement with published experimental data.

Biomass fuels are considered as alternative fuels for different energy sectors. This thesis project considers three different solid and dry biomass fuels: Rice Husk, Wood Chips and Sugarcane Bagasse. Experiments are carried out to analyze the combustible components of the produced syngas by gasification process of solid Biofuels. The Concentration of the three major components (CO, H2, CH4) of syngas are obtained by locally made gas analyzer system. Three different solid biomass fuels are investigated for different amount of fuel (by mass) and different air flow rates. 
The results indicated that the presence of CO is kept almost constant & obtained highest concentration after the combustion period of syngas. On the other hand, it has found that CH4 concentration of about 400 PPM is required to start the combustion of syngas. The combustion period of different biofuels shows that with the increase of mass of biofuel the combustion period is enhanced & rice husk has longer combustion period over the other biofuels. However, syngas from the sugarcane bagasse shows the highest heating value among others. Another findings is the that rice husk also took the least amount of time to produce combustible syngas. But it was easier for wood chips and sugarcane bagasse to ignite the fuel for the start of gasification process.

In this work, biomass (eucalyptus spp.) gasification has been investigated in a two-stage downdraft reactor by using different gasifying agents such as: air, air + saturated steam, and O 2 + saturated steam. The utilization of low quality saturated steam for gasification in different mixtures with air and O 2 is the main novelty of this paper. Thus, the influence of different gasifying agents was assessed on the concentrations of CO, H 2 and CH 4 and hence, on the lower heating value (LHV), the syngas power and the cold gasification efficiency. Since the type and flow of gasifying agent control the biomass consumption in downdraft gasifiers, the equivalence ratio (ER) and the steam-to-biomass ratio (SBR) were calculated by means of a mass balance. The results showed that low quality steam can increase remarkably the H 2 concentration and the LHV of syngas despite its low temperature. Particularly, when O 2 + saturated steam is fed to the gasifier, the H 2 concentration varied between 27.4 and 35.9 vol.%, while the LHV was between 7.13 and 8.35 MJ/N m 3 , i.e. almost twice the produced when only air or air + saturated steam is used. The optimum ER seems to be below 0.412, while the SBR is found between 0.495 and 1.032. Under this conditions, the cold gasification efficiency was between 70 and 75%. Moreover, the O 2 seems to mitigate in a better way the negative effect of the low temperature of the saturated steam given the lower tar concentration in syngas (58.74–64.18 mg/N m 3) respect to those found with air + saturated steam (91.41–91.95 mg/N m 3). This paper concludes that saturated steam can be used blended either with air or O 2 (being better with O 2) for biomass gasification in two-stage downdraft reactors and therefore, the requirements of superheated steam are not so important as in other gasification processes.

Two-zone solar-driven gasifier offers high conversion and favorable syngas quality. A drop-tube zone provides efficient radiative heat transfer for rapid pyrolysis. A trickle-bed increases solids residence time and enhances the overall heat transfer. The two-zone reactor prototype demonstrated improved performance over the drop-tube. Solar energy was stored in the syngas and the biomass was energetically upgraded.

The ever increasing concerns over fluctuating price of oil and the possible future supply constrains have reinforced the need for alternative fuel resources. Use of synthesis gas (syngas) to generate fuels through a microbial route would likely be an option to address part of this challenge. Syngas fermentation offers a pathway for sustainable synthesis of fuels and chemicals with lots of advantages over catalytic syngas conversion. This work reviews the available literature on production of second generation biofuels from syngas using various biocatalysts. The potential of syngas fermentation using acetogenic, hydrogenogenic and methanogenic organisms have been surveyed. A vast variety of biofuels and biochemicals including ethanol, acetate, hydrogen, butanol, butyrate, methane and etc. have been produced from gaseous substrates using microbial catalysts. The role of various parameters including medium composition, fermentation pH, trace elements, reducing agents and mass transfer limitations on bioconversion process has been extensively discussed. From this survey of literature it has been deduced that despite years of research and endeavors, fermentation of syngas to biofuels is still a relatively immature technology and long-term view for this potential conversion should be undertaken for future commercial deployments.

The residual liquid biomass from agricultural and agroindustrial processes, in general
way, represents a renewable resource in significant amount, without an economically and
environmentally sustainable destination. For instance, the solution concerning glycerin stocks, remaining from the vegetable oil transesterification for obtaining biodiesel, has been postponed due to the lack of engineering alternatives appropriate to the proper utilization of this biomass. Therefore, the development of a liquid biomass gasification reactor based on partial oxidation has been initiated, where a non conventional combustion technology has been employed, Filtration Combustion, as a design basis for the reactor conception, in which the reference biomass used was glycerol. This work, eminently experimental, was carried out to build a gasification reactor prototype, in laboratory scale, in which its burner is completely filled by ceramic spheres of alumina (Al2O3), thus forming a inert porous matrix, which is partially immersed in glycerol at its bottom end and which involves a heat exchanger installed at the top of the reactor. The process is investigated to identify some key design features such as: reactor operation limit in terms of fuel-air mixtures; occurrence of instability phenomena; combustion wave propagation velocity; and influence of the main operation parameters, equivalence ratio, fuel consumption rate, and air and water flow rates into the reaction. Although all experimentation has been restricted to test the gasifier for the production of synthesis gas by partial oxidation method, theoretical investigation was broader, comprising the autothermal reforming. The experiments, supported by monitoring instruments and chromatographic analysis, were supported by a theoretical study based on a simplified analytical model, considering the global reaction of partial oxidation associated with water-gas shift reaction. Experimental results have demonstrated the feasibility of the process, providing operational stability over a wide range of equivalence ratio, and conversion efficiency (>20%) of glycerol to syngas, while maintaining energy extraction from reaction.

Fossil fuels are the major source of energy but the quantities of these are limited and use of these causes greenhouse effect by net addition of CO2 to earth atmosphere and also there is an issue of scarcity of fossil fuels (i.e. Petrol, LPG, and CNG) in the world. Especially in developing country like India, fossil fuel price is also very high. So, current objective is to find a substitute for a fossil fuel. Before existence of fossil fuel, biomass was the only source of energy which was understood by mankind and utilized as a fuel. Gasification of biomass allows overcoming these issues. Energy extraction from biomass with considering environmental aspect is a challenge. Gasification is thermo chemical process which converts biomass into synthesis gas (" syngas "). Syngas mainly comprises of Hydrogen (H2) and Carbon Monoxide (CO), which has capability to further burnout and releases energy. Syngas can be used for power production, heating application and liquid fuel production. There are several reactors available for gasification process; present study is focused on downdraft gasifier reactors. It is focused on production of syngas and effect of various parameters like equivalence ratio, moisture content of biomass wood used on composition of syngas. Therefore, intention is to produce a substitute gaseous fuel syngas from biomass by using fixed bed downdraft gasifier.

In this study, a coal gasification model is developed based on nine simultaneous reactions. For given gasification temperature and pressure, the air/fuel and water vapor/fuel ratio are optimized for maximum H2/CO ratio by parametric study. Furthermore, the cold gas efficiency and higher heating value of the synthesis gas produced are computed for each case. Optimum locations of investigated parameters are also searched for maximizing cold gas efficiency and higher heating value of the synthesis gas.

Syngas operations require separation of CO 2 and hydrogen for hydrogen production at refineries and petrochemical plants, and potentially for combined hydrogen production and CO 2 capture at integrated gasification combined cycle (IGCC) power plants. Membranes that selectively permeate CO 2 have attracted significant interest, because the purified hydrogen is retained at high pressure, thus avoiding costly downstream recompression. In this work, Polaris ™ thin film composite membranes were evaluated for CO 2 removal from syngas: these membranes are highly permeable to CO 2 and reject the other major components of syngas, including hydrogen, carbon monoxide and methane. Part I of this study describes the three-stage development of Polaris membranes for CO 2 /H 2 separation, including: laboratory parametric tests of membrane stamps using pure-and mixed-gas streams, pilot-scale tests of membrane modules using real syngas at a coal-fired gasification plant, and field demonstration of a membrane system producing liquid CO 2 . The gasification plant where the field tests were conducted is at the National Carbon Capture Center (NCCC) in Wilsonville, AL. The membrane demonstration system processed 227 kg/h of syngas (equivalent to a 0.15 MW e IGCC power plant) containing $ 9% CO 2 , and produced a liquid CO 2 stream containing 95 þ% CO 2 . Part II of this study will explore the potential opportunities for the use of CO 2 -selective membranes in commercial hydrogen purification and CO 2 capture, including the results of techno-economic analyses for various process designs.

This paper presents the results of the theoretical study of the process of low-temperature plasma-assisted reforming of ethanol into molecular hydrogen in the electric discharge in a gas channel with liquid wall (DGCLW) in the regime where the discharge is ignited by the breakdown with the air injection between tubular electrodes and then it burns in the ethanol-water mixture self-sustainingly without air supply. The numerical modeling clarifies the nature of non-thermal conversion and explains the kinetic mechanism of nonequilibrium plasma-chemical transformations in the gas-liquid system and evolution of hydrogen during the reforming as a function of discharge parameters and ethanol-water ratio in the mixture.

Seeking appropriate approaches to utilize the crude glycerol produced in biodiesel production is very important for the economic viability and environmental impacts of biodiesel industry. Gasification may be one of options for addressing this issue. Co-gasification of hardwood chips blending with crude glycerol in various loading levels was undertaken in the study involving a pilot scale fixed-bed downdraft gasifier. The results indicated that crude glycerol loading levels affected the gasifier's performance and the quality of syngas produced. When crude glycerol loading level increased, the CO, CH 4 , and tar concentrations of the syngas also increased but particle concentration decreased. Though further testing is suggested, downdraft gasifiers could be run well with hardwood chips blending with liquid crude glycerol up to 20 (wt%). The syngas produced had relatively good quality for fueling internal combustion engines. This study provides a considerable way to utilize crude glycerol.

In order to produce synthesis gas (syngas), four reforming processes including two stand-alone primary and secondary reformers and two combined configurations are investigated. With changing operating parameters and arrangement of the reformers (i.e. stand-alone, parallel, and series), the syngas may be obtained for different applications such as methanol, Fischer-Tropsch (FT), and ammonia synthesis. After study of several arrangements, the selected cases are simulated. Due to the shift some reforming duty from the primary reformer to the secondary one, the primary size and the total fired duty are reduced. The Non-Sorting Genetic Algorithm II (NSGA-II) optimization method is applied for the problem based on the practical point of view. It is shown that the parallel case is preferable in accordance to the high productivity object. For an optimum point, parallel case has 58% of productivity of syngas more than that of series one. However, the series configuration consumes lower fuel (361.1 kmol h−1, in comparison to the parallel case with 437.19) and releases lower amount of CO2 emission. It is shown that the series arrangement has an average of 13.22% of released CO2 molar flow less than that of parallel arrangement.

A research and development program is under way at the Idaho National Laboratory (INL) to assess the technological and scale-up issues associated with the implementation of solid-oxide electrolysis cell technology for efficient high-temperature hydrogen production from steam. This work is supported by the US Department of Energy, Office of Nuclear Energy, under the Nuclear Hydrogen Initiative. This paper will provide an overview of large-scale system modeling results and economic analyses that have been completed to date. System analysis results have been obtained using the commercial code UniSim, augmented with a custom high-temperature electrolyzer module. Economic analysis results were based on the DOE H2A analysis methodology. The process flow diagrams for the system simulations include an advanced nuclear reactor as a source of high-temperature process heat, a power cycle and a coupled steam electrolysis loop. Several reactor types and power cycles have been considered, over a range of reactor outlet temperatures.

Shift Conversion Catalysts:  Operating Manual
Contents
Introduction
High temperature shift catalysts
Low temperature shift catalysts
Catalyst storage, handling, charging and discharging
Health and safety precautions
Reduction and start-up of high temperature shift catalysts
Operation of high temperature shift catalysts
Reduction and start-up of low temperature shift catalysts
Operation of low temperature shift catalysts

The Kinetics of CO2 reforming of natural gas to produce synthesis gas (CO C H2) has been investigated using 2 g of 0.5% wt of each of the catalysts; rhodium, ruthenium and iridium supported on -alumina. The experiments were carried out in a tubular reactor at three temperature levels namely 600, 700, 800ıC and four gas weight hourly space velocities; 18000, 36000, 45000, and 60000 ml g􀀀1 h􀀀1.
The reaction was found to obey first-order kinetics for the depletion of both of the reacting components; CH4 and CO2 on all the investigated catalysts. At the same temperature, CO2 had a higher reaction rate constant, k0, as compared to CH4 for all the catalysts. This was more pronounced for Rh/-alumina catalyst, which occupied the highest reaction rates. Activation Energies were calculated from the Arrhenius relation

Rice husk has been recognized as a potential source of energy. Thus, the main objective of this work was to develop a rice husk gasification process. Diffuse reflectance infrared spectra reveal that partial oxidation of rice husk at reaction temperatures below 1000 K would also allow recover valuable of amorphous silica materials. In the laboratory-scale fixed-bed and bench-scale downdraft experimental approaches, gasification of rice husk was accompanied by a substantial production of syngas at 760-900 K. It appears that in order to generate 10 kW electric power, approximately 28 kgrh of rice husk must be gasified. The rice husk gasification process, in terms of heat requirements, can be self-sustaining. q

We have developed appropriate and excellent catalysts for direct DME synthesis. The catalysts, Cu-Zn/Al 2 O 3 catalysts prepared by the sol-gel method, produce DME with high DME activity and high DME selectivity under milder reaction temperature and pressure compared with the usual direct DME synthesis catalysts (mixed catalysts of methanol synthesis catalysts and methanol dehydration catalysts). It will be the reason why the methanol synthesis active sites (copper) and the methanol dehydration active sites (alumina) on the sol-gel Cu/Al 2 O 3 catalysts exist closer than those of the mixed catalysts.

The disposal of plastic solid waste (PSW) has become a major worldwide environmental problem. New sustainable processes have emerged, i.e. either advanced mechanical recycling of PSW as virgin or second grade plastic feedstock, or thermal treatments to recycle the waste as virgin monomer, as synthetic fuel gas, or as heat source (incineration with energy recovery). These processes avoid land filling, where the non-biodegradable plastics remain a lasting environmental burden. Within the thermal treatments, gasification and pyrolysis gain increased interest. Gasification has been widely studied and applied for biomass and coal, with results reported and published in literature. The application to the treatment of PSW is less documented. Gasification is commonly operated at high temperatures (>600˚C to 800˚C) in an airlean environment (or oxygen-deficient in some applications): the air factor is generally between 20% and 40% of the amount of air needed for the combustion of the PSW. Gasification produces mostly a gas phase and a solid residue (char and ashes). The use of air introduces N 2 in the product gases, thus considerably reducing the calorific value of the syngas, because of the dilution. The paper will review the existing literature data on PSW gasification, both as the result of laboratory and pilot-scale research. Processes developed in the past will be illustrated. Recently, the use of a sequential gasification and combustion system (at very high temperatures) has been applied to various plastic-containing wastes, with atmospheric emissions shown to be invariably below the legal limits. Operating results and conditions will be reviewed in the paper, and completed with recent own lab-scale experimental results. These results demonstrate that gasification of PSW can be considered as a first order reaction, with values of the activation energy in the order of 187 to 289 kJ/mol as a function of the PSW nature.