Feedstock For Chemical Industry Research Articles

Experimental investigation of alterations in coal fracture network induced by thermal treatment: Implications for CO2 geo-sequestration

Hydrogen-rich syngas, produced by underground coal gasification (UCG) process, is a valuable feedstock for chemical industry. However, it can contain large quantities of carbon dioxide (CO2), which requires separation and sequestration to reduce the carbon footprint of the process. This study explores mechanisms influencing coal permeability when CO2 is injected back into the coal through existing gasification chambers. Two main mechanisms affecting permeability are thermal effects associated with underground coal gasification and CO2-related coal matrix swelling.The effects of thermal processes and CO2 flooding on the fracture network of the coal are investigated through a series of comprehensive experiments. Thermal treatment of the studied sample at a temperature of 210 °C shows a notable effect on fracture morphology, increasing width and permeability by up to a factor of 2 and 5, respectively. CO2 flooding, on the other hand, impairs fracture network due to chemisorption driven processes, leading to irreversible changes. Following CO2 flooding experiment, fracture porosity decreases by a factor of three and subsequently permeability declines by 70–80 % within the studied effective stresses range. Our characterization study indicates that thermal treatment significantly increases permeability, compensating for impairments to the fracture network associated with CO2 injection.

High efficiency electricity and gas cogeneration through direct carbon solid oxide fuel cell with cotton stalk biochar

For the first time, biochar derived from a renewable resource, cotton stalk, is used as the feedstock of direct carbon solid oxides fuel cells (DC-SOFCs) for electricity and gas cogeneration. It turns out that the cotton stalk biochar has plenty of naturally grown K and Ca, which are active catalysts for the reverse Boudouard reaction in DC-SOFCs. This natural advantage of the cotton stalk biochar enables an extremely high power density of an anode-supported DC-SOFC at 850 °C, 0.9 W cm−2, which is the highest among those of the reported DC-SOFCs. Meanwhile, high concentration of CO gas, which is an important feedstock for chemical industry, is obtained from the DC-SOFCs. The energy conversion efficiency of the electricity-gas cogeneration of DC-SOFCs reaches over 70%. A novel method, using compressed char, is proposed and carried out for continuous supply of cotton stalk char to a DC-SOFC. The present work has demonstrated the feasibility and advantages of cogenerating electricity and gas through DC-SOFCs with biochar derived from cotton stalk as the feedstock.

Molybdenum, tungsten doped cobalt phosphides as efficient catalysts for coproduction of hydrogen and formate by glycerol electrolysis

H2 and formate are important energy carriers in fuel-cells and feedstocks in chemical industry. The hydrogen evolution reaction (HER) coupling with electro-oxidative cleavage of thermodynamically favorable polyols is a promising way to coproduce H2 and formate via electrochemical means, highly active catalysts for HER and electrooxidative cleavage of polycols are the key to achieve such a goal. Herein, molybdenum (Mo), tungsten (W) doped cobalt phosphides (Co2P) deposited onto nickel foam (NF) substrate, denoted as Mo-Co2P/NF and W-Co2P/NF, respectively, were investigated as catalytic electrodes for HER and electrochemical glycerol oxidation reaction (GOR) to yield H2 and formate. The W-Co2P/NF electrode exhibited low overpotential (η) of 113 mV to attain a current density (J) of −100 mA cm−2 for HER, while the Mo-Co2P/NF electrode demonstrated high GOR efficiency for selective production of formate. In situ Raman and infrared spectroscopic characterizations revealed that the evolved CoO2 from Co2P is the genuine catalytic sites for GOR. The asymmetric electrolyzer based on W-Co2P/NF cathode and Mo-Co2P/NF anode delivered a J = 100 mA cm−2 at 1.8 V voltage for glycerol electrolysis, which led to 18.2 % reduced electricity consumption relative to water electrolysis. This work highlights the potential of heteroelement doped phosphide in catalytic performances for HER and GOR, and opens up new avenue to coproduce more widespread commodity chemicals via gentle and sustainable electrocatalytic means.

Photocatalytic Transformation of Biomass and Biomass Derived Compounds-Application to Organic Synthesis.

Biomass and biomass-derived compounds have become an important alternative feedstock for chemical industry. They may replace fossil feedstocks such as mineral oil and related platform chemicals. These compounds may also be transformed conveniently into new innovative products for the medicinal or the agrochemical domain. The production of cosmetics or surfactants as well as materials for different applications are examples for other domains where new platform chemicals obtained from biomass can be used. Photochemical and especially photocatalytic reactions have recently been recognized as being important tools of organic chemistry as they make compounds or compound families available that cannot be or are difficultly synthesized with conventional methods of organic synthesis. The present review gives a short overview with selected examples on photocatalytic reactions of biopolymers, carbohydrates, fatty acids and some biomass-derived platform chemicals such as furans or levoglucosenone. In this article, the focus is on application to organic synthesis.

Emerging Applications, Developments, Prospects, and Challenges of Electrochemical Nitrate‐to‐Ammonia Conversion

AbstractAmmonia is not only an important feedstock for chemical industry but also a carbon‐free energy carrier and a safe storage media for hydrogen. Due to the advantages compared to Haber–Bosch process, electrochemical NO3−‐to‐NH3conversion via nitrate reduction reaction (NO3−RR) received attention. Recently, “green hydrogen” generated from water electrolysis shows promise to become the energy for future but limited by the safety of storage and transportation. This review proposes electrochemical NO3−‐to‐NH3conversion can store renewable electric energy and “green hydrogen” into NH3, which is a potential solution for solving the puzzle of “green hydrogen” storage and transportation. Moreover, the theoretical insights of NO3−RR and electrocatalyst design are discussed. Finally, the challenges and opportunities in this field are elucidated. This review provides a novel perspective for NO3−RR and accelerates the development of effective electrocatalysts for NO3−‐to‐NH3conversion.

Towards Application of Electro-Fermentation for the Production of Value-Added Chemicals From Biomass Feedstocks.

According to recent social demands for sustainable developments, the value of biomass as feedstocks for chemical industry is increasing. With the aid of metabolic engineering and genome editing, microbial fermentation has been developed for producing value-added chemicals from biomass feedstocks, while further improvements are desired for producing more diverse chemicals and increasing the production efficiency. The major intrinsic limitation in conventional fermentation technologies is associated with the need for balancing the net redox equivalents between substrates and products, resulting in limited repertories of fermentation products. One solution for this limitation would be “electro-fermentation (EF)” that utilizes bioelectrochemical systems for modifying the intracellular redox state of electrochemically active bacteria, thereby overcoming the redox constraint of fermentation. Recent studies have attempted the production of chemicals based on the concept of EF, while its utility has not been sufficiently demonstrated in terms of low production efficiencies. Here we discuss EF in terms of its concept, current status and future directions, which help us develop its practical applications to sustainable chemical industries.

Transformation of low-rank coal to clean syngas and power via thermochemical route

An emerging gasification was proposed for the transformation of low-rank coal to clean syngas and electricity. The excess heat from char combustion was used to evaporate moisture in coal and to generate power via steam turbine generator. The simulation was developed in the Aspen Plus based on the proper thermodynamic model. The validation exhibited a good concurrence between the present model and the experiments under the same condition with the relative error <10% in the pyrolysis stage. The moisture content reduced the energy efficiency by ∼10% but increased the H2 production by ∼50% which results in the increase of H2/CO up to 10. The highest energy and exergy efficiencies (91% and 79%, respectively) was observed on the O2 equivalence ratio and steam to ratio of 0.21 and 0.06, respectively. O2 is an appropriate gasifying agent to produce syngas as the energy source, while steam gives high-quality syngas as the feedstock for chemical industries. The CO2 emission of the proposed configuration is below 50 kg CO2/GJ (half of the conventional coal combustion, ∼100 kg CO2/GJ) when the fraction of char to combustor is less than 0.4.

Electrochemical reduction of CO2 to CO in organic electrolyte with HCl oxidized to Cl2 on anode for phosgene synthesis

Phosgene is an important feedstock in chemical industry. It can be used as an acylating agent to produce numerous high-value chemicals. In this work, we have constructed a novel membrane electrolysis cell for CO2 reduction to CO in organic electrolyte, with HCl oxidized to Cl2 on the anode in aqueous solution. The obtained CO and Cl2 can be used as feedstock to produce phosgene. Through this route, CO2 can be converted to high-value products, and meanwhile, chlorine can be recovered from HCl-containing industrial waste gasses. Based on our experimental results, CO2 can be efficiently reduced to CO, and HCl can be efficiently oxidized to Cl2. Our designed electrolyzer has a promising utilization perspective in phosgene chemical industry.

Ammonia and borane activation by Tantalum Carbide cluster anion Ta2C4−: A theoretical approach

Activation of C–H, B–H as well N–H sigma bonds has been a subject of fundamental interest due to potential feedstock in chemical industry. The co-operative effect of the metal centers in a di-nuclear carbide cluster Ta2C4− for methane C–H activation and dissociation has recently been revealed, in which a molecule of hydrogen is evolved. Based on that, we have explored reaction pathways for ‘E−H’ sigma bond activation and dissociation processes of gaseous Ammonia (E: N) and Borane (E: B) using the stable form of the aforesaid complex at DFT levels. The geometries and energetics associated with the reactions are found to be method insensitive. The course of the reaction is initiated by a 1:1 precursor complex formed between the cluster and N (/B)H3. This complex formation is found to be more exothermic than that of its methane counterpart. In case of BH3, considerable lengthening of two B–H bonds in the first step is observed which implies that the two B–H bonds are activated simultaneously under the influence of Ta2C4−. But for NH3, N–H bond lengthening as well as activation is observed to be insignificant in this precursor complex. The chemical nature of the participating hydrogen atoms is inspected by NPA analysis (‘protic’ type in NH3 and ‘hydride’ type in BH3).The overall dehydrogenation procedures for both the molecules are found to be multi-step with high exothermicity. Highly negative net energy change in terms of Gibbs Free Energy (−31.03 kcal/mol for ammonia and −31.36 kcal/mol for borane) as well as Enthalpy (−33.68 kcal/mol for ammonia and −34.13 kcal/mol for borane), in forming a H2 molecule with stable Ta2C4N(/B)H− complex, with respect to the reactant pair govern the thermodynamic feasibility of the overall process. In a nutshell, this computational study provides a detail understanding of the activation and dissociation processes of the concerned gaseous molecules, which will be beneficial for further experimental studies.

Heterogeneous Organocatalysts for the Reduction of Carbon Dioxide with Silanes

The utilization of carbon dioxide (CO2 ) as feedstock for chemical industries is gaining interest as a sustainable alternative to nonrenewable fossil resources. However, CO2 reduction is necessary to increase its energy content. Hydrosilane is a potential reducing agent that exhibits excellent reactivity under ambient conditions. CO2 hydrosilylation yields versatile products such as silylformate and methoxysilane, whereas formamides and N-methylated products are obtained in the presence of amines. In these transformations, organocatalysts are considered as the more sustainable choice of catalyst. In particular, heterogeneous organocatalysts featuring precisely designed active sites offer higher efficiency due to their recyclability. Herein, an overview is presented of the current development of basic organocatalysts immobilized on various supports for application in the chemical reduction of CO2 with hydrosilanes, and the potential active species parameters that might affect the catalytic activity are identified.

Influence of Power‐to‐Fuel Plant Flexibility Towards Power and Plant Utilization and Intermediate Hydrogen Buffer Size

AbstractConversion of intermittent renewable energy into synthetic fuels and chemicals is required to secure long‐distance transport and feedstock for chemical industry. Due to the fluctuating energy generation, process intensification and feed flexibility are essential. This contribution investigates the importance of feed flexibility on the buffer size with applying a 20:80 scenario of wind/solar energy generation. The degree of power and plant utilization are calculated. With the capability to accept a lower load bound of 17 % after only 10 min, a minimum tank capacity of only 1.3 h is calculated to avoid a fuel plant stop throughout a calendar year. Additional tank capacity for peak power compensation in the range of ∼10 h is beneficial for the utilization degree of power and under the prerequisite of a load‐flexible fuel plant.

Utilization possibilities of Albizia amara as a source of biomass energy for bio-oil in pyrolysis process

ABSTRACTPyrolysis is one of the potential routes to harmless energy and useful chemicals from biomass. The pyrolysis of Albizia amara was studied for determining the main characteristics and quantities of liquid products. Particular investigated process variables were temperature from 350 to 550°C, particle size from 0.6 to 1.25 mm, and heating rate from 10 to 30 °C/min. The maximum bio-oil yield of 48.5 wt% at the pyrolysis temperature of 450°C was obtained at the particle size of 1.0 mm and at the heating rate of 30 °C/min. The bio-oil product was analyzed for physical, elemental, and chemical composition using Fourier transform infrared spectroscopy and gas chromatography spectroscopy. The bio-oil contains mostly phenols, alkanes, alkenes, saturated fatty acids and their derivatives. According to the experimental results, the pyrolysis bio-oil can be used as low-grade fuel having heating value of 18.63 MJ/kg and feedstock for chemical industries.

Conversion of cotton residues to bio-oil and chemicals through flash pyrolysis in a fluidised bed reactor

Pyrolysis process offers solution to utilise huge quantity of biomass to produce fuel for energy needs. This paper describes the development of a new model for waste cotton shell pyrolysis. This model calculates the minimum fluidisation velocity for various sand particles for better fluidisation. Cotton shell wastes were subjected to pyrolysis at atmospheric pressure under inert gas atmosphere in a fluidised bed setup to determine the effect of operation parameters. The sand particle size 0.71 mm offered better fluidisation and is more economical as it utilises low hydrogen flow rate. The maximum yield of bio-oil 51 wt% can be obtained under the operation parameters of 450°C pyrolysis temperature, 1 mm particle size at sweep gas flow rate of 1.75 m3/h. In addition, the characterisation study of the bio-oil has been done for its physical and chemical analysis with gas chromatography mass spectroscopy. The elements and its derivatives found in the GC-MS analysis are used as a feed stock for chemical industries.

Highly carbon resistant multicore-shell catalyst derived from Ni-Mg phyllosilicate nanotubes@silica for dry reforming of methane

Dry reforming of methane (DRM) has been a popular research topic since it consumes two kinds of so-called “green gas” and produces syngas (mixture of CO and H2) which is commonly used as fuel or feedstocks for chemical industry. In this report, we describe a multicore-shell catalyst derived from Ni-Mg phyllosilicate nanotubes@silica and test it for DRM. After Ni-Mg phyllosilicate nanotubes (PSNTS) were synthesized, a layer of mesoporous silica with a thickness of ∼10nm was coated by a modified Stöber method of hydrolysis of tetraethyl orthosilicate (TEOS) in an ethanol solution mixed with ammonia and cetrimonium bromide (CTAB). After coating, the thermal stability was significantly improved. Upon reduction by H2 at high temperature, multiple small Ni particles were observed to be supported along the nanotube as well as encapsulated by silica shell. When tested for dry reforming of methane, this multicore-shell catalyst showed a high and stable conversion during a 72h durability run at 750°C and much improved carbon resistance than uncoated sample which decomposed at such a high temperature. Due to its high thermal stability and excellent carbon resistance, it is believed that this catalyst can be used for other high temperature and high carbon coking reaction such as biomass gasification.

Quantitative model for predicting the desorption energy of water contained in lignite

Due to the high moisture content (25–65%) dewatering is essential for the clean and efficient utilization of lignite as fuel or feedstock for chemical industry. In order to quantitatively evaluate the desorption energy of contained water content, a prediction model was proposed in this paper based on Lennard-Jones 10-4-3 solid–fluid potential equation and Clausius–Clapeyron principle using lignite pore structure and specific surface area. Based on the proposed model, the drying behavior of two typical Chinese lignite respectively collected from coal mine at Xinjiang and Inner Mongolia districts were experimentally studied and intelligent gravimetric analysis (IGA) was employed for model evaluation. Results show that the water content of original coal sample are 22.4% and 37.6% by weight for Xinjiang and Inner Mongolia lignite, respectively. After air drying at 40 °C, the water content can be dramatically reduced to 13.4% and 17.9%. The overall dewatering energy of the retained moisture after air dying are 38.84 kJ/(100 g air dried coal) for Xinjiang lignite and 53.57 kJ/(100 g air dried coal) for Inner Mongolia lignite. From IGA analysis, it was found that the gradient of the desorption energy of Xinjiang lignite against water content can be separated into three main water desorption stages according to the energy cost.

Ethylbenzene dehydrogenation in the presence of carbon dioxide over magnesia-supported iron oxides

In recent years, several works have been addressed to decrease carbon dioxide emission or to capture, to storage and to use it. An attractive option is its use as feedstock of chemical industry, especially in dehydrogenation reactions (such as ethylbenzene dehydrogenation to produce styrene), providing an exothermic process which can be operated at lower temperatures, making negligible the cracking products. Aiming to find alternative catalysts for this reaction, magnesia-supported iron oxides were studied, being prepared by two different methods. The classical impregnation produced a spinel (MgFe2O4) co-existing with magnesia containing Fe3+ species, this catalyst showing higher specific surface area and being more active and selective than magnesia. Moreover, the deposition of iron nanoparticles through a magnetic fluid on magnesia produced magnesia-supported hematite nanoparticles co-existing with magnesia containing Fe3+ species. In this case, the specific surface area and the activity were even higher and the solid is much more reducible than the other sample. These findings were associated to hematite nanoparticles and to the lower tendency of iron species to diffuse into magnesia lattice. They show that the Fe3+ species are more active and selective to styrene as hematite nanoparticles than when they are in the environment of magnesium ferrite.

Combined effect of heat and radiation on degradation of cellulose

Cellulose is the most common biopolymer of the plant origin. It is regarded as the most important renewable raw material for the future chemistry and fuel power generation. Contemporary processes for cellulose conversion still cannot compete with the oil refining technologies in terms of the range of products to be used as feedstock for chemical industry [1]. However, as the petroleum economy loses its global position, the importance of designing and developing appropriate cellulose biomass processing methods to meet the demands of different market sectors for raw materials increases.

Thermal and catalytic degradation of polyethylene wastes in the presence of silica gel, 5A molecular sieve and activated carbon

A comparative study of thermal and catalytic degradation of polyethylene wastes has been carried out with the aim of obtaining chemical compounds with potential use in the chemical industry and the energy production. Polyethylene wastes were obtained from polyethylene bags used in supermarkets. Catalysts utilized in the study were silica gel, 5A molecular sieve and activated carbon. The pyrolysis was performed in a batch reactor at 450, 500 and 700°C during 2h for each catalyst. The ratio catalyst/PE was 10% w/w and the solid and gaseous products were analyzed by gas chromatography and mass spectrometry. The optimum operation temperature and the influence of the three catalysts are discussed with regards to the products formed. The best temperature for degradation with silica gel and activated carbon as catalysts was 450°C and with 5A molecular sieve was 700°C. Degradation products of PE (solid fraction and gas fraction) are depending on temperature and catalyst used. External surface and structure of catalysts were visualized by Scanning Electron Microscopy (SEM) and the contribution on product distribution is commented. All products from different degradations could be used as feed stocks in chemical industry or in energy production based on the value of heat of combustion for solid fraction (45000J/g), similar to the heat of combustion of commercial fuels.

Terpenoid biomaterials

Terpenoids (isoprenoids) encompass more than 40 000 structures and form the largest class of all known plant metabolites. Some terpenoids have well-characterized physiological functions that are common to most plant species. In addition, many of the structurally diverse plant terpenoids may function in taxonomically more discrete, specialized interactions with other organisms. Historically, specialized terpenoids, together with alkaloids and many of the phenolics, have been referred to as secondary metabolites. More recently, these compounds have become widely recognized, conceptually and/or empirically, for their essential ecological functions in plant biology. Owing to their diverse biological activities and their diverse physical and chemical properties, terpenoid plant chemicals have been exploited by humans as traditional biomaterials in the form of complex mixtures or in the form of more or less pure compounds since ancient times. Plant terpenoids are widely used as industrially relevant chemicals, including many pharmaceuticals, flavours, fragrances, pesticides and disinfectants, and as large-volume feedstocks for chemical industries. Recently, there has been a renaissance of awareness of plant terpenoids as a valuable biological resource for societies that will have to become less reliant on petrochemicals. Harnessing the powers of plant and microbial systems for production of economically valuable plant terpenoids requires interdisciplinary and often expensive research into their chemistry, biosynthesis and genomics, as well as metabolic and biochemical engineering. This paper provides an overview of the formation of hemi-, mono-, sesqui- and diterpenoids in plants, and highlights some well-established examples for these classes of terpenoids in the context of biomaterials and biofuels.

BP plans world-scale PTA plant in Belgium

The interest in natural gas as an alternative feedstock for ethylene production stems mainly from its clean burning qualities, its domestic resource base, and its commercial availability. As the price of crude oil increases and an oil shortage looms, in the future, it becomes a concern for scientists trying to use natural gas as an alternative source of energy and as a feedstock in chemical industries. Methanol is one of the prime candidates for providing liquid fuels from natural gas as an alternative from traditional petroleum-based sources. In this work, a commercial-scale (223 tons/day) methanol plant, operating at steady state, which uses catalytic partial oxidation as a primary route (for synthesis gas production) from non-reacted methane coming from Oxidative Coupling of Methane (OCM) reaction has been designed. The main reason that motivates the realization of this work is to exploit the availability of unreacted methane, coming from the exit flue gas products of the OCM reactor, and thus, design an alternative process for methanol production via OCM and the co-generation of electricity that can make the process economically attractive and designed so as to be industrially implemented. The total project investment, based on total equipment cost, as well as variable and fixed operating costs, was developed based on mass and energy balance information taken from ASPEN ICARUS® simulation results. The basis of the analysis is a world-scale conventional methanol plant that converts 368000 m3 per day of methane into 223 tons per day of methanol and generates 4019 kW of electricity. Capital and operating costs are for an arbitrary remote location where natural gas is available at €12.60 per 1000 m3. Payout time for this process, with an OCM plant, is around 4 years. This analysis suggests areas for research focus that might improve the profitability of natural gas conversion. Overall, the process described here appears to be feasible for the methanol production using non-reacted methane that comes from the OCM reaction process. This process can be implemented to enable optimum utilization of the methane gas based on market demand.