Fixed bed downdraft gasification of paper industry wastes

The two main wastes generated from secondary fibre paper mills are rejects (composed mainly of plastics and fibres) and de-inking sludge, both of which are evolved from the pulping process during paper manufacture. The current practice for the disposal of these wastes is either by land-spreading or land-filling. This work explores the gasification of blends of pre-conditioned rejects and de-inking sludge pellets with mixed wood chips in an Imbert type fixed bed downdraft gasifier with a maximum feeding capacity of 10kg/h. The producer gases evolved would generate combined heat and power (CHP) in an internal combustion engine. The results show that as much as 80wt.% of a brown paper mill's rejects (consisting of 20wt.% mixed plastics and 80wt.% paper fibres) could be successfully gasified in a blend with 20wt.% mixed wood chips. The producer gas composition was 16.24% H, 23.34% CO, 12.71% CO 5.21% CH and 42.49% N (v/v%) with a higher heating value of 7.3MJ/Nm. After the removal of tar and water condensate the producer gas was of sufficient calorific value and flow rate to power a 10kWe gas engine. Some blends using rejects from other mill types were not successful, and the limiting factor was usually the agglomeration of plastics present within the fuel

The role of thermo-catalytic reforming for energy recovery from food and drink supply chain wastes

Disposal of food and drink wastes, including packaging wastes, has a significant cost and environmental impact. All carbon containing wastes have an energy potential and the food industry should focus on recovering that energy to offset their reliance on fossil-fuel derived energy sources. This paper focuses on the novel use of intermediate pyrolysis for decarbonizing the food chain, through the treatment of food and packaging waste, to recover energy. The TCR is a versatile technology which overcomes many of the traditional problems associated with fast pyrolysis and can thermo-chemically convert a range of different feedstocks, including inaccessible lignin and some inorganic, recalcitrant materials. The feedstocks are converted into new fuel sources; char, bio-oil (thermally stable) and permanent gases, for further electrical and heat generation. Ultimately with the use of the TCR technology, the food production industry could look to using decentralized power generation located on-site of large food processing facilities to optimize their energy efficiencies

The intermediate pyrolysis of de-inking sludge to produce a sustainable liquid fuel

De-inking sludge is a waste product generated from secondary fibre paper mills who manufacture recycled paper into new paper sheets; it refers directly to the solid residues which evolve during the de-inking stage of the paper pulping process. The current practice for the disposal of this waste is either by land-spreading, land-filling or incineration which are unsustainable. This work has explored the intermediate pyrolysis of pre-conditioned de-inking sludge pellets in a recently patented 20 kg/h intermediate pyrolysis reactor (The Pyroformer). The reactor is essentially two co-axial screws which are configured in such a way as to circulate solids within the reactor and thus facilitate in the cracking of tars. The potential application of using the volatile organic vapours and permanent gases evolved would be to generate both combined heat and power (CHP) located at paper making sites. The results show that de-inking sludge could be successfully pyrolysed and the organic vapours produced were composed of a mixture of aromatic hydrocarbons, phenolic compounds and some fatty acid methyl esters as detected by liquid GC-MS. The calorific value of the oil after condensing was between 36 and 37 MJ/kg and the liquid fuel properties were also determined, permanent gases were detected by a GC-TCD and were composed of approximately 24% CO, 6% CH and 70% CO (v/v%). The solid residue from pyrolysis also contained a small residual calorific value, and was largely composed of mainly calcium based inert metal oxides. The application of applying intermediate pyrolysis to de-inking sludge for both CHP production and waste reduction is in principle a feasible technology which could be applied at secondary fibre paper mills

Experimental investigation of performance, emission and combustion characteristics of an indirect injection multi-cylinder CI engine fuelled by blends of de-inking sludge pyrolysis oil with biodiesel

De-inking sludge can be converted into useful forms of energy to provide economic and environmental benefits. In this study, pyrolysis oil produced from de-inking sludge through an intermediate pyrolysis technique was blended with biodiesel derived from waste cooking oil, and tested in a multi-cylinder indirect injection type CI engine. The physical and chemical properties of pyrolysis oil and its blends (20 and 30 vol.%) were measured and compared with those of fossil diesel and pure biodiesel (B100). Full engine power was achieved with both blends, and very little difference in engine performance and emission results were observed between 20% and 30% blends. At full engine load, the brake specific fuel consumption on a volume basis was around 6% higher for the blends when compared to fossil diesel. The brake thermal efficiencies were about 3-6% lower than biodiesel and were similar to fossil diesel. Exhaust gas emissions of the blends contained 4% higher CO2 and 6-12% lower NOx, as compared to fossil diesel. At full load, CO emissions of the blends were decreased by 5-10 times. The cylinder gas pressure diagram showed stable engine operation with the 20% blend, but indicated minor knocking with 30% blend. Peak cylinder pressure of the 30% blend was about 5-6% higher compared to fossil diesel. At full load, the peak burn rate of combustion from the 30% blend was about 26% and 12% higher than fossil diesel and biodiesel respectively. In comparison to fossil diesel the combustion duration was decreased for both blends; for 30% blend at full load, the duration was almost 12% lower. The study concludes that up to 20% blend of de-inking sludge pyrolysis oil with biodiesel can be used in an indirect injection CI engine without adding any ignition additives or surfactants

Inhibitory effect of Acacia hamulosa methanolic extract on the corrosion of mild steel in 1 M hydrochloric acid

The flora of Saudi Arabia comprises about 18 species of Acacia species including Acacia hamulosa Benth. The methanolic extract of the flowering tops of A. hamulosa was tested for its radical scavenging activity toward 2,2-diphenyl-1-pricylhydrazyl (DPPH) radical and the activity was compared with L-ascorbic acid, quercetin and Trolox as standards. The total phenolic content was determined using Folin-Ciocalteu method. In addition the methanolic extract has been evaluated as a corrosion inhibitor for steel in 1 M HCl solution by means of weight loss measurements, potentiodynamic polarization, electrochemical impedance spectroscopy (EIS). Tafel polarization study revealed that extract of Acacia hamulosa acts as a cathodic type inhibitor. Inhibition was found to increase with increasing concentration of the extract of Acacia hamulosa. Values of inhibition efficiency calculated from weight loss, Tafel polarization curves, and EIS are in good agreement. The effect of temperature on the corrosion behaviour of mild steel in 1 M HCl with addition of extract was also studied and thermodynamic parameters were determined and discussed.               KEY WORDS: Acacia hamulosa, Extract, Polyphenols, Antioxidant corrosion, Electrochemical study Bull. Chem. Soc. Ethiop. 2018, 32(2), 323-335.DOI: https://dx.doi.org/10.4314/bcse.v32i2.1

Efficacy of Pelargonium graveolens essential oils against some postharvest fungal diseases of apple

Background: Postharvest diseases that occur in apples are often caused by various pathogenic fungi, causing serious economic loss. The pathogenic fungi Penicillium expansum, Rhizopus stolonifer and Botrytis cinerea are among the most common pathogens in apples. The goal of this study was to see whether Moroccan Pelargonium graveolens essential oil (PGEO) could protect apple fruits from fungal infections after they were harvested (in vitro).Methods: PGEO was characterized by GC-MS and for antifungal assessment, in vitro poisoned food (PF) and volatile activity testing (VA) were carried out.Results: The investigation revealed that PGEO was effective against the three tested phytopathogenic fungi in a dose-dependent manner and this antifungal activity increased with the volatile activity test. The MIC value was 2 µL/mL for B. cinera, and R. stolonifer, and 1 µL/mL for P. expansum. Volatile fraction stops the growth of B. cinera at 40 µL / disc (QMI = 40 µL / disc), and of P. expansum and R. stolonifer at 80 µL / disc (QMI = 80 µL / disc).Conclusion: The current findings show that Moroccan PGEO has powerful antifungal activities, suggesting that it might be used instead of synthetic fungicides to combat apple post-harvest infections.Keywords: Pelargonium graveolens; Antifungal activity; Essential oil; Poisoned food; Volatile activity test; Apple

Hydrogen effect modeling on Ziegler-Natta catalyst and final product properties in propylene polymerization

Hydrogen, as chain transfer agent, effects on kinetic of propylene polymerization; consequently variation of hydrogen concentration leads to change final product properties and also activates site of used catalyst. This phenomenon is one of the most important process variables is to adjust the final product properties and optimize the operating conditions. This work has attempted to present a mathematical model that cable to calculate the most important indices of end used product, such as melt flow index, number and weight average molecular weight and poly dispersity index. The model can predict profile polymerization rates determining important kinetic parameters such as the activation energy, lumped deactivation reaction initial reaction rate and deactivation constant. The mathematical model was implemented in Matlab/Simulink environment for slurry polymerization in laboratory scale. The modeling approach is based on polymer moment balance method in the slurry semi-batch reactor. In addition, in this work have provided a model that calculating fraction activated sites catalyst via hydrogen concentration. The model was validated by experimental data from lab scale, reactor. The experimental and model outputs were compared; consequently, the errors were within acceptable range.               KEY WORDS: Mathematical modeling, Propylene polymerization, Kinetics study, Hydrogen response, population balance Bull. Chem. Soc. Ethiop. 2018, 32(2), 371-386.DOI: https://dx.doi.org/10.4314/bcse.v32i2.1

Clonal differences in Staphylococcus aureus bacteraemia-associated mortality.

The bacterium Staphylococcus aureus is a major human pathogen for which the emergence of antibiotic resistance is a global public health concern. Infection severity, and in particular bacteraemia-associated mortality, has been attributed to several host-related factors, such as age and the presence of comorbidities. The role of the bacterium in infection severity is less well understood, as it is complicated by the multifaceted nature of bacterial virulence, which has so far prevented a robust mapping between genotype, phenotype and infection outcome. To investigate the role of bacterial factors in contributing to bacteraemia-associated mortality, we phenotyped a collection of sequenced clinical S. aureus isolates from patients with bloodstream infections, representing two globally important clonal types, CC22 and CC30. By adopting a genome-wide association study approach we identified and functionally verified several genetic loci that affect the expression of cytolytic toxicity and biofilm formation. By analysing the pooled data comprising bacterial genotype and phenotype together with clinical metadata within a machine-learning framework, we found significant clonal differences in the determinants most predictive of poor infection outcome. Whereas elevated cytolytic toxicity in combination with low levels of biofilm formation was predictive of an increased risk of mortality in infections by strains of a CC22 background, these virulence-specific factors had little influence on mortality rates associated with CC30 infections. Our results therefore suggest that different clones may have adopted different strategies to overcome host responses and cause severe pathology. Our study further demonstrates the use of a combined genomics and data analytic approach to enhance our understanding of bacterial pathogenesis at the individual level, which will be an important step towards personalized medicine and infectious disease management

Chemical Additives for Corrosion Control in Desalination Plants

The addition of chemical additives has been considered as a standard operation in water treatment systems. This chapter discusses the chemical additives used for the control of corrosion in desalination systems. Specifically, corrosion inhibitors for various metallurgies, biocides, and oxygen scavengers are covered. The pros and cons of the additive chemicals have been highlighted. The need to utilize green corrosion inhibitors based on plants and ionic liquids materials have been emphasized. This class of materials are environmentally friendly, cheap, and readily available