A Gasification Technology to Combine Oil Sludge with Coal-Water Slurry:CFD Analysis and Performance Determination

The development of more environment-friendly ways to dispose of oil sludge is currently regarded as a hot topic.In this context,gasification technologies are generally seen as a promising way to combine oil sludge with coal–water slurry(CWS)and generate resourceful fuel.In this study,a novel five-nozzle gasifier reactor was analyzed by means of a CFD(Computational fluid dynamic)method.Among several influential factors,special attention was paid to the height-to-diameter ratio of the gasifier and the mixing ratio of oil sludge,which are known to have a significant impact on the flow field,temperature distribution and gasifier performances.According to the numerical results,the optimal height-to-diameter ratio and oil mixing ratio are about 2.4:1 and 20%,respectively.Furthermore,the carbon conversion rate can become as high as 98.55%with the hydrolysis rate reaching a value of 53.88%.The consumption of raw coal and oxygen is generally reduced,while the effective gas production is increased to 50.93 mol/%.

Application of organic polymeric flocculants in centrifugal dewa-tering of oil refinery sludge

In order to evaluate the applicability of the organic polymeric flocculants(OPF) in the treatment of oil refinery sludge, experiments were conducted to show that OPF have better performance of flocculation than inorganic flocculants. Both the anionic and cationic OPF have satisfactory flocculation efficiency in oil sludge treatment, but the latter are more cost efficient. Among the over 20 types of flocculants tested, 2 OPF(CPAM 2 and HPAM 2) were selected as the treatment agents, based on their good treatment performances, oil resistance and economic feasibility. It was demonstrated in the industrial scale centrifugal dewatering experiments that the application of either CPAM 2 or HPAM 2 could achieve high treatment efficiency of the oil sludge dewatering and reduce the COD of centrifugal liquid to less than 1000 mg/L.

Removal of phenol by activated carbons prepared from palm oil mill effluent sludge

The study was attempted to produce activated carbons from palm oil mill effluent （POME） sludge. The adsorption capacity of the activated carbons produced was evaluated in aqueous solution of phenol. Two types of activation were followed, namely, thermal activation at 300, 500 and 800%, and physical activation at 150% （boiling treatment）. A control （raw POME sludge） was used to compare the adsorption capacity of the activated carbons produced. The results indicated that the activation temperature of 800℃ showed maximum absorption capacity by the activated carbon （POME 800） in aqueous solution of phenol. Batch adsorption studies showed an equilibrium time of 6 h for the activated carbon of POME 800. It was observed that the adsorption capacity was higher at lower values ofpH （2--3） and higher value of initial concentration of phenol （200--300 mg/L）, The equilibrium data were fitted by the Langmuir and Freundlich adsorption isotherms. The adsorption of phenol onto the activated carbon POME 800 was studied in terms of pseudo-first and second order kinetics to predict the rate constant and equilibrium capacity with the effect of initial phenol concentrations. The rate of adsorption was found to be better correlation for the pseudo-second order kinetics compared to the first order kinetics.

Pyrolysis behaviors of oil sludge based on TG/FTIR and PY-GC/MS

Pyrolysis is an alternative technology for oil sludge treatment.Thermogravimetric Analysis-Fourier Transform Infrared Spectroscopy and Pyrolysis-Gas Chromatography/Mass Spectrometry were employed to investigate the pyrolysis process and products of oil sludge.The pyrolysis process was divided into five stages:drying and gas desorption,oil volatilization,main pyrolysis,semicoke charring,and mineral decomposition.The main reaction temperatures ranged from 497.6 K to 753.2 K.The products were mainly composed of pairs of alkane and alkene(carbon number ranges from 1 to 27).The mechanisms consisted of random chain scission followed by end chain scission at high temperatures with volatilization occurring during the whole process.This study is useful not only for the proper design of a pyrolysis system,but also for improving the utilization of liquid oil products.

Physiological and biochemical characteristic of Miscanthus×giganteus grown in heavy metal-oil sludge co-contaminated soil

The effect of oil sludge and zinc,present in soil both separately and as a mixture on the physiological and biochemical parameters of Miscanthus×giganteus plant was examined in a pot experiment.The opposite effect of pollutants on the accumulation of plant biomass was established:in comparison with uncontaminated control the oil sludge increased,and Zn reduced the root and shoot biomass.Oil sludge had an inhibitory effect on the plant photosynthetic apparatus,which intensified in the presence of Zn.The specific antioxidant response of M.×giganteus to the presence of both pollutants was a marked increase in the activity of superoxide dismutase(mostly owing to oil sludge)and glutathione-S-transferase(mostly owing to zinc)in the shoots.The participation of glutathione-S-transferase in the detoxification of both the organic and the inorganic pollutants was assumed.Zn inhibited the activity of laccase-like oxidase,whereas oil sludge promoted laccase and ascorbate oxi-dase activities.This finding suggests that these enzymes play a part in the oxidative detox-ification of the organic pollutant.With both pollutants used jointly,Zn accumulation in the roots increased 6-fold,leading to increase in the efficiency of soil clean-up from the metal.In turn,Zn did not significantly affect the soil clean-up from oil sludge.This study shows for the first time the effect of co-contamination of soil with oil sludge and Zn on the phys-iological and biochemical characteristics of the bioenergetic plant M.×giganteus.The data obtained are important for understanding the mechanisms of phytoremediation with this plant.

Co-Pyrolysis Characteristics and Kinetic Analysis of Oil Sludge with Different Additives

The addition of effective additives can effectively improve the pyrolysis performance of oil sludge(OS)and have a great potential to reduce pyrolysis costs.In the present study,co-pyrolysis performance of OS with different proportions of additives at a heating rate of 10°C/min was conducted in a thermal analyzer.Walnut shell,Fe_(2)O_(3),K_(2)CO_(3),PVC and the pyrolysis char produced from OS at the final pyrolysis temperature of 700℃were selected as the additives.TG results showed that the OS pyrolysis with and without additives can be divided into five reaction stages,which include volatilization of free water,the escape of light components,the cleavage of heavy components,carbon decomposition and inorganic minerals decomposition.The addition of additives decreased the maximum weight loss rate when the blending ratio was 5 wt%during OS pyrolysis.Kinetic analysis revealed that the overall activation energy of pyrolysis reaction was lower during pyrolysis of OS with the addition of walnut shells and pyrolysis char.The activation energy of three main reaction stages all decreased during co-pyrolysis of OS with K_(2)CO_(3)and PVC.

Effects of temperature on pyrolysis products of oil sludge

Temperature is the determining factor of pyro-lysis,which is one of the alternative technologies for oil sludge treatment.The effects of final operating temper-ature ranging from 350 to 550uC on pyrolysis products of oil sludge were studied in an externally-heating fixed bed reactor.With an increase of temperature,the mass fraction of solid residues,liquids,and gases in the final product is 67.00%–56.00%,25.60%–32.35%,and 7.40%–11.65%,and their corresponding heat values are 34.4–13.8 MJ/kg,44.41–46.6 MJ/kg,and 23.94–48.23 MJ/Nm 3,respectively.The mass and energy tend to shift from solid to liquid and gas phase(especially to liquid phase)during the process,and the optimum temperature for oil sludge pyrolysis is 500uC.The liquid phase is mainly com-posed of alkane and alkene(C_(5)–C_(29)),and the gas phase is dominantly HC S and H 2.