Conceptual carbon-reduction process design and quantitative sustainable assessment for concentrating high purity ethylene from wasted refinery gas

The direct emission of waste refinery gas after combustion will cause a severe greenhouse effect.Recovering high-value-added ethylene from wasted refinery gas has fundamental economic and environmental significance. Due to the complexity of the composition of refinery waste gas, designing and optimizing the whole recovery process is still a challenging task. Herein, a novel process(SCOAS) was proposed to obtain polymer-grade ethylene from wasted refinery gas through a direct separation process,and heat pump-assisted thermal integration optimization(HPSCOAS) was carried out. The unique feature of the novel approach is that a new stripper and ethylene reabsorber follow the dry gas absorber to ensure ethylene recovery and methane content. An industrial model, shallow cooling oil absorption(SCOA), and concentration combined cold separation system of ethylene unit using wasted refinery gas was established to analyze the technology and environment. Based on the detailed process modeling and simulation results, the quantitative sustainability assessment of economy and environment based on product life cycle process is carried out. The results show that compared with the traditional process when the same product is obtained, the total annual cost of the HPSCOAS process is the lowest, which is 15.4% lower than that of the SCOA process and 6.1% lower than that of the SCOAS process. In addition,compared with the SCOA process and the HPSCOAS process, the SCOAS process has more environmental advantages. The non-renewable energy consumed by SCOAS is reduced by about 24.8% and 6.1%, respectively. The CO_(2) equivalent is reduced by about 38.6% and 23.7%.

Surfactant-Enhanced Washing of Soils Contaminated with Wasted-Automotive Oils and the Quality of the Produced Wastewater

An old automotive industrial site located at Mexico City with many years of operation and contaminated with heavy oil hydrocarbons, particularly spent oils, was assessed for restoration using the surfactant enhanced soil washing (SESW) process. The main goal of this study was to characterize the contaminated soil in terms of TPHs, BTEX, PAHs, and metals contents as well as microbiologically (total heterotrophs and specific degrading microorganisms). We also aimed to determine the surfactant type and concentration to be used in the SESW process for the automotive waste oil contaminated soil. At the end, sixteen kg of contaminated soil were washed and the produced wastewater (approximately 40 L) was characterized in terms of COD, BOD;solids, and other physico-chemical parameters. The soil contained about 14,000 mg of TPH/kg soil (heavy fraction), 0.13 mg/kg of benzo (k) fluoranthene and 0.07 mg/kg of benzo (a) pyrene as well as traces of some metals. Metals concentrations were always under the maximum concentration levels suggested by Mexican regulations. 15 different surfactants were used to identify the one with the capability to achieve the highest TPH removal. Surfactants included 5 anionics, 2 zwitterionic, 5 nonionics and 3 natural gums. Sulfopon 30 at a concentration of 0.5% offered the best surfactant performance. The TPH removals employing the different surfactants were in the range from 38% to 68%, in comparison to the soil washing with water (10% of TPH removal). Once the surfactant was selected, 70 kg of soil were washed and the resulting water contained approximately 1300 mg/L of COD, 385 mg/L of BOD (BOD/COD = 0.29), 122 mg/L of MBAS, and 212 mg/L of oil and greases, among other contaminants.

Pricing Game Model of Wasted Clothing Recycling and Remanufacturing Based on Government Subsidy

In the global environment of pursuing resource regeneration and green environmental protection, more and more wasted clothing need to be solved. In order to make full use of the wasted clothing and save land and soil resources, an idea of wasted clothing's recycling and remanufacturing is put forward. In the new idea a pricing game model is established basing on Stacklberg differential game theory between traditional and remanufactured clothing. In this model, the differences in consumers' willingness to pay and the government's subsidies are considered. Government's optimal subsidy are obtained which ensure not only the interests of manufacturers but also environmental reputation and maximum social benefits. The study is helpful to push the wasted clothing's recycling and remanufacturing plan. It makes some index more precise quantification as government's subsidy, manufacturers and the social benefits. Government and manufactures can make the detailed cooperation plan reference to it.

Research on Selective Shredding of Wasted Printed Circuit Boards

Electronic scrap, especially wasted printed circuit boards (PCBs), is regarded as an environmental challenge. At present, the physical separation is thought to be the environmental friendly and economical method of treating and reutilizing electronic waste. An effective liberation of metals from non metallic components is a crucial step towards mechanical separation and recycling of wasted PCBs. In this paper, the selective shredding theory and mechanics characteristics of wasted PCBs were analyzed, and the shredded experiments of wasted PCBs by hammer mill were investigated. The result shows that the selective shredding exists in the wasted PCBs shredded process by hammer mill. The shredding velocity of non metallic components is far greater than that of metals in the wasted PCBs shredding, which makes the metals concentrate in the coarser fraction. And the impact force of hammer mill is superior to metal liberation from non metallic components, a satisfied metal liberation degree can be achieved in the wasted PCBs shredding by hammer mill.

Fermenting Saudi Wasted Dates by Using <i>Lactobacillus casei</i>(ATCC 393), <i>Acidophilus</i>(CICC 6088) and the Mixed-Culture Bacteria to Produce Lactic Acid

The Kingdom of Saudi Arabia produces over one million metric tons annually, which returns a 20% of wasted dates annually. Lactic acid and its derivatives are widely used in food, pharmaceutical and textile industries. There has been an increase in lactic acid production because it is used as a raw material to produce polylactic acid, a polymer that is used as a special medical and environmental friendly biodegradable plastic. This study aimed to use wasted dates to produce lactic acid by single culture Lactobacillus casei (ATCC 393), Lactobacillus acidophilus (CICC 6088) and the mixed culture using batch fermentation. The investigation results showed that the maximum concentration of lactic acid for ATCC 393, CICC 6088 and the mixed culture are 87, 84 and 84 g/l respectively. For single CICC 6088 and the mixed culture, the total percentage of glucose and fructose utilized was found to be 100%;76%, respectively, whereas in the case of the single culture ATCC 393, the total percentage of glucose and fructose were 100% and 72%, respectively. With regard to lactic acid concentration, and sugar consumption, the results revealed that the single culture ATCC 393 produced the optimum lactic acid of 87 g/l for 48 hr with initial sugar concentration of 90 g/l.

Introducing a proper hydrogen liquefaction concept for using wasted heat of thermal power plants-case study: Parand gas power plant

A hydrogen liquefaction concept with an innovative configuration and a capacity of 4 kg·s^(-1)(345.6 t·d^(-1))is developed.The concept involves an ammonia absorption refrigeration system for the pre-cooling of hydrogen and MR streams from 25℃ to-30℃.The ammonia absorption refrigeration system is fed by exhaust gases of the Pa rand gas power plant that are normally dissipated to the environment with a temperature of 546℃.The simulation is performed by Aspen HYSYS V9.0,using two separate equations of state for simulating hydrogen and MR streams to gain more accurate results especially for ortho-para conversion.Results show that conversion enthalpy estimated by Aspen HYSYS,fits very well to the experimental data.Determining the important independent variables and composition of MRs are done using trial and error procedure,a functional and straightforward method for complicated systems.The minimum temperature limit in the cooling section is lowered,and an ortho-para converter is implemented in this section.The proposed concept performs well from energy aspects and leads to COP and SEC equal to 0.271 and 4.54 kW·h·kg^(-1),respectively.The main advantage of this study is in the low SEC,eliminating the losses of the distribution network,and improving the ability of the hydrogen liquefaction for energy storage in off-peak times.

Feasibility Study on Fabrication of Geopolymer Bricks by Wasted Grinding Wheel at Room Temperature

In this study,the feasibility of producing eco-friendly bricks by using geopolymer technology and a waste grinding wheel(WGW)from the grinding wheel industries was investigated.Nowadays,in order to meet industrial needs,for instance,in Taiwan,approximately 500,000 grinding wheels are used annually.That is,a large number of“waste”grinding wheels are produced.Furthermore,few studies have been conducted on the use of WGWs as raw materials in geopolymer applications.The use of geopolymer technology to form bricks can avoid the utilization of clay and cement and even prevent the use of a high-temperature process in kilns.Moreover,it can decrease CO_(2) emission and energy consumption and thus,protect the environment.In this study,the following three major factors were considered:press-forming pressure(70 and 100 kgf/cm2),NaOH molar concentration(2 and 4M),and the ratio of binder fineaggregate(1:3,1:4,and 1:5).Under these conditions,the specimens were tested using the compressive strength test,water absorption test,microstructure analysis,a freezing–thawing test and toxicity characteristic leaching procedure test.The optimal formulation was composed of 1:4 binder fine-aggregate ratio,4M NaOH concentration,and 100-kgf/cm2 pressure.Furthermore,we used a WGW and achieved a compressive strength of 50.6 MPa after 28 days,which was greater than 32 MPa and conformed to the Grade A brick standard of National Standards of the Republic of China(13295).In conclusion,this brick fabrication method based on geopolymer technology was not only beneficial to the environment but also improved the efficiency of reutilizing WGW.

Effective Therapeutic Feeding with Chickpea Sesame Based Ready-To-Use Therapeutic Food (CS-RUTF) in Wasted Adults with Confirmed or Suspected AIDS

Wasting has been observed as a common feature of the human immunodeficiency virus (HIV) disease since the first reports and its presence increases the risk of death. There is no consensus on how to manage wasting associated with HIV. The goal of this study was to assess the effectiveness of a locally made Chickpea Sesame Based RUTF (CS-RUTF) in treating wasting associated with HIV in developing countries. Chronically sick adults from Mangochi Health District (Malawi) with wasting and confirmed or presumptive clinical diagnosis of HIV were recruited for the study. Subjects received a daily ration of 500 grams of CS-RUTF for 3 to 5 months. Nutrition status changes and mortality were used to assess the effectiveness of the intervention. There were 3 patterns of anthropometric responses continuous weight gain (WG), static weight (SW) and continuation weight loss (WL). The distribution of the 3 patterns is 53.9% (82/154) for the WG pattern, 9.1% (14/154) for the SW pattern and 37.0% (57/154) for the WL pattern. For the WG pattern, the overall median weight gain was 4.6 (2.4 to 7.1) kg. It was 5.7 (3.5 to 7.8) kg for those who completed 3 months of sup-plementation. MUAC and BMI changes followed similar pattern than weight change. Not being on HAART, acute diarrhoea during follow up, episode of reduced appetite during follow up, missing at least one visit were identified as risk factors for intervention failure. Overall, 38.5% (72/187) of study participants died during the intervention. In conclusion, despite that the study confirms the limited impact of food based interventions on mortality among wasted HIV positive individuals, it also suggests that supplementation with CS-RUTF may be an effective intervention for reversing wasting associated with HIV if combined with HAART and specific treatment of severe opportunistic infection causing diarrhoea and reducing appetite.

Recovery of Tungsten and Cobalt from Wasted Tungsten Carbide

The collected tungsten carbide/cobalt scrapped waste typically contains approximately 90% tungsten carbide and 10% cobalt.A nitric method is used to extract tungsten and cobalt from tungsten-containing waste.The waste is first dissolved in nitric acid,which then makes cobalt soluble and becomes cobalt nitrate solution.The waste also oxidizes tungsten carbide to insoluble tungstenic acid precipitate.If tungsten carbide scraps are obtained from leftover of LCD glass cutting,after applying the same process as above,the remaining glass also needs to be separated from the tungstenic acid.XRF analysis shows that 93.8% of cobalt and 97.72% of tungsten can be obtained separately by this wet chemical method.By ICP analysis,no more tungsten ion remains after 2 h reaction in the cobalt recovery when 12 N of nitric acid is used for oxidation.The recovery materials obtained for tungsten are tungsten oxide and for cobalt a mixture of Co3O4 and CoO.

Fluidized bed combustion of high water content alcohol extracted herb residue and the impacts of blending wasted activated coke

Combustion of herb residues(HRs)for heat recovery is a good way for their utilization,but there exists such a problem as high concentration NOx emission in flue gas.The alcohol extracted herb residue(AEHR),one special type of HRs,was chosen as the object and was subjected to immediate combustion in a fluidized bed reactor to investigate the characteristics of its resulting NOx emission.The results showed that,most of the NOx in the flue gas was produced from the char nitrogen(C-N);as the fuel water content increased,the NOx emission concentration exhibited a trend of first decreasing and then increasing;and a properly low combustion temperature inhibited the NOx emission upon the premise of ensuring full combustion.Air staging combustion was adopted to effectively control NOx:the NOx emission concentration in the flue gas was reduced to 296 mg⋅m􀀀3 and the NOx emission reduction rate reached 46.51%compared to conventional combustion.Co-combustion by blending wasted activated coke(WAC)into the AEHR helped both stabilize the combustion state and reduce further the NOx emission.When the blending ratio of WAC fell within a proper range of 20-30%,the NOx emission concentration in the flue gas was as low as 231.4 mg⋅m􀀀3.In addition to the dilution effect of the combustion flue gas of the blended WAC,the local reducing atmosphere caused by its incomplete combustion as well as its strong absorbability and catalytical effect was accountable for the further decrease of the NOx emission concentration.

The Effects of Different Feeding Practices on the Nutritional Status of Infants below 12 Months Old in the Kumba 1 Sub-Division

Appropriate feeding practices are important during infancy for good health, growth and development of infants and children. WHO revised its earlier recommendation of Exclusive Breastfeeding (EBF) of infants from 4 to 6 months of age to EBF until about 6 months of age, with the addition of complementary foods thereafter. This recommendation confirms that breast milk alone is sufficient to meet infants’ nutritional requirements for the first 6 months of life. The main objective of this study was to investigate the effect of various feeding practices on the Nutritional status of infants 0 - 12-month-old in the Kumba 1 Sub-Division. A descriptive cross-sectional study was conducted from December 2019 to August 2020. A total of 341 nursing mothers and their infants 0 - 12 months of age were recruited. Socio-demographic factors and the different feeding habits of the children were assessed using a semi-structured questionnaire. Nutritional status was assessed using anthropometric measurements. The overall proportion of infants who exclusively breastfed for 6 months was 69.2% and those who were mix-fed were 30.8% in the study area. The overall prevalence of malnutrition in the population was 61.0%. Among the malnourished children, 53.1% were underweight, 19.6% were wasted and 10.0% were stunted. Though not significant, the prevalence of wasting (21.0%) and underweight (58.3%) was higher among Mix-Fed (MF) children when compared to their EBF counterparts. Feeding practices affected the nutritional status of the infants. Underweight and wasting were observed among infants on Complementary Feeding (CF), although some exclusively breast-fed infants were stunted. Hence, nursing mothers should try as much as possible to practice EBF as recommended by WHO and can practice CF when the child is above six months.

An Overview of the Resources and Environmental Issues from Wasted Food in Urban Catering across China

There is growing global concern over food waste and its impacts on resources, environmental issues and food security, especially in developing countries. However, knowledge of food waste, in particular, the food wasted by consumers in restaurants, is entirely inadequate in China. Here, based on media reports and documents about food waste we provide an overview of food wasted by consumers in restaurants in China. We roughly estimated total food waste in order to uncover the seriousness of this large issue. We collected international literature referring to food waste and provided a detailed explanation of the resources and environmental costs associated with food waste. Ultimately we propose a conceptual diagram on research into catering food waste by consumers to evaluate resources and environmental costs based on life cycle assessment in China. This work will stimulate interdisciplinary research in this field.

Particle agglomeration and inhibition method in the fluidized pyrolysis reaction of waste resin

This work investigated the pyrolysis reaction of waste resin in a fluidized bed reactor.It was found that the pyrolysis-generated ash would adhere to the surface of ceramic particles,causing particle agglomeration and defluidization.Adding kaolin could effectively inhibit the particle agglomeration during the fluidized pyrolysis reaction through physical isolation and chemical reaction.On the one hand,kaolin could form a coating layer on the surface of ceramic particles to prevent the adhesion of organic ash generated by the pyrolysis of resin.On the other hand,when a sufficient amount of kaolin(-0.2%(mass))was added,the activated kaolin could fully contact with the Na+ ions generated by the pyrolysis of resin and react to form a high-melting aluminosilicate mineral(nepheline),which could reduce the formation of low-melting-point sodium sulfate and thereby avoid the agglomeration of ceramic particles.

Volumetric lattice Boltzmann method for pore-scale mass diffusionadvection process in geopolymer porous structures

Porous materials present significant advantages for absorbing radioactive isotopes in nuclear waste streams.To improve absorption efficiency in nuclear waste treatment,a thorough understanding of the diffusion-advection process within porous structures is essential for material design.In this study,we present advancements in the volumetric lattice Boltzmann method(VLBM)for modeling and simulating pore-scale diffusion-advection of radioactive isotopes within geopolymer porous structures.These structures are created using the phase field method(PFM)to precisely control pore architectures.In our VLBM approach,we introduce a concentration field of an isotope seamlessly coupled with the velocity field and solve it by the time evolution of its particle population function.To address the computational intensity inherent in the coupled lattice Boltzmann equations for velocity and concentration fields,we implement graphics processing unit(GPU)parallelization.Validation of the developed model involves examining the flow and diffusion fields in porous structures.Remarkably,good agreement is observed for both the velocity field from VLBM and multiphysics object-oriented simulation environment(MOOSE),and the concentration field from VLBM and the finite difference method(FDM).Furthermore,we investigate the effects of background flow,species diffusivity,and porosity on the diffusion-advection behavior by varying the background flow velocity,diffusion coefficient,and pore volume fraction,respectively.Notably,all three parameters exert an influence on the diffusion-advection process.Increased background flow and diffusivity markedly accelerate the process due to increased advection intensity and enhanced diffusion capability,respectively.Conversely,increasing the porosity has a less significant effect,causing a slight slowdown of the diffusion-advection process due to the expanded pore volume.This comprehensive parametric study provides valuable insights into the kinetics of isotope uptake in porous structures,facilitating the development of porous materials for nuclear waste treatment applications.

Continuous Preparation of Chitosan‑Based Self‑Powered Sensing Fibers Recycled from Wasted Materials for Smart Home Applications

Currently,the gradual depletion of fossil resources and the large amount of plastic waste are causing serious harm to the land and marine ecology.The rapid development of wearable smart fibers is accompanied by rapid growth in the material demand for fibers,and the development of green and high-performance biomass-based fibers has become an important research topic to reduce the dependence on synthetic fiber materials and the harm to the environment.Here,chitosan is first prepared from the waste material by chemical methods.Then the chitosan-based self-powered induction fibers are prepared by electrospinning core wire technique.Chitosan-based self-powered sensing fiber is ultra-light and flexible,which can achieve about 2500 collisions without damaging the surface.Chitosan-based self-powered sensing fiber can also be used in smart home sensing applications to control home appliance switches with a light touch,which has a great application prospect in smart home and wearable fields.

New Insights into Microplastic Contamination in Different Types of Leachates: Abundances, Characteristics, and Potential Sources

Municipal solid waste(MSW)is an important destination for abandoned plastics.During the waste disposal process,large plastic debris is broken down into microplastics(MPs)and released into the leachate.However,current research only focuses on landfill leachates,and the occurrence of MPs in other leachates has not been studied.Therefore,herein,the abundance and characteristics of MPs in three types of leachates,namely,landfill leachate,residual waste leachate,and household food waste leachate,were studied,all leachates were collected from the largest waste disposal center in China.The results showed that the average MP abundances in the different types of leachates ranged from(129±54)to(1288±184)MP particles per liter(particlesL1)and the household food waste leachate exhibited the highest MP abundance(p<0.05).Polyethylene(PE)and fragments were the dominant polymer type and shape in MPs,respectively.The characteristic polymer types of MPs in individual leachates were different.Furthermore,the conditional fragmentation model indicated that the landfilling process considerably affected the size distribution of MPs in leachates,leading to a higher percentage(>80%)of small MPs(20–100 lm)in landfill leachates compared to other leachates.To the best of our knowledge,this is the first study discussing the sources of MPs in different leachates,which is important for MP pollution control during MSW disposal.

Bearing capacity of circular footings on multi-layered sand-waste tire shreds reinforced with geogrids

The presence of waste tires poses an environmental challenge as they occupy a significant amount of land and are expensive to dispose in landfills.However,reusing waste tires can address this issue when waste tires are used in geotechnical applications.To determine the viability of this approach,laboratoryscale tests were conducted to investigate load-bearing capacity of circular footings on sand-tire shred(STS)mixtures with shredded waste tire contents of 5%e15%by weight and three different widths of shreds.The investigation focused on analyzing the thickness of layers composed of STS mixtures,the soil cap,and the impact of geogrids on bearing capacity.The results indicate that a specific mixture of sand and tire shreds provides the highest footing-bearing capacity.In addition,the optimal shred content and size were found to be 10%by weight and 2 cm×10 cm,respectively.Furthermore,for a given tire shred width,a particular length provides the largest bearing capacity.The results agree well with that of previous research conducted by the first author and his colleagues in direct shear and California bearing ratio(CBR)tests.The primary finding of this research is that the use of two-layered STS mixtures reinforced by geogrids significantly enhances the bearing capacity.

Facile molybdenum and aluminum recovery from spent hydrogenation catalyst

Industrial catalyst waste has emerged as a hazardous pollutant that requires safe and proper disposal after the unloading process.Finding a valuable and sustainable strategy for its treatment is a significant challenge compared to traditional methods.In this study,we present a facile method for the recovery of molybdenum and aluminum contents from spent Mo-Ni/Al_(2)O_(3) hydrogenation catalysts through crystallization separation and coprecipitation.Furthermore,the recovered molybdenum and aluminum are utilized as active metals and carriers for the preparation of new catalysts.Their properties were thoroughly analyzed and investigated using various characterization techniques.The hydrogenation activity of these newly prepared catalysts was evaluated on a fixed-bed small-scale device and compared with a reference catalyst synthesized from commercial raw reagents.Finally,the hydrogenation activity of the catalysts was further assessed by using the entire distillate oil of coal liquefaction as the raw oil,specifically focusing on denitrogenation and aromatic saturation.This work not only offers an effective solution for recycling catalysts but also promotes sustainable development.

Copper slag assisted coke reduction of phosphogypsum for sulphur dioxide preparation

The reduction of phosphogypsum(PG)to lime slag and SO_(2)using coke can effectively alleviate the environmental problems caused by PG.However,the PG decomposition temperature remains high and the product yield remains poor.By adding additives,the decomposition temperature can be further reduced and PG decomposition rate and product yield can be improved.However,the use of current additives such as Fe_(2)O_(3)and SiO_(2)brings the problem of increasing economic cost.Therefore,it is proposed to use solid waste copper slag(CS)as a new additive to reduce PG to prepare SO2,which can reduce the cost and meet the environmental benefits at the same time.The effects of proportion,temperature and thermostatic time on PG decomposition are investigated by experimental and kinetic analysis combined with FactSage thermodynamic calculations to optimize the roasting conditions.Finally,the reaction mechanism is proposed.It is found that adding CS to the coke and PG system can increase the rate of PG decomposition and SO_(2)yield while lowering the PG decomposition temperature.For example,when the CS/PG mass ratio increases from 0 to 1,PG decomposition rate increases from 83.38%to 99.35%,SO_(2)yield increases from 78.62%to 96.81%,and PG decomposition temperature decreases from 992.4℃to 949.6℃.The optimal reaction parameters are CS/PG mass ratio of 1,Coke/PG mass ratio of 0.06 at 1100℃for 20 min with 99.35%PG decomposition rate and 96.81%SO_(2) yield.The process proceeds according to the following reactions:2CaSO_(4)+ 0.7C + 0.8Fe_(2)SiO_(4)→0.8Ca_(2)SiO_(4)+ 0.2Ca_(2)Fe_(2)O_(5)+ 0.4Fe_(3)O_(4)+2SO_(2)+ 0.7CO_(2)Finally,a process for decomposing PG with coke and CS is proposed.

Study on synergistic leaching of potassium and phosphorus from potassium feldspar and solid waste phosphogypsum via coupling reactions

To achieve the resource utilization of solid waste phosphogypsum(PG)and tackle the problem of utilizing potassium feldspar(PF),a coupled synergistic process between PG and PF is proposed in this paper.The study investigates the features of P and F in PG,and explores the decomposition of PF using hydrofluoric acid(HF)in the sulfuric acid system for K leaching and leaching of P and F in PG.The impact factors such as sulfuric acid concentration,reaction temperature,reaction time,material ratio(PG/PF),liquid–solid ratio,PF particle size,and PF calcination temperature on the leaching of P and K is systematically investigated in this paper.The results show that under optimal conditions,the leaching rate of K and P reach more than 93%and 96%,respectively.Kinetics study using shrinking core model(SCM)indicates two significant stages with internal diffusion predominantly controlling the leaching of K.The apparent activation energies of these two stages are 11.92 kJ·mol^(-1)and 11.55 kJ·mol^(-1),respectively.