scholarly journals Modeling of a Plasma-Based Waste Gasification System for Solid Waste Generated Onboard of Typical Cruiser Vessels Used as a Feedstock

Designs ◽  
2020 ◽  
Vol 4 (3) ◽  
pp. 33
Author(s):  
Hossam A. Gabbar ◽  
Davide Lisi ◽  
Mohamed Aboughaly ◽  
Vahid Damideh ◽  
Isaac Hassen
Keyword(s):  
Sewage Sludge ◽  
Process Model ◽  
Electrical Power ◽  
System Model ◽  
Treatment Unit ◽  
Cold Gas Efficiency ◽  
Pre Treatment ◽  
Waste Gasification ◽  
Syngas Cleaning ◽  
Gas Efficiency

In this paper, a model for a single stage plasma gasification system for marine vessels characterized by significant waste production is proposed. The main objective of the model is to investigate the effects of different feedstock compositions on key parameters, such as electrical power produced and heat recovered. The different types of waste generated onboard are described along with their environmental impacts. Specific attention is given to solid wastes, sewage sludge and plastic wastes as potential feedstock. Their average generation, proximate and ultimate analysis are defined, as input to the process model. The process assumptions used in the simulation model are illustrated. The system model is divided into five units: the pre-treatment unit; the gasification unit; the syngas cleaning unit; the energy conversion unit; and the heat recovery unit. Four operational scenarios are investigated to consider several variations of composition of the main feedstock. From the results of the simulations, the system model shows good feedstock flexibility, and the possibility of operating in net electricity gain conditions. The cold gas efficiency of the process is also assessed and its maximum value is obtained for the highest concentrations of sewage sludge (33.3%) and plastic (16.7%). Other parameters investigated are the combustion temperature, sorbent consumption in the cleaning process, feedstock and syngas lower heating value LHV.

Co-gasification of High-ash Sewage Sludge and Straw in a Bubbling Fluidized Bed with Oxygen-enriched Air

2018 ◽  
Vol 16 (5) ◽  
Author(s):  
Miaomiao Niu ◽  
Baosheng Jin ◽  
Yaji Huang ◽  
Hongyan Wang ◽  
Qing Dong ◽  
...  
Keyword(s):  
Sewage Sludge ◽  
Fluidized Bed ◽  
High Alumina ◽  
Cold Gas Efficiency ◽  
Bubbling Fluidized Bed ◽  
Polycyclic Aromatic ◽  
Gasification Efficiency ◽  
Waste Gasification ◽  
Gas Efficiency ◽  
Bed Material

Abstract Gasification is a promising technology to utilize solid wastes. Co-gasification of high-ash sewage sludge and straw were studied in a fluidized bed using oxygen-enriched air. Several factors influencing co-gasification performance were investigated, including the blending ratio of straw (BR, 0–100 %), the oxygen percentage of enriched air (OP, 30.2–50 %) and the bed material type (high alumina bauxite, calcined dolomite and olivine). The results indicated that the proper increase in BR led to higher syngas yield and an increase in OP caused an increase in combustible gas components, both showing improvements for waste gasification. Correspondingly, the maximum cold gas efficiency was obtained at BR of 50 % and OP of 44.7 %, respectively. Additionally, calcined dolomite exhibited the maximum advantage in the reduction of heavy polycyclic aromatic hydrocarbons (PAHs), promoting the production of H2 and CO. The addition of high alumina bauxite was favored for improving syngas yield and gasification efficiency.

The Optimization of Thermal Pre-Treatment Time for Extracellular Polymeric Substances Extraction from Sewage Sludge

2015 ◽  
Vol 768 ◽  
pp. 496-505 ◽  
Author(s):  
Yu Yi Zheng ◽  
Hong Lin ◽  
Zhi Long Lin ◽  
Yi Fang Zeng ◽  
Yu Fang Yu ◽  
...  
Keyword(s):  
Experimental Data ◽  
Sewage Sludge ◽  
Process Model ◽  
Extracellular Polymeric Substances ◽  
Treatment Time ◽  
Soluble Sugar ◽  
Analytic Hierarchy ◽  
Pre Treatment ◽  
Hierarchy Process ◽  
Optimum Extraction

This study aims to find out the optimum extraction time varied from 5 min to 60 min for extracellular polymeric substances (EPS) from sewage sludge pretreated at 80 °C. The change of the contents of EPS and its components under different time limit were recorded and compared. The results showed: the contents of soluble protein, TOC, soluble sugar and DNA was increased by 579.17 mg/l, 514.25 mg/l, 132.79 mg/l, and 34.69 mg/l, respectively, with the increase of thermal pre-treatment time during the process, and the DNA content increased the least, which indicating that the effect of thermal pre-treatment at 80 °C on cell lysis of sewage sludge was small. The EPS content, as a whole, was increased with the increase of thermal pre-treatment time. By analyzing the experimental data with the Analytic Hierarchy Process Model, which was used to identify the optimum thermal pre-treatment time of extracting EPS, the results showed that the effectiveness of EPS extraction from sludges was 30 min>60 min>50 min>20 min>40 min>10 min>5 min. Therefore, the 30 min was choosed as the optimum thermal pre-treatment time.

The Effect of Biomass Contents with Heavy Metal on Gasification Efficiency during Fluidized Bed Gasification Process

2012 ◽  
Vol 512-515 ◽  
pp. 575-578
Author(s):  
Hsien Chen ◽  
Chiou Liang Lin ◽  
Wun Yue Zeng ◽  
Zi Bin Xu
Keyword(s):  
H2 Production ◽  
Heating Value ◽  
Gasification Process ◽  
Cold Gas Efficiency ◽  
Zn Concentration ◽  
Lower Heating Value ◽  
Gasification Efficiency ◽  
Waste Gasification ◽  
Gas Efficiency ◽  
Cu And Zn

Catalysis was used to increase the H2 production, syngas heating value, enhanced carbon conversion efficiency and cold gas efficiency during gasification. Due to Cu and Zn were abundant in waste according to previous researches, this research discussed the effect of Cu and Zn on artificial waste gasification. The syngas composition and total lower heating value (LHV) were determined in this study. The results showed that the existence of Cu and Zn increased production of H2 and CO. However, the production of CH4 and CO2 decreased. At same time, total LHV was also increased. Additionally, the different Cu concentration affected gas composition and LHV, but the effect of Zn concentration was not significant.

scholarly journals Effect of Gasification Temperature on Synthesis Gas Production and Gasification Performance for Raw and Torrefied Palm Mesocarp Fibre

2020 ◽  
Vol 19 (2) ◽  
pp. 138
Author(s):  
Najwa Hayati Abdul Halim ◽  
Suriyati Saleh ◽  
Noor Asma Fazli Abdul Samad
Keyword(s):  
Synthesis Gas ◽  
Gas Production ◽  
Energy Applications ◽  
Gasification Process ◽  
Cold Gas Efficiency ◽  
Bubbling Fluidized Bed ◽  
Pre Treatment ◽  
Gas Efficiency ◽  
Solid Biomass ◽  
Gasification Temperature

Biomass gasification is widely used for converting solid biomass into synthesis gas for energy applications. Raw biomass is commonly used as feedstock for the gasification process but it usually contains high moisture content and low energy value which lowering synthesis gas production. Thus, torrefaction as a pre-treatment process is necessary in order to upgrade the properties of feedstock for producing more synthesis gas production and improving gasification performance. The objective of this work is to study the effect of gasification temperature on the synthesis gas production and gasification performance using raw and torrefied palm mesocarp fibre (PMF). The gasification process is conducted using bubbling fluidized bed using steam as gasifying agent. Based on experimental work, by increasing gasification temperature from 650 – 900 °C, the compositions of hydrogen and carbon monoxide gases were enhanced greatly while carbon dioxide and methane gases were decreased for both raw and torrefied PMF. In terms of gasification performance, synthesis gas yield for raw and torrefied PMF is increased from 0.91 to 1.23 Nm3/kg and 1.10 to 1.35 Nm3/kg respectively. Besides, lower heating value (LHV) of torrefied PMF is 0.04 MJ/Nm3 higher than raw PMF at 900 °C. The result showed that the percentage of cold gas efficiency (CGE) reached maximum of 67% for raw PMF while carbon conversion (CC) at 85.6% for torrefied PMF at a gasification temperature of 900 °C. The higher CC obtained by torrefied PMF is because of the increment of carbon content from 45.2% to 53.7% as a result of torrefaction. Gasification temperature of 800 °C showed the best performance of the PMF gasification since the maximum performances of LHV is achieved and started to decrease once the gasification temperature is operated beyond 800 °C.

scholarly journals Studies on the Gasification Performance of Sludge Cake Pre-Treated by Hydrothermal Carbonization

Energies ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1442 ◽  
Author(s):  
Sang Yeop Lee ◽  
Se Won Park ◽  
Md Tanvir Alam ◽  
Yean Ouk Jeong ◽  
Yong-Chil Seo ◽  
...  
Keyword(s):  
Sewage Sludge ◽  
Moisture Content ◽  
Energy Recovery ◽  
Calorific Value ◽  
Hydrothermal Carbonization ◽  
Treatment Technique ◽  
Gasification Process ◽  
Cold Gas Efficiency ◽  
Sludge Cake ◽  
Gas Efficiency

Proper treatment and careful management of sewage sludge are essential because its disposal can lead to adverse environmental impacts such as public health hazards, as well as air, soil, and water pollution. Several efforts are being made currently not only to safely dispose of sewage sludge but also to utilize it as an energy source. Therefore, in this study, initiatives were taken to valorize sewage sludge cake by reducing the moisture content and increasing the calorific value by applying a hydrothermal treatment technique for efficient energy recovery. The sludge cake treated at 200 °C for 1 h was found to be the optimum condition for hydrothermal carbonization, as, in this condition, the caloric value of the treated sludge increased by 10% and the moisture content removed was 20 wt.%. To recover energy from the hydrothermally treated sludge, a gasification technology was applied at 900 °C. The results showed that the product gas from hydrothermally treated sludge cake had a higher lower heating value (0.98 MJ/Nm3) and higher cold gas efficiency (5.8%). Furthermore, compared with raw sludge cake, less tar was generated during the gasification of hydrothermally treated sludge cake. The removal efficiency was 28.2%. Overall results depict that hydrothermally treated sewage sludge cake could be a good source of energy recovery via the gasification process.

Pilot Plant Study of an Upgraded Rotating Biological Contactor

1993 ◽  
Vol 28 (10) ◽  
pp. 361-368 ◽  
Author(s):  
Y. Watanabe ◽  
Y. Iwasaki ◽  
S. Masuda
Keyword(s):  
Pilot Plant ◽  
Municipal Wastewater ◽  
Electrical Power ◽  
Experimental Results ◽  
Municipal Wastewater Treatment ◽  
Combined System ◽  
Rotating Biological Contactor ◽  
Treatment Unit ◽  
Rotating Speed ◽  
Pre Treatment

This paper deals with the experimental results obtained by the pilot plant of an upgraded Rotating Biological Contactor(RBC). This is a two-story RBC which is designed to simultaneously achieve the biological oxidation and removal of detached biomass in the trough. The authors constructed a three-stage pilot plant with an octagonal stainless mesh contactor 2 m across to collect the design information of an upgraded RBC. The municipal wastewater treatment was conducted to examine the RBC's performance. According to experimental results, with a contactor rotating speed of 2 rpm.the effluent TOC and NH4−N concentrations were about 10 g/m3 and 5 g/m3, respectively, at the hydraulic loading of 70 l/m2/d, corresponding to a BOD loading of about 8 g/m2/d. The electrical power consumption of the RBC was 0.005 kWh/m2/d at a contactor rotating speed of 1 rpm. A jet mixed separator(JMS) was used as the physico-chemical pre-treatment unit of the RBC. With the addition of a coagulant,simultaneous flocculation and sedimentation of the suspended particles occurred in the JMS. This combined system of the JMS and RBC produced a clean effluent.

scholarly journals An Experimental Investigation of Sewage Sludge Gasification in a Fluidized Bed Reactor

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
L. F. Calvo ◽  
A. I. García ◽  
M. Otero
Keyword(s):  
Sewage Sludge ◽  
Fluidized Bed ◽  
Heating Value ◽  
Fuel Feed ◽  
Hot Gas ◽  
Cold Gas Efficiency ◽  
Fuel Characterization ◽  
Fluidized Bed Gasifier ◽  
Gasification Efficiency ◽  
Gas Efficiency

The gasification of sewage sludge was carried out in a simple atmospheric fluidized bed gasifier. Flow and fuel feed rate were adjusted for experimentally obtaining an air mass : fuel mass ratio (A/F) of0.2<A/F<0.4. Fuel characterization, mass and power balances, produced gas composition, gas phase alkali and ammonia, tar concentration, agglomeration tendencies, and gas efficiencies were assessed. Although accumulation of material inside the reactor was a main problem, this was avoided by removing and adding bed media along gasification. This allowed improving the process heat transfer and, therefore, gasification efficiency. The heating value of the produced gas was 8.4 MJ/Nm, attaining a hot gas efficiency of 70% and a cold gas efficiency of 57%.

scholarly journals Membrane condenser as emerging technology for water recovery and gas pre-treatment: current status and perspectives

2019 ◽  
Vol 1 (1) ◽  
Author(s):  
Adele Brunetti ◽  
Francesca Macedonio ◽  
Giuseppe Barbieri ◽  
Enrico Drioli
Keyword(s):  
Current Status ◽  
Innovative Technology ◽  
Water Recovery ◽  
Treatment Unit ◽  
Treatment Stage ◽  
Treatment Technologies ◽  
Pre Treatment ◽  
And Control

Abstract The recent roadmap of SPIRE initiative includes the development of “new separation, extraction and pre-treatment technologies” as one of the “key actions” for boosting sustainability, enhancing the availability and quality of existing resources. Membrane condenser is an innovative technology that was recently investigated for the recovery of water vapor for waste gaseous streams, such as flue gas, biogas, cooling tower plumes, etc. Recently, it has been also proposed as pre-treatment unit for the reduction and control of contaminants in waste gaseous streams (SOx and NOx, VOCs, H2S, NH3, siloxanes, halides, particulates, organic pollutants). This perspective article reports recent progresses in the applications of the membrane condenser in the treatment of various gaseous streams for water recovery and contaminant control. After an overview of the operating principle, the membranes used, and the main results achieved, the work also proposes the role of this technology as pre-treatment stage to other separation technologies. The potentialities of the technology are also discussed aspiring to pave the way towards the development of an innovative technology where membrane condenser can cover a key role in redesigning the whole upgrading process.

scholarly journals Control of Heat Pumps with CO2 Emission Intensity Forecasts

Energies ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2851 ◽  
Author(s):  
Kenneth Leerbeck ◽  
Peder Bacher ◽  
Rune Grønborg Junker ◽  
Anna Tveit ◽  
Olivier Corradi ◽  
...  
Keyword(s):  
Process Model ◽  
Electrical Power ◽  
Heating System ◽  
Heat Pumps ◽  
Thermal Capacity ◽  
Building Codes ◽  
Thermal Mass ◽  
Thermostatic Control ◽  
Co2 Emission Intensity ◽  
Floor Heating

An optimized heat pump control for building heating was developed for minimizing CO 2 emissions from related electrical power generation. The control is using weather and CO 2 emission forecasts as inputs to a Model Predictive Control (MPC)—a multivariate control algorithm using a dynamic process model, constraints and a cost function to be minimized. In a simulation study, the control was applied using weather and power grid conditions during a full-year period in 2017–2018 for the power bidding zone DK2 (East, Denmark). Two scenarios were studied; one with a family house and one with an office building. The buildings were dimensioned based on standards and building codes/regulations. The main results are measured as the CO 2 emission savings relative to a classical thermostatic control. Note that this only measures the gain achieved using the MPC control, that is, the energy flexibility, not the absolute savings. The results show that around 16% of savings could have been achieved during the period in well-insulated new buildings with floor heating. Further, a sensitivity analysis was carried out to evaluate the effect of various building properties, for example, level of insulation and thermal capacity. Danish building codes from 1977 and forward were used as benchmarks for insulation levels. It was shown that both insulation and thermal mass influence the achievable flexibility savings, especially for floor heating. Buildings that comply with building codes later than 1979 could provide flexibility emission savings of around 10%, while buildings that comply with earlier codes provided savings in the range of 0–5% depending on the heating system and thermal mass.

scholarly journals Improvement of Biogas Quality and Quantity for Small-Scale Biogas-Electricity Generation Application in off-Grid Settings: A Field-Based Study

Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3088
Author(s):  
Henry Wasajja ◽  
Saqr A. A. Al-Muraisy ◽  
Antonella L. Piaggio ◽  
Pamela Ceron-Chafla ◽  
Purushothaman Vellayani Aravind ◽  
...  
Keyword(s):  
Electricity Generation ◽  
Relevant Literature ◽  
Electrical Power ◽  
Process Efficiency ◽  
Electricity Production ◽  
Small Scale ◽  
Buffer System ◽  
Biogas Plants ◽  
Operational Practices ◽  
Pre Treatment

Small-scale electrical power generation (<100 kW) from biogas plants to provide off-grid electricity is of growing interest. Currently, gas engines are used to meet this demand. Alternatively, more efficient small-scale solid oxide fuel cells (SOFCs) can be used to enhance electricity generation from small-scale biogas plants. Most electricity generators require a constant gas supply and high gas quality in terms of absence of impurities like H2S. Therefore, to efficiently use the biogas from existing decentralized anaerobic digesters for electricity production, higher quality and stable biogas flow must be guaranteed. The installation of a biogas upgrading and buffer system could be considered; however, the cost implication could be high at a small scale as compared to locally available alternatives such as co-digestion and improved digester operation. Therefore, this study initially describes relevant literature related to feedstock pre-treatment, co-digestion and user operational practices of small-scale digesters, which theoretically could lead to major improvements of anaerobic digestion process efficiency. The theoretical preamble is then coupled to the results of a field study, which demonstrated that many locally available resources and user practices constitute frugal innovations with potential to improve biogas quality and digester performance in off-grid settings.

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