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.

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%.

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 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.

Simulation of Enriched Air-Steam Biomass Gasification in a Bubbling Fluidized Bed Gasifier

2014 ◽  
Vol 699 ◽  
pp. 510-515
Author(s):  
Miao Miao Niu ◽  
Ya Ji Huang ◽  
Bao Sheng Jin
Keyword(s):  
Fluidized Bed ◽  
Steam Injection ◽  
Biomass Gasification ◽  
Carbon Conversion ◽  
Gasification Process ◽  
Cold Gas Efficiency ◽  
Oxygen Percentage ◽  
Bubbling Fluidized Bed ◽  
Gas Efficiency ◽  
Cold Gas

A model was developed for the enriched air-steam biomass gasification in a bubbling fluidized bed (BFB) gasifier using Aspen Plus. Restricted equilibrium method was used to eliminate the deviation caused by the diffusion effect of gas-particle. The model has been divided into three stages (drying and pyrolysis, partial combustion and gasification) for predicting the gasifier performance. Simulation results for gas composition, carbon conversion and cold gas efficiency versus oxygen percentage and steam to biomass ratio (S/B) were compared with the experimental results. Higher oxygen percentage improves the gasification process, increases the production of H2 and CO and results in better gasification efficiency. With increasing oxygen percentage, the production of CO2 and CH4 show decreasing trends. Steam injection enhances the H2 and CO2 production but decreases CO and CH4 production. Carbon conversion presents a slight decrease trend over the S/B range, while cold gas efficiency is first constant and then decreased.

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 Experimental Investigation of Radial Gas Dispersion Coefficients in a Fluidized Bed

10.14311/1568 ◽  
2012 ◽  
Vol 52 (3) ◽  
Author(s):  
Jiří Štefanica ◽  
Jan Hrdlička
Keyword(s):  
Fluidized Bed ◽  
Formation Rate ◽  
Combustion Efficiency ◽  
Tracer Gas ◽  
Cold Model ◽  
Nox Formation ◽  
Gas Dispersion ◽  
Bed Height ◽  
Bubbling Fluidized Bed ◽  
Bed Material

In a fluidized bed boiler, the combustion efficiency, the NOX formation rate, flue gas desulphurization and fluidized bed heat transfer are all ruled by the gas distribution. In this investigation, the tracer gas method is used for evaluating the radial gas dispersion coefficient. CO2 is used as a tracer gas, and the experiment is carried out in a bubbling fluidized bed cold model. Ceramic balls are used as the bed material. The effect of gas velocity, radial position and bed height is investigated.

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