2 nd International Conference on Sustainable Energy and Resource Use in Food Chains Low temperature gasification of poultry litter in a lab-scale fluidized bed reactor Giannis Katsaros, Daya Shankar Pandey, Alen Horvat, Savvas Tassou Brunel University London Paphos, Cyprus, 17.10.2018 RCUK Centre for Sustainable Energy Use in Food Chains
2 nd International Conference on Sustainable Energy and Resource Use in Food Chains Background Meat production increases continuously throughout the years reaching annual global production of 315 million tons in 2015. Among the different meat segments poultry is expected to have the highest development. In UK , 32 % increase of slaughtered poultry between 1995-2015. Key drivers for the growth of poultry production Shorter production cycles, cheaper prices and better nutritional image. RCUK Centre for Sustainable Energy Use in Food Chains 2
2 nd International Conference on Sustainable Energy and Resource Use in Food Chains Background In 2014, 1.4 billion tons of manure were generated in EU member states. Intensive livestock farming, causes large accumulation of waste in concentrated areas. Manure land applications as an organic fertiliser is the first management option if possible. Over application of manure leads to excessive fertilization of agricultural land. Associated problems are eutrophication, nitrate leaching, crop toxicity, odours and emissions of greenhouse gases. What are the alternatives?? RCUK Centre for Sustainable Energy Use in Food Chains 3
2 nd International Conference on Sustainable Energy and Resource Use in Food Chains Path 1: Biological On-farm combustion treatment Solids Liquids Path 2: Gasification Anaerobic Solid/Liquid Heat & power digester separation generation Path 3: Re-burning Path 4: Co-firing Effluent Path 5: Combustion Phosphorus Liquids Liquids for Solids removal pond irrigation Raw manure, urine, bedding etc. IGCC Drying Gasification systems Ash Re-burning coal Heat & power Grinding with biomass generation Co-firing coal Fertilizer and biomass RCUK Centre for Sustainable Energy Use in Food Chains 4
2 nd International Conference on Sustainable Energy and Resource Use in Food Chains Gasification technology Gasification is a thermochemical process during which a carbon based feedstock is dissociated in a high temperature environment and is converted into a combustible gas by the supply of a gasification agent in a reduced environment. 𝐵𝑗𝑠 𝑔𝑚𝑝𝑥 𝑠𝑏𝑢𝑓 ൗ 𝐶𝑗𝑝𝑛𝑏𝑡𝑡 𝑔𝑚𝑝𝑥 𝑠𝑏𝑢𝑓 𝑏𝑑𝑢𝑣𝑏𝑚 𝐹𝑆 = 𝐵𝑗𝑠 𝑔𝑚𝑝𝑥 𝑠𝑏𝑢𝑓 ൗ 𝐶𝑗𝑝𝑛𝑏𝑡𝑡 𝑔𝑚𝑝𝑥 𝑠𝑏𝑢𝑓 𝑡𝑢𝑝𝑗𝑑ℎ𝑗o𝑛𝑓𝑢𝑠𝑗𝑑 Pyrolysis Gasification Combustion ER=0 ER=0.1-0.4 ER>1 Increase of oxygen content RCUK Centre for Sustainable Energy Use in Food Chains 5
2 nd International Conference on Sustainable Energy and Resource Use in Food Chains Different applications of gasification RCUK Centre for Sustainable Energy Use in Food Chains 6
2 nd International Conference on Sustainable Energy and Resource Use in Food Chains Challenges of gasification (TAR) Syngas contains different kind of impurities, such as tar, particles, sulphur compounds and alkali metals. Tar is a mixture of complex hydrocarbons which cause fouling and clogging of the equipment located downstream when temperature falls below tar dew point. Different tar concentration limits apply depending on the final application, e.g. in internal combustion engines the maximum limits are 50-100 mg total tar /Nm 3 . Presence of tar and the subsequent cleaning required increase the complexity and the total costs of the plant. RCUK Centre for Sustainable Energy Use in Food Chains 7
2 nd International Conference on Sustainable Energy and Resource Use in Food Chains Challenges of gasification (Agglomeration) Agglomeration is caused by melting of the inorganic components of the fuel. Bed agglomeration can result in de-fluidization and consequently complete shut down of the gasifier. Most well known inorganic compound that can cause agglomeration is Potassium (K) . When silica sand is applied as bedding material, it can potentially form a low melting potassium silicate. RCUK Centre for Sustainable Energy Use in Food Chains 8
2 nd International Conference on Sustainable Energy and Resource Use in Food Chains Challenges of gasification (Agglomeration) RCUK Centre for Sustainable Energy Use in Food Chains 9
2 nd International Conference on Sustainable Energy and Resource Use in Food Chains Characterisation of poultry litter Ultimate Analysis Proximate Analysis (%) wt. (%) – dry basis Component 9.71 Carbon 14.3 42.72 Hydrogen 5.51 Nitrogen 20.7 3.93 Sulphur 0.64 Chlorine 69.6 0.29 Oxygen 32.59 LHV (MJ/kg, dry) 16.78 Ash FC VM Moisture Ash composition (dry basis) Oxides Al Ca Fe Mg Na P K Si mg/kg 1200 15500 1600 8200 4200 10200 27700 7300 RCUK Centre for Sustainable Energy Use in Food Chains 10
2 nd International Conference on Sustainable Energy and Resource Use in Food Chains Experimental facility Operating conditions Feedstock: Poultry litter Silica sand used as a bed material Feeding rate 0.5 kg/h (as received basis) Air and nitrogen as fluidisation mediums Gasification set-point temperature 700°C Minimum fluidisation velocity 0.036 m/s Equivalence ratio 0.17/0.21/0.25 where, (1) biomass hopper (2) feeding screws (3) air preheater (4) gasifier reactor (5) cyclone (6) valve (7) hot filter (8) cold filter (9) flare RCUK Centre for Sustainable Energy Use in Food Chains 11
2 nd International Conference on Sustainable Energy and Resource Use in Food Chains Effect of ER on gas composition, gas yield, and LCV CO 2 , H 2 and CO increase with ER Both gas yield and LCV increase with ER while CH 4 and C 2 H 4 show a stable trend RCUK Centre for Sustainable Energy Use in Food Chains 12
ሶ ሶ 2 nd International Conference on Sustainable Energy and Resource Use in Food Chains Effect of ER on carbon conversion efficiency and cold gas efficiency 𝐷𝐷𝐹 = 𝐷 𝑒𝑠𝑧_𝑏𝑡 𝐷 𝑒𝑠𝑧_𝑗𝑜𝑞𝑣𝑢 𝐷𝐻𝐹 = 𝑀𝐷𝑊 ∗ 𝑛 𝑒𝑠𝑧_𝑏𝑡 𝑀𝐷𝑊 ∗ 𝑛 𝑒𝑠𝑧_𝑔𝑣𝑓𝑚 RCUK Centre for Sustainable Energy Use in Food Chains 13
2 nd International Conference on Sustainable Energy and Resource Use in Food Chains Effect of ER on tar evolution (a) (b) Styrene xylene, phenol and naphthalene Decline of total tar concentration the most abundant tar compounds as ER increases Tar dew point 100 ° C at ER 0.17 RCUK Centre for Sustainable Energy Use in Food Chains 14
2 nd International Conference on Sustainable Energy and Resource Use in Food Chains Mass balance of gasification test (ER 0.25) Product gas: 17 % Gasifier Gasifier Product gas : 72% Carbon Sulphur Cyclone fines: Bed : 8% Bed : 23% 48 % Cyclone fines: 2.4% Gasifier Product gas : 84% Hydrogen Nitrogen Product gas: Bed : 0.05% Gasifier 102 % Cyclone fines: 0.4% RCUK Centre for Sustainable Energy Use in Food Chains 15
2 nd International Conference on Sustainable Energy and Resource Use in Food Chains Conclusions No sign of agglomeration was detected at 700 ° C and all the experiments were conducted successfully. Gasification of poultry litter resulted in the production of low calorific value syngas. Carbon Conversion Efficiency increased with ER acquiring the highest value of 72% at ER 0.25 and T 700 ° C. Amount of total detectable tar was low, showing a decreasing trend with ER. However the impact of tar on the performance of downstream processes is mostly related to tar composition and concentration. Higher temperatures of gasification and the use of additives should be tested in order to investigate the operational feasibility and their impact on process performance parameters. RCUK Centre for Sustainable Energy Use in Food Chains 16
2 nd International Conference on Sustainable Energy and Resource Use in Food Chains Acknowledgements RCUK Centre for Sustainable Energy Use in Food Chains 17
2 nd International Conference on Sustainable Energy and Resource Use in Food Chains RCUK Centre for Sustainable Energy Use in Food Chains 18
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