Biogas Plant Design and Engineering for Food Waste/Animal Waste

Product Name: Biogas Plant Design and Engineering for Food Waste/Animal Waste Model NO.: ALONG BIOGAS Feedstock: Food Waste, Animal Manure, Organic Waste Biogas Production: 20000 Nm3/Day Fermentation Temp.: Thermophilic 52~55 Degree.C Biogas Utilization: CNG, Power Generation Commercial Profit: CNG for Gas Station, Electric Power to Mains Grid Power Generation: 2MW Jenbacher, Containerized Type Trademark: ALONG BIOGAS Transport Package: Wooden Case Specification: Complete System Origin: China HS Code: 8486909000 Product Description Hunan Along New Energy Technologies Co., Ltdcan provide a entire solution from waste to energy, scope of equipment supply covers waste pre-treatment, anaerobic fermentation, biogas cleaning, Combined Heat&Power Unit(CHP), Bio-natural Gas making system, biogas flare/boiler and all auxiliary materials, in conjunction with services of process design, equipment selection, installation and operation & maintenance support.ALONG BIOGAS is also professional in sewage treatment with non-production of biogas, with purpose of cleaning waste water for recycling of process water or being discharged environmental friendly.General Process Description for each stage of a complete BiogasProject1. Waste Materialand Pre-treatmentSingle or mixture of multiple substrates with high content of organic substance can be used for biogas production. Waste materials and by-products are accrued in conjunction with every single manufacturing operation,fromAnimal husbandrySlaughterhousesThe food-production industry and the food-processing industryAgriculture raw and residual waste, e.g. Strew,semi-rotten vegetable&fruitSupermarkets, e.g. spoiled food productsBreweries (malt spent grains)RestaurantsJuice productionThe ethanol industry (mash)The biofuel industry, e.g. glycerinePurification plants: Sewage sludgeThe animal feed industryFor feedstock in forms of solid or solid-liquid mixture, such as crop stalks, fruit and vegetable waste, food waste, etc., they should be shred to a fine dimension before fed into digester. Involving equipment such as shredders, crushers, beater, grinding system,dissolving devices etc. Kitchen garbageor community waste,due to itscomplex compositions,special manual or automatic sorting devices are needed.Separation process occupies a large proportion in the stage of pre-treatment of waste materials, to remove large particles of inorganic suspended solids, debris and the like contained in the waste water. The equipment used aregenerally like screw-squeezed,spiral centrifugal,rotary mechanical grille, inclinedsievingseparator.Grease-water separator or horizontal spiral centrifuge to be used for grease separation if waste contains oil.For waste materials with high consistence of fiber, long impuritiesand the like,cutting and grinding devices are requiredfor further processing. For example poultry droppings, which contains soft feathers, it's difficult for primary solid-liquid separation to removeit, a special cutting&grinding system is wantedto solvesuch problem.The feedstock should be cleaned,in order to ensure that it is harmless(from the point of view of hygiene) and it's free of pathogens,to avoid bad affection for microbiological process in digester.2. Anaerobic FermentationIn the heated and air-tight digester,the biomass ferments in conjunction with the production of methane,mixed with other by-product gas,it's so called biogas.The microbiological process in digester takes place in four stages,hydrolysis - acidification - acetic acid formation - methane formation.According to the characteristics of TS total solids, SS suspended solids, COD, BOD etc in the waste water,wewillchoose the bestsuitable anaerobic fermentation processamong the following types:-CSTR Reactor (Continuous Stirring Tank Reactor). The feedstock to be fed intodigester through bottom entrance. Digester is equipped with mechanical agitators, enableswaste materialsto be in full contact withmicro-organisms.The biogas slurry is automatically discharged and the residue is periodically pumped out of digester. Biogas generatedis collected in the gas holder at the top of the reactor or flowsinto the free-standing gas holderon the ground. Proper TS(total solid)content varies in the range6% to 12%, HRT(hydraulic retention time)varies from20to 30 daysdepending on the actual TS% and reactor temperature.-USR Reactor (Up-flowSolid Reactor). USRreactor isasimplestructure, suitable for sewage with highcontent ofsuspended solids. Waste is pumped into digester from bottom of reactor, and contact withactivated sludge during up-flowing, so that the biomassto be quickly fermented. Unprocessed biomass solid particles and microorganisms remainsinsidereactorby natural sedimentation, and the bio-liquidoverflows from the upper part of the digestor. Proper TS(total solid)content varies in the range3% to 5%, HRT(hydraulic retention time)is about 10~15days.-UASB Reactor (Up-flow Anaerobic Sludge Blanket). The feedstockenters digesterthrough the water distributor at the bottom of the reactor. Above the water-distributorthere is a high concentration, highly active sludge blanket, where most of the organic matter is dissolved and fermentedto methane and carbon dioxide. Due to the stirring of waterflowsand bubblesthat full of biogas, there is a floating sludge layer above the sludge blanket. Gas,Liquid and sludge particle Solids are separated automatically through a special three-phases mechanical separator. Biogasflows intothe gas storage chamber, sludge particles automatically fall to the sludge blanket, slurry gets out of reactor at clarification chamber. Proper TS(total solid)content is about 1%, HRT(hydraulic retention time)is about 5 days.-EGSB Reactor (Expanded Granular Sludge Blanket). EGSB is the third generation of anaerobic reactors developed on the basis of UASB. Unlike UASB, EGSB has a dedicated sewage recovery device. The expanded Blanketof granular sludge improves contactingbetween organic matter and microorganisms in the fluid, enhances the mass transfer effect and improves the biochemical reaction rate of the reactor, thereby greatly improving the efficiency of the reactor treatment. EGSB reactor is always incylindrical column shapewitha highheight/diameter ratio, generally up to 3~5,can be upto 15 to 20 metershigh. EGSB has high loadingability, the organic loading rate(OLR)is 2~3 timeshigher than UASB, up to 6 ~ 18mgCOD / m³.d.-IC Reactor (Internal Circulation). IC is an internal looptype ofanaerobic reactor, similar to theseries oftwo UASBtanks, and like EGSB, with a bigheight/diameter ratio. The biggest difference in operation between IC and UASB isthe performance of bearing shockload, IC can automatically dilute the input materialsthrough the internal circulation, effectively ensuringthe stabilityof input fluid concentration in the first reaction chamber. The second advantage is that it only requires a short residence time, suitable for considerable biodegradablesewage withhigh SS content. IC has a significant advantage over UASB,due to the highflow rate of IC, SS does not accumulate in the reactor, and sludge can maintain high activity.The material for the above reactors can be enamel steel tank, made of titanium-alloy enamel steel plate, with double-sided enamel coating, beautiful appearance, easy to clean, easy maintenancewith good wear resistance, corrosion resistance, impact resistance,insulation performance, anti-static; No special anti-corrosion treatmentrequired, lifetime designedfor30 yearsat least.In addition,the above reactors can be also LIPP tanks under unique construction method. During construction,the steel coils with a certain width are taken into the molding machineby uncoiler,to be processedinto the required geometry, and thento be bended and seamedthrough bending machine, to form a round of spiral protruded ridge with 30mm-40mm width at outer side of tank, playingthe role of strengthening the tank.3. Biogas Storage ProcessFor tank type of digester, structure of integrated all-in-one with biomass fermentation and biogas storage combined together is always welcome by customers,in order to reduce investment.The biogas storage is in the form of double-membrane gas holder mounted on top of tank.It consists of inner/outer membrane,support,air blower,anchoring device and other auxiliaries.It can also be free-standing type on the ground when tank is very high,to avoid affection of speedy wind for safety.Top of tank has to be covered by steel plates too,what's more,additional civil works for gas holder is caused.In this regard,it will increase the investment significantly.Another simple design is gas bag that made of reinforced single PVC membrane,anchored in specif area on the ground.No special biogas storage devices required when digester is HDPE enclosed anaerobic lagoon or floating soft digester that made of PVC membrane;4. Biogas PurificationBiogas pre-treatment process is mainly to remove hydrogen sulfide, moisture and solid impurities inthe rawbiogas, reduce corrosion and wearfor subsequent equipment. Biogas pressureto beincreased for transportation and regulated to meet the requirements of inlet pressure of follow-up equipment,involving equipment such as roots blower with explosion-proof motor under anti-corrosion treatment.Moisture and solid impurities can be removed throughphysical meanswhile the most difficult is the removalof hydrogen sulfide. Traditional methods arechemical dry type(iron oxide) and chemical wet type(sodium carbonate) or a combination of both, orthe latest biological desulphurization technology(oxygen-absorbing microbial absorption solution).Our patented ALBS series integrated biogas pre-treatment system,provides all-in-one solution to perform the above functions,it mainly includes the following:- Desulphurization tanks;- Water&particles removal tanks;- Roots blowers, 2 units(one for operation,the other for standby);- Constant-pressure feed system(Variable frequency drive,LCD display etc);- Instruments,like pressure gauge,flow meter etc;- base steel frameworks.A on-line biogas analyzer is strongly advised,to measure the main components (methane,hydrogen sulfide,carbon dioxide,oxygen etc) in the purified biogas.5 Biogas Utilization5.1 Bio-natural Gas.If biogas is usedto produce CNG(Compressed Natural Gas) for vehicle or gas grid networks, except the above biogas pre-treatment, decarburization process is required for further treatment.Now wecould provide containerized type biogas upgrading system in conjunction with the four kinds of mature technologies,including MS(Membrane Separating),PSA(Pressure Swing Absorption), MEA/MEDA(Mono Etobaccool Amine/ Methyldiethanolamine) and DWW(Pressurized Water Washing).The subsequent compressor is to be installed for increasing pressure to a certain degree(e.g. 20Mpa),to be fed into tank lorrythrough gas dispenser.5.2 Combined Heat and Power(CHP).Purified biogas is combusted in the internal combustion engine of Combined Heat&Power Plant(CHP);Electricity for which compensation can be obtained is generated,for local use or connected with power grid networks. The heat from engine jacket water and exhaust can be used for digester heating,or return to respective company for warming,bathing etc.The CHP can be regulated in terms of its utilization.Consequently,it can correspond to various remuneration regulations and be complemented through other heating concepts.Wecould provide quality CHP with high electrical efficiency,low oil consumption and long overhaul time.Our ACG and ADG series CHPs are associated with world-famous engine technologies,such as USA Cummins and German Deutz.Single unit capacity from 20kW to 400kW,to be configured automatic air-fuel ratio system,automatic oil feed system,exhaust purification mechanism and Grid connection cabinet,etc.according to customers' actual requirements.5.3 Biogas Boiler.Purified biogas can be used for producing hot-water or steam through boiler,which is equipped with high efficient burner. Hot water and steam generated are always used for material drying.This kind of utilization is very popular with food-processing factories,feed mill plants etc. Biogas production is not depending on climatic factors,and it can be stored and converted into energy at any time,it can meet base-load and peak-load requirements.Each country and region for the pressure vessel has a corresponding quality and safety standards,Special attention should be paid to boiler design and quality control,make it be subject to the quality standard as local relevant authority requires.6. Digestate TreatmentDigestate means residue and slurry after fermentation,berich in N.P.K, humic acid, organic matter and trace elements.Therefore the solid substance of digestate can be used as soil additive or compost,and the resultant liquid nutrient concentrate replaces the mineral fertilizers.And the separated water is processed so that it can be directly routed in the surrounding water body or can be used as processing water.Fermentationresiduefrom bottom of digesteris generally with water content 15~20%, aftersedimenttreatment,through a dedicated solid-liquid separation equipment, after dried under sunshine and bag packed,the precipitations can be made forsolid organic fertilizer.This is a relatively primitive approach, suitable for customers with little budget on small biogas plant.For the project with big digestateoutput, considering the return on investment, the solid organic fertilizer can be processed into granular fertilizer. The general process includes solid-liquid separation, batching system, mixing system, granulation, hot air oven drying and cooling , Dust removal, screening systems and packing machine.The slurry flows out of digester at upper position,together with the filtration liquid from residue,it can be used for nearby plant irrigation or horticultural purpose after further processing.If waste material is solid like livestock manure etc,slurry could be partially returned to pre-mixer with raw waste,in order to reduce water consumption,but have to keep carbon/nitrogen balance of feestock,which is best at 25 : 1.7. Further Treatment of SlurryIn order to prevent pollution on the environment, in thecountries and regionswithstrictlaws ofenvironmental protection,the fermented slurry still has to be cleaned further.ALONG could offer solutions to solve this problem byair flotation, A/O(Anaerobic-Oxic) or A2/O(Anaerobic-Anoxic-Oxic) technologies.Their common function is to remove organic matters in slurry.After treatment,the purified water can be discharged environmental friendly.What's more,we can provide membrane separating technologies for treating slurry further.The water after purified can be used for process water for local usage in customers' plant,such as food-processing industry.The whole biogas project and sewage treatment process design principles:1. Advanced technology, reliability, and adaptability.1.1 According to the actual situation of the plant, choose the most advanced technology program.1.2 According to the actual situation of the local, choose a successful case of the project to ensure that the project can be long-term stable operation.1.3 According to the owners of economic conditions and operational skills level, select the most appropriate program, easy to actual operation and maintenance.2. The principle of maximizing economic efficiency2.1 to ensure the advanced nature of technology on the basis of optimizing the process and the various unit design, reduce one-time investment to ensure the best cost-effective and the shortest payback period.2.2 follow the concept of circular economy, the entire field of energy flow analysis and design, to minimize energy consumption, to ensure that biogas projects for enterprises to bring the overall maximum benefits.3. The principle of maximizing environmental and social benefits3.1 to the product (biogas, biogas residue, biogas slurry) to make full use of, and focus on design and landscaping, so that the overall area of the station area and the harmonization of the community.3.2 The design and implementation of the process to comply with national and local laws and regulations and industrial policies to ensure that the project in line with local environmental, economic and social development planning, after the completion of the project can improve public heating, catering and other energy, and play an exemplary role in driving the local economy And social development.