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Advanced Sequential Batch Gasification ProcessTechnology Presentation
FRIDFINNUR EINARSSONMechanical Engineer M.Sc.
ASBG Environmental Ltd.Glasgow, United Kingdom
Gösun [Environmental] ehf.Keflavík, Iceland
tel (UK): +44 (0) 7503 982179tel (Iceland): +354 853 8892
[email protected]@gmail.com
Fridfinnur (FINNI) EinarssonMechanical Engineer M.Sc. - Process Inventor
• Twenty five year experience with complex mechanical engineering projects, incineration, gasification, energy recovery and emission control technologies as; Plant Engineer, Plant Manager, Systems Designer, Equipment Manufacturer, Project Director, Technology Director, Commissioning Director and Technology Developer. Inventor of two patent protected Fixed Hearth Batch Gasification Processes:
• BATCH WASTE GASIFICATION PROCESS (BWGP) (WO2008068781 A1) filed in December 2006 (https://register.epo.org/application?number=EP07827613)
• Patent rights now owned by Waste to Energy Canada Inc., Vancouver, BC, Canada.
• This Fixed Hearth Batch Gasification technology has been marketed as Batch Oxidation System or BOS, Continuous Batch Oxidation System or cBOS, Small Batch Oxidation System or sBOS and Mobile Batch Oxidation System or mBOS.
• All Gasification Processes and Equipment designs for projects by Waste to Energy Canada Inc. and its predecessors Waste2energy Inc. and Enerwaste Europe Ltd. have been headed by F. Einarsson since 2006.
• ADVANCED SEQUENTIAL BATCH GASIFICATION PROCESS (ASBG) (WO2013179313 A1) filed in May 2012(https://register.epo.org/application?number=EP13740373)
• Patent rights are owned by Einarsson’s family business
• The ASBG process design is the latest evolution of Fixed Hearth Batch Gasification both for Sequential and Non-Sequential systems.
• Although based on the same technology platform as the BWGP and many other Batch Gasification/Incineration Processes, the ASBG Process and Equipment Design is unique and it provides solutions to important sensitivity deficiencies and equipment longevity issues known in previous process and equipment designs. This is especially important in sequentially operated systems but also beneficial to smaller non-sequential systems.
ASBG – Advanced Sequential Batch Gasification Process• The Advanced Sequential Batch Gasification (ASBG) process is run sequentially in multiple
gasification chambers connected via duct work to a common syngas combustion chamber. Standard system layout consists of four gasification chambers and one syngas combustion chamber. Single or dual gasification chamber systems are also available but cannot be run sequentially 24/7.
• The waste batch is gasified with precisely controlled flow of recirculated flue-gas and air blown under the waste batch. Air is circulated in the gasification chambers external cooling jackets which warms up and is following used as combustion air in the syngas combustion chamber. All fans and burners are automatically controlled with feedback signals from various parts of the process.
• The ASBG process design is the latest advancement of Fixed Hearth Batch Gasification Technologies and is especially beneficial when used in sequentially run systems. Systems with single or dual gasification chambers also benefit from this improved process and equipment design.
Sequential Fixed Hearth Batch Gasification and the advantages of ASBG• For good smooth process and continuous even production of heat for recovery it is imperative that each gasification chamber has a
proportionally long gasification process stage and short final combustion and cool down process stages. This ensures efficient turnaround of the gasification chamber i.e. the time from the ignition of the chamber batch to the next time a batch can be ignited in the chamber and more importantly the proportion of that time the chamber is in effective gasification producing energy rich syngas.
• Extended periods of final combustion of waste batches does result in extend cooldown time due to the high gas temperatures and heat build-up in the chamber linings during the final combustion stage. This is a problem in previous versions of Fixed Hearth Batch Gasification Systems as the cooling air used has to be used as combustion air in the syngas combustion chamber.
• The gasification process gives of combustible syngas but the final combustion gives hot fully combusted flue-gas. The temperature in the syngas combustion chamber can be raised with the syngas but not with the flue-gas. Therefore it is important to have at least one of the four gasification chambers in active gasification producing syngas. If this is not possible the temperature in the syngas combustion chamber has to be raised with auxiliary fuel.
• Poor turnaround time and extreme temperature cycling have been found to be sensitivity and equipment longevity issues with previous Fixed Hearth Batch Gasification Process systems, resulting in early decay of refractory lining, chamber seals and various other equipment components.The ASBG process design eliminates these sensitivity and longevity issues. Reduces turnaround time significantly and extreme temperature cycling. Reduces; fuel consumption, particulate carryover and NOx production and has improved quality of the syngas and high ash quality.The external cooling of the gasification chambers, the re-circulation of flue-gas and the precise control of under air/gas flows allows this significant improvement.
Waste Types
GasificationThe ash discharge and waste loading is a consecutive process typically done once every 16 to 24 hours each gasification chamber, the duration of the process depends on waste heat value.
Ash may be discharged in larger system by telehandler where the ash is pushed from the front of the chamber through a door opening at the back of the chamber onto a conveyor system.
The chambers are typically loaded to about 95% of the chamber volume with unsorted waste. The gasification is started with a small ignition flame for a few minutes.
The gasification and therefore the rate of the syngas production is modulated by a precisely controlled flow of air and recirculated flue-gas flow under the waste.
The gasification chambers are equipped with a cooling jacket where the combustion air for the syngas combustion is preheated.
Syngas CombustionSyngas combustion is done in the syngas combustion chamber with precisely controlled flow of preheated air from the gasification chamber cooling jackets. The precise flow control ensures final combustion under optimally controlled conditions.
The overall flue gas flow is controlled to secure minimum residency time of 2+ seconds in the chamber after the last injection of air, at maximum flow.
The temperature is controlled to a set point above the required minimum, commonly 900oC or 1125°C depending waste type and applicable regulation.
The design of the chamber is optimized to promote very rapid mixing of the syngas and the combustion air with active vortex flow at high temperatures.
Syngas Combustion Chamber
Syngas Combustion Chamber
Gas flow simulation
Heat Recovery SystemThe fully combusted super hot flue-gas flows to the energy recovery boiler system where heat is recovered.
The boilers can be simple fire tube boilers or more complex water tube boilers to either heat water or produce saturated or superheated steam depending on the use of the heat.
The cooled flue-gas enters the emission control system typically at about 180-200°C
Electricity Production
Pre-designed Siemens Turbine Generator sets Dargavel
Turbine Generator and switch gear sets
Emission ControlGases are typically treated by injecting dry caustic regents and carbon powder to reduce acidic compounds (mainly HCl and SO2.), heavy metals, furans and dioxins.
The rate of caustic regents dosing is variable and depends on the waste composition.
No specific NOx treatment is necessary since the process produces very limited amounts of nitrogen oxides and far lower than allowed to emit according to EU regulations.
Wet scrubbing equipment can also be used depending clients preference.
• Ronald Reagan Ballistic Missile Defence Test Site, Kwajalein Atoll, Parallel/Sequential Batch Gasification System (30 t/d)
• Process and equipment design. Project in progress, equipment manufacturing to be complete in the spring of 2017. Shipping to the remote site and installation in 2017.
• Old Crow, Yukon, Canada, Batch Gasification System (1 t/d)• Process and equipment design, commissioned in 2012
• US Air Force, Wake Island Atoll, Batch Gasification System (2 t/d)• Process and equipment design, commissioned in 2010
• Ascot Environmental, Dumfries, UK, Sequential Batch Gasification System (120 t/d)• Process and equipment design, gasification equipment construction, installation and commissioning, emission control equipment
construction, installation and commissioning, commissioned in 2009
• Cayman Islands Department of Environmental Health, Batch Gasification System (4 t/d)• Process design, commissioned in 2008
• City of Egegik, Alaska, USA, Batch Gasification System (6 t/d)• Process design, commissioned in 2008
• Sorpsamlag, Húsavík, Iceland, Parallel/Sequential Batch Gasification System (20 t/d)• Process design, project EPC contractor (gasification, energy recovery and emission control), commissioned in 2006
Fixed Hearth Batch Gasification Projects using Einarsson’s Process Designs
Húsavík, Iceland; Sequential/Parallel Batch Gasification System
Parallel/Sequential Batch Gasification System commissioned in 2006.
Process capacity 20 t/d total, 10 t/d in each of the two gasification chambers.
Energy recovery by single pass fire tube boiler, recovered energy used in district heating system.
Dry scrubber emission control system, two parallel sets of reaction vessels and baghouses using sodium bicarbonate and active carbon.
Sequential Batch Gasification System, first commissioned in 2009.
Process capacity of 120 t/d total, 60 t/d each process train.
Fully Sequential operated for 24/7 waste processing and electricity production.
The recovered energy used to produce electricity for the national grid (6 MW export).
Emission control by dry scrubber system; reaction vessels and baghouses using sodium bicarbonate and active carbon.
Dumfries, Scotland; Sequential Batch Gasification System
Old Crow, Yukon, Canada; Discontinuous Batch Gasification System
Batch Gasification System in Old Crow, Yukon, Canada commissioned in 2012. Process capacity of 1 t/d.
Waste to Energy Canada Inc. engaged with FE, in December 2011 for heading the design of the gasification equipment part of the project.
Design challenges were among other that since there are no roads to Old Crow and the only possible freight method was by plane. The equipment had to be balanced within the container with respect to the freight plane maximum payload and balance which was successfully completed.
CONTACTASBG Environmental Ltd.Glasgow, United Kingdom
Gösun [Environmental] ehf.Keflavík, Iceland
tel (UK): +44 (0) 7503 982179tel (Iceland): +354 853 8892
