TECHNICAL DETAILS:
Consumables:
1.1kg fuel (+-9% depending on circumstances like fuel ash-content, temperature, pressure and other factors) is required for 1kW electricity + appr 5.4MJ heat. For higher ash-content fuel, instead of 1.1kg, a better approximation is 1.08kg+ 2*A where A=ash-content of fuel, say 0.01 for woodchips and 0.06 for certain straw.
For 250 kWe at 96% utilization, this means 264kg / hour (6.3 ton / day).
Oxygen is not required, only air.
Appr. 0.05 kg water is required per kg of fuel (for gas-cleaning), this depends on startup/shutdown cycles (tar formation is minimum after the system is warmed up, see http://x-dsl.hu/images/BlueFlame/BlueFlame-8334.avi for a flare that burns tar-free gas from a warmed-up reactor, before scrubber ).
Appr. 0.003 kg lubricating engine oil is required per kg of fuel.
Nitrogen: a few kg for emergency shutdown. Not required for normal operation.
Planned maintenance required: appr. 2 hours / week (4 hours per month for oil-change and thorough cleaning + 1 hour per week to clean dedicated parts ). The system is designed to run automatically for about 8000 hours a year. If the fuel is mechanically sufficient for feed-in, and cleaning-maintenance is properly done, unplanned (eg. temperature or pressure-drop based) shutdowns (eg. fuel bridging, pipe clogging, or some valve stuck) should be rare and allow 8000+ hours / year operation with about 20-50 hours of unplanned maintenance per year.
Fuel-properties:
The 630mm internal diameter reactor, nominal 300kW cold-gas (practical with 80-110 kWe genset) supports woodchips and sufficiently sized crop residues (upto 70mm size). Tests are definitely required for any special fuel (other than G30 woodchips) or fuel mixtures.
The 950mm internal diameter reactor, nominal 700kW cold-gas (practical with 160-250 kWe genset) supports woodchips and sufficiently sized crop residues (upto 90mm size). Tests are recommended for any special fuel (other than G30 woodchips) or fuel mixtures.
In general, the reactors that we can manufacture require ash-fusion temperature of the fuel (or fuel mixture) to be above 930 Celsius (this is not very demanding, easy to meet), and fuel should "flow" similar to woodchips. Agricultural residues must be cut to sufficiantly sized (30-70mm) slices before feedin to the vertical air-lock.
Non-woodchip (eg. agricultural residue) fuel also needs tests for the bigger, 250kWe (950mm internal diameter reactor, nominal 700kW cold-gas), but it's easy to cut crops and crop residues to be sufficient for feed-in through a 300mm airlock.
Economy - maintenance and amortization costs:
At nominal power, calculate 0.01 EUR / kWh for the gas-producer system. We can guarantee this cost level for wearing parts if the system is operated properly with woodchips or agricultural residues.
Note that municipal waste is not suitable to blend into fuel (neither legally, nor technically): Cl and F (eg. from PVC and PTFE) would significantly increase the wear of the internal 1.4841 reactor vessel (normally 0.1mm / year wear, beyond 10+ year lifetime).
We offer 1500 RPM syncronous-generators from http://www.meccalte.it/ (peak power rating at 40C ambient appr 5-10% higher than engine shaft-power with woodgas-air mixture) and 12 Liter displacement 6cyl engines with spark-ignition cylinder head from Tedom ( http://motor.tedom.eu/ from Czech Republic ) and 10.35 Liter displacement MAN-licence engine from Hungary , normally aspirated (non-turbo). These (CHP parts) are included in the indicated system cost.
Using the customer's preferred engine (if it has spark-ignition cylinder head) or genset might be possible: it must be evaluated, and might incur extra latency and costs. For example 25 Liter or bigger engines can be chosen from yamz.ru or other sources (Asia, EU or USA).
At nominal power, calculate 0.02 EUR / kWh for engine/genset (including oil-change, filters, and 20000 hour overhaul, replacement of bearings, cyl liner, valve-seats, valves and 80000 hour engine-block replacement) to have a genset operational indefinitely.
Utilization of 450C exhaust gas (waste heat) is possible with Rankine, ORC, Kalina, Stirling or Ericsson cycle for improved electrical efficiency, but we don't (at this time, in 2012) provide such option (but exhaust => water heat exchanger is an option).
below 150kWe: start-up requirement is 6 kW (peak 9kW) 400V, 3 phase, for appr 1-1.5 hour. After warm-up only appr 3kW. This includes augers, blowers, compressed air, hydraulic supply (for push-floor feed-in) and controllers necessary for plant operation.
above 150kWe: start-up power requirement is 12 (peak 18 kW) 400V, 3 phase, for appr 1-1.5 hour. After warm-up only appr 6kW. This includes augers, blowers, compressed air, hydraulic supply (for push-floor feed-in) and controllers necessary for plant operation.
Indicative base prices for woodchips producer-gas CHP plant (400V, 3-phase synchron-generator, gas-engine genset, 60/80C water) net prices:
250 kWe CHP (with gas-producer based on 950mm reactor): 698000 EUR (2795 EUR / kWe) woodchips, and agricultural residues (based on tests with given fuel or fuel-blend).
95 kWe CHP (with gas-producer based on 630mm reactor): 298000 EUR (3136 EUR / kWe) designed primarily for woodchips.
800-1000 kWe CHP with gas-producer based on 1900mm reactor: this is not currently under manufacturing. Estimated price appr 2500 EUR / kWe (including genset, but without the CHP heat exchangers).
Voltage: 400V is the default. We've seen 10kV generators, and we'll query generator-manufacturers if they would manufacture 22kV generators in the < 1MW range.
We assume that fuel is compliant to feed-in (eg. not sawdust and not bridging), appr 15-25% moisture content (dry base), and that required "daily storage" size is 2.5 days of 30-40mm woodchips (Friday to Monday).
We assume that plant location and shipping address is in EU, available with 30ton truck, to an industrial location (not a ship or residential place) and there is enough room. For the smallest 630mm reactor for 3 pieces of 20' containers (6*2.5m + sidewalks around) on ground-level, with 0-6 m between them, at least one of them outdoors or in a room with very good ventillation options, with concrete floor, kids and unauthorized persons kept away. Audible noise level is appr. 58dB at plant fence, can be improved if necessary with improved engine container insulation.
We use strict phase separation (4-stage air-gasification gas-producer) to produce gas with very low tar-levels from the reactor after the system is warmed up.
This makes the maintenance period (cleaning heat-exchangers and filters) longer: from days to weeks (roughly same as the engine-oilchange period of 500 hours).
The gasifier is made for long operation runs (min 5-20 days, preferrably more). Expect 1.5 hour warmup time. Weekly startups might be OK, but daily starts are not (inconvenient for the crew, and wears parts quicker).
Gas-producer turndown minimum is 30% of rated power.
Above 250 kWe, we recommend 2 engines for no extra price. This means better efficiency at part load and better availability (eg. when 1 gas-engine is under maintenance). This means no extra cost (operation or acquiring) compared to, say a bigger engine with twice as many cylinders.
6100 MJ / hour = 1694 kWth
appr 172 kW producer gas after air-preheater (300 Celsius), 0.7kg / sec * 240 kJ /kg = 172 kW
appr 570 kW is exhaust heat (450 Celsius) 1.5 kg /sec * 380 kJ / kg (includes a condensation stage)
appr 872 kW is coolant (desired 75C return line to the engine, so return line from your plant should preferrably be max 65C or below).
appr 80 kW is convected and radiated (gas-producer + gas-cleaner + engine), can be ventillated to dry the wood-chips next-room
These are approximate figures.
The exhaust to liquid straight-tube type heat exchanger can be less than 100 EUR / kWth (condensing-type is more expensive). Optionally exhaust to air heat-exchanger costs about twice as much.
The coolant to liquid heat-exchanger cost is very low, appr. 20 EUR / kWth.
In short, hot water is easy to obtain without major investment costs.
However, consider that the plant requires fuel with very low moisture content (target should be max 15%, but even lower is better).
Fuel that might be suitable for an oxidation-type burner system (such as the boiler of a Rankine system) might be unsuitable for feed-in to the airlock of a gasifier:
There is some chance that active drying will be desirable or required some part of the year.
A rotary-drum drier, or a rotating-bed dryer with stationary-drum or a batch drier can be used.
Unfortunately we don't know the "best" (easy to operate, utilizing waste heat, reliable and economical) option for drying, although we are consulting manufacturers about dryer options.
Let us know if you have a partner with experience with a good, economical drying process (continuous or batch).
For smaller systems, the daily storage (often Friday-Monday) hydraulic "pushfloor" container is prebuilt from steel, our contracted partner can deliver that (size details required for price, but indicative price: appr 100 EUR / kWe for 100-250kWe system).
For bigger systems it could be less costly, but better option to build on-site by your local construction partner: weather-protection ROOF for the floor-level hydraulic pushfloor might be a good option.
Belt-conveyor is required in any case, to lift to a tray located 5m above ground level (possibly/preferrably from a bunker minus 1m, that is slightly below ground). 12m long belt conveyor can be purchased domestically ( a few thousand EUR).
that is perfect size fuel. The feed-in system for bigger reactors is 314mm trough and 280mm auger so it is more tolerant to fuel size than the smaller reactors (the smallest uses 160mm trough).
1.1 ton (+-9%) woodchip fuel gives 1 MWh (electricity) + 6.1 GJ heat (more
heat is available with condensating heat exchangers, for extra cost).
Turn-key plant is ~2500 EUR / kWe (above 500kWe), but actual price depends
on a few factors, see below.
Start-up power requirement is 18 kW (400V, 3 phase, for appr 1-1.5 hour),
This includes augers, blowers, compressed air, hydraulic supply (for
push-floor feed-in) and controllers necessary for plant operation. We assume that fuel is 30-40mm woodchips (eg. not sawdust and not straw), appr 15-25% moisture content (dry base), and plant is next to existing fuel-silo.
"Daily storage" (with push-floor) for 1 day (or 2.5 days for Friday to
Monday) storage is also possible as an option.
We assume that plant location and delivery address is reachable with 28 ton
trucks, to an industrial location (eg. not a ship), min 400m2 floorspace
near the fuel-silo to provide enough room for 8 big 40' container-size units
(8*12*2.5m + room for forklift) on ground-level (gasifier, gasifier-HE,
gensets, CHP-HE, control, electricity, accessories, emergency-cooler), with
6 m road between them, at least one of them outdoors or in a barn, with
concrete floor, kids and unauthorized persons kept away.
Let us know if some of our assumptions is wrong.
Let us know the required syncron-generator voltage (to connect to your grid
mains).
Let us know if sufficient capacity liquid cooling is available, eg. a river
or lake (even artificial, eg. with waterworks). Useful instead of
air-cooling during "summer emergency".