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Entrained bed flash pyrolysis of biomass at pilot plant scale - 200 Kg/h

Objective

Egemin will design, construct, operate and evaluate a flash pyrolysis pilot plant for wood. The feed rate will be 200 kg/hr. The production of liquid pyrolysis products will be maximized.
A flash pyrolysis process has been designed based on an entrained bed system. The process is autothermal and the construction of the pilot plant has started.

The plant consists of the fuel reception and storage system, the feeding system, the entrained bed reactor, the propane burner, the condensation system and the recycle loop.
In the fuel reception and storage system the biomass is delivered ready for use to the pilot plant location. It is transported there by truck and the truck empties the load pneumatically into a main storage silo of about 10 m{3} which can provide sufficient material for several days operation. The silo is equipped with a bag filter for the pneumatic feeding and with 4 extraction screws at its bottom for feeding the biomass to the buffer silo. The 4 screws as well as the geometry of the storage silo ensure that bridges will not be formed. The storage silo is provided with maximum and minimum indicators.
The feeding system consists of the buffer silo, a gas tight screw extractor, an inclined transport screw and the high speed feeding screw.
The reactor is cylindrical and vertically placed. The inlet for the carrier gas (which is accomplished with a tangetial flow) is very close to the inlet for the biomass from the feeding screw. This creares a swirl for improved mixing and heat transfer between the feed particles and the hot gases.
The condensation system consists of the cyclone, the condenser and the filter. The condenser is a Venturi scrubber, with direct cooling by recycled oil. The biooil is collected into a large vessel below the scrubber while the pyrolysis gases leaving the vessel pass through a woven fibre filter.
A substoichiometric propane burner is used to produce the carrier gas (or to supplement the recycled carrier gas). The control of the temperature of the carrier gas, which should be about 800 C at the reactor inlet, is accomplished by cooling with carrier gas and/or nitrogen. The expected biooil yield is 60 weight % at an average operating temperature of 550 C and a mean residence time of 0.6 s.
The work covers the production of liquid pyrolysis products by flash pyrolysis of wood. The operation combines very short residence time heating in non- oxidizing conditions and at moderate temperatures (400 - 600 C). With the assistance of several thermal experts, i.e. Prof. Dr. J. Baeyens and Dr. K. Maniatis, Egemin has evaluated the state of the art of international technology in the field and has closely monitored the various developments. As a result, a flash pyrolysis pilot plant of 200 kg/h. biomass capacity will be built and operated in Belgium.

Various innovative design aspects are included.

Five group of tasks are included in the work programme :

- engineering and design

- manufacturing, erection and commissioning

- experimentation, involving the study of varying the major parameters :

temperature 400 - 600 C
feed rate
feedstock (biomass size 0-5 mm).
feedstock characteristics
residence time 0-1 sec.
effect of condensation temperature

- process evaluation and development of scale-up data

- Participation in the coordinated programme of Joule biomass pyrolysis activities and active exchange of experimental findings with other Joule research groups.

The commissioning will take place in January 1991.

The subsequent experimental investigations will cover the variation of process parameters.

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

Egemin NV
Address
1201,Bredabaan
2900 Schoten
Belgium

Participants (1)

CENTRE FOR RENEWABLE ENERGY SOURCES (CRES)
Greece
Address

19400 Koropi