DE29806690U1 - Device for generating heating and electrical energy using thermally gasified biomass - Google Patents

Description

The invention relates to a device for generating heating and electrical energy using thermally gasified biomass, a so-called biomass cogeneration plant, which allows the use of solid biomass to generate electricity and heat in a decentralized application.

Raw materials or residues from agriculture and forestry as well as from the processing/further processing industry are suitable as biomass. The biomass can be left in its natural state or, to a certain degree,

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Niemannsweg 133 · D-24105 Kiel · Telephone (04 31) 8 40 75 · Fax (04 31) 8 40 77 MUNICH - BREMEN - BERLIN - FRANKFURT - DÜSSELDORF - POTSDAM - BRANDENBURG - HÖHENKIRCHEN - KIEL - LEIPZIG - ALICANTE

e-mail: Postjiuslcr@BochnKrt.Bochmcrt.de

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They are used in a contaminated state and are available in lumpy, pelletized or briquetted form.

This also creates opportunities for direct disposal in factories or on landfills, reducing volume and pollutants.

Unlike conventional stationary heating power plants or combined heat and power plants, it is now desirable to design such combined heat and power plants for mobile use, for example for a one-week standby period if required by a company that generates solid biomass seasonally, or to enable stationary use without structural measures.

The problems that arise here are in particular how to create a device that can be transported in a container, for example, without complex filters and in as compact a form as possible.

According to the invention, this is solved by the features of the main claim. The subclaims give advantageous embodiments of the invention.

In particular, the washing of the gases to remove particles by pre-injecting the generated gases into a gas engine is important for low-maintenance operation of the engine, which can therefore also be operated over large areas of different gas compositions without polluting the environment.

In addition to the electrical energy generated by the generator coupled to the engine, engine heat extracted from the cooling circuit and also from the engine exhaust gas can be fed into a local heating network or, if

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If this is not possible, it can be released via an additional cooler.

Further advantages and features of the invention emerge from the following description of a preferred embodiment of the invention.

The resulting biomass can be in lumpy or compacted form. Depending on the water content, the biomass can be dried using waste process heat in a drying screw in order to achieve an optimal residual moisture content of the biomass of approx. 20%.

Depending on its consistency, the biomass is fed via an automatic conveyor system to a lock on the top of a reactor, with the reactor's filling level being monitored via sensors attached to it.

The proposed reactor is one based on the so-called double-fire process, in which a very clean gas free of high-molecular components is produced in a combination of descending and ascending thermal gasification with two defined fire zones.

In an upper zone, the carbonization and subsequent cracking of the carbonization gases in the ember bed takes place. In a lower zone, arranged above the grate, which is important for ash removal, the gasification of the constantly newly formed charcoal and a subsequent cracking of the gases generated in the upper area takes place with the addition of air. With reaction temperatures in the upper fire zone of up to 1,200 ⁰ C, temperatures of around 900 ⁰ C are to be provided in the lower fire zone. The gasification takes place at a negative pressure of

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BOEHMERT & BOEHMERT

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up to 300 mm WS. This requires a gas outlet temperature of up to 500 ⁰ C.

Depending on the incoming biomass, the resulting gas has the following main components:

CO / H ₂ / CH ₄ / C _n H _n , / CO ₂ / N ₂
with different weightings.

After leaving the gasifier, the gas is cooled to approx. 40 ⁰ C in a cleaning and cooling device. Depending on requirements, this gas treatment is carried out using one or more of the following devices: cyclone, venturi scrubber, quench, or preferably with a tube cooler with a disintegrator scrubber. A cyclone to separate the larger ash particles is always required directly behind the reactor. The quench represents an alternative to the design with the tube cooler.

Depending on the biomass, a post-reaction of the gas can also take place just behind the reactor via a coke bed, whereby any hydrocarbons still present in the start-up state can be absorbed. When the operating state is reached and the gas temperatures are higher, the absorbed hydrocarbons are released again from this coke and can be burned in an exhaust flare if necessary.

The advantage of using a tube cooler is that the heat can be extracted for biomass drying and also for further use. Condensate that accumulates during cooling and cleaning can be evaporated using an integrated water evaporation system. A tube cooler also has

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the advantage that in a container, if a mobile structure is chosen, it can be arranged horizontally in the ceiling area close to a radiator-like cooling device that communicates with the outside environment.

When using a disintegrator scrubber, the gas is advantageously cleaned intensively by impact and shock exposure with the addition of water and cooled at the same time. The scrubber is designed in such a way that it provides the suction power to extract the gas from the reactor and the downstream system components. In a downstream droplet separator, the gas is freed from any water droplets still carried along with it.

The resulting purity of the gas after leaving the gas cleaning plant is 10 mg/Nm ³ solids, with the particle size being less than λμηη. The water separated in the drip separator is then collected in a collecting tank, where the heavy particles settle to the bottom with the addition of flocculants if necessary. The washing water can be circulated, and if additional water occurs due to higher wood moisture, this is drained off through an overflow and fed to the water evaporation plant, if provided.

The dirt absorbed by the water can be separated again using an additional filter, whereby the residue separated by the filter, which consists of approx. 90% carbon, can be mixed back into the gasification material so that it can be disposed of again in an environmentally friendly way.

A partial flow of the water pre-cleaned by sedimentation can then be passed through a double filter as required.

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ter, whereby in a first stage of fine wood or coal and a second stage of activated coke any fine dirt and any hydrocarbons still contained in the water are separated. The loaded activated coke can then also be added back to the gasification material and thus disposed of in an environmentally friendly manner. In a preferred embodiment, the gas is also passed through a gas dryer.

The cleaned and cooled gas is mixed as a lean gas in a mixing device with air to form an ignitable gas mixture under the control of an O ₂ probe (lambda probe) and fed to a large-volume gas engine with a subsequent catalyst, which is controlled by low compression and a power in ignition timing and ignition voltage adapted to the reactor gas by sensors or by observation.

A mechanically coupled asynchronous or synchronous generator can then be operated in parallel or island operation as required. The reactor part and the motor-generator part are controlled by a PLC. If necessary, online system control and diagnosis of the entire process can be integrated via remote monitoring.

Claims (9)

BOEfiMjERT «Je BJj^iMÖ^t l" E 5064 CLAIMS 1. Device for generating heating and electrical energy using thermally gasified biomass, characterized by: - a gasification reactor for converting biomass into essentially pure gases freed from high molecular weight components, a cooler to cool the gases leaving the gasification reactor to about 40 ⁰ C, - a washing device to remove particles from the gases, an O ₂ -controlled air mixing device for the scrubbed gases, and a gas engine for generating mechanical energy, to which a generator is coupled. 2. Device for generating heating and electrical energy using thermally gasified biomass according to claim 1, characterized in that the gasification reactor is a reactor that can be filled from above in a double-fire process with two reaction zones, an upper zone operated at about 1200 ⁰ C and a lower zone operated at about 900 ⁰ C, which is designed for filling &mdash;&mdash; w www VSV BOEHMJiRT &B#^iMER<f:' operation at a negative pressure of approx. 3 00 min water column. 3. Device according to one of the preceding claims, characterized in that the cooler is a tube cooler the heat of which is fed back to the biomass dehydration in a drying screw. 4. Device according to one of the preceding claims, characterized in that a disintegrator washer is provided as a cooler and washing device for mixing the combustion gases with water. 5. Device according to claim 4, characterized in that excess water accumulating in the disintegrator washer is fed to a water evaporator which is operated by the heat of the reactor and/or the gases emerging from the reactor. 6. Device according to one of the preceding claims, characterized by a double filter made of activated carbon for the water enriched with particles in the disintegrator washer. 7. Device according to one of the preceding claims, characterized by a mixing device for the combustion gases with air, controlled by a lambda probe. 8. Device according to one of the preceding claims, characterized by gas sensors on the gas flow supplied to the gas engine and on its exhaust gas flow for controlling the gas engine in terms of ignition timing and ignition voltage according to the detected values. 9. Device according to one of the preceding claims, characterized by a container in which a gas engine is arranged under thermal insulation of the gasification reactor with subsequent horizontal arrangement of the tube cooler in the ceiling area.