DE4342165C1 - Process for the utilisation of biomass energy - Google Patents

Abstract

The process is suitable for the utilisation of the energy in particular of cyclically renewable biomasses, refuse, wastes, but also coal. According to the invention, the process stages drying, low-temperature carbonization and gasification are coupled using a gas turbocharger to a combined cycle power station process, the gasification using engine exhaust gas or gas turbine exhaust gas as gasification medium. The invention has the advantage that the process stages drying, low-temperature carbonization and gasification can be realised under atmospheric pressure and thus using simple apparatuses, with simultaneous increase of the yield of electrical energy from 30 to 50% in comparison with the prior art. <IMAGE>

Description

The invention relates to a method for the energetic use of organic mass, especially based on fast growing trees and others Plants and other organic solids, such as dewatered Sludge, garbage of all kinds, but also coal.

The invention can be used in particular for land use economic areas and recultivated mining areas for the cyclical Production of renewable fuels for the carbon dioxide neutral Generation of electrical energy and heat, but also for use adequate disposal of municipalities, commerce, agriculture and industry of garbage and other organic waste.

The prior art is characterized by a large number of pre and practical applications for the energetic use of Plants and organic waste to municipal waste, Commercial, industrial and agricultural. One in November 1981 by the Kernforschungsanlage Jülich GmbH held the seminar State of the art for thermal gas generation from biomass, d. H. of the Gasification and degassing, together, which is still the state of the art Technology largely characterized (reports from the nuclear research facility Jülich-Jül-Conf-46, Nov. 1981, ISSN 0344-5798). Determine accordingly Processes for combustion, degassing and gasification individually or in Combining the state of the art with the following objectives: - Production of Combustion gas as a heat energy source for generating steam through combustion, - Production of high calorific solid and liquid fuels such as wood coal and liquid, oil-like tars due to smoldering and degassing, Production of fuel gas while avoiding solid fuels Gasification.

DE 31 01 259 A1 describes a method for producing a combustible Ren pure gas from coal, in which coal particles, the volatile combustible material contained in a non-oxidizing  Atmosphere with heat-laden solids at temperatures up to Pyrolyzed 540 ° C and after separating volatile constituents with steam and an oxygen-containing gas to produce flammable gas. However, this procedure is based on the use of a special type of partially volatile constituents liberated, limited artificial coal and therefore not suitable for. B. Bio to use mass energetically.

In the gasification process, the process management decides whether receive the liquid and large molecular carbonization products or likewise be gasified by oxidation.

Although the production of charcoal and oil-like tars has an impact to cover the fuel and fuel requirements in development countries can afford, the processes that give up smoldering products always under criticism from the perspective of environmental pollution. This applies in particular the resulting aqueous gas condensates and production-related ones Impurities related to tar production. DC and fluidized bed gasification processes enable that Generation of almost tar-free fuel and synthesis gases. It draw net that these processes due to their environmental friendliness The future belongs, especially because of known synthesis In this way, liquid raw materials such as Methanol, fuels such as gasoline, but also protein can be produced nen.

The transition to such production goals and to the scheduled cyclical Production of biomass for energetic and possibly material use is associated with the demand for efficient, environmentally friendly Process suitable for biomass of different quality and under of different origins as well as industrial feasibility, even in fewer developed countries. Fixed bed gasifier with DC gasification or Double fire technology ensure  largely tar-free gasification gas, but with respect to Performance - related to the efficiency of the end product - and These procedures do not correspond to environmental protection current and future requirements. How to get there Power plants based on combustion processes or gasification of biomass energetic today Efficiency - based on the possible technical Work - between 20 and 30%.

The invention therefore has the task of a method for energetic use of biomass and organic Propose waste that is in line with the state of the art Technology is characterized by a higher effectiveness act on applied useful energy, such as electrical energy and heat as well as a through Gasification produced gas quality, which for the energetic table use in a gasification downstream Combined heat and power is optimal and one compared to that State of the art low-pollution energy conversion enables.

The aim of the invention is one compared to the prior art Technology related to specific investments and Operating costs more effective use of biomass and other organic solids with process related simple devices as well as a higher society acceptance of such processes through improved Reliability and environmental friendliness.

The invention solves the technical problem by better exergetic integration of the energeti process stages required for the use of biomass, and by thermal processing of the biomass  through drying and smoldering, as a result of which the Pro gasification stage a high space / time yield reached.

According to the invention, the mixture of steam and Smoldering gas from the drying and smoldering process stage of biomass or other organic solids Engine or gas turbine exhaust at pressures up to 1.0 MPa and Burned temperatures up to 1500 ° C, ent standing combustion gas as a gasifying agent and we Belmedium for the autothermal gasification of the solid, koh products containing carbon dioxide from the smoldering to fuel gas in a fluidized bed at pressures up to 1.0 MPa and tem temperatures up to 1200 ° C used. Through tangential on Conduction of the gasification agent into the fluidized bed react Tor is achieved that the solid, carbonaceous Products rotate in the gasification reactor, causing their Residence time in the gasification reactor is extended. Not gasified carbon is converted into gasification switched cyclone separated from the gasification gas and the Gasification fed again, so that the gasification practically table in a rotating circulating fluidized bed he follows. Depending on the type and the procurement it is the biomass or the organic solids possible according to the invention, the proposed gasification optionally to couple with a smoldering with indirect Heat transfer to ensure the heat demand of the Drying and smoldering, with the heat coming from the gasification emerging from the fluidized bed gasification gas, engine or gas turbine exhaust gas taken indirectly or with a smoldering in a fixed or fluidized bed, that works on the principle of purging gas, where as the purge gas and heat transfer medium 500 to 1000 ° C hot Gasification gas from fluidized bed gasification used  is that after heat is given off to the biomass or the organic solid with water vapor, tar and others volatile smoldering products, the gasification again is fed. It is also in accordance with the invention that that required for the combustion of the carbonization gas Gas turbine exhaust gas from the gas turbine of a gas turbocharger is removed, which is charged with combustion gas by burning proprietary, compressed fuel gas with compressed air at 0.5 to 4.0 MPa with an excess of air, based on the min minimum air requirement of complete combustion, of min at least 100% was generated, and which the compressor for the compression of the chilled and cleaned Gasification gas drives while the fuel gas that not for driving this gas turbocharger Compression of the gasification gas is needed as Fuel in a known gas steam power plant, best consisting of a gas turbine plant with a waste heat boiler and water steam cycle process with steam turbines and heat extraction, is used.

The benefit of the invention is enhancement the electrical energy yield in energetic use of biomass and other organic solids by 30 up to 50% compared to the prior art at ver comparable overall energy efficiency as well as the Low pollution conversion of this natural and waste burning fabrics in a suitable for high-performance engines fuel.

Embodiment

The invention is described below with the help of the technological outline shown in Fig. 1 of a biomass CHP plant with an electrical and thermal energy output of 12 MW each. The biomass, in this example wood, is supplied as raw material or as wood chips. In the case of the delivery of raw wood, after separation of foreign substances, such as stones, iron and others, it is shredded using known technology, e.g. B. with shredders ( 1 ). The wood chips are also introduced into a device ( 2 ) which is gas-tight and suitable for drying and smoldering the biomass with the aid of known lock systems. In the example, the principle of the plate dryer is used, whereby this process stage is heated with counter-current thermal oil. The gas mixture resulting from drying and smoldering is separated from the simultaneously produced charcoal from the drying / smoldering process stage ( 2 ). While the charcoal may be subjected to further shredding or in some cases supplied to an external use, the steam containing carbonization gas is fed directly to a combustion chamber ( 3 ) and burned there with gas turbine exhaust gas at temperatures of 1000 to 1200 ° C. Charcoal produced in the smoldering is fed to the fluidized bed gasification reactor ( 4 ), where it is fluidized and gasified using the gasification agent produced in ( 3 ) by combustion of carbonization gas with gas turbine exhaust gas. The resulting gas is roughly dedusted in the cyclone ( 5 ), which is directly connected to the fluidized bed gasifier ( 4 ), and fed to a multi-stage, indirect gas cooling system at 850 to 1100 ° C. The coarse material separated in the cyclone ( 5 ) contains non-gasified carbon, which is why it is returned to the fluidized bed gasifier ( 4 ) using known technology. In the course of indirect cooling of the gasification gas, the gasification gas gives off most of its physical enthalpy in the recuperator ( 19 ) to the purified fuel gas compressed in ( 13 ) and in the recuperator ( 6 ) to a heat transfer oil that is used for the indirect heating of the drying and smoldering is used in ( 2 ). The indirect cooling of the gasification gas is continued with the recuperator ( 7 ), which generates water vapor and cools the gasification gas to 150 ° C.

The gasification gas is then dedusted mechanically in ( 8 ). A further cooling and fine cleaning takes place in the spray dryer ( 9 ), which is used for the evaporation of the washing solutions and the separation of the resulting salts from the subsequent chemical gas washing ( 10 ). The gasification gas does not yet reach its water vapor dew point in this spray dryer ( 9 ). The gasification gas is cooled down to its water vapor dew point in the chemical gas scrubbing ( 10 ). The dusted and chemically cleaned gasification gas is separated by the separation of gas water, which is washed in the gas ( 10 ) and z. B. is used as process water for the operation of a wet cooling plant, indirectly cooled to 30 ° C in ( 11 ). The thus treated Verga sungsgas reaches the quality of fuel gas, suitable for the operation of high-temperature gas turbines ( 12 ), which, coupled with a gas compressor ( 13 ), as a gas turbine for the compression of the fuel gas z. B. on a for the operation of gas turbine combustion chambers ( 14 ) übli chen pressure of 2.0 MPa and the generation of gasification medium for fluidized bed gasification in ( 3 ) or gekop pelt with an air compressor ( 15 ) and electrical generator ( 16 ), as Gas turbine plant is required for the generation of electrical energy. The exhaust gas from the gas turbine system ( 12 , 15 , 16 ) and the excess gas from the turbocharger ( 12 , 13 ) are fed to a waste heat boiler ( 17 ), which is equipped with an additional firing system ( 18 ), and where there is indirect heat dissipation from water vapor processes and hot water systems Chilled 70 to 150 ° C.

Claims (4)

1. Process for the energetic use of biomass, in particular based on fast growing trees and other plants and other organic solids, such as dewatered sludge, waste of all kinds, but also coal, in which the conversion of solid organic substances into fuel gas by drying , Smoldering and gasification and the conversion of the gasification gas thus generated into electrical energy and heat by combination with a gas steam power plant, characterized in that the mixture of steam and carbonization gas from the pro cess stage drying and smoldering with engine or gas turbine exhaust gas at pressures up to 1, 0 MPa and temperatures up to 1500 ° C burned, and the resulting combustion gas as a gasifying agent and fluidizing medium for the autothermal gasification of solid, carbon-containing products from the smoldering to fuel gas in a fluidized bed at pressures up to 1.0 MPa and temperatures up to 1200 ° C is used. 2. Process for the energetic use of biomass Claim 1, characterized in that the process stage Gasification using a gas steam power plant process a gas turbocharger is coupled, the gas turbine with combustion gas generated by burning ver in-house fuel gas with an air excess of min at least 100%, based on the minimum air requirement of the complete combustion, at 0.5 to 4.0 MPa is proposing a compressor for compression of the cooled and cleaned gasification gas, and the exhaust gas of the fluidized bed gasification as Verga medium and fluidizing medium is supplied.   3. Process for the energetic use of biomass Claim 1, characterized in that the solid, koh Products containing carbon dioxide from the smoldering process in the We Fluidized bed gasification is rotating and circulating the by placing the gasification gas tangentially into the vortex Shift gasification initiated and not gasified coal using a cyclone from the gasification gas separated and returned to gasification. 4. Process for the energetic use of biomass Claim 1, characterized in that the vertebrae stratified gasification is optionally coupled with a Smoldering with indirect heat transfer or one working on the principle of carbonization purging Smoldering, the purge gas and heat transfer medium 500 to 1000 ° C hot, proprietary gasification gas used.