RU2737833C1 - Autonomous electric generation method and device - small solid fuel power plant for its implementation - Google Patents

Abstract

FIELD: electric power engineering.

SUBSTANCE: invention relates to small distributed power engineering and is intended for decentralized power supply, as well as environmentally safe disposal of solid municipal wastes, and is aimed at solving technical problem of increasing efficiency of autonomous power generation using small power plants based on local energy resources - solid low-grade carbon-containing material - off-grade biomass, peat, brown coal with minimization of harmful emissions. Prepared raw material is subjected to steam-air gasification in dense layer simultaneously in several cylindrical reverse-inclined rotary-reactors with steam-water jacket, fuel gas is used in gas-piston engines of power units. Gasification in the reactor is carried out alternately in modes of reverse and direct processes with cleaning of fuel gas by means of filtration through the formed layer of activated carbon and with cooling - water evaporation and air. Preliminary raw material is subjected to recuperative air drying with conductive heating due to fuel gas heat by construction of closed water circulation circuit for reactor heat protection, production and cooling of fuel gas, as well as heat from cooling of engines and exhaust gases cleaned before release of activated carbon. Method is implemented by means of small solid-fuel power plant in fuel preparation, gasification and electric power stations in semi-stationary and mobile (with integration of units) design.

EFFECT: low cost of electric power, increased compactness, readiness, reliability, durability, repairability and electric efficiency of electric power station, continuity of its autonomous operation, provision of environmental safety.

10 cl, 12 dwg

Description

The invention relates to a small distributed electric power industry based on the processing of local, primarily renewable energy resources, namely solid low-grade carbonaceous raw materials - biomass, including substandard in the form of production and consumption waste, peat, brown coal, etc., by gasification for use in autonomous power plants in the interests of building a sustainable system of decentralized energy supply, as well as solving the problem of environmentally safe disposal (recycling) of municipal solid waste.

The Energy Strategy of Russia for the period up to 2030 provides for “... the development of small-scale energy in the area of decentralized energy supply by increasing the efficiency of the use of local energy resources, including new types of fuel obtained from various types of biomass”, which refers to low-grade fuels with high humidity (up to 85% or more), low energy density, low calorific value, heterogeneity of the fractional composition, but at the same time it has significant advantages over fossil carbon-containing raw materials, namely renewability, almost complete absence of sulfur, as well as other harmful to equipment and the environment of chemical elements and compounds, abundance and availability. Unrefined substandard biomass (wood waste, agricultural waste, production and consumption waste, including solid municipal waste.), As well as other local types of fuels, primarily based on low-grade solid carbon-containing raw materials (peat and its processed products, brown coal) , in the aggregate, make up fuel resources, the use of which is potentially possible in the regions (territories) of their formation, production, production and the economic efficiency of consumption of which is limited to the regions (territories) of their origin / Decree of the Government of the Russian Federation of 22.02.2012 N 154 "On requirements for heat supply schemes, the procedure for their development and approval ”/. They represent a cheap (with low, zero or negative cost) and currently practically unused source of local energy resources.

Despite the dominance of traditional energy, there are vast regions in Russia where the development of energy supply in terms of economic, environmental and social conditions, as well as the conditions of resource supply, should be considered taking into account the large-scale use of small autonomous power plants using renewable energy sources.

First of all, these can include zones of autonomous power supply, the area of which is about 70% of the territory of the whole country, where, according to various estimates, from 10 to 20 million people live. Also, potential users of renewable energy can be: zones of centralized energy supply with a large shortage of electricity and significant material losses and social problems due to frequent outages of energy consumers, settlements with a difficult environmental situation, objects with morally and physically worn out traditional energy equipment, recreational zones.

The most serious drawback of “big power engineering” is the huge losses of useful energy when it is delivered from producers to end consumers. Even with the use of the latest achievements of science and technology in developed countries, these losses amount to 60 ... 70%. In addition, many economic, environmental, geographic and geological constraints, as well as safety and environmental requirements, are driving the construction of large power plants. Environmental restrictions, high land and water costs, significant capital expenditures, government regulations and many other obstacles create difficulties around the world for the construction of new powerful power plants.

In this regard, one of the promising areas of development of the world energy is the creation of infrastructure for distributed energy production - distributed energy. Distributed power generation - the concept of distributed energy resources - implies the presence of many consumers who produce heat and electricity for their own needs, directing the surplus to the general network. Such a scheme ensures a decrease in electricity losses during transportation due to the maximum proximity of electric generators to electricity consumers, and also leads to a decrease in the number and length of power lines.

Distributed power generation (distributed power generation) is characterized by low maintenance costs, low environmental pollution and high efficiency.

The areas of effective use of small autonomous power plants as a technical basis for distributed power generation can also include maintaining a balance of demand, taking into account the prospects for the development of a global non-carbon economy, ensuring sustainable power supply in areas with long-term emergency situations, at charging stations for electric vehicles, creating an environmentally friendly alternative to waste incineration technologies, especially in megacities, with the elimination or significant reduction of harmful emissions into the atmosphere (greenhouse gases, primarily CO ₂ , nitrogen oxides and other emissions) and pollution (discharges) of water resources. Raw materials base - local low-grade raw materials, including renewable raw materials - biomass (industrial waste, solid municipal waste, etc.), peat and brown coal, as well as products of their processing.

Obtaining electricity from solid biomass, which is a universal type of high quality energy, is based both on traditional methods of direct combustion and on modern thermochemical technologies / GOST R 54531-2011 Non-traditional technologies. Renewable and alternative energy sources. Terms and definitions / and are carried out through the use of thermal power plants (TPP), in particular, condensing power plants, however, their electrical efficiency, especially in terms of power plants of low power, is extremely low and the possibilities of its growth within the framework of existing technologies are limited due to the fact that most of the energy is on the removed, so-called "waste" heat, which is often difficult to effectively use in practice.

The most significant disadvantages of methods for generating electricity based on technologies for direct combustion of biomass:

- low overall and electrical efficiency (significant heat losses), which does not allow building a sustainable energy system on their basis;

- the problem of harmful emissions into the atmosphere (fly ash containing heavy metals; soot; carbon monoxide; oxides of sulfur and nitrogen; chlorine compounds; dioxins and polyaromatic hydrocarbons) has not been solved, complex and expensive cleaning of flue gases is required (according to estimates, the cost of a modern more than 60% of the cost of treatment facilities);

- slags, as a rule, contain unburned carbon and polyaromatics;

- the possibilities of using wet and high-ash biomass are limited, the lower limit of the calorific value of wet and high-ash organic matter, at which its autogenous (self-sustaining) combustion is possible without the use of additional fuel, corresponds to the Tanner condition (the so-called Tanner triangle): relative humidity W <50 %, ash content A <60%, carbon content C> 25%;

- the complexity of the automation of technological processes, because due to the low heat of combustion, high humidity and heterogeneity of biomass, its preliminary processing (grinding, compaction, drying, homogenization, etc.) or refining (production of fuel granules - pellets, fuel briquettes) is required;

- it is required to remove a large amount of "waste" heat and, accordingly, a large consumption of cooling water;

- bulky equipment.

The most universal way to use such types of raw materials is their high-temperature thermochemical conversion, or gasification at temperatures of 800-1300 ° C in the presence (blast) of air or oxygen and water vapor to obtain a fuel (otherwise generator) gas - a mixture of H ₂ , CO , СО ₂ , NO _x , СH ₄ / GOST R 54531-2011. Unconventional technologies. Renewable and alternative energy sources. Terms and definitions / carried out in gasifiers (otherwise: gasifier reactors, gas generators, converters). At the same time, gas, which is a cheap, convenient and environmentally friendly energy carrier, depending on its quality, is subsequently used in a power plant (burned in a boiler unit or used as a power gas, i.e. for direct energy production in an engine - gas piston or gas turbine). This allows you to significantly save on expensive equipment for gas cleaning of flue gases and equipment for the disinfection of recyclable waste. In addition, during gasification, the underburning of fuel is significantly lower in comparison with direct combustion, and there is practically no soot (unreacted carbon) in the resulting gas and ash residue.

An innovative direction for the development of distributed power generation is the development of small modular installations up to 1 MW of unit capacity. Installations operate on air (less often oxygen) blast, at atmospheric and medium pressure, medium (up to 1200 ° C), less often - high (1600-1800 ° C) temperatures in dense, fluidized beds and in a stream, using mainly low-grade fuels (brown coal, peat, biomass). Development level - mostly pilot and demonstration projects. The features of air blast installations include:

- low-quality gas (a significant amount of ballast - N ₂ , H ₂ O, CO ₂ , as well as tar and soot);

- unregulated ratio H ₂ / CO;

- bulkiness, complexity and high cost with low efficiency;

- low availability.

However, the potential benefits of these units are significant:

- focus on the use of local fuels;

- compactness, mobility, low weight;

- work without pressurization (at atmospheric pressure) on air or enriched air blast and with solid ash removal (without slag formation);

- factory readiness.

Existing technologies and designs for gasification of solid (condensed) carbon-containing fuels are very diverse / A. Samylin, M. Yashin. Modern designs of gas generating plants. - LesPromInform, No. 1, 2009, p. 78-85; Zheleznaya T.A., Geletukha G.G. Review of modern technologies for biomass gasification. - Prom. heat engineering, 2006, v.28, no. 2, p. 61-75; V. V. Kopytov Gasification of condensed fuels: a retrospective review, current state of affairs and development prospects - M: Infra-Engineering, 2012 - 504 p., P. 263-271 /. From an environmental point of view, their main advantage is a relatively low level of negative impact on the environment. This is primarily due to the rather long (especially for gasification in a dense layer) presence of gaseous products of gasification of condensed fuels, first in the oxidation (combustion) zone at temperatures from 1000 ... 1200 ° C and above, and then in the reducing (oxygen-free) formation zone combustible fuel gas. Under such conditions, thermal decomposition and reductive dechlorination of the most dangerous substances - dioxins, furans, polychlorinated biphenyls, benzo (a) pyrenes and other polycyclic aromatic hydrocarbons - occurs.

Low-grade carbonaceous feedstocks that are intended for use as a fuel in the present invention are generally characterized by increased ash (high ash feedstock) and / or tar (high bituminous feedstock) and moisture (wet feedstock) contents. In this regard, combustible fuel (otherwise, generator) gas obtained from such substandard raw materials according to existing gasification technologies (schemes) has properties that do not allow it to be used as a power gas, i.e. for direct power generation in the engine

- gas piston or gas turbine installation, namely:

- high temperature (300 ... 700 ° С) and, accordingly, low density, which leads to a deterioration in the filling of the engine and a drop in its power;

- low volumetric calorific value due to the high content of ballast (air nitrogen, moisture, carbon dioxide); so, for the most high-calorie gas obtained with air blast - less than 4000 kJ / m ^{3 of} dry gas, for the most high-calorie gas for steam-oxygen blast under pressure - about 15000 kJ / m ³ / Handbook. “Boilers and power plants on biofuel. Modern technologies for generating heat and electricity using various types of biomass. " Ovsyanko A.D., Pechnikov S.A., St. Petersburg, Biofuel portal WOOD-PELLETS.COM. 2008 360 p. with ill; from. 138-143 /;

- high content of harmful impurities (ash, coal dust, soot, resinous substances, sulfur compounds, moisture), which disrupt the normal operation of the engine, cause premature wear of rubbing parts and engine failure.

Such properties of the resulting fuel gas - high temperature, the presence of moisture, dust and tar, low calorific value, low pressure - when it is used to generate electricity using technologies that are effective for natural gas (in open and semi-closed cycle plants - in gas piston units, gas turbine plants), lead to a significant complication and increase in the cost of equipment (multi-stage cleaning, cooling and drying systems, booster compressors are required), a significant decrease in the efficiency of the used power units, and the bulkiness of the installations.

The method of power generation based on gas piston units has become widespread in practice / G.G. Tokarev. Gas generating vehicles. State scientific and technical publishing house of machine building. lit., M., 1955 /. So, the well-known typical solid-fuel gas-piston power plant / cm. Directory. "Boilers and power plants on biofuel ...". from. 248-253 /, consists of sections for fuel preparation, gasification, power generation and recycling water system. At the same time, the fuel preparation section includes equipment for the preliminary preparation of fuel from raw materials - conveyors, a metal detector, a crusher for crushing chips, a vibrating sieve for removing substandard chips, a control and automation system. At the gasification section, a gasifier reactor - a WBG400 gas generator with purification plants for cooling, drying and cleaning the produced gas (cyclone, Venturi scrubber, wet blower, gas dryer, active and passive fine filters, control filter, etc.) is installed. The power generation section is a generator set with a gas piston engine and control cabinets. The section of the circulating water system is designed to organize a closed system of process water used to cool the produced gas, and is a block-modular treatment facility (pipelines, pumps, tanks, treatment units, control panel, cooling tower or heat exchanger).

The power plant operates in CHP mode, providing an output electric power of 250 kW and a thermal power of 469 kW, with an overall efficiency of about 50% in nominal mode, taking into account useful heat recovery.

Essential features of the above solution, similar to the features of the claimed invention:

- availability of fuel preparation, gasification and power generation sections)

- gasification of solid fuel in a reactor-gasifier according to the scheme of the direct process of vapor-air gasification in a dense bed;

- use of purified and cooled fuel gas in a gas piston engine;

- the use of a water heat exchanger in a closed cooling system of the resulting fuel gas.

However, this and similar technical solutions using shaft-type reactors have inherent disadvantages that significantly limit the area of their effective use in the interests of small-scale distributed electric power industry, namely:

- low electrical efficiency (-18%) due to the need to cool the fuel gas (energy losses up to 20%), as well as the prevailing share (2/3 or more) of the thermal component in the output power;

- low efficiency of converting solid fuel into gaseous (gasification efficiency up to 80%) due to thermal and chemical losses from fuel underburning (soot, sinking into the ash pan, carbon carryover in the form of dust);

- high content of harmful emissions (CO, NO _x ) into the atmosphere due to the use of gas piston engines in the technological chain of power generation;

- restrictions on the use of substandard raw materials (moisture content not higher than 0.20);

- low operational and technical characteristics of installations, a significant specific weight per unit of power and dimensions, the presence of a complex multistage system for cleaning, cooling and drying gas, a low degree of automation.

At the same time, a number of technical solutions are known aimed at increasing the efficiency of gasification of carbon-containing, and in particular, low-grade raw materials, as well as ensuring the required level of technical, economic and operational and technical characteristics of power plants in general through innovative gasification technologies, as well as integration technological processes of fuel preparation, gasification and power generation.

Known methods and installations for the production of electricity on the basis of a two-stage technological scheme, providing at the first stage gasification of fuel biomass, and at the second stage - combustion of the resulting fuel gas and conversion of thermal energy into mechanical energy in a heat engine (engine) of a closed cycle, where the working fluid circulates in a closed loop without communication with the atmosphere. Such a scheme is preferable from the point of view of minimizing the harmful effect on the environment by reducing harmful emissions into the atmosphere. As a result of reducing or eliminating the requirements for cleaning fuel gas, not only is gas cleaning equipment simplified and cheaper, but the calorific value of the gas also increases due to the combustible low- and high-molecular organic compounds (for example, alcohols and, especially, resins) contained in it. In addition, if the operation of cooling the produced gas is excluded, while saving on the appropriate equipment, the physical heat of the hot gas contributes to the heating of the working fluid of the power plants, and the issue of disposal of liquid secondary waste (gas condensate) is also removed. At the same time, proven technologies based on such well-known closed-cycle engines as a steam turbine unit (STU), a steam piston engine (SPE), a steam-screw engine (PVM), and an organic cycle turbine (ORC) can be used in low-power power plants. Such solutions are offered in the well-known "Method for producing electricity from substandard (wet) fuel biomass and a device for its implementation" (patent RU 2631455, Varochko A.G., Zabegaev A.I., Tikhomirov I.V., published date 22.09. 2017).

The method involves the production of electricity according to a two-stage technological scheme with gasification of raw materials in a gasifier reactor of a direct process of vapor-air gasification in a dense bed, in particular, a cylindrical inclined rotating gasifier reactor in a filtration combustion mode with superadiabatic heating, which makes it possible to efficiently gasify raw materials, including high-ash / Kislov V.M. Gasification of wood and its components in a filtration mode. Abstract of a thesis for the degree of Ph.D. IPHF RAS, Chernogolovka, 2008; Zaychenko A.Yu. Influence of solid phase motion on the character of filtration combustion. Abstract dissertation. for the degree of Ph.D. Chernogolovka - 2008. IPCP RAS /, and subsequent direct combustion of the resulting hot fuel gas and conversion of thermal energy into electricity by means of a thermal (steam) engine and an electric generator.

The invention provides for the recuperation of the "waste" heat of the steam spent in the heat engine by means of its condensation in a closed circuit of the circulation of the working fluid (water / organic coolant) of the heat (steam) engine according to a two-stage air cooling scheme, including a continuous interstage combined convective air-heater and conductive (contact ) drying of the feedstock, the air used in the required volume is fed into the reactor-gasifier as a gasifying agent. The implementation of the invention is assumed by introducing a condensation-drying unit into the device, connected to the outlet of a heat (steam) machine for exhaust steam and structurally representing a two-stage air steam condenser containing a steam line in the form of series-connected units - a module of the 1st condensation stage, a bypass collector steam and condensate drain with integrated (built-in) rotating drying drum, module of the 2nd stage of condensation. It is proposed to use various types of heat engines - PTU, FDA, RPM, ORC turbine.

Essential features of the above solution, similar to the features of the claimed invention:

- gasification of fuel in the reactor of the direct process of steam-air gasification in a dense bed, in particular in a cylindrical inclined rotating reactor, preferably in a filtration combustion mode with superadiabatic heating;

- air-convection drying of the original substandard (wet) raw material in a condensation-drying unit with an integrated (built-in) rotating drying drum due to heat loss recovery with the supply of waste air in the required volume to the reactor as a gasifying agent.

It is also known "A method for generating electricity from substandard (wet) fuel biomass and a device for its implementation" (patent RU 2631456, Varochko A.G., Zabegaev A.I., Tikhomirov I.V., published on September 22, 2017), which differs from the above in that the raw material for power generation, before being fed to gasification, is additionally subjected to conductive-convective drying with flue gases, which are purified by an organic adsorber with replaceable filter elements before being released into the atmosphere. Accordingly, in addition to the essential features of the above solution, similar features of the claimed invention, include:

- conductive heating of solid fuel after drying before loading into reactors due to the heat of exhaust gases;

- purification of flue (exhaust) gases by filtration through replaceable filtering elements made of organic adsorbent - activated carbon.

The above inventions make it possible to increase the electrical efficiency, expand the range of used cheap low-grade raw materials in terms of substandard ones, including the moisture content (up to 0.70 ... 0.85), fuel biomass, while minimizing the harmful effect on the environment and ensuring the autonomy of the production process electricity.

However, these solutions have a number of disadvantages that limit the possibilities of their effective use in distributed energy, namely, the cumbersomeness of equipment - heat engines, heat exchangers, steam boilers, the laboriousness of its maintenance, as well as the complexity and high cost due to the need to install additional special gas burners and afterburners for low calorific fuel gas. In addition, the proposed use in power plants of low power (up to 1 MW) for the power generation of closed-cycle engines (PTU, RPM, FDA, ORC turbine) is significantly inferior in efficiency (electrical efficiency) to the proven technologies based on gas piston engines / cm. A. Samylin, M. Yashin. Modern designs ... "/.

A well-known technical solution is aimed at eliminating these shortcomings - "Method for gasification of solid fuel and a device for its implementation (patent RU 2663144, Tikhomirov I.V., Egorov O.V., Zabegaev A.I., published on 01.08.2018), which is closest to the claimed invention in the combination of the following essential features.

The method provides for the gasification of solid low-grade carbon-containing raw materials, which is used as biomass, including substandard (both high-ash and high-bituminous) in the form of production and consumption waste, as well as peat, brown coal, with the subsequent use of the resulting combustible fuel gas directly in engines internal combustion - gas piston power plants, primarily for power generation.

The process of vapor-air gasification in a dense bed is carried out simultaneously in several (not less than two) cylindrical inclined rotating reactors as part of a poly-reactor gasifier (reactor cluster). It is a sequence of two alternating phases - modes that implement reverse and direct gasification processes. In one (first) phase, solid fuel is loaded into the upper part of the reactor - previously prepared (compacted and / or crushed, if necessary) raw material and a gasifying agent - air - is fed directly into the reaction zone, where the solid fuel moving there is partially oxidized (burned) and partially gasified (according to the reverse process), and its main part in the form of coke moves to the activation zone, where it is subjected to treatment with superheated steam at a temperature above 800 ° C and is accumulated in the form of activated carbon in the buffer zone, and the resulting vapor-gas mixture is removed from the reactor. In the other (second) phase, vapor-air gasification is carried out in a dense bed (by a direct process, preferably in the filtration combustion mode with superadiabatic heating) of the accumulated activated carbon, providing its reverse movement, with the supply of a vapor-gas mixture to the reaction zone, withdrawn from other (adjacent) reactors operating in the first phase, and with counter-filtration through a moving layer of activated carbon of the resulting combustible fuel gas, which is removed from the reactor and after cooling - water evaporation and air - is fed for direct use as a power gas in power plants, in particular, in gas piston engines of power units, as well as with the removal from the reactor of solid residues of gasification - ash.

A device for implementing this method - a poly-reactor gasifier (reactor cluster) - consists of several (two or more) jointly operating cylindrical inclined rotating (reversible) reactors with the ability to change the reactor rotation mode, including a reversible (pendulum with a change in the direction of rotation) mode, water evaporative a heat exchanger of a steam generator and a gas-air heat exchanger for cooling the combustible fuel gas removed from the reactors and a manifold gas pipeline for supplying it as a power gas to gas piston engines, as well as a hopper for ash. In this case, each reactor is equipped with a loading device with a hopper for raw materials, a steam-water jacket built into the space inside the double side wall of the reactor, consisting of an outer wall - a shell and an inner wall of the working chamber with a perforated section to ensure injection of superheated steam from the steam-water jacket into the working chamber of the reactor , an unloading device and blowing channels for supplying a gasifying agent - air to the reaction zone of the working chamber of the reactor. In the working chamber, an activation zone with a branch pipe for withdrawing the vapor-gas mixture into the vapor-gas outlet channel-collector (directly or through the inter-wall cavity of the reactor) and a buffer zone for the accumulation of activated carbon coming from the activation zone with a movable expansion piston with a variable speed of movement and with a hollow a rod for the removal of combustible fuel gas, as well as a discharge device for the removal of solid residues of gasification - ash - from the working chamber of the reactor into the ash bin. The operation of the reactor is carried out in the phase (mode) of the reverse gasification process and in the phase (mode) of the direct gasification process with a change of phases by rotating the reactor in a vertical plane to ensure the reverse movement of the gasified solid fuel inside the reactor.

The above essential features together form a technological scheme for obtaining clean cooled gas for direct use by gas piston engines in power generation, which, in turn, due to the exclusion of equipment for cleaning and drying fuel gas, can significantly increase the compactness and mobility of the installation, reduce the cost of equipment, its installation and operating costs, to increase efficiency (gasification efficiency and electrical efficiency), as well as autonomy of power generation, which is limited only by the need for an external source (reserve) of water.

However, the disadvantages that limit the possibilities of its effective use in small distributed power engineering include significant restrictions on the permissible relative humidity of raw materials (up to 0.15 ... 0.20), insufficient efficiency of reactor thermal protection, significant heat losses and a high content of harmful emissions (CO, NO _x ) into the atmosphere due to the use of gas piston units in the technological chain of power generation.

The present invention is aimed at solving the technical problem of increasing the efficiency of autonomous power generation using low-power power plants operating on solid low-grade carbon-containing raw materials - substandard biomass, and primarily with a high moisture content, including production and consumption waste, peat, brown coal, etc. ., while minimizing the harmful effect on the environment.

The proposed invention provides the following technical results.

Firstly, the range of used cheap low-grade raw materials in terms of moisture content (up to 0.7 ... 0.8) is expanding, which can significantly reduce the cost of electricity. This is achieved by the fact that in the course of preliminary preparation, the wet raw material, before being fed to the reactors for gasification, is subjected to air-convection drying with conductive heating using the heat of the obtained fuel gas by cooling and condensing water vapor obtained as a result of evaporative cooling of the fuel gas, and using heated air after air cooling of fuel gas. In addition, heated air is also used to dry the raw material, which is exhausted in the cooling systems of the gas piston engines of power units, and before loading the raw material into the reactors, additional conductive heating is carried out by means of exhaust gases from the gas piston engines of power units. To accomplish this, a fuel preparation section with a condensation-drying unit for air-convection drying of raw materials with its conductive heating and a raw material hopper with the possibility of additional conductive heating of raw materials after drying before loading into reactors is formed as part of the device. In this case, structurally, these elements are designed as heat exchangers ensuring efficient recuperative use of heat from cooled fuel gas and cooled gas piston engines.

Secondly, the efficiency of thermal protection (water cooling) of the used reactor increases, and, accordingly, its compactness, reliability and durability due to the supply of water in the form of condensate to its steam-water jacket from the created closed (without discharge to the outside) water circulation loop, including a reservoir of water-condensate , a water evaporative heat exchanger - a steam generator and a condensation-drying unit, with an external input to replenish the water flow, which also removes the need for water treatment equipment and allows you to exclude a separate section of the recycled process water system as a whole.

Thirdly, the efficiency of power generation increases - electrical efficiency, due to the utilization (recuperation) of heat from cooling the resulting fuel gas and gas-piston engines of power units for drying raw materials in a condensation-drying unit, as well as heat of exhaust gases for heating raw materials in the raw material bin after drying before loading into reactors.

Fourthly, minimization of the harmful effect on the environment is achieved due to the fact that the exhaust gases of gas piston engines of power units are purified by filtering them through a layer of activated carbon (with the adsorption of harmful substances contained in them, primarily nitrogen oxides) obtained in the first phase of the gasification process and entering the adsorption cavity of the movable expansion piston of the reactor.

Fifth, adaptation (flexibility) to variable load (electricity consumption) is additionally ensured while maintaining a constant (optimal) mode of operation of the reactors due to the possibility of promptly changing the number (by disconnecting / connecting separate gas piston engines) of simultaneously operating power units, using a storage unit at the output an electricity generating cluster, as well as installing a combustible fuel gas storage device - a gas holder (variable or constant volume). The operation of the equipment in this mode, in turn, increases its availability, reliability, durability and maintainability, which ensures the continuity of the autonomous power generation process.

Sixth, high equipment compactness and mobility (transportability) of the power plant are additionally achieved through design solutions for the full integration (unification) of multifunctional fuel preparation and gasification units into a single fuel block.

The essence of the invention is illustrated in FIG. 1-12.

Figure 1 shows a general flow diagram illustrating the essence of the proposed method at the resource-energy level of description, in the form of a sequence of stages of converting the feedstock into electricity.

FIG. 2 shows a structural and functional diagram of a small solid fuel power plant for implementing the proposed method of autonomous power generation.

FIG. 3 shows the process flow diagram of the process of heat recovery and purification of exhaust gases of gas piston engines of power units.

FIG. 4-6 show the structural and functional diagrams of the main element of a small solid fuel power plant - a cylindrical reversible (inclined rotating) reactor (in a vertical position) when operating in the phase (mode) of the reverse gasification process.

FIG. 7-9 shows a structural and functional diagram of the main element of a small solid fuel power plant - a cylindrical reversible (inclined rotating) reactor (in a vertical position) when operating in the phase (mode) of the direct gasification process.

FIG. 10-11 shows the structural and layout diagram of a small solid fuel power plant for a particular case of its construction with full integration of the main functional elements (units) of fuel preparation and gasification into a single fuel block.

FIG. 12 shows graphs of the dependence of the lower calorific value Q of the feedstock on its relative humidity (total moisture content) W.

The initial energy resource for electricity generation is solid low-grade (substandard, including moisture content) carbon-containing raw materials - biomass (both primary and in the form of production and consumption waste), peat, brown coal, etc. (Fig. 1). As a rule, for its use as a solid fuel in the proposed method, uniformity of its granulometric (fractional) composition is required, if necessary, achieved by means of its mechanical processing - grinding (for lumpy raw materials) and / or compaction (for raw materials with low bulk density or finely dispersed materials ), to ensure gas permeability and flowability (mixing) of the resulting fraction (at the stage of preliminary preparation 1) in subsequent successive technological operations at the stages of drying 2, heating 3 and gasification 4 of solid fuel. Combustible fuel gas obtained at gasification stage 4 (as a result of high-temperature thermochemical conversion of solid carbon-containing fuel), the temperature of which reaches 300 ... 700 ° С, passes through cooling stage 5 and at temperatures up to 30 ... 50 ° С is supplied to internal combustion engines - gas piston engines for power generation stage 6 with the receipt of electricity for consumers.

This technological process of converting raw materials into electricity has the following essential features.

1. Drying stage 2 provides for air-convection drying of wet raw material - solid fuel with recuperative use of heat removed at cooling stage 5 by conductive heating of the mixed raw material during cooling and condensation of water vapor obtained as a result of evaporative cooling of fuel gas, and with blowing air heated by air cooling of the fuel gas. In this case, in addition, heated air can be used, spent in the cooling system of gas piston engines of power units (see power generation stage 6).

2. Heating stage 3 assumes conductive heating of solid fuel supplied after drying stage 2 with heat recovery from exhaust gases of gas piston engines of power units (power generation stage 6).

3. At the gasification stage 4, a continuous process of vapor-air gasification in a dense bed is carried out simultaneously in several (at least two) jointly operating cylindrical reversible (inclined rotating) reactors (reactor cluster), in each of which the process is a sequence of two alternating phases - modes of reverse and direct gasification processes with an intermediate transformation of the gasified solid fuel into activated carbon, which provides the output of clean fuel gas, namely, without impurities (tar, ash particles, unreacted carbon, soot) and ballast (water vapor).

Air (heated and humidified) and water-condensate after drying stage 2 are used as gasifying agents.

The activated carbon obtained as a result of partial gasification in the reverse process mode is additionally used for cleaning the exhaust gases of 7 gas piston engines of power units from harmful toxic impurities (nitrogen oxides NO _X , soot, hydrocarbons, CO).

4. Cooling stage 5 includes evaporative water cooling of fuel gas using condensate water after drying stage 2 and water from outside to replenish its consumption at gasification stage 4, as well as additional air cooling to reduce the fuel gas temperature from 300 ... 700 ° C to 30 ... 50 ° C.

5. At the stage of power generation 6, combustible fuel gas - cooled, without harmful impurities and ballast - is used in gas-piston engines of power units to generate electricity supplied to consumers. The heated air exhausted in the cooling system of gas piston engines can also be supplied to drying stage 2.

The method of autonomous power generation is carried out by means of a device - a small solid fuel power plant, which works as follows.

The above stages of the technological process of power generation are implemented in three sections: the fuel preparation section 8, the gasification section 9 and the power generation section 10 (Fig. 2).

Fuel preparation section 8. This section implements the technological stages of drying 2 and heating 3 of raw materials - solid fuel.

Solid low-grade (substandard, including moisture content) carbon-containing raw material F after preliminary preparation - mechanical treatment (if necessary) is continuously or dosed into the condensation-drying unit 11 through its loading gate 12 into the rotating drying drum 13, where air convection drying with blowing with a drying agent - heated air A, pumped through the inlet manifold air duct 14 from the cooling elements in the gasification sections 9 (gas-air heat exchanger 15) and power generation 10 (standard cooling system of gas piston engines of power units 16). At the same time, in the inner working cavity of the drying drum 13, solid particles of wet raw materials F, while mixing, are blown by the flow of a drying agent - heated air A, which is both a heat carrier and a desiccant. At the same time, conductive (indirect) heating of the raw material occurs with water vapor coming from the water evaporative heat exchanger - steam generator 17 - fuel gas cooler at the gasification section 9 through the steam line 18 into the internal steam line of the condensation-drying unit 11, where the steam gives off heat to the particles of the wet raw material F, which are intensively with the heat transfer surface of the inner working cavity of the drying drum 13. In this case, the steam is cooled and condensed, and the flowing condensate is collected in the collector (the space between the two coaxial cylinders, the inner is a rotating drying drum 13, the outer is a stationary shell - a casing) and is discharged through the pipeline 19 into water tank 20.

When drying can be used (alternatively or alternately) modes of direct-flow or counter-current flow of raw materials F and drying agent - air A. In this case, the drying drum 13 can be installed at an angle to the horizon to provide the required speed of movement of the biomass F (for known technical examples, this is 3- 4 °). The tilt of the drum and its rotation ensure the movement of the raw material F under the action of gravity (and, possibly, the air pressure for the direct-flow mode) from the loading sluice 12 to the unloading sluice 21. The drum rotation frequency can be variable and determined by the parameters of the raw material being dried (for known technical examples it is 1.5-9 rpm), the angle of inclination of the drum can also vary. On the inner surface of the drying drum 13, paddle, sector, screw or other nozzles are installed, providing mixing of the raw material and its uniform distribution over the cross section of the drum, which intensifies the drying process, providing a large contact surface area between the particles of the raw material and the drying agent.

The used air in the required volume is supplied through the outlet air duct 22 to the gasification section 9 to the polyreactor gasifier - the reactor cluster 23 as a gasifying agent, and the excess exhaust air is discharged into the atmosphere, for example, through the exhaust pipe 24.

The preferred option for the technical implementation of the condensation-drying unit 11 can be considered the option with an integrated (built-in) rotating drying drum and a two-stage air cooling circuit, including continuous inter-stage combined drying of raw materials (for an example of technical implementation, see "Method of generating electricity ..." patent RU 2631455).

Dried raw material F from the condensation-drying unit 11 (through its discharge gate 21) is continuously or dosed into the raw material hopper 25 (through its loading gate 26), where it is accumulated and subjected to conductive (contact) heating due to the heat of the exhaust gases coming through the initial section 27 of the gas pipeline-collector of exhaust gases from the electricity generating cluster 28 from the gas piston engines of the power units 16 (the temperature of the exhaust gases at the engine outlet can reach 300 ... 400 ° C). Passing through the internal gas supply cavities 29 (see Fig. 3), the exhaust gases give off heat to the particles of the raw material F in contact with the heat transfer surface of the inner working cavity of the raw material hopper 25, and enter through the intermediate section 30 of the exhaust gas collector gas pipeline into the reactor cluster 23. The heated raw material - solid fuel F through the unloading locks 31 is supplied to the gasification section 9 (to the reactors of the reactor cluster 23).

Gasification section 9. In this section (Fig. 2), the technological stages of gasification 4 and cooling 5 (see Fig. 1) are implemented as part of the gasification process - thermochemical conversion of prepared (dried and heated) raw material - solid carbon-containing fuel into combustible fuel gas, suitable for direct efficient use in gas-piston engines of power generators 16, namely, free of tar, soot, water, etc. impurities and cooled to an acceptable temperature (no higher than 30 ... 50 ° C). For this, a polyreactor gasifier is included in the gasification section 9 - a reactor cluster 23 of several (at least two) jointly operating cylindrical reversible (inclined rotating) reactors, as well as a fuel gas pipeline-manifold 32 with a water evaporative heat exchanger - a steam generator 17 and a gas-air heat exchanger 15 for cooling combustible fuel gas G removed from the reactors and supplied to the gas-piston engines of power units 16. In this case, the design of each reactor makes it possible to operate both in the phase (mode) of the reverse gasification process (reactors 33, Fig. 2), and in the phase (mode) direct gasification process (reactors 34, Fig. 2) with a phase change by changing the inclination (rotation) of the reactor in the vertical plane and providing a reverse movement of the gasified fuel inside the reactor. It is also possible to change the mode (direction, speed) of rotation of each reactor around its axis.

The reactor, operating in the phase (mode) of the reverse gasification process (Fig. 4-6), is connected by its loading device 35 with the raw material hopper 25 through its corresponding discharge gate 31 (see Fig. 3), from where the prepared (dried and heated ) solid fuel F, filling the pyrolysis (coking) zone 36 of the working chamber of the reactor.

The reactor is equipped with a built-in steam-water jacket 37 (for an example of technical implementation, see "Method for gasification of fuel biomass and device for its implementation", patent RU 2631811, Zabegaev A.I., Tikhomirov I.V. et al., Published on June 29, 2017) , providing thermal protection of the walls of the reactor in high-temperature zones of the working chamber, with a perforated section for injecting superheated steam from the steam-water jacket 37 into the working chamber, and blowing channels 38 for supplying the gasifying agent / oxidizer - air to the reaction zone 39 of the working chamber, where it moved there into in the form of coke, the fuel is partially oxidized (burned out), ensuring that a temperature of 900 ... 1100 ° C is reached, which is necessary, firstly, for the implementation of thermal processes in the pyrolysis zone 36 and, secondly, for partial air gasification of the fuel and obtaining a layer of hot coal, which moves further to the activation zone 40, where at a temperature of at least 800 ° C it is subjected to treatment with water vapor superheated due to heat about the flow from the reaction zone 39 and supplied by self-injection from the steam-water jacket 37 through the perforated wall 41.

The gases formed in the pyrolysis zone 36 (volatile fractions, resin vapors) with an admixture of combustible fuel gas obtained as a result of the process of partial gasification of fuel in the reaction zone 39 and the activation zone 40 and the volume of which is limited by the regulation of the air blast rate and steam supply, as well as the residence time fuel in the reaction zone 39, together with unreacted steam, make up a steam-gas mixture, which is removed through the circulation pipe 42 into the steam-gas channel-collector 43 (directly or through the sectioned inter-wall cavity 44 of the reactor). At the same time, to ensure reliability (in case of possible failures of the circulation pipe 42), additional (duplicate) circulation pipes can be equipped, going out into separate sections of the sectioned inter-wall cavity 44 (see Fig. 5, 6), equipped with independent outlets to the steam-gas channel-collector 43 ...

Activated carbon obtained as a result of the treatment of coal in the activation zone 40 with superheated steam (with a corresponding decrease in temperature due to endothermic reactions) is accumulated in the buffer zone 45 located below by lowering (with a movement speed regulated to ensure optimal operating parameters of the process) the movable expansion piston 46 which is hollow. In this case, the internal adsorption cavity 47 is filled with produced activated carbon C during the movement of the expansion piston 46 from the initial position to position 48 by opening the flaps 49. The movement of the expansion piston 46 stops at position 48 with an emphasis on the end wall 50 of the reactor, while the buffer zone 45 filled with activated carbon, and the lateral cylindrical wall 51 of the expansion piston in position 48 together with the casing 52 and the end wall 50 of the reactor form an annular chamber 53, which is used to filter / purify the exhaust gases of the engines of gas piston power units after the reactor is switched to the phase (mode) of the direct gasification process ...

Transfer of the reactor to the specified mode (Fig. 7-9) is carried out by means of its rotation (reverse) in the vertical plane. In this case, the loading device 35 is disconnected from the hopper for raw materials 25 (see Fig. 4), and in the pyrolysis (coking) zone 36, the prepared (including dried and heated) fuel remaining there is fixed as a "pillow" supporting the layer accumulated in buffer zone 45 of activated carbon.

In addition to the continuing air blast through the blowing channels 38 from the vapor-gas channel-collector 43 (directly or through the sections of the inter-wall cavity 44 of the reactor and the circulation pipe 42), the vapor-gas mixture begins to flow from the reactors operating in the phase (mode) of the reverse gasification process into the working chamber of the reactor , moreover, into the reaction zone 39, which gradually moves to the place of the activation zone 40 (see Fig. 4) due to the formation of the cooling zone 54, where the accumulation of solid residues of gasification - ash R, which, as the reactor rotates, is poured out through the channels of the unloading device 55 and dedicated sections of the inter-wall cavity 44 into the ash bin 56. The ash discharge rate R from the reactor is determined by choosing the design parameters of the unloading device and the operating parameters of the reactor (rotation speed, air blast speed) so that the position of the reaction zone 39 in the reactor in phase ( mode) of the direct gasif process ication remained constant.

In the mode of the direct gasification process, almost complete decomposition of the tars of the incoming steam-gas mixture in the high-temperature (900 ... 1100 ° C) redox reaction zone 39 is ensured, the completion of the reactions of gasification of fuel carbon with the formation of mixed (air and water) combustible fuel gas:

C + O ₂ → CO ₂ +97650 kcal / mol

2С + О ₂ → 2СО + 58860 kcal / mol

2CO + O ₂ → 2CO ₂ +136440 kcal / mol

СО ₂ + С → 2СО - 38790 kcal / mol

C + H ₂ O = CO + H ₂ - 28380 kcal / mol

C + 2H ₂ O = CO ₂ + 2H ₂ - 17970 kcal / mol,

Moreover, the reduction reactions of carbon (in the form of red-hot activated carbon) with carbon dioxide and water vapor are endothermic (with heat absorption), which makes it possible to limit the temperature to the level of the beginning of melting of biomass - 1150 ° C / cm. Directory. "Boilers and power plants on biofuel ...", p. 32 / and thus exclude possible slagging in the working chamber of the reactor, including when using other low-grade raw materials (brown coal, peat).

Thus, in the working chamber, a direct process of gasification of activated carbon accumulated in the buffer zone 45 is realized, when by means of air blast, supplemented, firstly, by the supply of a steam-gas mixture and, secondly, by superheated water vapor from the steam-water jacket 37 to obtain the necessary ( preferably stoichiometric) the ratio with the gasified carbon of the fuel, with the formation of a gas flow that passes sequentially through the cooling zone 54, the reaction zone 39 and further in the form of the resulting combustible fuel gas (a mixture of active components - carbon monoxide CO and hydrogen H ₂ with a small proportion of methane CH ₄ and oxygen O ₂ and passive components - carbon dioxide CO ₂ and a significant proportion of nitrogen N _{2 of} air / see the Handbook. "Boilers and power plants on biofuel ..." pp. 117-118, 140-143 /), is filtered through the moving towards it a layer of activated carbon in the buffer zone 45 and then removed through the opened one (for example, under its own weight) gas valve 57 and hollow stem 58 and further into the fuel gas line-manifold 32.

Purification of the resulting fuel gas from impurities (ash particles, unreacted fuel carbon, soot, possible traces of tar) occurs due to adsorption in a layer of activated carbon in the buffer zone 45. A high degree of processing of solid fuel and purification of fuel gas is provided due to the length of the buffer zone 45 , as well as the high reactivity of the fuel - activated carbon (based on the original, mainly vegetable, including wood raw materials), its gas permeability and flowability (mixing).

Since the produced combustible fuel gas has a too high temperature (up to 700 ° C and higher), recuperative water evaporative cooling is provided in the gasification section 9 for its use as a power gas in gas piston engines (Fig. 2).

Combustible fuel gas discharged from reactors 34, operating in the phase (mode) of the direct gasification process, enters the fuel gas pipeline-manifold 32, where it is cooled in a water evaporative heat exchanger - steam generator 17, where water circulating through a closed circuit, as well as additionally (to replenish the flow) water from the outside. In this case, the water vapor obtained as a result of heat exchange is fed through the steam line 18 to the internal steam line of the condensation-drying unit 11.

The efficiency of cooling the combustible fuel gas (to reduce its temperature to the required values) can be increased by additional air cooling. To do this, the gas is cooled in a gas-air heat exchanger 15, where atmospheric air is supplied, which then, in a heated state, enters the fuel preparation section 8 (through the inlet air duct 14 into the drying drum 13 of the condensation-drying unit 11). The cooled fuel gas flows to the power generation section 10 to the power generation cluster 28 for use as power gas. At the same time, to ensure the stability of the fuel gas supply in conditions of its variable flow rate (fluctuations in the output power, shutdown of individual gas piston engines), the fuel gas pipeline 32 can be equipped with a combustible fuel gas storage device - a gas holder 61.

Simultaneously with the process of gasification of the activated carbon accumulated in the buffer zone 45 of the reactor, operation 7 of cleaning the exhaust gases coming from the gas piston engines of the power units 16 (see Fig. 2, 3) is carried out along the initial section 27 of the exhaust gas collector gas pipeline, through the raw material hopper 25, along the intermediate section 30 of the exhaust gas manifold gas pipeline into an annular chamber 53, which is divided into sections, some of which are inlet 59, and others - outlet 60 for exhaust gases. The latter are filtered through a layer of activated carbon separated in the phase (mode) of the reversed process, loaded into the adsorption cavity 47 of the expansion piston, passing through its perforated side walls 51, and then entering through the hollow rod 58 into the outlet part 62 of the exhaust gas collector gas pipeline and further to exhaust to atmosphere through exhaust pipe 24.

After the completion of gasification of the entire volume of activated carbon accumulated in the buffer zone 45, the expansion piston is lowered to the lower position, where the flaps 49 open and the spent activated carbon is discharged into the reaction zone 39 for gasification with complete decomposition of adsorbed harmful components, including toxic nitrogen oxides NO _x , as well as soot and hydrocarbons.

Power generation section 10. This section implements the technological stage of power generation 6 - generating electricity for external consumers, as well as for its own energy consumption (drives of reactors and drying drum, fans and pumps, charging devices, an igniter for starting the gasification process, etc.), from fuel gas by means of power units 16 with gas piston engines and alternators (within cluster 28). In conditions of reduced power consumption, some of the power units 16 can be quickly turned off, and the surplus fuel gas produced can be accumulated in the gas holder 61. In addition, to smooth out fluctuations in power consumption, as well as to ensure its own power consumption (initial start-up, emergency guaranteed power supply), a storage electricity - battery pack with energy converter 63.

A particular case of the technical implementation of the proposed method of autonomous power generation provides for the full integration (combination) of multifunctional fuel preparation and gasification units into a single fuel block, structurally representing a horizontally located system of coaxially nested cylindrical chambers - cavities (Fig. 10, 11), in which functional units are located. Through the loading gate 64, the wet raw material enters a cylindrical drying cavity 65 with a rotating wall 66 and nozzles 67, which is a drying drum similar to the drying drum 13, the operation of which was described earlier (see Fig. 2). In this case, mechanical processing (grinding / compaction) of the feedstock can be carried out in advance or by equipping the loading sluice 64 with the necessary devices (grinders, crushers, mills, presses).

Inside the drying cavity 65 is a cylindrical central cavity 68 with a reactor cluster. It is divided by partitions 69 into reactor sections, in each of which, in a plane perpendicular to the axis of rotation of the cylinder system, a cylindrical reversible (inclined rotating) reactor 70 is installed, operating in the phase (mode) of the reverse process 71 or in the phase (mode) of the direct gasification process 72 with the change phase (mode) by turning. The dried and heated raw material - solid fuel during the rotation of the wall 66 is loaded through the loading device 38 into the reactors in the phase (mode) of the reverse process 71. The collector cavity 73 contains the steam-gas channel-collector 43, the channels for supplying gasifying agents - air and water (with tank), a fuel gas pipeline-collector 32, as well as ash discharge channels. The resulting fuel gas G is cooled in a gas-air heat exchanger 15 and a water evaporative heat exchanger - a steam generator 17, from which steam enters the inner annular steam-pipe cavity 74, where it is cooled and condensed. To reduce heat loss, the fuel block is equipped with an insulating shell 75.

The exhaust gases from the gas piston engines of the power generating units of the power generating cluster 28 enter the central cavity 68, where the reactor sections and the internal adsorption cavities of the reactors pass sequentially, which provides conductive heating of the feedstock in the drying cavity 65 and their cleaning before being released into the atmosphere.

The technical effect of the proposed solutions can be assessed as follows.

Firstly, the economy significantly increases (the cost of electricity is reduced), since the spectrum of cheap low-grade raw materials used in terms of moisture content expands due to the construction of a technological scheme with systemic recovery of energy losses, namely, the use of heat from the resulting fuel gas during its cooling (evaporative and air ), heat from the cooling system and exhaust gases of gas piston engines of power units for drying and heating raw materials at the fuel preparation section.

The energy, and, accordingly, the consumer value of fuel is determined mainly by its calorific value - the amount of energy per unit mass of fuel that can be used to generate heat / electricity. In particular, the quality of biomass as a fuel is assessed by the lower heating value (LTS) Q, which largely depends on the moisture content of the fuel. Its quantitative indicator - relative humidity (total moisture) W _o - is one of the most important variable characteristics of the fuel, largely determining its cost and, ultimately, the efficiency of its energy use in practice. For reference data / see. the above Reference. "Boiler houses and power plants on biofuel ..."; Biomass as a source of energy. Ed. S. Soufer, O. Zaborski. - M., Mir, 1985 / the average relative humidity of low-grade cheap raw materials can be 0.33 ... 0.5 for freshly cut and 0.5 ... 0.8 for wet (transported by water) wood, up to 0.7 - for urban sludge waste water, 0.6 ... 0.85 - for manure, up to 0.55 and more - for agricultural waste, 0.15 ... 0.35 - for solid waste.

The relationship between the above characteristics can be expressed by the following ratio / cm. the above "Method of generating electricity ...", patent RU 2631455 /:

where Δt _w is the temperature of heating the raw material moisture from the current value to 100 ° C

Q _c - NTS of dry matter of fuel;

C _w = - specific heat capacity of water;

L _y = - specific heat of vaporization.

Taking Δt _w = 80 ° (from 20 ° C to 100 ° C); C _w = 4.1872 kJ / kgK; L _γ = 2250 kJ / kg, we get

From the examples shown in FIG. 10 graphs of the dependence of the NTS Q of the feedstock on its relative humidity W ₀ it follows that theoretically the upper limit of the value W _o of the feedstock used due to the proposed solutions can be significantly increased (from 0.15 ... 0.20 for the prototype to 0.7 ... 0 , 8), which allows you to process almost any kind of wet solid low-grade raw materials. At the same time, a certain decrease in the upper limit relative to the theoretically possible one is associated with the need to consume electricity for the plant's own needs.

Secondly, the efficiency of thermal protection (water cooling) of the reactor is increased due to more intensive heat removal when water is supplied to its steam-water jacket (instead of the steam-water mixture) in the form of condensate from the created closed (without discharge to the outside) water circulation loop, including a water-condensate reservoir , a water evaporative heat exchanger - a steam generator and a condensation-drying unit, with an external input to replenish the water flow, which increases the compactness, reliability and durability of the reactor, and also removes the need for water treatment equipment and eliminates a separate section of the recycled process water system as a whole.

Thirdly, the efficiency of power generation increases - electrical efficiency due to the systemic recovery of thermal energy components generated in the process of gasification (heat of the cooled fuel gas) and power generation (heat of the cooling system of gas piston engines of power generators and exhaust gases), through their utilization (use) in the process fuel preparation (drying and heating of raw materials with an increase in its energy value - calorific value according to Fig. 10).

Proceeding from the fact that for modern gas-piston power plants the ratio of electric and thermal power is 1: 1.2, and for small, or mini-CHP plants, this ratio can be 1: 1.9 (see, for example, the above Reference. " Boilers and power plants on biofuel ... ", p. 253), based on the proposed solutions that ensure the redistribution of output power towards the electrical component, the electrical efficiency can potentially be increased by 2.2 ... 2.9 times (excluding heat exchange losses). So, for the given known analogue - a typical small solid-fuel gas piston power plant / cm. the above Reference. "Boilers and power plants on biofuel ...", p. 253 / rated electrical power 250 kW electrical efficiency can be increased from 18% to 40 ... 52%.

Fourth, environmental safety is achieved, because harmful influence on the environment is completely excluded, and without any additional equipment (filters, neutralizers, etc.) and consumables (special adsorbents). Gaseous and solid waste from electricity generation - exhaust gases from gas piston engines and ash - do not contain any harmful (toxic) components. The most toxic nitrogen oxides NO _x , carbon monoxide CO, as well as soot and hydrocarbons are adsorbed in a separate layer of activated carbon and then completely decompose in the high-temperature (900 ... 1100 ° C) zone of the reactor. The high reactivity of activated carbon during gasification makes it possible to almost completely eliminate the presence of carbon and soot residues in the ash. The air used in technological processes is returned to the atmosphere without harmful impurities. In addition, a harmful effect on water resources is excluded, since the water used in technological processes circulates in a closed loop without emissions to the outside.

Fifth, the continuity of the power plant operation is ensured by adapting to changing load conditions (fluctuations in power consumption), as well as in the event of failures (planned operational and long-term shutdowns) of individual units of the reactor cluster and power generating cluster, by installing gas storage tanks (gasholder) and electricity (battery pack with an electricity converter). At the same time, maintaining a constant (optimal) operating mode of the reactors increases their efficiency (gasification efficiency), availability, reliability, service life and maintainability. Full autonomy of work is ensured in the presence of an external source of water or its necessary supply at the power plant.

Sixth, the high compactness of the power plant equipment, which is additionally achieved through design solutions for the full integration (combination) of multifunctional fuel preparation and gasification units into a single fuel block using technical solutions for the construction of compact reactors with a water jacket (see the above patent RU 2631811) ... Thus, it becomes possible to create a small-sized mobile power plant both in a semi-stationary and in a mobile version with the placement of all equipment on one transport unit of various bases (road, rail, water), which significantly expands the scope of its mass application in distributed small electric power industry.

Claims (10)

1. A method of autonomous power generation with gasification of solid low-grade carbon-containing raw materials, which is used as biomass in the form of production and consumption waste, as well as peat, brown coal, and the use of the obtained combustible fuel gas in gas piston engines of power units, providing for the process of steam-air gasification in a dense layer simultaneously in several (at least two) cylindrical inclined rotating reactors, in each of which the process is a sequence of two alternating phases - modes of reverse and direct gasification processes, where in one phase (reverse process) solid fuel is loaded - previously prepared ( compacted and / or crushed, if necessary) raw materials - in the upper part of the reactor and a gasifying agent - air - is fed into the reaction zone of the reactor, where the solid fuel moving there is partially oxidized (burned) and partially gasified, and the bases Its most part in the form of coke moves to the activation zone, where it is treated with superheated water vapor at temperatures above 800 ° C and accumulates in the form of activated carbon in the buffer zone, and the resulting vapor-gas mixture is removed from the reactor, and in another phase (direct process), steam-air gasification of accumulated activated carbon is carried out, preferably in a filtration combustion mode with superadiabatic heating, ensuring its reverse motion, with supplying air and water vapor to the reaction zone of the reactor, as well as a vapor-gas mixture withdrawn from other reactors operating in the phase of the reverse process, and with counter-filtration through a moving layer of activated carbon of the resulting combustible fuel gas, which is removed from the reactor and after cooling - water evaporation and air - is fed for use as a power gas in gas piston engines of power units, as well as with the removal of solid residues from the reactor gasification - ash, characterized in that substandard (wet) raw materials are preliminarily subjected to air-convection drying with conductive heating in the process of cooling and condensation of water vapor obtained as a result of evaporative water cooling of the fuel gas, and with blowing air heated as a result of air cooling of the fuel gas, and the exhaust gases of gas piston engines are purified by filtration through a separate layer of activated carbon. 2. The method of autonomous electric power generation according to claim 1, characterized in that heated air is also used for drying the raw material, which was exhausted during cooling of gas piston engines of power units. 3. The method of autonomous power generation according to claim 1 or 2, characterized in that the exhaust gases of gas piston engines of power units are used for additional conductive heating of solid fuel after drying before loading into reactors. 4. The method of autonomous power generation according to claim 1, or 2, or 3, characterized in that the water obtained by condensation of water vapor during drying of the raw material and the air used to dry the raw material in the required controlled volume, preferably in a stoichiometric ratio with the gasified fuel are fed into the reactors as gasifying agents. 5. A device for autonomous power generation - a small solid fuel power plant based on local solid low-grade carbon-containing raw materials, which is used as biomass in the form of production and consumption waste, as well as peat, brown coal, containing a gasification section as part of a reactor cluster of several (at least two ) jointly operating cylindrical inclined rotating reactors and a steam-gas channel-collector, while each reactor, having the ability to change the angle of inclination and rotation mode, is equipped with a loading device, a steam-water jacket built into the space inside the double side wall of the reactor, consisting of an outer wall - a casing and the inner wall of the working chamber with a perforated section to ensure the injection of superheated steam from the steam-water jacket into the working chamber of the reactor, blowing channels for supplying the gasifying agent - air to the reaction zone of the working chamber of the reactor, in which the activation zone with p a pipe for circulation of a steam-gas mixture connected to a steam-gas channel-collector (directly or through a sectioned inter-wall cavity of the reactor) and a buffer zone for accumulating activated carbon coming from the activation zone, with a movable (with adjustable speed of movement) expansion piston with a hollow rod for removing fuel gas into the fuel gas pipeline-collector, as well as an unloading device for removing solid residues of gasification - ash - from the working chamber of the reactor into the ash bunker, with the possibility of alternating operation of each reactor in the phases - modes of reverse and direct gasification processes by rotating the reactor in a vertical plane and ensuring the reverse movement of the gasified solid fuel in the working chamber of the reactor, as well as the fuel gas pipeline-manifold with a water evaporative heat exchanger-steam generator and a gas-air heat exchanger for collecting and cooling the fuel g from the reactors a phase with its supply to the gas piston engines of power units, characterized in that it includes fuel preparation and power generation sections, while the fuel preparation section includes a condensation-drying unit for air-convection drying of raw materials with conductive heating and a bunker for raw materials with the possibility of additional conductive heating , while the condensation-drying unit is structurally a heat exchanger - an air steam condenser containing an internal steam line with an integrated (built-in) rotating drying drum with heat-conducting walls, while the internal steam line at the inlet is connected to the steam outlet of the water evaporative heat exchanger-steam generator, and its branch pipe condensate drainage - to the water reservoir, the outlet of which is connected to the steam-water jackets of the reactors and to the water evaporative heat exchanger-steam generator with the possibility of supplying additional water to it from the outside, while the outlet for air gas-air a flat exchanger through a manifold air duct is connected to a drying drum, which is equipped with loading and unloading locks for transferring dried raw materials to a raw material hopper, which is equipped with loading and unloading locks for unloading raw materials into reactors and is structurally designed as a heat exchanger for conductive heating of raw materials with exhaust gases of gas piston engines of power units , for which it is equipped with internal cavities, which are integral parts of the exhaust gas manifold gas pipeline. 6. A device for autonomous power generation according to claim 5, characterized in that the movable expansion piston of each of the reactors is hollow with the possibility of entering (loading) into it and pouring out (unloading) from it activated carbon accumulated in the buffer zone, and the gas pipeline-collector between its outlet from the raw material hopper and the inlet to the exhaust pipe has a section made in the form of parallel channels, each of which has an inlet and outlet through the adsorption cavity of the movable expansion piston of the corresponding reactor for filtering exhaust gases through a separated layer of activated carbon. 7. A device for autonomous power generation according to claim 5 or 6, characterized in that the inlet and outlet for exhaust gases in the adsorption cavity of the movable expansion piston of each of the reactors are formed by perforating the side walls of the movable expansion piston, which, when pulled out from the buffer zone of the working chamber of the reactor together with the shell and the end wall of the reactor form a sectioned chamber in the end part of the reactor connected by means of its inlet and outlet sections into one of the parallel channels of the exhaust gas manifold gas pipeline, and the connections are made through valves that open when the movable expansion piston is fully extended from the buffer zone reactor. 8. A device for autonomous power generation according to claim 5, or 6, or 7, characterized in that the air duct is additionally connected to air outlets from the cooling system of gas piston engines of power units. 9. A device for autonomous power generation according to claim 5, or 6, or 7, or 8, characterized in that all functional elements (units) of the fuel preparation and gasification sections are structurally integrated (combined) into a single fuel block in the form of a horizontal or under a small the inclination to the horizon of a system of coaxially nested cylindrical chambers-cavities as part of a drying cavity with a rotating wall and nozzles, inside which there is a central cavity with a reactor cluster, divided into reactor sections with cylindrical inclined rotating reactors with the possibility of changing their inclination by turning in a plane perpendicular to the axis rotation of a system of cylindrical chambers-cavities, a collector cavity with a steam-gas channel-collector, channels for supplying gasifying agents - air and water, a fuel gas pipeline-collector and an ash discharge channel, as well as cavities for a gas-air heat exchanger and a water evaporative heat exchanger - steam generator erator, while the loading sluice of the drying cavity can be equipped with devices for mechanical processing (grinding, compaction) of the feedstock, and the fuel block as a whole is covered with a heat-insulating shell. 10. A device for autonomous power generation according to claim 5, or 6, or 7, or 8, or 9, characterized in that the power units are combined into a power generating cluster with the ability to quickly start / stop the gas piston engines of power units, an electricity storage device is connected to the output of the power generating cluster - an accumulator unit with an electric power converter, and the fuel gas pipeline-collector is equipped with a fuel gas accumulator - a gasholder.

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