Gas Piston Engines Research Articles

INTEGRATED TECHNOLOGY OF BIOGAS UTILIZATION OF SOLID HOUSEHOLD WASTE LANDFILLS WITH THE PRODUCTION OF ELECTROCITY, HEAT AND CARBON DIOXIDE

The presence of carbon dioxyl as a non-combustible admixture in the landfill biogas of solid household waste and the absorption of ambient air into the layer of landfill waste, and therefore its entry into the landfill gas, significantly reduces the concentration of methane in it, which affects the efficient operation of the gas piston engine of the power plant and the reduction of volumes electricity generation. With the use of computer modeling for the composition of biogas with an increased content of N2 and a reduced concentration of CH4 £ 32 %, calculations were made on the enrichment of biogas to concentrations of CH4 in it of 36–44 % due to the use of CO2 amine absorption technologies, in which the costs for the regeneration of the absorbent are compensated by the produced thermal energy of the gas piston engine of the power plant. The removal of carbon dioxide from biogas makes it possible to simultaneously increase the concentration of methane in it at the input to the heat engine, which contributes to the stable and efficient operation of the gas piston engine of the power plant and the increase in the amount of electricity generation as a result of energy utilization of landfill gas. The use of complex biogas utilization technology in the cogeneration mode allows obtaining not only electricity, but also heat, which can be used in absorption amine technologies for CO2 extraction from biogas and thus reducing carbon dioxide emissions into the atmosphere. Bibl. 17, Fig. 9, Tab. 3.

Повышение энергетической эффективности газопоршневой ТЭС за счет комплексного использования тепловых вторичных энергоресурсов

Recently, the advantages and prospects to use piston gas internal combustion engines for the combined generation of electrical and thermal energy have become increasingly obvious. The range of single capacities of gas piston units (GPU) ranges from 0,1 MW to tens of MW, which makes them more attractive when designing various power facilities. Most brands of gas piston units can operate in co-generation mode, that is, as a combined heat and power plant that simultaneously generates electrical and thermal energy. The purpose of this study is to substantiate the possibility of integrated use of heat of the cooling systems of the gas piston engine of a thermal power plant (TPP). The studies conducted are carried out using well-known methods of thermodynamic calculation of the internal combustion engine cycle, of determination of the components of its thermal balance and thermal calculation of the equipment for utilization of secondary thermal energy resources. The results of the analysis of the heat losses of the GPU drive engine have showed that the total losses during its operation are about 11544,5 kW. Average potential heat losses with flue gases are 45,87 %, and low-potential heat losses with water in cooling systems and oil in lubrication systems are 53,14 %. A schematic diagram is proposed for the integrated utilization of thermal renewable energy resources (RES) at a gas piston thermal power plant. The main difference between the proposed scheme and the existing technical solutions is the utilization of the heat of the low-temperature charge air cooling system after the second section of the compressor and the heat of the engine lubrication system. An analysis of the expenditure part of the energy balance of the drive engine in case of the integrated use of thermal RES in the GPU cycle, has showed that the implementation of energy-saving measures will make it possible to usefully use up to 93,05 % of the supplied energy in the generation of electrical and thermal power.

РОЗРОБКА АВТОНОМНОГО ЕНЕРГОЗАБЕЗПЕЧЕННЯ ПЕРЕСУВНОЇ ПОВЕРХНЕВОЇ ДЕГАЗАЦІЙНОЇ УСТАНОВКИ

Currently, in connection with the difficult situation with energy supply, issues related to the application of new measures to conserve energy resources as well as the introduction of new promising technologies using alternative energy sources, such as mined methane, have gained great importance. The problem of methane from coal deposits is of particular importance. This problem primarily concerns the safety of miners' work, methane production as an alternative source of energy resources, and solving environmental problems related to methane emissions into the atmosphere of coal mining enterprises. The problem of reducing the efficiency of degassing is caused by the long length of the degassing pond and the depth of cleaning operations. The use of a mobile surface degassing unit makes it possible to effectively carry out degassing and achieve significant volumes of extracted gas with a methane content of up to 80%, but high costs of electricity complicate its operation. Therefore, the paper proposes an autonomous power supply for a mobile surface degassing plant. For the autonomous power supply of a mobile surface degassing plant, it is advisable to use an electric generator since an uninterrupted supply of electricity is important. Gas power plants are widely used in industrial enterprises. In accordance with the power consumption of the electrical equipment of the mobile surface degassing plant, the work justified and selected a gas power plant and electric power equipment for the autonomous power supply of the mobile surface degassing plant. The gas-piston power plant is designed for the production of electrical energy and can be both the main and backup source. As a fuel, mainline natural gas with an average supply pressure or methane mine gas is used. The basic configuration of the power plant is a liquid-cooled gas-piston engine based on a diesel unit. A technological scheme for connecting the gas power plant to a mobile vacuum pumping unit and its power supply scheme has been developed, which will increase the safety of cleaning works, solve the issue of methane utilization, significantly reduce electricity costs, and improve the environmental situation in the industrial region.

Energy prosumerism using photovoltaic power plant and hydrogen combustion engine: Energy and thermo-ecological assessment

Renewable Energy Sources (RES) represent an attractive way to save natural resources and improve the overall impact of power systems on the environment. A continuous increase of share of RES in national energy mixes is observed, and due to the energy policy of the European Union and many other countries, further increase is expected. A disadvantage of RES is their random, weather-dependent availability, which requires energy storage. A promising method of integrating RES with the energy system is the use of hydrogen as an energy carrier (e.g. coupling RES with electrolyzers in order to directly use the renewable electricity for production of hydrogen). In the present work, a simulation of cooperation of a photovoltaic power plant with a gas piston engine fueled by hydrogen was performed, with and without the presence of energy storage. The aim of the analysis is twofold. First, the “compensation losses” due to forced part-load operation of the engine coupled with RES are evaluated and compared with “storage losses” resulting from the thermodynamic imperfectness of the storage; this allows to calculate the minimum round-trip efficiency of storage required for positive energy effect. The “compensation losses” have been determined to be of the order of magnitude of 2%, and the minimum round-trip efficiency of storage to be at the level of 85%. Second, a thermo-ecological analysis was carried out to determine the impact of the source of hydrogen on the overall ecological effectiveness of the system. Contrary to the commonly used measure of “energy efficiency” describing a local balance boundary, thermo-ecological cost (TEC) evaluates the consumption of non-renewable exergy within a global balance boundary. The analysis confirmed that comparing various hydrogen production methods (especially renewable and non-renewable) in terms of local energy efficiency is inadequate, because it does not tell much about their sustainability. For a hydrogen energy system basing on the water electrolysis – hydrogen transport/storage – combustion in a gas piston engine pathway to be considered sustainable, the input electricity to the electrolysis process should be characterized by TEC lower than ∼0.15 J∗/J, a value which even some renewable energy sources fail to achieve.

The Possibility of Using Superconducting Magnetic Energy Storage/Battery Hybrid Energy Storage Systems Instead of Generators as Backup Power Sources for Electric Aircraft

The annual growth rate of aircraft passengers is estimated to be 6.5%, and the CO2 emissions from current large-scale aviation transportation technology will continue to rise dramatically. Both NASA and ACARE have set goals to enhance efficiency and reduce the fuel burn, pollution, and noise levels of commercial aircraft. However, such radical improvements require radical solutions. With the current traditional aircraft designs based on gas turbines or piston engines, these goals are infeasible. Small-scale aircraft have successfully proven emission reductions using energy storage systems, such as Alice aircraft. This paper involves an investigation of the possibility of using superconducting magnetic energy storage (SMES)/battery hybrid energy storage systems (HESSs) instead of generators as backup power sources to improve system efficiency and reduce emissions. Two different power system architectures of electric aircraft (EA) were compared in terms of reliability and stability in a one-generator failure scenario. As weight is crucial in EA designs, the weights of the two systems were compared, including the generators and energy storage systems. The two EA systems were built in Simulink/MATLAB to compare their reliability and stability. With the currently available technologies, based on the energy density of 250 Wh/kg for lithium-ion batteries and a power density of 8.8 kW/kg for generators, the use of the generators as backup sources proved more efficient than the use of HESS. The break-even point was observed at 750 Wh/kg for battery energy density. Any value more than the 750 Wh/kg energy density makes HESS lighter and more efficient than generators.

Prospects for the creation of a domestic hydrogen gas piston engine

Prospects for the creation of a domestic hydrogen gas piston engine

Оценка экологических показателей автомобильных двигателей, конвертированных на газовое топливо

The article describes the technical characteristics for two gasoline engines that are converted to methane fuel. The study was carried out on the basis of mathematical modeling in the Diesel-RК program. It is shown that the conversion of gasoline engines to methane leads to a power reduction in the range of 7.5% with a decrease in specific fuel consumption to 12%, as well as a reduction in NOx emissions by 2–3 times. It is revealed that an increase in the compression ratio to 15 leads to an increase in the power and environmental friendliness of the gas piston engine.

Оценка экологических показателей автомобильных двигателей, конвертированных на газовое топливо

The article describes the technical characteristics for two gasoline engines that are converted to methane fuel. The study was carried out on the basis of mathematical modeling in the Diesel-RК program. It is shown that the conversion of gasoline engines to methane leads to a power reduction in the range of 7.5% with a decrease in specific fuel consumption to 12%, as well as a reduction in NOx emissions by 2–3 times. It is revealed that an increase in the compression ratio to 15 leads to an increase in the power and environmental friendliness of the gas piston engine.

Техніко-економічні показники технологій теплової енергетики, що експлуатуються в маневрених режимах

There is a deficit in united energy system of Ukraine of installed capacity of flexible generation units which are able to quickly reach the operating mode, change the power generation levels in a wide range. To model additional measures increasing the flexibility of the power system, it is necessary to know the technical and economic indicators of thermal power technologies and its specific operating modes. The purpose of the article is to determine: efficiency factors depending on the power unit load; start-up costs depending on downtime duration and different fuel prices; the influence of maneuvering modes on lifetime resource indicators; as well as comparison of indicators for various technologies of thermal energy. The following thermal power technologies: natural gas, hard or bituminous coal fired steam turbine supercritical pressure, steam-gas, gas turbine open cycle and gas piston engines. The calculation formulas allowing estimate the influence of the power plant operation mode on the efficiency is obtained. The results of calculation of the start-up specific costs depending from the type of the unit and the idle time is presented. The different values of thermal power unit start-up cost are presented depending on idle time. As an example, the balancing of 660 MW electric power with different equipment composition are considered. The analysis of the results shows that the highest start-up cost is for coal-fired steam turbine plants, and the composition of the equipment with the lowest start-up cost varies depending on the downtime: up to 2 hours, 2 – 5 hours, more than 5 hours. Formulas for recalculating the cost of starting at different fuel prices are obtained. The influence of maneuvering modes on the lifetime resource indicators of thermal power plants is also presented. The conventional thermal power generators of the united energy system of Ukraine have actually overcome their physical capabilities to ensure effective load following, therefore, it is necessary to introduce new highly flexible capacities, and the proposed formulas and results could be helpful to determine the volumes and characteristics of new thermal power plants needed to implement into power system. Keywords: thermal power, maneuverable mode, efficiency, downtime, start-up cost, service life

Ways to solve the problem of converting diesel locomotives to gaseous fuel

The Government of the Russian Federation has set the task of expanding the field of application of gaseous fuels in the national economy. In accordance with this task, an agreement of June 17, 2016 was developed on cooperation between PJSC Gazprom, JSC Russian Railways, JSC Sinara Group, JSC Transmashholding in the use of natural gas as a motor fuel, which provides for the production of shunting gas locomotives and mainline diesel locomotives and gas turbine locomotives. This work is a continuation of the work begun in the 1990s to create, fine-tune and test diesel locomotives using natural gas as a motor fuel. The conversion of diesel locomotives to gaseous fuel can be carried out in two ways: creation of diesel locomotives with gas piston engines and the modernization of diesel locomotives of the existing fleet by converting the diesel engines of these locomotives to use the gas-diesel cycle. A comparison of these options is given and solutions are proposed that allow using gas-diesel cycle on diesel locomotives. Mathematical models for calculating the performance indicators of a gas-diesel generator plant in operating modes and separately for the fuel supply process are presented, their features and some calculation results are presented. The experimentally determined reasons for the impossibility of operation of the power plant in the gas-diesel cycle of a shunting diesel locomotive based on TEM18 below the fourth position of the driver's controller are theoretically substantiated. The minimum required structural changes to the standard fuel equipment are determined, which are necessary to ensure stable operation of a diesel locomotive on gaseous fuel. A comparative assessment of the efficiency of converting diesel locomotives to gaseous fuel is carried out and the cost of fuel consumed per hour of operation is determined, depending on the degree of fuel replacement with gas when the locomotive is operating in average operating modes.

Comparative analysis of the energy efficiency of different types co-generators at large scales CHPs

The comparative engineering analysis for the following cogenerator types have been performed: eleven Jenbacher piston engines J920 (Jenbacher, 11xJ920) with an installed power capacity per engine of 9.52 MW; 2 S Gas Turbines SGT-800 (Siemens 2 x SGT-800) with an installed power capacity of each turbine of 56.35 MW; one General Electric Gas Turbine 6F.03 (GE 1 × 6F.03) with the installed power capacity of 83.05 MW. Considered variants of co-generators should replace ineffectively operating existing unit in summer mode in a large scale CHP, which includes steam boiler TGMP-344A and steam turbine T-250/300-240-2. A multi-parameter analysis was performed to select a cogeneration plant and for the first time is one of the largest district heating plants of Central and Eastern Europe, incorporating several different technologies (gas turbine installation, gas-piston engine). Comprehensive analysis of significant components (technical, economic, environmental, noise, etc. specific) allows making the right investment decision.

Some aspects of the use of natural gas motor fuel in diesel locomotives

Due to the increase in the cost of diesel fuel, much attention is paid to the use of alternative types of fuel on diesel locomotives. Variants of using fuel obtained from coal, plants, gas fields and hydrogen are considered. Natural gas is the cheapest and most accessible today. The use of specially designed gas-piston engines on diesel locomotives, operating when the gas-air mixture is ignited from an external source, is the most attractive option. However, this approach has certain disadvantages:• it is necessary to create a new engine, since the modernization of existing engines requires serious structural changes;• gas piston engine operates essentially according to the Otto cycle and has lower efficiency and power indicators as compared to a diesel engine;• when modernizing existing diesel locomotives, switching to the Otto cycle excludes the possibility of using diesel fuel.Conversion of diesel locomotives to gas fuel must be carried out using the gas-diesel cycle. This approach is most acceptable for the modernization of diesel locomotives of the existing fleet, since it preserves the thermal performance of the engine and makes it possible to transfer diesel locomotives back to operation on diesel fuel. The main obstacle to the transfer of diesel locomotives to the gas-diesel cycle is the low degree of replacement of diesel fuel with gas. This circumstance is determined by the significant difficulties in ensuring the operation of the engine in the gas-diesel cycle at low loads and idling. It is necessary to ensure a stable supply of ignition fuel in these modes and guaranteed ignition of the gas-air mixture from it. The solution to this problem is ensured by maintaining a given stoichiometric ratio in the gas-air mixture and a temperature sufficient to ignite the ignition portion of the fuel.The main way to regulate the stoichiometric ratio is to reduce the amount of air entering the cylinders by throttling it at the engine inlet. This article discusses the methodology for calculating the performance of the engine when throttling the air inlet.

Контроль параметров процесса наполнения газопоршневого двигателя методом малых отклонений

A mathematical model of estimation of thermal and effective parameters of the most important part of cogeneration system of gas piston engine working in cogeneration mode was developed. Parameters of fresh air intake stroke with variable conditions of the environment using the method of small deviations were studied. The advantages of using the method of small deviations are the possibility of linearization of calculation equations as well as making calculations of not absolute but relative parameter change. The main parameters of fresh air intake by a cylinder are parameters of combustible mixture at the end of the intake stroke: combustible mixture pressure pa, the level of compression ε, the level of heating of fresh charge during the intake ΔT, parameters of residue gases (quantity Mr, pressure pr and temperature Tr), temperature of combustible mixture Tк. Using the method of small deviations for estimation of influence of the temperature of combustible mixture on effective values of gas piston engine led to an important finding: relative change of specific effective fuel consumption (economical part of gas piston engine exploitation) is in reverse relation to squared relative difference of temperature of supercharging air. In addition, cooling of supercharging air will positively influence temperatures inside engine cylinders and consequently fuel burning temperature. In turn, lowering the fuel burning temperature will improve ecological impact of the engine and reduce exhaust of harmful components into the atmosphere, in particular NOx.

Increasing mining dump trucks operation efficiency with the use of gas piston engines

Research aim is to analyze the prospects for increasing the efficiency of heavy-duty mining dump trucks operation through the use of natural gas as the main energy carrier. Research methodology included bench tests of a gas piston engine (GPE) KAMAZ mod. 820.60-260 with a capacity of 191 kW and the construction of forecast values of GPE parameters for the BELAZ-75319 mining dump truck with a load capacity of 240 tons. Results. A mathematical model and technique have been developed that allows predicting the main parameters of a gas piston engine and optimizing its economic and environmental characteristics. The use of natural gas as a motor fuel, with an unchanged engine design, leads to a decrease in its power. Currently, gas modifications are being created on the basis of existing diesel engines, and it is not always possible to implement any design measures at this stage. To realize all the capabilities of a gas engine, it should initially be designed for gas motor fuel. This technique is based on the experimental data of low-power gas piston engines and can be used for high-power gas engines studies intended for installation on mining dump trucks. Conclusions. Increasing the efficiency of mining dump trucks in the near future is possible through the use of natural gas as the main energy carrier. The use of natural gas as a motor fuel allows to increase the life of the engine, reduce the noise level and toxicity of exhaust gases, and reduce fuel costs.

Technological capabilities of direct-flow stabilizers in gas-piston engines

The present study describes problems related to the rational use of associated petroleum gas. In particular, the problem of effective gas flow stabilization at the gas-piston engine outlet is investigated. The analysis is applied to such kind of engine stabilizers and detailed studies revealed their major drawbacks. A hypothesis concerning the efficiency of using a direct-flow stabilizer (turbulizer/swirler) as a flow stabilizer is proposed. Simulation flow modeling in the direct-flow stabilizer is carried out. The simulation is carried out with the help of the SolidWorks Flow Simulation program for different profiles of the stabilizer flow section. The hypothesis on the efficient use of such units is confirmed. In terms of flow swirling the most effective flow section of the direct-flow stabilizer is revealed.

Selective oxycracking of associated petroleum gas into energy fuel in the light of new data on self-ignition delays of methane-alkane compositions

Preliminary selective oxycracking of heavy methane homologues theoretically allows using associated petroleum gas (APG) for power generation in gas-piston engines thus significantly decreasing its flaring. But practical implementation of this possibility is impossible without clear understanding of the dependence of fuel characteristic of hydrocarbon gases on their composition. Experimental investigations in the temperature range 523–1000 K at p0 = 1 atm and φ = 1 of self-ignition delays of complex gas mixtures imitating real APG have shown that quantitative influence of the addition of all C2-C6 alkanes on the self-ignition delay of methane is almost the same. The addition of any C2-C6 alkane at a level of 1% two-three times decreases the self-ignition delay of methane. The addition of any C2-C6 alkane at a level of 10% makes self-ignition delay practically indistinguishable from the self-ignition delay of added alkane itself. The delay of self-ignition of complex methane-alkane mixtures is determined only by the total concentration of heavy alkanes and within the measurement errors does not depend on their component composition. Available kinetic mechanisms of low-temperature oxidation of paraffinic hydrocarbons C1-C5 confirm these results. Therefore, to obtain certified gas fuel for gas-piston engines, it is necessary to remove practically all C2+ alkanes. Selective oxycracking of C2+ alkanes provides 82–85% conversion of ethane and the almost complete conversion of all the heavier alkanes. When using air as an oxidizer, it allows converting into certified fuel associated gas containing up to 10% C2+ alkanes, that is, almost all gas from the first and second stages of associated gas separation.

Повышение экономичности процессов генерации теплоты в коммунальной теплоэнергетике и теплотехнологиях на основе комбинированных когенерационно-теплонасосных технологий

Наиболее эффективной технологией генерации электрической и тепловой энергии для нужд коммунальной теплоэнергетики и теплотехнологий является комбинированная выработка энергии с использованием современных когенерационных установок на основе газопоршневых двигателей и газотурбинных установок, работающих на природном газе или биогазе. Комбинированная выработка энергии на такой базе существенно снижает затраты топлива в сравнении с традиционной раздельной выработкой электроэнергии на тепловых конденсационных электростанциях или на теплоэлектроцентралях и тепловой на котельных установках. Дальнейшее заметное повышение энергоэффективности процессов генерации теплоты для рассматриваемых нужд может быть достигнуто путем включения в процесс теплонасосных установок, т.е. создание комбинированных когенерационно-теплонасосных установок. Они будут иметь наивысшую топливную экономичность в сравнении со всеми существующими в традиционной теплоэнергетике. Это обусловлено целым рядом факторов. Современные когенерационные установки (КГУ) на базе газопоршневых двигателей (ГПД) и газотурбинных установок (ГТУ) имеют электрический к.п.д. выше, чем тепловая электростанция (ТЭС) или теплоэлектроцентраль (ТЭЦ) – 30…45 % и 28…35 %, соответственно. В котлах-утилизаторах более эффективно используется высокотемпературная сбросная теплота двигателей, в результате чего суммарный к.п.д. установок достигает 85…88 %. Такие установки обеспечивают децентрализацию производства электрической и тепловой энергии, поэтому на автономных КГУ существенно ниже, а иногда практически отсутствуют потери в электрических и тепловых сетях, достигающие в централизованных системах 8…12 % и 15…30%, соответственно. Немаловажным является и то, что они повышают надежность работы всего объекта, делая его независимым от внешних сетей. Включение в процесс генерации теплоты теплонасосной установки (ТНУ) вызывает заметное повышение энергоэффективности, увеличивая топливную экономичность, благодаря использованию практически даровой низкопотенциальной теплоты природного, промышленного или бытового происхождения, а также высокой эффективности преобразования в ТНУ этой теплоты в теплоту более высокого потенциала с использованием электрической энергии КГУ.
 Целью работы является оценка перспектив применения комбинированных когенерационно-теплонасосных установок на базе ГПД и ГТУ для повышения энергоэффективности и энергосбережения при генерации теплоты в коммунальной теплоэнергетике и теплотехнологиях, в частности, в процессах сушки.

РЕЗЕРВИ ПІДВИЩЕННЯ ЕФЕКТИВНОСТІ ТРАНСФОРМАЦІЇ ТЕПЛОТИ УСТАНОВКИ АВТОНОМНОГО ЕНЕРГОЗАБЕЗПЕЧЕННЯ

It is analyzed the efficiency of heat conversion in the integrated electricity, heat and cooling supply of the enterprise. The installation for energy supply includes two JMS 420 GS-N.LC GE Jenbacher cogeneration gas engines manufactured as cogeneration modules with heat exchangers for removing the heat of exhaust gases, scavenge gas-air mixture, cooling water of engine and lubricating oil. The heat of hot water is transformed by the absorption lithium-bromide chiller AR-D500L2 Century into the cold, which is spent on technological needs and for the operation of the central air conditioner for cooling the incoming air of the engine room, where from it is sucked by the turbocharger of the engine. The presence of significant heat losses, which account for about 30% of the total heat removed from the cogeneration gas piston module and is due to the inconsistency of the joint operation modes of the absorption lithium-bromide chiller and the gas piston engine, was revealed. This inconsistency is caused by the contradictory conditions of their effective operation according to the temperature of the return coolant at the outlet of the absorption lithium-bromide chiller and the entrance to the engine cooling system. The thermal state of the gas piston engine is ensured by maintaining the temperature of the return coolant at the entrance to it is not higher than 70 °C. At the same time, during the transformation of the heat of the coolant into the cold in an absorption lithium-bromide chiller, the temperature decreasing in the machine is no more than 10 ... 15 °С, that is, up to 75 ... 80 °С, if the temperature of the heat coolant outlet from the cogeneration gas piston module, i.e. at the inlet of the absorption lithium-bromide chiller, 90 °С. Therefore, the return coolant is additionally cooled in the "emergency heat release" radiator by removing its heat into surroundings. It is shown the possibility of increasing the cooling capacity of the system by conversion of the return coolant exhaust heat into cold in absorption lithium-bromide and ejector chillers through the data procession of monitoring the heat conversion system in the integrated energy plant.

АНАЛІЗ ЕФЕКТИВНОСТІ ОХОЛОДЖЕННЯ ПОВІТРЯ КОГЕНЕРАЦІЙНОГО ГАЗОПОРШНЕВОГО МОДУЛЯ УСТАНОВКИ АВТОНОМНОГО ЕНЕРГОЗАБЕЗПЕЧЕННЯ

The analysis of the efficiency of cooling air of cogeneration gas-piston module of installations for combined production of electric energy, heat, and cold is performed. The installation for energy supply includes two JMS 420 GS-N.LC GE Jenbacher cogeneration gas-piston engines manufactured as cogeneration modules with heat exchangers for removing the heat of exhaust gases, scavenge gas-air mixture, cooling water of engine and lubricating oil. The heat of hot water is transformed by the absorption lithium-bromide chiller AR-D500L2 Century into the cold, which is spent on technological needs and for the operation of the central air conditioner for cooling the incoming air of the engine room, wherefrom it is sucked by the turbocharger of the engine. The temperature of the scavenge gas-air mixture at the entrance to the working cylinders of the engine is maintained by the system of recirculating cooling with the removal of its heat into surroundings by the radiator. Because of significant heat influx from working engines and other equipment, as well as through the enclosures of the engine room from the outside to the air-cooled in the central air conditioner in the engine room, from where it is sucked by a turbocharger, the air temperature at the inlet of the turbocharger is quite high: 25...30 °C. At elevated temperatures of the ambient air at the inlet of the radiator for cooling scavenge gas-air mixture and the air at the turbocharger inlet the fuel economy of engine is falling, which indicates the need for efficient cooling of air. The efficiency of cooling the air of the gas-piston module was estimated by a reduction in the consumption of gaseous fuel and the increase in electric power of the engine. For this purpose, the data of monitoring on the fuel efficiency of the gas-piston engine with the combined influence of the ambient air temperature at the inlet of the radiator and the air at the turbocharger inlet were processed to obtain data on their separate effects and to determine the ways to further improve the air cooling system of the gas-piston module.

Possibility of the use of exothermic-reactions heat from thermal destruction of biomass to increase the energy efficiency of the torrefaction process

New results of investigation of exothermic effects accompanying the process of plant biomass torrefaction are presented in this paper, which is a continuation of experimental research carried out on the model lab-scale test-bench and devoted to the study of the exothermic effect. A distinctive feature of this work is using of a large-scale pilot torrefaction unit as a test item. This unit operation as close as possible simulates the processes taking place during industrial torrefaction. At this work stage a truncated version of the torrefaction unit was used (the upper hopper was demounted). Experimental data obtained on a pilot torrefaction unit confirm the possibility of exothermic reactions heat usage for process intensifying. It is shown that such operation mode provides increased unit productivity on conditions that gas piston engine is operating at a constant power mode. The characteristics of the fuel obtained in the proposed process organization, as well as the fuel obtained as a result of torrefaction process excluding the influence of exothermic effect heat, are compared. As the main directions of further research, the problem of low-temperature pyrolysis volatile products utilization and the development of operating parameters at a full-scale torrefaction unit have been chosen.