scholarly journals The concept of measurement of calorific value of gaseous fuels

2020 ◽  
Vol 207 ◽  
pp. 01025
Author(s):  
Jaroslaw Markowski ◽  
Pawel Imilkowski ◽  
Marcin Nowacki ◽  
Damian Olejniczak ◽  
Jacek Madry ◽  
...  

The issue of measuring and determining the calorific value of fuels is related to thermodynamic analysis of the effects of the combustion process aimed at determining the amount of heat transferred to the environment. Currently, there are several methods for determining the calorific value of fuels and their methodology is related to the type of fuel being analyzed. These methods are quite complicated and require the use of specialized measuring equipment. The energy demand of modern civilization along with the need to protect the natural environment prompts the search for new ways to generate energy directed at sources other than conventional fossil fuels. Technologies related to the use of biogas, synthesis gas obtained in biomass or waste gasification processes are being introduced. The use of these fuels in industrial processes of generating heat and electricity requires caloric stability of the fuel. The caloric stability of the fuel is necessary to ensure the stability of thermal energy conversion processes that translate directly into the set values of generated electricity using electric machines. One way to assess the energy quality of a fuel is to measure its calorific value. There are several methods for determining the calorific value of a fuel, but they all require special measurement conditions. The article presents the author’s concept of a calorimeter dedicated to the analysis of the calorific value of gaseous fuels.

2020 ◽  
Vol 154 ◽  
pp. 02003
Author(s):  
Grzegorz Pełka ◽  
Wojciech Luboń ◽  
Przemysław Pachytel

In the municipal and residential sector in Poland, as many as 50% of households are heated by solid fuel boilers. Most often these are, unfortunately, inefficient boilers, fired with low-quality coal. This study characterizes the market of boilers for solid fuels in Poland, and also presents the main apportionment of these devices, due to the different criteria that characterize them. The current legal changes in the scope of energy and emission requirements for solid fuel boilers are also discussed. The main purpose of this work is to analyze the real efficiency of the solid fuel over-fired boiler used, depending on the fuel burned in it. The process of burning selected fuels (seasoned wood, coal and pea coal) in the boiler was preceded by tests of these fuels to determine their energy parameters, such as moisture, ash content, the share of volatile matter and calorific value. In the next step, the energy efficiency obtained by the tested solid fuel boiler during the combustion of selected solid fuels was compared. The highest efficiency was achieved during the combustion of pea coal, and the lowest was achieved during the combustion of wood. In any case, the nominal efficiency value was achieved. Solutions that could improve the quality of the combustion process in this type of boiler were proposed.


2015 ◽  
Vol 776 ◽  
pp. 443-448 ◽  
Author(s):  
Hendry Sakke Tira ◽  
Yesung Allo Padang ◽  
Mirmanto ◽  
Hendriono

The dependence of human being on fossil fuels has decreased significantly the conventional energy resources. To overcome this problem it is required alternative substitute fuels which are cheap and accessible which biogas is one of the fuels. Nevertheless, the use of biogas has not yet been maximized because of the low calorific value which is produced from the process without purification. The circulated water absorption method is one mean of effective biogas purification. Under this method it is expected to increase the level of methane (CH4) and to reduce both the level of carbon dioxide (CO2) and hydrogen sulfide (H2S). In order to obtain the aim, the research was carried out under variations of water and biogas volumetric flow rate. The results show that the highest quality of biogas produced was under the variation of water volumetric flow rate of 15 lt/min with biogas volumetric flow rate of 1 lt/min which increased the level of methane (CH4) from 59.36 % to 62.8 % and decreased the carbon dioxide (CO2) content from 33.53 % to 26.8 %, and hydrogen sulfide (H2S) from 208.33 to 86 ppm. Lower biogas and water volumetric rates allowed longer contact between biogas molecule and absorbent. This resulted in an opportunity for absorbent more active to dissolve carbon dioxide and hydrogen sulfide in biogas. These compounds then flowed outward of the scrubbing unit along with the absorbent. The research proved that the raw biogas purification by circulated water scrubbing method was an effective mean in enhancing the quality of biogas.


Author(s):  
Raffaela Calabria ◽  
Fabio Chiariello ◽  
Patrizio Massoli ◽  
Fabrizio Reale

In recent years an increasing interest is focused on the study of micro gas turbines (MGT) behavior at part load by varying fuel, in order to determine their versatility. The interest in using MGT is related to the possibility of feeding with a wide range of fuels and to realize efficient cogenerative cycles by recovering heat from exhaust gases at higher temperatures. In this context, the studies on micro gas turbines are focused on the analysis of the machine versatility and flexibility, when operating conditions and fuels are significantly varied. In line of principle, in case of gaseous fuels with similar Wobbe Index no modifications to the combustion chamber should be required. The adoption of fuels whose properties differ greatly from those of design can require relevant modifications of the combustor, besides the proper adaptation of the feeding system. Thus, at low loads or low calorific value fuels, the combustor becomes a critical component of the entire MGT, as regards stability and emissions of the combustion process. Focus of the paper is a 3D CFD analysis of the combustor behavior of a Turbec T100P fueled at different loads and fuels. Differences between combustors designed for natural gas and liquid fuels are also highlighted. In case of natural gas, inlet combustor temperature and pressure were taken from experimental data; in case of different fuels, such data were inferred by using a thermodynamic model which takes into account rotating components behavior through operating maps of compressor and turbine. Specific aim of the work is to underline potentialities and critical issues of the combustor under study in case of adoption of fuels far from the design one and to suggest possible solutions.


2021 ◽  
Vol 14 (2) ◽  
pp. 125-129
Author(s):  
Gatot Setyono ◽  
Navik Kholili

Ethanol is an alternative fuel to replace fossil fuels. Ethanol's high octane value can substitute for power in spark-ignition engines (SI). Gasoline mixed with ethanol will reduce the calorific value generated and intensify the combustion process in the combustion chamber. Through the engine performance test, we can find out the increase in the performance of the SI engine. Several essential variables can improve engine performance, such as gasoline-ethanol variations, iridium spark plugs, and hydroxy gas generators (HHO). This research uses an experimental method by utilizing gasoline (octane-92)-ethanol variations (35%, 45%, and 55% v/v) with the intake of hydroxy gas during the combustion process. The SI automatic transmission engine has a capacity of 124.8 cubic centimeters (one cylinder-four stroke), a compression ratio of 11/1, fuel injection, and iridium spark plugs. Engine performance test using chassis dyno test with engine speed variations of 4000-9000 rpm. This study resulted in optimal performance on a 55% increase in gasoline-ethanol mixture with an intensify in output-power, pressure, and thermal efficiency at an engine-speed of 8000 rpm. It is contrary to the specific fuel consumption has decreased.


2014 ◽  
Vol 592-594 ◽  
pp. 1559-1563
Author(s):  
Thangaraju Rajasekaran ◽  
K. Duraisamy ◽  
K.R. Arvindd ◽  
D. Thamilarasu ◽  
Venkatachalam Chandraprabu ◽  
...  

Depletion of fossil fuels, unaffordability of conventional fuels (petrol, diesel) and atmospheric pollution lead researchers to develop alternative fuels. Fuels derived from renewable biological resources used in diesel engines are known as biodiesel. Biodiesel is environmental friendly liquid fuel similar to petrol and diesel in combustion properties. Increasing environmental concern, diminishing petroleum reserves and agriculture based economy of our country are the driving forces to promote biodiesel as an alternate fuel. Hydrogen seems to be viable fuel to meet sustainable energy demand with minimum environmental impact. Hydrogen has high calorific value and clean burning characteristics which makes it effective fuel for future. It was found that hydrogen usage reduce emissions such as CO2and HC. India is one of the largest producers of neem oil and its seed contains 30% oil content. It is an untapped source in India, so the neem oil usage will be a best option. The investigation made on pure neem oil and neem oil with hydrogen addition at different flow rate (2 lpm & 4 lpm) in CI engines. The result shows that, brake thermal efficiency of neem oil with 4 lpm hydrogen was increased to 7.98% compare to pure neem oil at 4 Nm torque and fuel consumption of neem oil with 4 lpm hydrogen was decreased to 13.49% compared to pure neem oil at 4 Nm torque.


2012 ◽  
Vol 512-515 ◽  
pp. 1106-1112
Author(s):  
Da Wei Hu ◽  
Yan Min Wang ◽  
Ai Zhi Yu

Coal as the world's most widely used fossil fuels, during the combustion process large amounts of greenhouse gas emission, which has a huge impact on global climate warming. However, coal is a nonrenewable resource, and the energy conservation is imperative. This paper, through analyzed the essential of coal combustion, and the feasibility and means for coal saving by using chemical intervention combustion. After tested the practical effects of chemical intervention coal combustion catalyst, which provided by Guangzhou Fenfang Environmental Protection Technology Co., Ltd. The results shown, the as received basis net calorific value at constant volume of the selected coal sample improved 8% which was tested by an oxygen bomb calorimeter, almost 1/6 sulfur was fixed in the cinder and the practical application coal saving effects in new dry rotary kilns and thermal power plants were more than 6%. Therefore, the chemical intervention combustion method has important significance in research and practical for coal saving and reducing emissions of pollutants.


2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Giovanni Nicoletti ◽  
Roberto Bruno ◽  
Natale Arcuri ◽  
Gerardo Nicoletti

In order to compare solar-hydrogen and the most used fossil fuels, the evaluation of the “external” costs related to their use is required. These costs involve the environmental damage produced by the combustion reactions, the health problems caused by air pollution, the damage to land from fuel mining, and the environmental degradation linked to the global warming, the acid rains, and the water pollution. For each fuel, the global cost is determined as sum of the market price and of the correspondent external costs. In order to obtain a quantitative comparison, the quality of the different combustion reactions and the efficiency of the technologies employed in the specific application sector have to be considered adequately. At this purpose, an entropic index that considers the degree of irreversibility produced during the combustion process and the degradation of surroundings is introduced. Additionally, an environmental index that measures the pollutants released during the combustions is proposed. The combination of these indexes and the efficiency of the several technologies employed in four energy sectors have allowed the evaluation of the total costs, highlighting an economic scenario from which the real advantages concerning the exploitation of different energy carrier are determined.


2019 ◽  
pp. 452-452
Author(s):  
Ashkan Sehat ◽  
Fathollah Ommi ◽  
Zoheir Saboohi

Due to increasing global energy demand and the fact that a major source of the required energy is generated from fossil fuels, the combustion process has turned into a topic of interest in converting fossil fuels to energy. An ideal combustion system is one that can combine high engine efficiency with low fuel consumption and low emissions. Increasing humidity is a technique used by researchers for influencing the combustion process. The present study aims to review previously conducted researches in this regard. Based on viewpoints of these researches, the reviewed studies were categorized into four groups: (1) the case studies used; (2) the methodology applied; (3) the design guidelines considered; and (4) the performance parameters studied. It can be concluded from the reviewed articles that nitrogen oxide (NOx) reduction is the most significant advantage of increasing humidity in the combustion process, and has led to the widespread use of this method. The other studied emissions either remained constant or their respective increases were negligible.


Author(s):  
K.S. Kryzhanovskiy

The wide application of gaseous fuels in technology and energy, its high cost, pose the task of improving the quality of its use. The task of automation of technological processes of thermal units heated by natural gas is to increase the safety of operation and the efficiency of their operation. This problem is especially acute in conditions of continuous operation of thermal units, when the state of the environment varies from day to day and from summer to winter. The temperature of the air for combustion, its humidity, the heat of combustion of the gas and the atmospheric pressure fluctuate particularly sharply. In these conditions, when putting into operation the heat unit, it is necessary to set such tinctures that, in the event of unfavorable external conditions, there always was enough oxygen to completelyburn the gas. This can be achieved by increasing the efficiency of the automatic control system of the ratio of the combustion components and the temperature parameters of the unit, according to the optimal regime for each particular technological process. To achieve this goal, we used the results of research into the chemical processes of interaction of combustion products using means for measuring the electrical parameters of a flame based on physical methods of ionization control of the combustion process. The established features and obtained results made it possible to develop a device for monitoring the ionization properties of the combustion process, on their basis, automatic control systems of burners for industrial heat x aggregates. Bibl. 7, Fig. 3.  


2019 ◽  
Vol 4 (4) ◽  
pp. 329-337
Author(s):  
Mária Ambrus ◽  
Roland Szabó ◽  
Gábor Mucsi

Over the past decades, both the residential and industrial energy demand has increased due to the continuously growing consumption and production. As a large share of the electricity is still produced using fossil fuels, the utilisation of the by-products is a contemporary and pervasive issue. Fly ash is generated in large quantities in coal-fired power plants and has been proven to be an appropriate raw material for various industrial uses. Among others, it is applicable as an additive and lightweight aggregate in the cement and concrete industry, can be used for CO2 sequestration, glass foam production, catalyst production, or as a base material for geopolymers, as well. Geopolymers are inorganic polymers produced via the reaction between solid alumina and silica containing or alkali silicate materials in alkali media. Due to their numerous advantageous properties and wide variety of utilisation possibilities, research on fly ash base geopolymers became widespread topic. The quality of fly ash is determined by technical requirements, and the degree of quality control requirements depends on the final use. In certain fields of applications, standards and regulations have already been created to ensure the consistent quality of the final products made from fly ash, e.g. in the cement and concrete industry. There are various methods for fly ash processing, however, the methods to achieve the necessary properties are not standardised.


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