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SENEGAČNIK, A., KUŠTRIN, I., LENART, J., LEBAN, M., SEKAVČNIK, M.
FEASIBILITY STUDY OF COALMINE VENTILATION AIR METHANE UTILIZATION
KOMUNALNA ENERGETIKA / POWER ENGINERING, 11
During coal mining some dangerous and explosive gases are released. Due to safety reasons the mines should be intensively ventilated. Much of the released gas at coal mining is methane. Released gases are vented to surroundings with ventilation air and therefore the methane is not profitable used. One of the potential beneficial utilization of methane in ventilation air is the utilization as a power station air intake. This paper analyzes the possibility of using the ventilation air from the Velenje Coal Mine as an air intake for power plant Šoštanj Unit 5. The analysis shows that this utilization would have a positive effect in environmental and energy aspect.
MELE, J., SENEGAČNIK, A.
DYNAMIC SIMILARITY IN SCALING-UP FAST INTERNAL CIRCULATING FLUIDIZED BED GASIFIER
KOMUNALNA ENERGETIKA / POWER ENGINERING, 13
The article introduces research of particles dynamics in a cold flow model of FICFB (Fast Internal Circulating Fluidized Bed) biomass gasification process and its scale-up to hot industrial pilot plant. A laboratory unit has been made for the purposes of experimental research, which is three times smaller than the industrial pilot plant. Process was designed and experimentally tested on cold-flow model and scaled-up to hot industrial process. For a reliable scaling up similar flow conditions were achieved in both units. The results of the laboratory model shows as similar to those of the scale-up device if geometry, flow and Reynolds numbers are the same. Therefore, there is no need to bring an expensive full-scale gasification plant into the laboratory and actually test it. This is an example of "dynamic similarity".
KUŠTRIN, I., SENEGAČNIK, A., JAMŠEK, M.
HARMFUL EFFECTS OF AIR LEAKAGE INTO PULVERISED-COAL FIRED BOILER
KOMUNALNA ENERGETIKA / POWER ENGINERING, 18
The paper presents the reasons and consequences of uncontrolled air on the operation of steam boilers with dust firing i.e. combustion of coal crushed into powder. This type of combustion is more advanced than the combustion of solid fuels of larger granulation. It enables achieving higher output and efficiency. Several conditions must be fulfilled to enable quality combustion. One of these conditions is the optimum fuel to air ratio. This condition can be met if good control over the allocation of combustion air to the burner nozzles is possible. Usually it is possible to achieve from the perspective of installed measurement and control equipment but a major obstacle to this is an entry of uncontrolled air into the boiler. This makes it impossible to maintain optimum conditions for quality combustion.
MELE, J., SENEGAČNIK, A.
MINIMAL VELOCITY OF FULL FLUIDIZATION – A NEW DETERMINATION METHOD
KOMUNALNA ENERGETIKA / POWER ENGINERING, 20
The article introduces the method for characterization and control of fluidized beds with wide size distribution of particles. A laboratory unit has been made for the purposes of experimental research. Our goal is to make an automatic control protocol to find minimum necessary flow of fluidization fluid to run the process at full fluidization. On the basis of measured differential pressure and gas velocity, programme can find the optimal operation area. The method determines a single point among many points with almost same differential pressure and various gas velocities. This method can be used for controlling fully fluidized bed at minimum gas flows in CFB gasificators, fluidized bed furnaces, fluidized bed sanding machines, etc.
SENEGAČNIK, A.
FEASIBILITY STUDY OF COMBINED FIRING IN ANNULAR SHAFT KILN FOR LIME BURNING
KOMUNALNA ENERGETIKA / POWER ENGINERING, 4
The article deals with combined firing of wood chips and natural gas in the annular shaft kiln for lime production. Wood chips are gasified separately in the autonomous gasifier. Hot syngas from the gasifier is mixed with natural gas in the existing combustion chamber and then burned completely. The moisture content in the wood chips dictates the amount and calorific value of syngas. The simulation of syngas and natural gas co-combustion in the lower combustion chambers shows that can be up to 50 % of natural gas supplemented with the wood syngas made from the fresh wood chips.
SENEGAČNIK, A., GLAVINA, U., SEKAVČNIK, M.
ORC – ORGANIC RANKINE CYCLE ALSO IN SLOVENIA
KOMUNALNA ENERGETIKA / POWER ENGINERING, 15
The article deals with ORC (Organic Rankine Cycle) process. This is a thermodynamic power cycle for conversion low temperature heat into mechanical work. The working media is an organic refrigerant. Operating parameters are lower than in water cycle. Due to specific properties of refrigerant also the ORC process has some peculiarities. The article presents the ORC process, which is applied in the Slovenian industry. Generator power is 125 kW, working media is HFC245 fa (R245 fa). Some specific features and operating experience of ORC processes are addressed in this article.
SENEGAČNIK, A., SEKAVČNIK, M.
REPOWERING OF WASTE HEAT USING ORC IN SLOVENIA
KOMUNALNA ENERGETIKA / POWER ENGINERING, 6
The article deals with ORC (Organic Rankine Cycle) process. This is a working cycle for
conversion of low temperature heat into mechanical work. The working fluid is an organic
refrigerant. Due to specific properties of refrigerant also the ORC process has some
peculiarities. The article presents the ORC process, which will be applied in the Slovenian
industry providing a generator power of 120 kW. Some specific features of ORC processes
are addressed and the impact of implementation of heat exchangers is analysed. Analysis of
the impact of cooling water temperature on the operation of ORC process is also provided.
SENEGAČNIK, A.
FEASIBILITY STUDY OF A WOOD SYNGAS CO-FIRING IN ANNULAR SHAFT KILN FOR LIME BURNING
KOMUNALNA ENERGETIKA / POWER ENGINERING, 9
The article deals with the wood syngas as a partial supplementary fuel for lime burning in
the annular shaft kiln. Natural gas is a primary fuel. Wood chips are gasified with approved
technology in the counter current gasificator. As an oxidizer the mixture of air with recycled
flue gas with ~10 % oxygen is used. The moisture content in the wood chips dictates the
amount and calorific value of syngas. The simulation of syngas and natural gas cocombustion
in the lower combustion chambers shows that can be 20 % to 50 % of natural gas
supplemented with the wood syngas.
SENEGAČNIK, A., ZBAŠNIK SENEGAČNIK, M.
ENERGY EFFICIENT BUILDINGS ARE ALSO AN ENERGY STRATEGY
KOMUNALNA ENERGETIKA / POWER ENGINERING, 13
Passive house is an energy optimal building. It has very low energy demands for heating the building and sanitary water, with affordable expenses. In the paper a comparison of energy savings between buildings, built by Regulations about isolation and energy efficient use in buildings from 2002 and buildings, built by passive house standard. The calculations are based on new buildings built between 2003 and 2008. The same buildings, built by passive house standard would consume a lot less energy for heating, but electric energy consumption would increase a bit because of the heating pump usage.
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