Browsing by Author "Tokmurzin, Diyar"

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    Electricity and heating system in Kazakhstan: Exploring energy efficiency improvement paths
    (Energy Policy, 2013-09-01) Sarbassov, Yerbol; Kerimray, Aiymgul; Tokmurzin, Diyar; Tosato, GianCarlo; De Miglio, Rocco; Yerbol, Sarbassov
    Abstract The Kazakh energy system is less efficient than most other national energy systems. The electricity and heat sub-systems account for about one half of the difference between the primary energy supply and the final consumption. After reviewing the technology chains of electricity and heat generation, transmission and distribution and their organisation, this paper presents scenario studies on the possible evolutions of these sub-systems to 2030. It describes the representation of the heat and electricity chains in the MARKAL–TIMES-Kazakhstan model, with focus on the residential and commercial sectors, and some key input data assumptions. The main scenario drivers are the need to improve the efficiency of electricity and heat in the residential and commercial sectors and to reduce GHG emissions from the energy system as a whole. The model results point to the possibility of achieving cost effective energy efficiency improvement of more than 2% per annum and it would entail a net economic advantage to the country.
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    Optimization of Kazakhstan Coals Gasification Process in the Circulating Fluidized Bed Gasification Process
    (Nazarbayev University School of Engineering and Digital Sciences, 2020-09-25) Tokmurzin, Diyar
    Coal, coke, and semi-coke are critical feedstock for the production of iron and steel. For over a century coke and semi-coke has been produced from coal using the slow pyrolysis thermal treatment process in fixed bed coke ovens. The coke-oven slow pyrolysis process produces vast quantities of gaseous and liquid emissions associated with coal tar which are not and sometimes cannot be always captured and recycled. Contrary to this, fast pyrolysis associated with gasification processes produces less tar. In this work a novel method incorporating fast pyrolysis to produce semi-coke using circulating fluidized bed partial coal gasification is experimentally studied. The present study includes an investigation of coal fast devolatilization properties, a pilot scale experimental proof of concept, and optimization of the process. Fast pyrolysis characteristics are explored using a wire mesh reactor and a thermobalance reactor experiments, and semi-coke is produced using a high-volatile Shubarkol coal in a custom-built atmospheric lab-scale reactor comprising a riser, a cyclone, a loop seal, and fitted with mechanized systems for semi-coke retrieval. The reactor is operated autothermally, at temperatures varying from 700 to 1000oC. The experimental results indicate the operating conditions for maximum product output. The product characterization revealed that semi-coke gains distinctive characteristics, including lower density, lower volatile matter content, lower ash content, higher porosity, and higher crystallinity of the carbon matrix. In addition, a Computational Fluid Dynamics simulation employing the Eulerian-Lagrangian multiphase particle-in-cell approach reveals fluidization properties and further optimization opportunities.