Coal-conversion technologies, although used ubiquitously, are often discredited due to high pollutant emissions, thereby emphasizing a dire need to optimize the combustion process. The co-firing of coal/biomass in a fluidized bed reactor has been an efficient way to optimize the pollutants emission. Herein, a new model has been designed in Aspen Plus® to simultaneously include detailed reaction kinetics, volatile compositions, tar combustion, and hydrodynamics of the reactor. Validation of the process model was done with variations in the fuel including high-sulfur Spanish lignite, high-ash Ekibastuz coal, wood pellets, and locally collected municipal solid waste (MSW) and the temperature ranging from 1073 to 1223 K. The composition of the exhaust gases, namely, CO/CO2/NO/SO2 were determined from the model to be within 2% of the experimental observations. Co-combustion of local MSW with Ekibastuz coal had flue gas composition ranging from 1000 to 5000 ppm of CO, 16.2%–17.2% of CO2, 200–550 ppm of NO, and 130–210 ppm of SO2. A sensitivity analysis on co-firing of local biomass and Ekibastuz coal demonstrated the optimal operating temperature for fluidized bed reactor at 1148 K with the recommended biomass-to-coal ratio is 1/4, leading to minimum emissions of CO, NO, and SO2.

The energy transition is driving governments and industries to adopt various measures to reduce their climate impacts while maintaining the stability of their economy. Hydrogen technologies are one of the central topics in the energy transition. Different nations have different stances on it. Some governments see hydrogen as a decarbonization tool or part of their energy security strategy, while some others see it as a potential export commodity. While identifying priorities for the future, Kazakhstan should clearly define the role of hydrogen in the country’s long-term energy and decarbonization strategy. This work presents the first country-scale assessment of hydrogen technologies in Kazakhstan by focusing on policy, technology and economy aspects. A preliminary analysis has shown that Kazakhstan should approach hydrogen mainly as a part of its long-term decarbonization strategy. While coping with the financial risks of launching a hydrogen economy, the country can benefit from the export potential of low-carbon hydrogen in the near term. The export potential of low-carbon hydrogen in Kazakhstan is justified by its proximity to the largest hydrogen markets, huge resource base, and potentially low cost of production (in the case of blue hydrogen). Technology options for hydrogen transportation and storage for Kazakhstan are discussed in our work. The paper also identifies target hydrogen utilization areas in emission sectors regulated by Kazakhstan’s Emissions Trading System.

The challenge of meeting ever-pressing energy demand and reducing GHG emissions presents a significant challenge. One of the recent trends in the energy transition is hydrogen, which is experiencing unseen support from various stakeholders. Hydrogen roadmaps and net-zero strategies announced by governments and companies indicate that demand for low-carbon hydrogen will increase significantly. Therefore, it is essential to establish a reliable supply of low-carbon hydrogen. In our previous work, we have shown that Kazakhstan is located between the two largest hydrogen markets - China and Europe. Natural gas can be a feedstock material for low-carbon hydrogen, which is also known as blue hydrogen. Kazakhstan holds the 16th largest natural gas reserves in the world. Nevertheless, finding feedstock natural gas for hydrogen in Kazakhstan can be challenging. In 2020, the gross natural gas production in Kazakhstan reached 55.1 bcm of natural gas of which 34.8 bcm and 20.3 bcm are commercial and reinjected volumes, respectively. Commercial volumes are tightly used for rising domestic market and export. Reinjection volumes are also tightly used to maintain the production of oil in the largest hydrogen reservoirs of the country - Tengiz, Kashagan and Karachaganak. In our work, we propose an approach to use reinjected gas volumes for large-scale hydrogen production while keeping the oil production targets in the largest fields as before. CO2 emissions resulting from the hydrogen production would be used to replace currently reinjected natural gas in maintaining reservoir pressure. CO2 can decrease the viscosity of the reservoir fluid, thus enhancing oil recovery (EOR). This work presents the viability of the concept in the example of the Kashagan field by showing the material balance of both surface and subsurface processes. Several development scenarios were which also involved coproduction of elemental sulfur and methanol. Blue hydrogen production was modeled in Aspen Hysys v12.1.

Converting municipal solid waste (MSW) into valuable feedstocks, such as refuse-derived fuel (RDF), is a sustainable method according to the concept of waste management hierarchy. A heterogeneous composition with a good calorific value and lower emissions allows RDF to be used for energy recovery purposes. We have earlier analyzed the generation and thermochemical characteristics of the MSW produced in Kazakhstan. This work aims to study the combustion characteristics in terms of emissions and ash composition to evaluate the possibility of RDF co-firing with Ekibastuz coal. In particular, RDF is blended with high ash bituminous coal (Ekibastuz coal) and co-fired in the laboratory scale bubbling fluidized bed reactor (BFB) at a bed temperature of 850 °C. The co-firing tests of RDF to coal samples were conducted under various proportions to analyze flue gas compositions. Experiments were carried in the presence of bed material (sand), and the fuel particles were fed in batch mode into the hot riser. The BFB reactor had a height of 760 mm and internal diameter of 48 mm. The gaseous products in the flue gas were analyzed by FTIR spectrometry (Gasmet Dx4000). Ash composition was examined by XRD, XRF, SEM, and PSD. The results showed that a high RDF content decreased SO2 emissions to 28 ppm, while it negatively affected NOx release to 1400 ppm, owing to excess air. The emissions of gases from different blended samples and mineral transformations were investigated and discussed in this study.