Coke Oven Gas Research Articles

Energy-saving and emission-reduction potential of fuel cell heavy-duty trucks in China during the fuel life cycle.

Exploring alternative fuels and advanced vehicle technology is a crucial strategy for vehicle emission reduction. Fuel cell heavy-duty trucks (FC-HDTs) have a promising application prospect to alleviate the high energy consumption and emissions of road freight, but their environmental performance during the fuel life cycle should be further studied. This study is aimed at evaluating the fossil fuel consumption and GHG emissions of FC-HDTs in China using the updated GREET model. The results show that (1) comparing various hydrogen production pathways, it is found that the coke oven gas (COG) pathway can provide the best environmental performance, while the energy consumption and greenhouse gas (GHG) emissions of the coal gasification (CG) and grid power water electrolysis (GPWE) pathways will be significantly decreased in the future. (2) Among the involved vehicles in China, FC-HDT with GVWR18 has the greatest energy-saving and emission-reduction potential. (3) The application of carbon capture and storage (CCS) technology in hydrogen production is conducive to improving the emission-reduction effect of FC-HDT while increasing its energy consumption slightly. The key to achieving upstream carbon neutrality is to optimize the hydrogen production structure and electricity mix, along with adjusting the hydrogen production process and transportation mode. Furthermore, the fuel economy and payload of the FC-HDT affect its environmental performance, indicating the importance of improving the technology of the drivetrain, fuel cell, and hydrogen storage tank.

The effect of toluene trace admixtures on the plasma‐assisted oxygen trace removal from hydrogen‐rich gas mixtures in a surface dielectric barrier discharge reactor

AbstractA surface dielectric barrier discharge reactor was applied in the removal of oxygen traces from coke oven gas (COG), to which toluene was added as a model hydrocarbon contaminant. The adverse effect of toluene on O2 conversion was observed in a H2/N2/O2 mixture, while in synthetic COG consisting of H2, CH4, N2, CO, CO2, and O2, it remained unchanged. Online gas chromatography (GC) showed that the reactivity of toluene is mainly driven by H2/N2/O2. The accumulated residue was dissolved and analyzed by GC coupled with mass spectrometry. The identified reaction products suggest that toluene undergoes ring‐opening and functionalization.

A novel modeling strategy for the prediction on the concentration of H2 and CH4 in raw coke oven gas

A novel modeling strategy for the prediction on the concentration of H2 and CH4 in raw coke oven gas

Deposits in Coke Oven Gas Lines and Equipment at Coke Plants: A Review

Deposits in Coke Oven Gas Lines and Equipment at Coke Plants: A Review

Impact of carbon monoxide on performance and microbial community of extreme-thermophilic hydrogenotrophic methanation in horizontal rotary bioreactor

A novel horizontal rotary bioreactor was developed for upgrading biogas from coke oven gas at extreme-thermophilic condition. The introduction of CO decreased the outlet methane content from 80% to 50% due to insufficient H2. This hindrance was overcome by increasing the proportion of incoming hydrogen, coupled with a prolonged gas retention time from 24 to 72 h, leading to a restoration of methane content to 91.6%. Notably, CO and CO2 exhibited a competitive relationship to hydrogen, which was determined by their contents. The substitution of Methanothermobacter for Methanobacterium as the dominant genus was observed at 70 °C, with relative abundance exceeding 98%. Incorporation of CO increased bacteria diversity and fostered a syntrophic relationship between the bacterial community and M. thermautotrophicus. This study provides both theoretical basis and practical support for biogas upgrading from coke oven gas using a biofilm reactor, thus aiding its future industrialization prospects.

Impact of Hydrogenous Gas Injection on the Blast Furnace Process: A Numerical Investigation

Intensifying hydrogen use in the blast furnace is a key technology for significant coke and CO2 emissions reductions. The most straightforward approach is the implementation of high hydrogenous gas injection rates in the BF tuyeres. Yet this solution has not been widely implemented due to a lack of understanding of the impact on the furnace’s internal state. In this paper, a newly developed BF mathematical model is presented and validated on operation data. The model is next applied to investigate the effect of hydrogenous gas injection on the overall performance and internal state of the furnace. The current state of an industrial BF is used as a starting point, increasing the injection of coke oven gas, natural gas or pure H2 to the maximum where the limits for a safe and stable process are still obeyed. All three gases were found capable of significantly decreasing the coke rate, but only coke oven gas and pure H2 allowed for a significant reduction of the CO2 emissions. It was found that the indirect reduction of H2 is intensified by hydrogen enrichment partially at the expense of indirect reduction by CO. Furthermore, the water gas shift reaction is intensified at increased hydrogenous gas injection, affecting the CO and H2 utilization of the top gas. The study gives an insight into the feasibility of BF processes with high hydrogenous gases injection into the tuyeres and the resulting coke savings.

Potentials and benefit assessment of green fuels from residue gas via gas-to-liquid

This study aims to develop and evaluate the techno-economic-environmental performance of residue gas-to-gasoline hydrocarbon processes (residue gas-to-liquid, rGTL) via the dimethyl ether-to-gasoline (DTG) route for various single or mixed feedstocks of coke oven gas (COG), Linz–Donawitz gas (LDG), and blast furnace gas (BFG). Significant challenges in the process development have been overcome to generate the optimal syngas for fuel synthesis and the optimal operating conditions. It further compared the best co-feeding COG and LDG strategies and COG standalone with other residue gas-to-fuels, other gasoline technological routes of Fischer–Tropsch synthesis and methanol-to-gasoline, and other gasoline platforms of natural gas-to-gasoline and power-to-liquid. In this fuel synthesis framework, the DTG route is identified as the best technological route for residue gas-based gasoline, acting as a bridge between fossil and renewable gasoline at a market-competitive price and with a large CO2 equivalent (CO2eq) reduction. Additionally, the industrial and social impact of rGTL is investigated in various scenarios, in which the government's encouragement by lowering interest rates demonstrates a significant opportunity for implementing rGTL in a real commercial, industrial, and sustainable development society. Countries are encouraged to implement rGTL as a sustainable energy system for various reasons, for example, China and India with a huge potential to enlarge fuel markets; Brazil with cheaper gasoline; and France with massive CO2eq reduction. Therefore, this work assists stakeholders and governments in the strategic planning and policymaking related to the effective use of a country's resources toward sustainable development goals.

Enhancing the production of liquid hydrocarbons by coupling blast furnace gas (BFG) of steelwork with syngas in the GTL process

Steelwork is one of the main emitters of CO2 in the world. For this reason, many efforts are being made to reduce or avoid CO2 emissions by unit optimization or by carbon capture and storage (CCS) or utilization (CCU) processes. In the steelwork, three main off-gases are generated including the Blast Furnace Gas (BFG), the Coke-Oven Gas (COG), and the Basic Oxygen Furnace Gas (BOFG). Different processes and technologies can be proposed for recovery based on the volume and composition of the steelwork off-gases. In this paper, the BFG stream is utilized to improve the efficiency of the GTL process and reduce CO2 emissions. For this purpose, a part of the BFG gases is mixed with the syngas produced in the methane autothermal reforming process and injected into the Fischer-Tropsch reactor to produce liquid hydrocarbons. The BFG flow rate was determined according to the optimum H2/CO value. The pressure and volume of the reactor were set at 10 bar and 300 m3 for optimal hydrocarbon production. The simulation results showed that mixing a portion of the BFG with the syngas increases the C5 + production by 11268 bbl/day, while the CO2 emissions decreased by 146529 ton/yr.

A theoretical approach to evaluate the effect of hydrocarbon and CO2 injection on blast furnace raceway: step towards reduction of CO2 emission

ABSTRACT A novel raceway heat and material balance model is developed considering all physico-chemical phenomena surrounding the raceway of the blast furnace (BF). This model is unique, as it considers reactions based on thermodynamics and determines important parameters such as raceway adiabatic flame temperature (RAFT), bosh gas properties, raceway coke rate etc. Importantly, the model also predicts blowing parameters in case of known RAFT and permeability of the furnace. This paper focuses on the raceway regime only considering the effect of different injectants, H2, CO, CH4, CO2 and coke oven gas (COG). Firstly, the paper describes the modelling approach, based on thermodynamic, heat and material balances. The first part of the paper quantifies the effect of injectants on the raceway keeping the blowing parameters constant, whereas second part presents the changes of raceway properties as well as blowing parameters keeping RAFT and permeability of the furnace constant.

Effect of Zeolitic Imidazolate Framework Topology on the Purification of Hydrogen from Coke Oven Gas

This work aims to shed light on the performance of zeolitic imidazolate frameworks for hydrogen purification from coke oven gases (COG). Using molecular simulation, we model COG as a mixture of six gases and study the effect of ZIF topology on the separation performance. To do this, we compare similar structures, e.g., ZIF-8 and ZIF-11, and focus on obtaining information that explains why they behave differently while being so similar. Simulation results show that the structure with the smallest pore size best separates hydrogen from carbon monoxide and nonpolar molecules. The adsorption of carbon dioxide is also strongly affected by the polarizability of the structure. However, the adsorption of the other components (methane, carbon monoxide, nitrogen, and oxygen) is strongly dependent on their pore size. We also provide molecular information on the effect of phase transition on hydrogen purification using ZIF-7 as an example, which drastically changes the pore volume of the structure when it changes phase. These findings will help to select high-performance ZIFs for adsorption- or screening-based hydrogen purification.

Experimental and numerical study on laminar combustion characteristics of by-product hydrogen coke oven gas

The coke oven gas (COG) which mainly consists of H2, CH4 and CO is a kind of feasible by-product hydrogen that could be applied by combustion plants. This paper conducted experiments and numerical calculations to explore the combustion properties of COG. The laminar burning velocity (LBV) and flame stability of COG with different CO/CH4/H2 fractions were firstly tested. Then, based on the LBV results, a new chemical kinetic model was proposed and a mixing rule for quick estimating the LBV of COG was acquired. The influences of different COG components on LBV were obtained. The peak LBV of COG could achieve 100.2 cm/s when the highest tested hydrogen portion in COG was adopted at an equivalence ratio of 1.2. Concerning its application in real combustion plants, the exhaust emissions of CO and NO from the COG final combustion products were also detected by an emissions analyzer. The results showed that raising the hydrogen fraction in COG availed reducing CO at rich conditions through lowering the carbon fraction. The NO emission gained the peak value around the equivalence ratio of 0.9, which was found to be generally raised with the hydrogen fraction due to the increased combustion temperature.

Life cycle framework construction and quantitative assessment for the hydrogen fuelled ships: A case study

The integration of hydrogen energy into the maritime industry requires a comprehensive evaluation of the life cycle of hydrogen fuel, encompassing all stages from production to operational use in ships. This research aims to analyze the entire technology chain of marine hydrogen fuel. Six methods of hydrogen production, including steam methane reforming, coal gasification, coke oven gas, propane dehydrogenation, water electrolysis, and biomass gasification, are evaluated with regard to their energy consumption, environmental sustainability, and economic cost. The life cycle assessment is divided into two processes: hydrogen production and hydrogen fuel cell ship application. Calculations are based on a real-world case study of Dalian Port in China. A sensitivity analysis is also performed to assess the impact of various ship-specific conditions, such as speed, route distance, and transportation conditions, on the performance of hydrogen fuel-powered ships. The findings indicate that the current power cost structure does not necessarily make electrolytic hydrogen production the most environmentally responsible option. In the long-range route, the life cycle cost of water electrolysis is 2.49×106USD. Among the six methods, coke oven gas hydrogen supply method produces the highest carbon emissions. The optimal sailing speed of hydrogen fuel cell ships is between 14 and 14.5kn.

Simulation and multi-objective optimization of liquid hydrocarbons production by coupling Blast Furnace Gas with Coke Oven Gas of steelwork

Simulation and multi-objective optimization of liquid hydrocarbons production by coupling Blast Furnace Gas with Coke Oven Gas of steelwork

Comparative life cycle assessment of ammonia production by coke oven gas via single and coproduction processes

As an abundant H2-rich byproduct from coking production, coke oven gas (COG) is a favorable feedstock for ammonia production. Recently, three COG-based ammonia processes have been applied, including single process, coproduction of ammonia with methanol, and coproduction of ammonia with liquefied natural gas (LNG). To systematically evaluate the environmental impacts of three COG routes, a comparative life cycle assessment was conducted with industrial data. Besides, the effects of ammonia synthesis pressure and electricity sources to the total LCA result were discussed. The results indicate that the environmental impacts of COG-based single ammonia route are mainly generated from ammonia production stage, accounting for 69.63 % of the overall normalized results, in which electricity and COG are the dominated contributors. Therefore, employing electricity from renewables like wind, solar, hydro and nuclear could dramatically mitigate the environmental impacts with a reduction of 36.3 %–70.7 % in most environmental indicators. Scenario analysis proves that reducing synthesis pressure from 31.4 MPa to 15 MPa does not show remarkable environmental benefits as expected since higher pressure is more conducive to ammonia synthesis. In comparison with coal based and natural gas-based ammonia routes, COG routes have obvious energy-saving benefit. In three COG-based ammonia routes, the two coproduction routes accounted for 49.1 % and 78.6 % of the energy depletion as single production due to highly efficient utilization of resources and energy. Coproduction of ammonia with methanol route exhibits better environmental performance than these in coproduction of ammonia with LNG route. Therefore, coproduction of ammonia with methanol route is more favorable in COG to ammonia processes. This study intends to provide a valuable reference for COG utilization and ammonia production options through the life cycle aspect.

Optimization of the hydrogen production process coupled with membrane separation and steam reforming from coke oven gas using the response surface methodology

As a by-product of the coking industry, coke oven gas (COG) is often burned as fuel gas. However, COG contains a large amount of hydrogen. If hydrogen is recovered, the economic and environmental benefits of the coking industry can be improved. In this work, a novel automotive fuel cell hydrogen production process coupled with membrane separation (PRISM® Membrane Separator, polyimide hollow fiber membrane), pressure swing adsorption (PSA) and methane steam reforming (SMR) is proposed. The process uses membrane separation and PSA to produce high-purity hydrogen for fuel cells. The methane-rich membrane residue gas is used as the feed gas of the reforming reactor. The hydrogen-containing gas at the outlet of the reactor enters the membrane separator to further improve the hydrogen yield. In addition, based on the principle of temperature gradient utilization, the high-temperature gas at the outlet of the reactor is used as the heat source for the system. Through a synergy of separation and reaction, the process supports the low-cost and efficient production of fuel cell hydrogen from COG. The proposed process was established using UniSim Design. The key variables were determined by sensitivity analysis, and the response surface methodology based on Box–Behnken design (BBD) method was further used to optimize the key variables. The optimal operating variables are as follows: the area of the third hydrogen membrane (HM3) is 3000 m2, the reaction temperature is 917 K and the molar ratio of steam to methane (S/C) is 1.12. The cost of the hydrogen production process is 1.56 $/kg, which means it has good prospects for use in industrial applications.

Optimization of specific heating consumption of coke oven plant using flow meter calibration modification

Coke oven plant produces coke which acts as a reducing agent in blast furnaces. So, coke is an important material which is also called as a reducing agent. Coke is basically used for manufacturing of steel materials and extraction of metals. In an integrated steel plant coke is a prime material for making high grade of steels. In this present research work, the calibration of flow meter is modified. By this modification of gas flow meter calibration coke oven gas flow reduced from 17100Nm3/hrs to 16900Nm3/hrs, such as 200 Nm3 on hourly basis saving without any extra manpower cost. The proposed method is also cost effective as it saves Rs 6483000 every month for producing coke. This methodology is also helpful for reducing the manufacturing cost of coke in a recovery type of coke plant and stable oven operation and prolongation of coke oven life. Future advancements in this technique will allow us to minimize the need for money, which will revolutionize the nation's economy.

Effects of fuel injection and energy efficiency on the production and environmental parameters of electric arc furnace -heat recovery systems

A stoichiometric model of an electric arc furnace (EAF)-heat recovery system was constructed to display material, energy, and exergy behaviors, as well as production and environmental parameters, in order to study the effects of different fuel injection indexes. The injection of high-calorific value fuel (rather than hydrogen and biomass) reduces power consumption more effectively, but hydrogen utilization reduces the amount of off-gas and improves heat recovery slightly (0.06 MJ/Nm3) in the case of 30% energy efficiency. It is more efficient to directly use the energy released from fuel combustion in the furnace than to recover the heat in the off-gas, showing the importance to increase energy efficiency. In the scenario of improved equipment and technology using large amounts of hydrogen (20 m3/t) and biomass (40 kg/t), power consumption will reach 322 kWh/t. Near-zero carbon emissions (41.20 kg CO2/t) can be achieved in an EAF by using green power, green hydrogen, and advanced equipment and processes. However, realizing this process requires long-term transformation, including the use of coke oven gas rather than gray hydrogen, which has high upstream emissions. Moreover, there is a significant exergy loss in the off-gas heat recovery system (>70%), which requires the adoption of stoichiometric combustion and an increase in the efficiency of heat exchange.

Thermal management of natural gas production from coke oven gas by optimizing catalyst distribution and operation conditions

In this work, 3D particle-resolved CFD simulations have been performed to investigate the thermal effects of natural gas production from coke oven gas. The catalyst packing structures with uniform, gradient rise and gradient descent distribution and the operating conditions of pressure, wall temperature, inlet temperature and feed velocity are optimized for reduced hot spot temperature. The simulation results show that compared with packing structures with uniform distribution and gradient descent distribution, the gradient rise distribution could effectively reduce the hot spot temperature without affecting the reactor performance in the reactor with upflow reactants feeding, of which the reactor bed temperature rise is 37 K. Under the conditions with the pressure of 20 bar, wall temperature of 500 K, inlet temperature of 593 K, inlet flow rate of 0.04 m/s, the packing structure with gradient rise distribution exhibits the minimum reactor bed temperature rise of 19 K. By optimizing the catalyst distribution and operation conditions, the hot spot temperature of CO methanation process could be dramatically reduced by 49 K at the sacrifice of slightly reduced CO conversion.

Effects of hydrogen-rich fuel injection on the states of the raceway in blast furnace

The application of hydrogen-rich fuels such as hydrogen (H2), natural gas (NG), coke oven gas (COG), and recycling top gas (RTG) to blast furnace (BF) ironmaking can effectually reduce CO2 emissions. In this study, the characteristics in the tuyere and raceway with H2, NG, COG and RTG injection are compared. The simulation results show that COG starts to combust at the nearest place after leaving the gas lance, the gas velocity is highest at the tuyere and the penetrability of the gas is strongest in four cases; And the maximum temperature generated by combustion along the pulverized coal plume is the highest and the lowest, and the difference is higher as RTG and NG are injected from the gas lance. And the mole fraction of reducing gas produced in the raceway is the highest when NG is injected, followed by COG and RTG, and the least with H2 injection. Finally, the burnout of PC in the raceway from high to low: RTG injection (81.76%), H2 injection (79.86%), COG injection (78.04%), NG injection (75.72%) as the same rate of gas is injected. The research will provide a basis for the selection of hydrogen-rich fuel injection in practice.

Highly Efficient CO2 Capture and Utilization of Coal and Coke-Oven Gas Coupling for Urea Synthesis Process Integrated with Chemical Looping Technology: Modeling, Parameter Optimization, and Performance Analysis

The resource endowment structure of being coal-rich and oil-poor makes China’s production of coal-based ammonia and urea, with a low production cost and a good market, a competitive advantage. However, the process suffers from high CO2 emissions and low energy efficiency and carbon utilization efficiency due to the mismatch of hydrogen-to-carbon ratio between raw coal and chemicals. Based on the coal-to-urea (CTU) process and coal-based chemical looping technology for urea production processes (CTUCLAS&H), a novel urea synthesis process from a coal and coke-oven gas-based co-feed chemical looping system (COG-CTUCLAS&H) is proposed in this paper. By integrating chemical looping air separation and chemical looping hydrogen production technologies and the synergies between coal gasification, low-energy consumption CO2 capture and CO2 utilization are realized; the excess carbon emissions of the CTU process are avoided through coupling the pressure swing adsorption of COG, and the low carbon emissions of the proposed system are obtained. In this work, the novel process is studied from three aspects: key unit modeling, parameter optimization, and technical-economic evaluation. The results show that COG-CTUCLAS&H achieves the highest system energy efficiency (77.10%), which is much higher than that of the CTU and CTUCLAS&H processes by 40.03% and 32.80%, respectively, when the optimized ratio of COG to coal gasified gas is 1.2. The carbon utilization efficiency increases from 35.67% to 78.94%. The product cost of COG-CTUCLAS&H is increased compared to CTU and CTUCLAS&H, mainly because of the introduction of COG, but the technical performance advantages of COG-CTUCLAS&H make its economic benefits obvious, and the internal rate of return of COG-CTUCLAS&H is 26%, which is larger than the 14% and 16% of CTU and CTUCLAS&H, respectively. This analysis will enable a newly promising direction of coal and COG-based co-feed integrated chemical looping technology for urea production.