Abstract

Post combustion capture using chemical absorption is one of the most mature technologies, which can effectively reduce CO2 emissions from plants. But it usually comes with the cost of high energy consumption. Aiming to reduce the regeneration energy consumption of post combustion CO2 capture technology, a novel ammonia based CO2 capture process with bipolar membrane electrodialysis(BMED) and CO2 regeneration reactor is designed. In the CO2 regeneration reactor, the CO2 loaded by rich solvent is completely released and collected due to the reactions between the rich solvent and strong acid. After that, energy consumption of the BMED unit is effectively reduced because there is no bubble formation in the cell during the electrodialysis process. The performance of conventional amine based process and the novel process is evaluated by simulation and calculation. Result shows that the CO2 regeneration energy consumption of the novel process is as low as 1.80MJ/kgCO2, which is much lower than that of the conventional process(3.91MJ/kgCO2). Given the volatilization of the NH3, the treatments of escaped NH3 in the novel process is discussed. When the value-added products is considered, sent the escaped NH3 washing solution to the desulfurization part as absorbent may be a better choice than recovering NH3 with heating. With the development of the membrane technology, the energy consumption of the novel process will be further reduced. If combined with renewable energy technology, it is expected to be a new CO2 capture technology.

Abstract

The CO2 adsorption and desorption behaviors, including the CO2 adsorption capacity, CO2 adsorption/desorption kinetics and bed pressure drops under post-combustion CO2 capture conditions in both fluidized and fixed beds, were investigated for the first time using a solid amine sorbent in a temperature swing adsorption (TSA) experimental rig. The results show that the saturated CO2 adsorption capacities are basically the same in fluidized and fixed beds. However, the sorbent exhibits faster adsorption and desorption kinetics in a fluidized bed, as reflected by the fitted parameters of the Avrami kinetic model and the change of bed temperature during adsorption and desorption tests. Moreover, CO2 is not a suitable fluidizing gas in a desorber as high CO2 partial pressure inhibits the desorption process. The bed pressure drops in fluidized beds are much lower than that in fixed beds of same sorbent mass, especially at high superficial gas velocities and high sorbent loadings. By further discussion, a fluidized bed can also achieve lower equipment investment and less sorbent loading compared to multiple fixed beds in parallel. This study demonstrates the advantages of fluidized beds over fixed beds in large-scale TSA units in view of higher reactor efficiency, lower energy consumption and equipment investment.

Abstract

In view of the common problems of CCUS injection wells, such as casing pressure, difficulty in maintenance and high cost, in order to improve the wellbore integrity of injection wells and reduce comprehensive costs, the research and test of coiled tubing gas injection completion technology were carried out. By optimizing the stainless steel coiled tubing for well completion, the string can resist the corrosion of downhole long-term acidic environment, the leakage point is minimized, and the whole well completion under pressure can be conducted. A special gastight packer has been developed, which adopts a double rubber cylinder sealing structure. The gastight pressure bearing is 50MPa, and the unsealing tonnage is controlled below 8.0t, providing a means to solve the tripping problem caused by the low tensile strength of coiled tubing. Large diameter coiled tubing hanger, metal auxiliary sealing device, dual function safety release and gas seal connector are designed to meet the comprehensive requirements of the overall sealing performance of the gas injection string and the later operation under pressure. On this basis, a new process test was carried out for the first well of coiled tubing gas injection in Changqing Oilfield. It only takes 2.5 hours to lower the tubing string to the design depth. The testing of the large diameter coiled tubing hanger and metal auxiliary sealing device at the wellhead was normal, and the setting and verification of the gas seal packer were successful once. The success of this test provides a new solution for the completion of CCUS injection wells, which is of great significance in improving the integrity of injection wells, realizing safe gas injection throughout the life cycle of injection wells, and building Changqing Oilfield into the largest CCUS industrial base in China. It has a very broad application prospect.

Abstract

CO2 capture, transportation, storage and utilization in agriculture (CCUS) technology is a new technology with the potential to reduce CO2 emissions on a large scale. Considering the immature technology of CO2 pipeline long-distance transmission and the lack of relevant utilization technologies, it is necessary to develop a reproducible and efficient CCUS digital system. The research shows that different concentrations of CO2 have a promotion mechanism for plants in photosynthesis. On this basis, through various sensors, actuators and intelligent twin platforms, the problems of poor information communication and extensive management of CCUS in all aspects of agricultural application can be solved, giving new answers to the low-cost CO2 pipeline transportation and utilization of CCUS technology at the emerging stage. In this study, through the introduction of artificial intelligence and digital twin related technologies, the data of farmland soil physical and chemical properties are collected by using nitrogen, phosphorus, potassium, conductivity, PH value, temperature, humidity and other sensors, and the impact of exogenous carbon dioxide on plant photosynthesis, plant physiology and biochemistry, and plant growth yield is comprehensively analyzed. The demand for carbon dioxide is predicted through artificial intelligence technology, and carbon capture is conducted according to the prediction results, The carbon dioxide sensor can accurately measure the concentration and content of captured carbon dioxide; The captured carbon dioxide will be timely and accurately distributed to the corresponding farmland for soil improvement and crop yield increase. Visual modeling of the above process can visually see the overall operation process online. This research combines the virtual and real aspects of CCUS, and realizes the accurate evaluation, standardized management, visual real-time early warning, personalized analysis, intelligent decision-making and fine control of the whole process of agricultural CCUS supply chain. It has improved the intelligence and informatization level of the supply chain, as well as the intelligent service capability and circulation efficiency. In the future, we will modularize the components used in the above process to facilitate personalized configuration according to customer needs.

Abstract

Carbon dioxide displacement and storage is the most feasible technology to realize carbon neutralization, and also the key technology to improve the recovery of tight reservoirs. CO2 capture and carbonization can be achieved by precipitation of potassium carbonate by using the “Ethanol + KOH” solution system. The reaction process in the solution system is affected by the ethanol concentration, resulting in different CO2 carbonization amounts with the change of ethanol concentration. At the same time, the potassium-based acid salt generated by precipitation can react with water to complete the regeneration of ethanol. In this paper, experimental means are used to study the CO2 capture efficiency of the “Ethanol + KOH” system, monitor the ethanol content in the solution in real time, and screen out the best ethanol concentration suitable for the formation temperature. Add KOH to the solution, use the ethanol regenerated in the solution after carbonization reaction to carbonize again, and determine the maximum CO2 capture of “ethanol + KOH”. Based on the high temperature and high pressure core displacement device, the CO2 burial experiment after the injection of “Ethanol + KOH” solution was carried out to clarify the change rule of CO2 burial under the action of “Ethanol + KOH” system in low permeability cores. The research results show that “96% ethanol+3g KOH” can effectively capture CO2, and each capture will produce 4.56g precipitation on average. At the same time, after the core is saturated with “96% ethanol+3gKOH” solution, CO2 is injected to generate sediment, and the core permeability decreases by about 15%. The research results of this paper prove that, compared with direct injection of CO2 into the formation, injection of this system into the formation in advance can accelerate the CO2 carbonization process, thus effectively improving the CO2 burial efficiency.

Abstract

High penetration of renewable energy presents great challenges in the operation of a distribution grid, and load peak shaving and power smoothing cannot be ignored. The application of multiple shared energy storage systems is a promising solution to this problem. Therefore, in order to analyze the capability of multiple shared energy storage systems to smooth the aggregators’ total load curve, this paper proposes a day-ahead peak shaving model to optimize the coordinated operation strategy of energy storage and PV distributed generation systems. This model aims to minimize the residual load peak-to-valley difference, and comparative analyses are conducted. The results show that the proposed model can provide peak shaving effectively, and the application of multiple shared energy storage systems can enhance the stability of the combined net load.

Abstract

The V reservoir is ultra-thin, low-permeable sandstone with net pay of less than 3m and air permeability of 5.1 mD. Its primary recovery is 10% of OOIP due to low permeability and high heterogeneity. CO2 miscible flooding has been implemented since 1998 to improve oil displacement and increase oil production. This paper discusses a case study on the field to show effect of a new CO2 EOR scheme. This paper presents a CO2 flooding development plan specifically tailored to ultra-thin sandstone reservoirs with strong heterogeneity. A line drive flood pattern was designed to make full use of the anticlinal structure of the reservoir. Moreover, the development plan minimized the adverse effects of gravity segregation by injecting CO2 at the structurally high part of the reservoir and producing oil at the low part. The injection-production well pattern is designed to overcome facility constraints by placing vertical producers in the thicker part of the reservoir sand body, while horizontal producers in the thinner part of the edge sand body. The method of water and gas alternating injection was adopted to improve the sweep efficiency and have a better conformance control in the late stage of CO2 flood. The actual production results of the oilfield show that with the new CO2 flooding development plan, the recovery rate has increased by 22%, and the daily oil production has also increased from approximately17 m3/d before the implementation of the plan to 140 m3/d approximately. After historical matches, the dynamic model statistical calculation results of the reservoir numerical simulation also show that the CO2 miscible sweeping volume reaches more than 82% of the total sand volume. It is predicted that the ultimate recovery factory can reach higher than 50%. The above good oil displacement effect comes from the effectiveness of the following methods. The anticline structure has a favorable dip angle creating a gravity overriding effect on CO2 flood. When CO2 is injected at the high structure and migrates to the low structure, it fully interacts with the crude oil, boosting oil recovery. Horizontal wells are used in thin sand formations to significantly maximize contact with the reservoir and enhance oil flow. The technique of alternating gas and water injection is used with dynamically adjusted pressure to create a “gas lock,” blocking high permeability areas and reducing gas channeling. This paper depicts the guidance to efficiently develop the ultra-thin, low-permeable reservoir. The new scheme includes methods such as injecting CO2 into the high part of the reservoir and producing oil at the low part, using horizontal wells to produce thin sand bodies at the edge, and dynamically adjusting the gas and water alternating injection pressure to reduce gas channeling.

Abstract

The concentration of CO2 in the atmosphere has risen to 415 ppm from 280 ppm since the industrial revolution in the 1760s, and now it is going up at 2.5 ppm yearly. It is imperative to tackle CO2 emission and to decrease CO2 level in the atmosphere by use of proven CO2 capture, utilization, and storage (CCUS) technology. CCUS technology has been around for decades, and is used to strip CO2 from industry emissions as well as remove CO2 that’s already in the atmosphere. But CCUS technology was not funded and studied for climate mitigation efforts until the 1980s. Utilization of embodied CO2 from hard-to-abate industrial sectors such as steel, cement, glass, and aluminum is promising and emerging. Capturing and utilizing embodied CO2 in these sectors would reduce global carbon emissions significantly as they account for 25% of total emission globally, and 40% as in China. CO2 enhanced oil recovery (EOR), one of the mature and proven CCUS technologies, only consumes a very small portion of annual total carbon emissions. Some promising and emerging CCUS technologies- includes locking up embodied CO2 in concrete permanently with higher early compressive strength, carbon-neutral fuels for jets, CO2-based plastics, green polyurethane for textiles and flooring, and CO2-derived super-strong and superlight carbon fiber etc.. By 2030, it is estimated that those emerging CCUS technologies can dispose 360 million tons CO2 per year, merely 1% of total global equivalent CO2 emission in 2021. So more practical and solid CCUS technologies must be studied and developed, which will be critical to scaling the CCUS industry for humans to win the battle against excessive CO2 concentration in the atmosphere. The fight against global warming is a continuous effort and it never stops. This review concludes with a discussion that more research and studies should be funded to develop emerging, promising, and future CCUS technology for CO2 reduction in cost-effective, environment-friendly, and sustainable ways.

Abstract

In order to explore the investment strategy issues of biomass carbon capture and storage (BECCS) power plants and the influence of cost control and policy incentives on the investment strategy of BECCS power plants so as to realize the wide application of BECCS technology in China, based on real options theory, this paper establishes a triple tree model for investment decisions in BECCS power plants by fully considering uncertainties such as crude oil price, coal price, biomass fuel price, investment cost, and operation cost. The net present value (NPV) and total investment value (TIV) of the BECCS power plants are determined by the algorithm analysis to explore the investment decision problem of the BECCS power plants. In addition, this paper uses sensitivity analysis to explore the impact of carbon trading market, cost control and policy incentives on the investment strategy of BECCS power plants. The results show that (1) the TIV of BECCS power plants in 2021 is CNY 9468.95, so the investment project is feasible, but since the NPV of BECCS power plants in 2021 is less than zero, it is not suitable for immediate investment, and investors should postpone the investment to make a profit; (2) The decrease in coal price has the largest effect on the increase in NPV of BECCS power plants, and the decrease in biomass fuel price and the increase in the investment subsidy factor have a significant contribution to the increase in NPV of BECCS power plants, but even if the coal price and biomass fuel price change by -100% or the government takes the full amount of subsidy for the initial investment cost, immediate investment still cannot be achieved. Therefore, in addition to cost control and policy incentives under the current carbon trading market, the government has to seek other more effective ways to promote the deployment of BECCS power plants.

Abstract

As the power and heating industry is the sector with the largest incremental CO2 emissions globally, CCUS retrofitting by power companies is important to achieve the national carbon dioxide emission reduction macro policy. With the aim of exploring the interaction and choice of strategy between government, public and coal plants and to further explore the influence of incentives on coal plant behaviour so as to realize investment in CCUS retrofitting by coal plants, in this paper, we take the government, the public, and coal plants as three stakeholders, constructs the game model, construct the payoff matrix based on evolutionary game theory, calculate the replicator dynamics equations of each stakeholders, and the evolutionary stabilization strategy of the system is analyzed. In addition, this paper establishes the SD simulation model according to the concept of system dynamics, simulates the behavior evolution path of three stakeholders using Vensim software, and conducts sensitivity analyses on incentive policies and key parameters. The results show that: (1) There exists a stabilization strategy in the evolutionary game model, i.e., both the government and the public choose not to regulate and coal plants choose to invest in CCUS; (2) For China’s current domestic context in which only a carbon trading market exists, China has a significant advantage in the imposition of a carbon tax, which has a great motivator for coal plants to choose to invest in CCUS; (3) In terms of energy policy, the government can motivate coal plants to invest early in CCUS retrofits in order to implement carbon dioxide emission reduction technologies by increasing tariff subsidies for clean electricity; (4) By increasing penalties, the government can also motivate coal plants to invest in CCUS retrofits to promote the deploy CCUS.