Optimization of an Existing Coal-fired Power Plant with CO²Capture

Nowadays, the worsening environmental issue caused by CO2 emission is greatly aggravated by human activity. Many CO2 reduction technologies are under fast development. Among these, monoethanolamine (MEA) based CO2 capture technology has been paid great attention. However, when connecting the CO2 capture process with a coal-fired power plant, the huge energy and efficiency penalty caused by CO2 capture has become a serious problem for its application. Thus, it is of great significance to reduce the related energy consumption. Based on an existing coal-fired power plant, this paper proposes a new way for the decarburized retrofitting of the coal-fired power plant, which helps to improve the overall efficiency of the power plant with less energy and efficiency penalty. The decarburized retrofitting scheme proposed will provide a new route for the CO2 capture process in China.

Development of Carbon Dioxide Capture Technologies in Coal-Fired Power Plants

With a particular reference to China Huaneng Group's practices in CO_2 capture, this article presents a brief ing on the current development of CO_2 capture technologies in coal-fired power plants both in China and abroad. Sooner or later, the integration of CO_2 capture and storage (CCS) facility with coal-fired power plant will be inevitably put on the agenda of developers.

Environmental life cycle assessment of Indian coal-fired power plants

Coal is the backbone of the Indian power sector. The coal-fired power plants remain the largest emitters of carbon dioxide, sulfur dioxide and substantial amounts of nitrogen oxides, which are associated with climate and health impacts. Various CO2 mitigation technologies （carbon capture and storage--CCS） and SO2/NOx mitigation technologies （flue gas desulfurization and selective catalytic reduction） have been employed to reduce the environmental impacts of the coal-fired power plants. Therefore, it is imperative to understand the feasibility of various mitigation technologies employed. This paper attempts to perform environmental life cycle assessment （LCA） of Indian coal-fired power plant with and without CO2, SO2 and NOx mitigation controls. The study develops new normalization factors for India in various damage categories, using the Indian emissions and energy consumption data, coupled with the emissions and particulate emission to come up with a final environmental impact of coal-fired electricity. The results show a large degree of dependence on the perspective of assessment used. The impact of sensitivities of individual substances and the effect of plant efficiency on the final LCA results is also studied.

Optimal Bidding and Operation of a Power Plant with Solvent-BasedCarbon Capture under a CO2 Allowance Market： A Solution with aReinforcement Learning-Based Sarsa Temporal-Difference Algorithm

In this paper, a reinforcement learning （RL）-based Sarsa temporal-difference （TD） algorithm is applied tosearch for a unified bidding and operation strategy for a coal-fired power plant with monoethanolamine（MEA）-based post-combustion carbon capture under different carbon dioxide （CO2） allowance market con-ditions. The objective of the decision maker for the power plant is to maximize the discounted cumulativeprofit during the power plant lifetime. Two constraints are considered for the objective formulation. Firstly,the tradeoff between the energy-intensive carbon capture and the electricity generation should be made un-der presumed fixed fuel consumption. Secondly, the CO2 allowances purchased from the CO2 allowance mar-ket should be approximately equal to the quantity of COs emission from power generation. Three case stud-ies are demonstrated thereafter. In the first case, we show the convergence of the Sarsa TD algorithm andfind a deterministic optimal bidding and operation strategy. In the second case, compared with the inde-pendently designed operation and bidding strategies discussed in most of the relevant literature, the SarsaTD-based unified bidding and operation strategy with time-varying flexible market-oriented CO2 capturelevels is demonstrated to help the power plant decision maker gain a higher discounted cumulative profit.In the third case, a competitor operating another power plant identical to the preceding plant is consideredunder the same CO2 allowance market. The competitor also has carbon capture facilities but applies a differ-ent strategy to earn profits. The discounted cumulative profits of the two power plants are then compared,thus exhibiting the competitiveness of the power plant that is using the unified bidding and operation strat-egy explored by the Sarsa TD algorithm.

A coal-fired power plant integrated with biomass co-firing and CO_(2) capture for zero carbon emission

A promising scheme for coal-fired power plants in which biomass co-firing and carbon dioxide capture technologies are adopted and the low-temperature waste heat from the CO_(2) capture process is recycled to heat the condensed water to achieve zero carbon emission is proposed in this paper.Based on a 660 MW supercritical coal-fired power plant,the thermal performance,emission performance,and economic performance of the proposed scheme are evaluated.In addition,a sensitivity analysis is conducted to show the effects of several key parameters on the performance of the proposed system.The results show that when the biomass mass mixing ratio is 15.40%and the CO_(2) capture rate is 90%,the CO_(2) emission of the coal-fired power plant can reach zero,indicating that the technical route proposed in this paper can indeed achieve zero carbon emission in coal-fired power plants.The net thermal efficiency decreases by 10.31%,due to the huge energy consumption of the CO_(2) capture unit.Besides,the cost of electricity(COE)and the cost of CO_(2) avoided(COA)of the proposed system are 80.37/MWhand41.63/tCO_(2),respectively.The sensitivity analysis demonstrates that with the energy consumption of the reboiler decreasing from 3.22 GJ/tCO_(2) to 2.40 GJ/tCO_(2),the efficiency penalty is reduced to 8.67%.This paper may provide reference for promoting the early realization of carbon neutrality in the power generation industry.

Pilot testing of CO_(2) capture from a coal-fired power plant-Part 2:Results from 1-MWe pilot tests

Using a 1-MWe slipstream pilot plant,solid-sorbent-based post-combustion CO_(2) capture was tested at a coal-fired power plant.Results from pilot testing were used to develop a preliminary full-scale commercial design.The sorbent selected for pilot-scale evaluation during this project consisted of an ion-exchange resin that incorporated amines covalently bonded to the substrate.A unique temperature-swing-absorption(TSA)process was developed that incorporated a three-stage fluidized-bed adsorber integrated with a single-stage fluidized-bed regenerator.Overall,following start-up and commissioning challenges that are often associated with first-of-a-kind pilots,the pilot plant operated as designed and expected,with a few key exceptions.The two primary exceptions were associated with:(i)handling characteristics of the sorbent,which were sufficiently different at operating temperature than at ambient temperature when design specifications were established with lab-scale testing;and(ii)CO_(2) adsorption in the transport line between the regenerator and adsorber that preloaded the sorbent with CO_(2) prior to entering the adsorber.Results from the pilot programme demonstrate that solid-sorbent-based post-combustion capture can be utilized to achieve 90%CO_(2) capture from coal-fired power plants.

Pilot testing of CO_(2) capture from a coal-fired power plant-Part 1:Sorbent characterization

Post-combustion CO_(2)capture followed by sequestration is one of the only feasible means to significantly reduce CO_(2)emissions from existing fossil-fuel-fired power plants.This paper is Part 1 of a two-part paper highlighting key results from a project sponsored by the US Department of Energy and supported by industrial groups with the objective of demonstrating the viability of solid sorbents for CO_(2)capture.The overall objective of the effort was to validate solid sorbent-based post-combustion CO_(2)capture through slipstream pilot testing at a coal-fired power plant using a temperature-swing adsorption process.In Part 1 of this work,the results from laboratory characterization of the sorbent selected for the pilot-scale demonstration are presented.A great deal of research related to sorbent development and evaluation has occurred to date but,for the most part,these promising materials have yet to be paired with a feasible process and demonstrated at the pilot scale.The sorbent selected for pilot-scale evaluation under this project consisted of an ion-exchange resin that incorporated amines that were covalently bonded to the substrate.During the sorbent characterization portion of this work,the sorbent was characterized by a range of methods intended to provide information to support the design and operation of the pilot-scale CO_(2)-capture process,including equilibrium adsorption isotherms,adsorption and regeneration kinetics,impact of moisture and oxygen on CO_(2)working capacity,sorbent thermal properties,sorbent strength and attrition,and optimum particle-size distribution.This paper reports results from sorbent characterization testing and how these characteristics influenced the type and size of the CO_(2)-capture process equipment.In Part 2 of this work,results from tests of 1-MWe pilot-scale process equipment loaded with the sorbent described in Part 1 will be presented and analysed.

Post-combustion slipstream CO_(2)-capture test facility at Jiangyou Power Plant,Sichuan,China:facility design and validation using 30% wt monoethanolamine(MEA)testing

Given the dominant share of coal in China’s energy-generation mix and the fact that>50% of the power plants in the country are currently<15 years old,efforts to significantly reduce China’s CO_(2) footprint will require the deployment of CO_(2) capture across at least part of its fleet of coal-fired power plants.CO_(2)-capture technology is reaching commercial maturity,but it is still necessary to adapt the technology to regional conditions,such as power-plant design and flexible operation in the China context.Slipstream facilities provide valuable field data to support the commercialization of CO_(2) capture.We have built a slipstream facility at Jiangyou power plant in Sichuan that will allow us to explore China-relevant issues,especially flexible operation,over the next few years.We plan to share our results with the broader CO_(2)-capture and CO_(2)-storage(CCS)community to accelerate the deployment of CCS in China.This paper describes the design of the slipstream facility and presents results from our steady-state qualification tests using a well-studied benchmark solvent:30% wt monoethanolamine(MEA).The results from our MEA tests compare favorably to results reported from other slipstream-test facilities around the world,allowing us to commission our system and establish a reference baseline for future studies.

Flue Gas CO_2 Emission Reduction Technologies and Applications

The current status and trend of CO2 emission from coal-fired power plants in China are introduced. Main flue gas decarbonization technologies and their prospective of applications in China are discussed in two separate parts-capture and sequestration. It is stated that the selection of CO2 capture and sequestration technologies relates closely with the geographical location of power plants, with the destination of CO2 being the key. Further, it is suggested that industrialized test centers or test platforms of national or industrial level should be set up.