Air Permitting of IGCC Plants

00/00446 Comparison between IGCC and supercritical power plant processes

This paper investigates whether coal- or biomass-fired Integrated Gasification Combined-Cycle (IGCC) power plants can serve as an economically viable future technology for providing clean electricity and heat in Germany. In the context of CO2 emission reduction in power generation, energy conversion technologies that enable the implementation of Carbon Capture and Storage (CCS) need to be considered. IGCC is one such technology, as it utilizes coal or biomass but does not necessarily emit CO2. We therefore investigate whether IGCC plants can, from an economic perspective, be an alternative to nuclear and/or conventional coal-fired power plants. Our research is undertaken with the help of scenario analysis. The possible shut-down of nuclear power stations as well as of outdated coal-fired power plants, together with the evolution of CO2 prices, provides the starting point of our study. The option of hot gas cleaning in IGCC plants is of particular interest, as it is expected to significantly enhance the efficiency of IGCC technology and allows for combined heat and power production (CHP). Corresponding supplementary earnings (incl. subsidies) are compared with an increase in specific investment costs. Besides the hot gas cleaning advancement, we also investigate the injection of pure CO2 (separated from the IGCC process) into oilfields, as it reduces the costs of CO2 transport and storage through Enhanced Oil Recovery (EOR). Based on the results, a judgement on the ability of IGCC technology to replace nuclear power stations and/or conventional coal-fired power plants in Germany is made. Net present values calculated provide decision-support for energy suppliers about the if and when to invest in IGCC plants. We find that only a partial substitution of current power plants by IGCC facilities is reasonable, e.g. for locational reasons, whereas a complete abandonment of IGCC technology seems to be unlikely from the current point of view.

Integrated gasification combined cycle (IGCC) is considered as a viable option for low emission power generation and carbon dioxide sequestration. As a part of the process of IGCC plant design and development, modelling and simulation study of the whole IGCC process is important for thermodynamic performance evaluation, study of carbon capture readiness and economic analysis. The work presented in the paper is to develop such a whole system model and simulation platform. A simplified dynamic model for the IGCC process is developed, in which Texaco gasifier is chosen to give the basic representation for the IGCC process. The chemical equilibriums principle is used to predict the syngas contents in the modelling procedure. The influences of key parameters to regulate the input such as oxygen/coal ratio and water/coal ratio to syngas generation are studied. The simulation results are validated by comparing with the industry data provided by the Lu-nan fertilizer factory. Water-shift reactor, gas turbine and heat recovery steam-generation modules are modelled to study the dynamic performance with respect to the variation from the input of syngas stream. The simulation results reveal the dynamic changes in the plant outputs, including gas temperature, power output and mole percentages of hydrogen and carbon dioxide in the syngas. The process dynamic responses with three types of coal inputs are studied in the paper and their dynamic variation trends are presented via the simulation results.

Economic evaluation of IGCC plants with hot gas cleaning

Abstract. The Chinese government launched the Air Pollution Prevention and Control Action Plan in 2013, and various stringent measures have since been implemented, which have resulted in significant decreases in emissions and ambient concentrations of primary pollutants such as SO2, NOx, and particulate matter (PM). However, surface ozone (O3) concentrations have still been increasing in urban areas across the country. In a previous analysis, we examined in detail the roles of meteorological variation during 2013–2017 in the summertime surface O3 trend in various regions of China. In this study, we evaluated the effect of changes in multi-pollutant emissions from anthropogenic activities on O3 levels during the same period by using an up-to-date regional chemical transport model (WRF-CMAQ) driven by an interannual anthropogenic emission inventory. The Community Multiscale Air Quality (CMAQ) model was improved with regard to heterogeneous reactions of reactive gases on aerosol surfaces, which led to better model performance in reproducing the ambient concentrations of those gases. The model simulations showed that the maximum daily 8 h average (MDA8) O3 mixing ratio in urban areas increased by 0.46 ppbv per year (ppbv a−1) (p=0.001) from 2013 to 2017. In contrast, a slight decrease in MDA8 O3 by 0.17 ppbv a−1 (p=0.005) in rural areas was predicted, mainly attributable to the NOx emission reduction. The effects of changes in individual pollutant emissions on O3 were also simulated. The reduction of NOx emission increased the O3 levels in urban areas due to the nonlinear NOx and volatile organic compound (VOC) chemistry and decreasing aerosol effects; the slight increase in VOC emissions enhanced the O3 levels; the reduction of PM emissions increased the O3 levels by enhancing the photolysis rates and reducing the loss of reactive gases on aerosol surfaces; and the reduction of SO2 emissions resulted in a drastic decrease in sulfate concentrations, which increased O3 through aerosol effects. In contrast to the unfavorable effect of the above changes in pollutant emissions on efforts to reduce surface O3, the reduction of CO emissions did help to decrease the O3 level in recent years. The dominant cause of increasing O3 due to changes in anthropogenic emissions varied geographically. In Beijing, NOx and PM emission reductions were the two largest causes of the O3 increase; in Shanghai, the reduction of NOx and increase in VOC emissions were the two major causes; in Guangzhou, NOx reduction was the primary cause; in Chengdu, the PM and SO2 emission decreases contributed most to the O3 increase. Regarding the effects of decreasing concentrations of aerosols, the drop in heterogeneous uptake of reactive gases – mainly HO2 and O3 – was found to be more important than the increase in photolysis rates. The adverse effect of the reductions of NOx, SO2, and PM emissions on O3 abatement in Beijing, Shanghai, Guangzhou, and Chengdu would have been avoided if the anthropogenic VOCs emission had been reduced by 24 %, 23 %, 20 %, and 16 %, respectively, from 2013 to 2017. Our analysis revealed that the NOx reduction in recent years has helped to contain the total O3 production in China. However, to reduce O3 levels in major urban and industrial areas, VOC emission controls should be added to the current NOx-SO2-PM policy.

Optimized design and operating parameters for minimizing emissions during voc thermal oxidation

Greenhouse gas emissions from power generation will increase in future if the demand for electrical energy does not subside. Therefore capture and storage of carbon dioxide (CO2) will become important technologies for lowering the rate of increase of global CO2 emissions, or even reducing them. A promising technology for coal fired power cycles is the integrated gasification combined cycle (IGCC), where CO2 is separated from the syngas coming from the gasifier before the syngas is combusted in a more or less conventional gas turbine. But oxygen is required for the gasification process to achieve a high carbon conversion rate. The energy demand for the cryogenic air separation unit (ASU) lowers the net power output of the IGCC cycle. An alternative way of producing the oxygen could eliminate this disadvantage of the IGCC cycle. Oxygen transport membranes (also known as mixed conducting membranes – MCM) show a high potential for such applications in power cycles. In this paper results of an investigation on an IGCC cycle with CO2 capture and an integrated oxygen transport membrane (OTM) reactor are reported. The operating conditions of the membrane reactor have been analyzed; the feed inlet temperature and the pressure differences between permeate and retentate sides of the membrane reactor have been varied. The impact on the overall IGCC cycle has been discussed. The most optimistic assumptions give an overall net efficiency close to the case without CO2 capture. In this case the net efficiency is reduced by only 3 percentage points compared to an IGCC process without CO2 capture. But these assumptions lead to very challenging conditions for the membrane reactor. A pressure difference of 14.5 bar is assumed. Less severe operating conditions for the OTM reactor, which seem closer to realization, show less promising results. For sweep stream pressures of 10 and 15 bar the net efficiency ranges from 36% to 39%. This is in the range of an IGCC process with cryogenic ASU which achieves a net efficiency of 37% to 38%. It can be concluded that the integration of an OTM reactor into the IGCC cycle is an option with good prospects if the membrane is capable of bearing the challenging operating conditions. Calculations of investment costs have not been investigated in the frame of this work. Both the total capital costs and the durability are very important aspects for the membrane technology to be realized in power cycles such as IGCC.

This study identifies vital gas turbine (GT) parameters and quantifies their influence in meeting the DOE Turbine Program overall Integrated Gasification Combined Cycle (IGCC) plant goals of 50% net HHV efficiency, $1000/kW capital cost, and low emissions. The project analytically evaluates GE advanced F class air cooled technology level gas turbine conceptual cycle designs and determines their influence on IGCC plant level performance including impact of Carbon capture. This report summarizes the work accomplished in each of the following six Tasks. Task 1.0--Overall IGCC Plant Level Requirements Identification: Plant level requirements were identified, and compared with DOE's IGCC Goal of achieving 50% Net HHV Efficiency and $1000/KW by the Year 2008, through use of a Six Sigma Quality Functional Deployment (QFD) Tool. This analysis resulted in 7 GT System Level Parameters as the most significant. Task 2.0--Requirements Prioritization/Flow-Down to GT Subsystem Level: GT requirements were identified, analyzed and prioritized relative to achieving plant level goals, and compared with the flow down of power island goals through use of a Six Sigma QFD Tool. This analysis resulted in 11 GT Cycle Design Parameters being selected as the most significant. Task 3.0--IGCC Conceptual System Analysis: A Baseline IGCC Plant configuration was chosen, and an IGCC simulation analysis model was constructed, validated against published performance data and then optimized by including air extraction heat recovery and GE steam turbine model. Baseline IGCC based on GE 207FA+e gas turbine combined cycle has net HHV efficiency of 40.5% and net output nominally of 526 Megawatts at NOx emission level of 15 ppmvd{at}15% corrected O2. 18 advanced F technology GT cycle design options were developed to provide performance targets with increased output and/or efficiency with low NOx emissions. Task 4.0--Gas Turbine Cycle Options vs. Requirements Evaluation: Influence coefficients on 4 key IGCC plant level parameters (IGCC Net Efficiency, IGCC Net Output, GT Output, NOx Emissions) of 11 GT identified cycle parameters were determined. Results indicate that IGCC net efficiency HHV gains up to 2.8 pts (40.5% to 43.3%) and IGCC net output gains up to 35% are possible due to improvements in GT technology alone with single digit NOx emission levels. Task 5.0--Recommendations for GT Technical Improvements: A trade off analysis was conducted utilizing the performance results of 18 gas turbine (GT) conceptual designs, and three most promising GT candidates are recommended. A roadmap for turbine technology development is proposed for future coal based IGCC power plants. Task 6.0--Determine Carbon Capture Impact on IGCC Plant Level Performance: A gas turbine performance model for high Hydrogen fuel gas turbine was created and integrated to an IGCC system performance model, which also included newly created models for moisturized syngas, gas shift and CO2 removal subsystems. This performance model was analyzed for two gas turbine technology based subsystems each with two Carbon removal design options of 85% and 88% respectively. The results show larger IGCC performance penalty for gas turbine designs with higher firing temperature and higher Carbon removal.

Biological based emissions control has been demonstrated to be an efficient and cost effective alternative to thermal oxidation technology or flaring for volatile organic compounds (VOCs) from the forest products and paint and coatings industries. This type of technology applicationhas promising advantages such as the potential for a low carbon footprint, low secondary pollutants such as NOx and SOx, lower energy demands, and lower cost. The objective of this project was to design and implement a sequential field scale biotrickling-biofilter treatment unit to remove VOCs and hazardous air pollutants (HAPs) emissions at the Apache TAMU#2 well storage tank battery in Snook, Texas. The field scale biotreatment system included a biotrickling filter followed by a biofilter with the total treatment volume of 100 ft3, skid mounted on a 22 foot trailer. The biotrickling filter was packed with structured cross flow media with large surface area and high void fraction designed to remove the more water soluble compounds and control the humidity and temperature variations of the inlet gas stream. The biofilter unit was loaded with plastic spheres packed with compost which is referred to as the engineered media. Each of the bio-oxidation units was operated at the air flow rate of 25 CFM and empty bed residence time (EBRT) of 2 minutes. The system was inoculated with local stormwater and wastewater from a sedimentation basinclarifier of a local refinery to provide a mixed culture of microorganisms for degradation of the VOC emissions. VOC emissions were collected from the headspace of a storage tank battery leading into a pressure relief vent system. Based on the photo ionization detector (PID) measurements at the inlet of the bio-oxidation unit, the VOC concentration loadings was cyclic and appeared to be correlated to the gas lift cycle of liquid loading to the crude oil storage tank. During the evaluation period, the biotrickling unit demonstrated a surprisingly higher removal efficiency compared to the biofilter. This may be related to the more stable and higher density of biomass growth observed on the surface of the cross flow media. The lower removal efficiency in the biofilter unit could be due to the lack of uniform moisture and nutrients in the second vessel as a result of spray nozzle inefficiency. This aspect of operation can be further optimized by changing the nozzle and the frequency of watering/spraying of the compost media. A removal efficiency of 50-60% for the total VOCs, across the complete unit, was achieved during the 3 month evaluation period while the unit was operated at an average inlet VOC concentration of 400 ppm. The relatively high concentration of alkenes and alkanes (compared to aromatics and water soluble organics in this crude oil vapor), may have decreased the degradation of the total VOCs in the bio-oxidation unit because these long-chain compounds are more difficult to biodegrade by bacterial biofilms in an aerobic environment. The results suggest biological emission treatment systems may be cost effective when compared to thermal oxidizers and flares and should be evaluated as a Maximum Achievable Control Technology (MACT) to mitigate HAPs (and VOCs) from some oil and gas operations. This innovative biological emissions control technology effectively controlled the cyclic emissions produced at the remote site. The strong increase in removal of VOCs after the oil refinery wastewater inoculation suggests an important optimization parameter for more rapid acclimation and increased efficiency for the system in the future applications.

Incorporating IGCC and CaO sorption-enhanced process for power generation with CO2 capture

Safety survives privatisation

Solid low-level waste management guidelines

99/02507 Diagnostic and operation method of coal gasifier

97/02013 CO2 gasification of eucalyptus wood chars

Role of facilitated transport in the emissions of secondary raw materials