Improved Recovery Boiler Performance Through Control of Combustion, Sulfur, and Alkali Chemistry

This project involved the following objectives: 1. Determine black liquor drying and devolatilization elemental and total mass release rates and yields. 2. Develop a public domain physical/chemical kinetic model of black liquor drop combustion, including new information on drying and devolatilization. 3. Determine mechanisms and rates of sulfur scavenging in recover boilers. 4. Develop non-ideal, public-domain thermochemistry models for alkali salts appropriate for recovery boilers 5. Develop data and a one-dimensional model of a char bed in a recovery boiler. 6. Implement all of the above in comprehensive combustion code and validate effects on boiler performance. 7. Perform gasification modeling in support of INEL and commercial customers. The major accomplishments of this project corresponding to these objectives are as follows: 1. Original data for black liquor and biomass data demonstrate dependencies of particle reactions on particle size, liquor type, gas temperature, and gas composition. A comprehensive particle submodel and corresponding data developed during this project predicts particle drying (including both free and chemisorbed moisture), devolatilization, heterogeneous char oxidation, char-smelt reactions, and smelt oxidation. Data and model predictions agree, without adjustment of parameters, within their respective errors. The work performed under these tasks substantially exceeded the original objectives. 2. A separate model for sulfur scavenging and fume formation in a recovery boiler demonstrated strong dependence on both in-boiler mixing and chemistry. In particular, accurate fume particle size predictions, as determined from both laboratory and field measurements, depend on gas mixing effects in the boilers that lead to substantial particle agglomeration. Sulfur scavenging was quantitatively predicted while particle size required one empirical mixing factor to match data. 3. Condensed-phase thermochemistry algorithms were developed for salt mixtures and compared with sodium-based binary and higher order systems. Predictions and measurements were demonstrated for both salt systems and for some more complex silicate-bearing systems, substantially exceeding the original scope of this work. 4. A multi-dimensional model of char bed reactivity developed under this project demonstrated that essentially all reactions in char beds occur on or near the surface, with the internal portions of the bed being essentially inert. The model predicted composition, temperature, and velocity profiles in the bed and showed that air jet penetration is limited to the immediate vicinity of the char bed, with minimal impact on most of the bed. The modeling efforts substantially exceeded the original scope of this project. 5. Near the completion of this project, DOE withdrew the BYU portion of a multiparty agreement to complete this and additional work with no advanced warning, which compromised the integration of all of this material into a commercial computer code. However, substantial computer simulations of much of this work were initiated, but not completed. 6. The gasification modeling is nearly completed but was aborted near its completion according to a DOE redirection of funds. This affected both this and the previous tasks

Cryogenic carbon capture

Cryogenic Carbon Capture™ (CCC) removes CO2 from flue gas in a bolt on retrofittable, cost-effective, and energy-efficient process. The process also provides grid-level energy storage capable of storing and releasing energy at hundreds of megawatt rates at high efficiency and minimal cost beyond the costs of the carbon capture technology. The energy storage can level daily load fluctuations and responds to intermittent power sources on time scales comparable to solar and wind farms. The technology cools flue gases to their condensation (desublimation) point forming solid CO2, separates the solids from the residual gases, pressurizes the solids, and reheats both streams to room temperature. The process produces two nominally ambient-temperature streams: liquid CO2 at about 150 bar and the light gases at ambient pressure. Essentially all of the sensible heating occurs through energy integration. The technology primary advantages include (a) consumes minimal energy for CO2 capture (appx. 0.7 GJe/tonne CO2 for typical coal flue gas) (b) costs relatively little (2.5 cents/kWh or less increase in COE) (c) retrofits existing plants with virtually no upstream modification (d) removes essentially all other pollutants except CO, including SOx, NOx, Hg, PMxx, and HC; (e) requires no additional cooling water; (f) requires no steam or other resources from the process other than electrical power Fully integrated versions of the technology at up to 1 tonne of CO2/day have operated on fuels including subbituminous coal, bituminous coal, natural gas, biomass, municipal waste and tires and at sites that include utility power plants, cement kilns, heat plants, and pilot-scale research combustors. This presentation summarizes the technology, field test results, and development plans for this technology. Further information is available at www.sesinnovation.com

Barriers to gender-equitable HIV testing: going beyond routine screening for pregnant women in Nova Scotia, Canada

<p>Abstract</p> <p>Background</p> <p>Women and men face different gender-based health inequities in relation to HIV, including HIV testing as well as different challenges in accessing HIV care, treatment and support programs and services when testing HIV-positive. In this article, we discuss the findings of a mixed methods study exploring the various individual and structural barriers and facilitators to HIV counselling and testing experienced among a sample of adult women and men living in Nova Scotia, Canada.</p> <p>Methods</p> <p>Drawing from testing demographics, qualitative interview data and a review of existing testing policies and research, this paper focuses on understanding the gendered health inequities and their implications for HIV testing rates and behaviours in Nova Scotia.</p> <p>Results</p> <p>The findings of this research serve as the basis to further our understanding of gender as a key determinant of health in relation to HIV testing. Recognizing gender as a key determinant of health in terms of both vulnerability to HIV and access to testing, this paper explores how gender intersects with health equity issues such as access to HIV testing, stigma and discrimination, and sexual behaviours and relationships.</p> <p>Conclusions</p> <p>Drawing on the current gender and HIV literatures, in conjunction with our data, we argue that an enhanced, gender-based, context-dependent approach to HIV counselling and testing service provision is required in order to address the health equity needs of diverse groups of women and men living in various settings. Further, we argue that enhanced HIV testing efforts must be inclusive of both men and women, addressing uniquely gendered barriers to accessing HIV counselling and testing services and in the process moving beyond routine HIV testing for pregnant women.</p

NOx Control Options and Integration for US Coal Fired Boilers Quarterly Report

This is the eleventh Quarterly Technical Report for DOE Cooperative Agreement No: DE-FC26-00NT40753. The goal of the project is to develop cost effective analysis tools and techniques for demonstrating and evaluating low NO{sub x} control strategies and their possible impact on boiler performance for boilers firing US coals. The Electric Power Research Institute (EPRI) is providing co-funding for this program. This program contains multiple tasks and good progress is being made on all fronts. During this quarter, FTIR experiments for SCR catalyst sulfation were finished at BYU and indicated no vanadium/vanadyl sulfate formation at reactor conditions. Poisoned catalysts were prepared and tested in the CCS. Poisoning with sodium produced a noticeable drop in activity, which was larger at higher space velocity. A computer code was written at BYU to predict conversion along a cylindrical monolithic reactor. This code may be useful for monolith samples that will be tested in the laboratory. Shakedown of the slipstream reactor was completed at AEP's Rockport plant. Ammonia was connected to the reactor. The measurement of O{sub 2} and NO{sub x} made by the CEMs corresponded to values measured by the plant at the economizer outlet. Excellent NO{sub x} reduction was observed in preliminary tests of the reactor. Some operational problems were noted and these will be addressed next quarter

Educational strategies to enhance reflexivity among clinicians and health professional students: a scoping study

Reflexivity involves the ability to understand how one's social locations and experiences of advantage or disadvantage have shaped the way one understands the world. The capacity for reflexivity is crucial because it informs clinical decisions, which can lead to improvements in service delivery and patient outcomes. In this article, we present a scoping study that explored educational strategies designed to enhance reflexivity among clinicians and/or health profession students. We reviewed articles and grey literature that address the question: What is known about strategies for enhancing reflexivity among clinicians and students in health professional training programs? We searched multiple databases using keywords including: reflexivity, reflective, allied health professionals, pedagogy, learning, and education. The search strategy was iterative and involved three reviews. Each abstract was independently reviewed by two team members. Sixty-eight texts met the inclusion criteria. There was great diversity among the educational strategies and among health professions. Commonalities across strategies were identified related to reflective writing, experiential learning, classroom-based activities, continuing education, and online learning. We also summarize the 19 texts that evaluated educational strategies to enhance reflexivity. Further research and education is urgently needed for more equitable and socially-just health care

Clean Coal Program Research Activities

Although remarkable progress has been made in developing technologies for the clean and efficient utilization of coal, the biggest challenge in the utilization of coal is still the protection of the environment. Specifically, electric utilities face increasingly stringent restriction on the emissions of NO{sub x} and SO{sub x}, new mercury emission standards, and mounting pressure for the mitigation of CO{sub 2} emissions, an environmental challenge that is greater than any they have previously faced. The Utah Clean Coal Program addressed issues related to innovations for existing power plants including retrofit technologies for carbon capture and sequestration (CCS) or green field plants with CCS. The Program focused on the following areas: simulation, mercury control, oxycoal combustion, gasification, sequestration, chemical looping combustion, materials investigations and student research experiences. The goal of this program was to begin to integrate the experimental and simulation activities and to partner with NETL researchers to integrate the Program's results with those at NETL, using simulation as the vehicle for integration and innovation. The investigators also committed to training students in coal utilization technology tuned to the environmental constraints that we face in the future; to this end the Program supported approximately 12 graduate students toward the completion of their graduate degree in addition to numerous undergraduate students. With the increased importance of coal for energy independence, training of graduate and undergraduate students in the development of new technologies is critical

NOx Control Options and Integration for US Coal Fired Boilers Quarterly Report

This is the sixth Quarterly Technical Report for DOE Cooperative Agreement No: DE-FC26-00NT40753. The goal of the project is to develop cost effective analysis tools and techniques for demonstrating and evaluating low NOx control strategies and their possible impact on boiler performance for firing US coals. The Electric Power Research Institute (EPRI) is providing co-funding for this program. This program contains multiple tasks and good progress is being made on all fronts. Preliminary results from laboratory and field tests of a corrosion probe to predict waterwall wastage indicate good agreement between the electrochemical noise corrosion rates predicted by the probe and corrosion rates measured by a surface profilometer. Four commercial manufacturers agreed to provide catalyst samples to the program. BYU has prepared two V/Ti oxide catalysts (custom, powder form) containing commercially relevant concentrations of V oxide and one containing a W oxide promoter. Two pieces of experimental apparatus being built at BYU to carry out laboratory-scale investigations of SCR catalyst deactivation are nearly completed. A decision was made to carry out the testing at full-scale power plants using a slipstream of gas instead of at the University of Utah pilot-scale coal combustor as originally planned. Design of the multi-catalyst slipstream reactor was completed during this quarter. One utility has expressed interest in hosting a long-term test at one of their plants that co-fire wood with coal. Tests to study ammonia adsorption onto fly ash have clearly established that the only routes that can play a role in binding significant amounts of ammonia to the ash surface, under practical ammonia slip conditions, are those that must involve co-adsorbates

NOx Control Options and Integration for US Coal Fired Boilers Quarterly Report

This is the ninth Quarterly Technical Report for DOE Cooperative Agreement No: DE-FC26-00NT40753. The goal of the project is to develop cost effective analysis tools and techniques for demonstrating and evaluating low NOx control strategies and their possible impact on boiler performance for firing US coals. The Electric Power Research Institute (EPRI) is providing cofunding for this program. This program contains multiple tasks and good progress is being made on all fronts. Various subsystems of BYU's Catalyst Characterization System (CCS) were upgraded this quarter. Work on the CCS hardware and software will continue in the coming quarter. A preliminary test matrix of poisoning experiments in the CCS has been drafted that will explore the effects of at least three poisons: sodium, potassium and calcium. During this quarter, we attempted to resolve discrepancies in previous in situ measurements of catalyst sulfation. Modifications were made to the XPS analysis procedure that allowed analyses of uncrushed samples. Although the XPS and FTIR results are now more consistent in that both indicate that the surface is sulfating (unlike the results reported last quarter), they disagree with respect to which species sulfates. The CEM system for the multi-catalyst slipstream reactor arrived this quarter. Minor modifications to the reactor and control system were completed. The reactor will be shipped to AEP Rockport plant next quarter for shakedown and installation. In a parallel effort, we have proposed to make mercury oxidation measurements across the catalysts at the start of the field test. Pending approval from DOE, we will begin the mercury measurements next quarter

NOx Control Options and Integration for US Coal Fired Boilers Quarterly Report

This is the twentieth Quarterly Technical Report for DOE Cooperative Agreement No: DEFC26-00NT40753. The goal of the project is to develop cost-effective analysis tools and techniques for demonstrating and evaluating low-NO{sub x} control strategies and their possible impact on boiler performance for boilers firing US coals. The Electric Power Research Institute (EPRI) is providing co-funding for this program. At the beginning of this quarter, the corrosion probes were removed from Gavin Station. Data analysis and preparation of the final report continued this quarter. This quarterly report includes further results from the BYU catalyst characterization lab and the in-situ FTIR lab, and includes the first results from tests run on samples cut from the commercial plate catalysts. The SCR slipstream reactor at Plant Gadsden was removed from the plant, where the total exposure time on flue gas was 350 hours. A computational framework for SCR deactivation was added to the SCR model