Film-forming amine product as an alternative to carbohydrazide oxygen scavenger in high pressure boilers

Hydrazine has been largely replaced by carbohydrazide (CHZ) as an oxygen scavenger due to safety and health concerns and CHZ is now used in Saline Water Conversion Corporation (SWCC) high pressure boilers. However, the operational problem of phosphate hide-out has become a continuous challenge for the plant operators. Advances in boiler water treatment have shown that effective corrosion control and prevention of scaling can be achieved by using a mixture of filmforming and alkalizing amines and polycarboxylates [Film Forming Amine Product (FFAP)]. With the use of FFAP, carbohydrazide/ammonia treatment of make-up water and phosphate treatment in the drum will not be required. A uniform FFAP formulation was used throughout the test. The evaluation study was carried out at a boiler of the Yanbu Phase 1 Desalination and Power Plant (Mitsubishi) generating 60 MWh, with make-up water of 15 t h− 1 producing 330 t h− 1 steam at a pressure of 67 barg and temperature of 480 ◦C. The trial provided evidence that FFAP was a good alternative to use of an oxygen scavenger. Changeover from CHZ to FFAP without phosphate addition in the drum was done initially by dosing FFAP from both hydrazine tank and phosphate tank so that pH was maintained to the required values in both feed water and drum water. With the optimal dose rate (0.6 ppm) maintaining FFAP in the range of 0.3–1.0 ppm in feed water, all the key parameters (pH, ammonia and specific conductivity) were within the specified boiler design limits. The average corrosion rates on the water side were low for both CHZ and FFAP treatment (0.009 ± 0.001 mm y− 1), however FFAP treated coupons showed much lower corrosion rates compared to CHZ in the steam side (0.0006 ± 0.0003 mm y− 1 cf. 0.0075 ± 0.0006 mm y− 1)

Development and validation of a simplified algorithm for neonatal gestational age assessment - protocol for the Alliance for Maternal Newborn Health Improvement (AMANHI) prospective cohort study.

OBJECTIVE: The objective of the Alliance for Maternal and Newborn Health Improvement (AMANHI) gestational age study is to develop and validate a programmatically feasible and simple approach to accurately assess gestational age of babies after they are born. The study will provide accurate, population-based rates of preterm birth in different settings and quantify the risks of neonatal mortality and morbidity by gestational age and birth weight in five South Asian and sub-Saharan African sites. METHODS: This study used on-going population-based cohort studies to recruit pregnant women early in pregnancy (<20 weeks) for a dating ultrasound scan. Implementation is harmonised across sites in Ghana, Tanzania, Zambia, Bangladesh and Pakistan with uniform protocols and standard operating procedures. Women whose pregnancies are confirmed to be between 8 to 19 completed weeks of gestation are enrolled into the study. These women are followed up to collect socio-demographic and morbidity data during the pregnancy. When they deliver, trained research assistants visit women within 72 hours to assess the baby for gestational maturity. They assess for neuromuscular and physical characteristics selected from the Ballard and Dubowitz maturation assessment scales. They also measure newborn anthropometry and assess feeding maturity of the babies. Computer machine learning techniques will be used to identify the most parsimonious group of signs that correctly predict gestational age compared to the early ultrasound date (the gold standard). This gestational age will be used to categorize babies into term, late preterm and early preterm groups. Further, the ultrasound-based gestational age will be used to calculate population-based rates of preterm birth. IMPORTANCE OF THE STUDY: The AMANHI gestational age study will make substantial contribution to improve identification of preterm babies by frontline health workers in low- and middle- income countries using simple evaluations. The study will provide accurate preterm birth estimates. This new information will be crucial to planning and delivery of interventions for improving preterm birth outcomes, particularly in South Asia and sub-Saharan Africa

Characterization of new and fouled SWRO membranes by ATR/FTIR spectroscopy

Abstract Attenuated total reflection (ATR)–Fourier transform infrared (FTIR) spectroscopy was used to characterize the chemical nature of fouling species on different spiral wound membranes operated at Al-Jubail SWRO plant. Three membranes from different companies operated for a period of 1 year were opened for autopsy, and difference spectra were obtained for the fouled membrane from virgin membranes. The spectra of the foulants were easy to distinguish from the spectra of membrane material. The results showed that the membrane surface of the feed end element was more heavily fouled than the brine end of the element. ATR/FTIR indicated a distinct enhancement to the amide I (1650 cm−1) and amide II (1550 cm−1) bands indicative of protein, and the C–O stretching band associated with polysaccharides is visible near 1040 cm−1. The deposits removed from the surface of membranes showed distinctive bands at 3270 and 1080 cm−1 associated with amino group/polysaccharide

Film-forming amine product as an alternative to carbohydrazide oxygen scavenger in high pressure boilers

Hydrazine has been largely replaced by carbohydrazide (CHZ) as an oxygen scavenger due to safety and health concerns and CHZ is now used in Saline Water Conversion Corporation (SWCC) high pressure boilers. However, the operational problem of phosphate hide-out has become a continuous challenge for the plant operators. Advances in boiler water treatment have shown that effective corrosion control and prevention of scaling can be achieved by using a mixture of film-forming and alkalizing amines and polycarboxylates [Film Forming Amine Product (FFAP)]. With the use of FFAP, carbohydrazide/ammonia treatment of make-up water and phosphate treatment in the drum will not be required. A uniform FFAP formulation was used throughout the test.The evaluation study was carried out at a boiler of the Yanbu Phase 1 Desalination and Power Plant (Mitsubishi) generating 60 MWh, with make-up water of 15 t h−1 producing 330 t h−1 steam at a pressure of 67 barg and temperature of 480 °C.The trial provided evidence that FFAP was a good alternative to use of an oxygen scavenger. Changeover from CHZ to FFAP without phosphate addition in the drum was done initially by dosing FFAP from both hydrazine tank and phosphate tank so that pH was maintained to the required values in both feed water and drum water. With the optimal dose rate (0.6 ppm) maintaining FFAP in the range of 0.3–1.0 ppm in feed water, all the key parameters (pH, ammonia and specific conductivity) were within the specified boiler design limits. The average corrosion rates on the water side were low for both CHZ and FFAP treatment (0.009 ± 0.001 mm y−1), however FFAP treated coupons showed much lower corrosion rates compared to CHZ in the steam side (0.0006 ± 0.0003 mm y−1 cf. 0.0075 ± 0.0006 mm y−1)

The role of the viscous sublayer in calcium carbonate dissolution

Remineralization is a key component of post-treatment of desalinated water, particularly that obtained by thermal desalination, to avoid corrosion in distribution systems and address human health concerns. Dissolution of limestone under an elevated pressure of carbon dioxide is a common remineralization procedure. Prompted by the desire to optimize this process, we examined literature data on its kinetics and found that there was no consensus on the mechanism of dissolution or the nature of the rate-controlling step. We propose a steady-state model, where there is a locally constant concentration of solute in a surface layer of solvent, with the rate of dissolution controlled by transport into and out of this surface layer. This model can explain the wide variation reported in experimental rate coefficients for calcium carbonate dissolution and fit experimental data obtained under very different systems with physically reasonable values for the dimensions of the viscous sublayer

Monitoring of inorganic and organic pollutants in the desalinated water from thermal desalination plants

Monitoring of inorganic and organic pollutants in the produced water from Saline Water Conversion Corporation (SWCC) seawater desalination plants was carried out over 20 y on the eastern coast and 8 y on the western coast of the Kingdom of Saudi Arabia. Water samples from SWCC plants were analyzed with an emphasis on toxic elements such as mercury, arsenic, lead, cadmium, selenium, chromium, and toxic disinfection by-products (DBPs) such as trihalomethanes (THMs) arising due to chlorination. Considering the Saudi Arabian Standards Organization (SASO) and World Health Organization (WHO) guidelines for drinking water, results show compliance with all the values for the components analyzed and found to be under the SASO and WHO regulations. Over the 20 y of the study, elevated THM concentrations were found for all plants located on the Arabian Gulf in the years 2001–2003, and elevated arsenic concentrations for the same plants in 2007. The fact that these increased levels were reported for all plants on the Arabian Gulf suggest they arise from systemic environmental effects impacting this restricted body of water

Table1_Mother's care-seeking behavior for neonatal danger signs from qualified providers in rural Bangladesh: A generalized structural equation modeling and mediation analysis.doc

BackgroundNeonatal deaths contribute to nearly half (47%) of under-five mortality globally and 67% in Bangladesh. Despite high neonatal mortality, care-seeking from qualified providers for newborn danger signs remains low. Identification of direct and indirect factors and their pathways affecting care-seeking will help to design a well-targeted intervention. This study assessed the direct, indirect, and total effect of the predictive factors on neonatal care-seeking in Bangladesh.Materials and methodsThis was a cross-sectional baseline household survey conducted in 14 districts of Bangladesh in 2019 with 17,251 recently delivered women (RDW) with a live birth outcome in the preceding 15 months. We used a two-stage stratified cluster sampling process to select the samples from 14 districts. We investigated the inter-relationship of maternal background characteristics, maternal health utilizations, child/neonate factors, health service delivery-related factors and newborn danger sign knowledge with newborn care-seeking practices and estimated the direct, indirect, and total effects using Generalized Structural Equation Modeling (GSEM) and mediation analysis. p-value = 0.05 was considered statistically significant. The result of the mediation analysis was reported in Log Odds (LOD). The positive LOD (LOD > 0) implies a positive association.ResultsHalf of the mothers (50.8%) reported a neonatal illness and among them, only 36.5% mothers of sick neonates sought care from qualified providers. Our mediation analysis showed that maternal health utilization factors, i.e., 4 + antenatal care visits (ANC) from a qualified provider (LOD: 0.63, 95% CI: 0.49, 0.78), facility delivery (LOD: 0.74, 95% CI: 0.30, 1.17) and postnatal care (PNC) from a qualified provider (LOD: 0.50, 95% CI: 0.21, 0.78) showed the highest total effect over other factors domains, and therefore, were the most important modifiable predictors for qualified neonatal care-seeking. Other important factors that directly and/or indirectly increased the chance of newborn care-seeking from qualified providers were household wealth (LOD: 0.86, 95% CI: 0.70, 1.02), maternal education (LOD: 0.48, 95% CI: 0.32, 0.63), distance to nearest health facility (LOD: 0.20, 95% CI: 0.10, 0.30), community health worker's (CHWs) home visits during ANC (LOD: 0.24, 95% CI: 0.13, 0.36), neonatal danger sign counseling after delivery (LOD: 0.20, 95% CI: 0.06, 0.34) and women's knowledge of neonatal danger signs (LOD: 0.37, 95% CI: 0.09, 0.64).ConclusionThe inter-relationship and highest summative effect of ANC, facility delivery, and PNC on newborn care-seeking suggested the maternal care continuum altogether from ANC to facility delivery and PNC to improve care-seeking for the sick newborn. Additionally, referral training for unqualified providers, targeted intervention for poorer households, increasing CHWs home visits and neonatal danger sign counseling at the facility and community should also be considered.</p