Consensus on Operating Practices for the Control of Feedwater and Boiler Water Chemistry in Industrial and Institutional Boilers

The Water Technology Subcommittee of the ASME Research and Technology Committee on Water and Steam in Thermal Systems, under the leadership of Mr. Robert D. Bartholomew has revised the Consensus on Operating Practices for the Control of Feedwater Boiler Water Chemistry in Modern Industrial Boilers, first published in 1979 with prior revisions published in 1994 and 1998. The task group consisted of a cross section of manufacturers, operators, chemical treatment contractors and consultants involved in the fabrication and operation of industrial and institutional boilers. Members of this group are listed in the acknowledgments. This current document is an expansion and revision of the original, with reordered and modified texts where considered necessary. While significant revisions have been incorporated, it is recognized that there are areas of operating practice not addressed herein. Additional information is available from the references. It is the plan of the ASME Research Committee to continue to review this information, and revise and reissue this document as necessary to comply with advances in boiler design and water conditioning technology.

Methods for Measuring the Optimal Time for the Water Residence in the Denitrification Filter

Nitrate filters are widely used in various sectors of the national economy for the purpose of stable degradation of nitrates without complex technological changes and control, as well as for obtaining, for practical use, water free from impurities of various polluting substances. The relevance of the stated research topic is determined by the wide use of filters in various areas of water conditioning in order to improve the quality of consumed water, as well as the need to develop methods for qualitative measurements of the optimal time parameters for the water residence in the denitrification filter when using it. The purpose of this research work is the practical development of methods for measuring the optimal time for the water residence in a denitrification filter, in order to find optimal opportunities for eliminating harmful and polluting substances from water used for domestic and industrial needs. The methodology of this research involves the use of a combination of methods for the systematic study of practical application issues of denitrification filters in water purification systems, using the method of qualitative analysis of water conditioning problems that are important with reference to the need to obtain high-quality water in volumes sufficient to meet the current domestic and industrial needs. The results of this research work are of great importance from the point of view of studying the problematic issues of determining the optimal time parameters for the water residence in modern filters, in order to achieve optimal indicators of the cleaning quality. The results and conclusions of this research are of considerable practical value for water filter designers, solving practical problems of creating high-quality denitrification filters, as well as for ordinary users, for whom the issues of water purification for its further practical application are of great importance

Tribological performance of self-lubricated polyamide6/boric oxide composites after water conditioning

Purpose This paper aims to investigate the tribological performance, i.e. abrasion resistance, friction coefficient and wear rates, of self-lubricated water conditioned polyamide6/boric oxide composites. Design/methodology/approach Polyamide6 and polyamide6/boric oxide self-lubricated composites were immersed in water for 15 days to analyze the effect of water conditioning on friction, wear and abrasion resistance. Tribological testing on pin-on-disc tribometer and abrasion resistance testing on TABER abrader were performed to see the friction coefficient and wear rates of materials. The scanning electron microscopy (SEM) characterizations were performed to analyze the wear tracks. Findings Tribological testing results revealed the loss in abrasive resistance, but there was an improvement in frictional coefficient and wear rates with steel after water absorption. The SEM images clearly show less depth of wear tracks in water-conditioned materials than dry ones. Water conditioning was found supportive in the formation of smooth lubricating transfer film on steel disc during the tribological testing. Originality/value The tribological behaviour of polymer composites is different in dry and in high humidity or water conditions. Experiments were performed to investigate B2O3 solid lubricant filler effectiveness on tribological behaviour of water-conditioned polyamide composites. Bonding between polyamide6 and water molecules plus the formation of orthoboric acid was found advantageous in decreasing the friction coefficient and wear rates of composites.

Oxidization of hydrogen sulfide in biogas by manganese (IV) oxide particles

Hydrogen sulphide is corrosive to most metallic equipment such as pipelines, compressors, gas storage tanks, engines, turbines and other units. It acts as a strong poison for fuel cells and its combustion leads to SO2 emissions. Due to the problems associated with hydrogen sulphide, it is critical to remove it from biogas before further processing. The removal of hydrogen sulphide from biogas using MnO2, which acts as a sorbent and catalyst, was investigated. The research was conducted in a full-scale agriculture biogas plant using chicken manure and maize silage as substrate. The manganese dioxide (manganese (IV) oxide) was derived from the waste products of a water conditioning system, after manganese removal from drinking water. The obtained results showed significantly better adsorption of hydrogen sulphide and faster regeneration of the bed compared to the bed filled with hydrated iron oxides. The H2S concentration in the treated biogas dropped from about 1,650 to 0-5 ppm.

Weed control by 2,4-D dimethylamine depends on mixture water hardness and adjuvant inclusion but not spray solution storage time

Herbicides are an important tool in managing weeds in turf and agricultural production. One of the earliest selective herbicides, 2,4-D, is a weak acid herbicide used to control broadleaf weeds. Water-quality parameters, such as pH and hardness, influence the efficacy of weak acid herbicides. Greenhouse experiments were conducted to evaluate how varying water hardness level, spray solution storage time, and adjuvant inclusion affected broadleaf weed control by 2,4-D dimethylamine. The first experiment evaluated a range of water-hardness levels (from 0 to 600 mg calcium carbonate [CaCO3] L−1) on efficacy of 2,4-D dimethylamine applied at 1.60 kg ae ha−1 for dandelion and horseweed control. A second experiment evaluated dandelion control from spray solutions prepared 0, 1, 4, 24, and 72 h before application. Dandelion and horseweed control by 2,4-D dimethylamine was reduced when the CaCO3 level in water was at least 422 or at least 390 mg L−1, respectively. Hard-water antagonism was overcome by the addition of 20 g L−1 ammonium sulfate (AMS) into the mixture. When AMS was included in spray mixtures, no differences were observed at 600 mg CaCO3 L−1, compared with distilled water. Spray solution storage time did not influence dandelion control, regardless of water-hardness level or adjuvant inclusion. To prevent antagonism, applicators should use a water-conditioning agent such as AMS when applying 2,4-D dimethylamine in hard water.