Moisture Removal Techniques for a Continuous Emission Monitoring System: A Review

A continuous emission monitoring system (CEMS) is a well-known tool used to analyze the concentrations of air pollutants from stationary sources. In a CEMS, the presence of a high moisture level in a sample causes a loss of analytes due to artifact formation or absorption. This issue brings about a bias in the measurement data. Thus, moisture removal is an important pretreatment step. Condensation and permeation methods have been widely employed to remove moisture from the CEMS for gaseous compounds. In terms of particulate matter, dilution methods have been applied to reduce the moisture level in the gas stream. Therefore, condensation, permeation, and dilution methods are critically reviewed in this work. The removal efficiencies and recovery rates of analytes are discussed, as well as the advantages and disadvantages of each technique. Furthermore, the suitable applications of each technique are determined. Condensation methods have not been well documented so far, while permeation and dilution methods have been continuously studied. Many types of permeation materials have been developed. The limitations of each method have been overcome over the years. However, the most reliable technique has not yet been discovered.

Air pollution emissions from Chinese power plants based on the continuous emission monitoring systems network

To meet the growing electricity demand, China’s power generation sector has become an increasingly large source of air pollutants. Specific control policymaking needs an inventory reflecting the overall, heterogeneous, time-varying features of power plant emissions. Due to the lack of comprehensive real measurements, existing inventories rely on average emission factors that suffer from many assumptions and high uncertainty. This study is the first to develop an inventory of particulate matter (PM), SO2 and NOX emissions from power plants using systematic actual measurements monitored by China’s continuous emission monitoring systems (CEMS) network over 96–98% of the total thermal power capacity. With nationwide, source-level, real-time CEMS-monitored data, this study directly estimates emission factors and absolute emissions, avoiding the use of indirect average emission factors, thereby reducing the level of uncertainty. This dataset provides plant-level information on absolute emissions, fuel uses, generating capacities, geographic locations, etc. The dataset facilitates power emission characterization and clean air policy-making, and the CEMS-based estimation method can be employed by other countries seeking to regulate their power emissions.

Pemantauan Emisi dengan Continuous Emission Monitoring System (CEMS) dalam Pemanfaatan Minyak Pelumas Bekas Sebagai Subtitusi Bahan Bakar pada Produksi Kapur Tohor

Minyak pelumas bekas atau biasa disebut used oils yang berasal dari minyak pelumas bekas hidrolik, mesin-mesin, gear, lubrikasi, insulasi, heat transmission, grit chambers, oil water separator dan atau campurannya termasuk kedalam limbah bahan berbahaya dan beracun (B3) dari kegiatan industri. Limbah B3 (LB3) tersebut memiliki simbol mudah terbakar dan berkategori bahaya 1. Used oils tersebut dapat dimanfaatkan sebagai substitusi sumber energi dengan tetap mempertimbangkan ketersediaan teknologi maupun baku mutu lingkungan hidup agar tidak menimbulkan pencemaran udara. Tujuan penelitian ini yaitu untuk mengevaluasi sistem pemantauan dan pengendalian pencemaran udara pada pemanfaatan limbah minyak pelumas bekas, yaitu sebagai subtitusi bahan bakar pada produksi kapur tohor apakah telah sesuai dengan persyaratan peraturan dan perundangan Republik Indonesia (RI). Metode penelitian menggunakan triangulasi teknik dengan cara mengumpulkan data yang berbeda-beda agar diperoleh data dari sumber yang sama. Sumber data dan lokasi penelitian dilakukan di unit produksi kapur tohor yang berada di daerah tambang terbuka Grasberg PT Freeport Indonesia (PTFI). Hasil pemantauan emisi pemanfaatan used oils dengan minyak solar dengan continuous emission monitoring system (CEMS) telah memenuhi persyaratan dan peraturan perundangan RI. Metode pengambilan sampel CEMS yang diterapkan yaitu in stack dilution extractive untuk memantau parameter partikulat dan gas. Pengendalian pencemaran udara lainnya dilakukan dengan sejumlah tindakan dan pengelolaan lainnya. Upaya pengelolaan tersebut dapat berupa kegiatan pemeliharaan dan penggantian rutin unit filter bag pada baghouse, pemeliharaan induced draft (ID) fan, pengendalian dan pematauan tekanan udara, dan persentase debit campuran antara used oils dan minyak solar.

Analysis and Treatment Measures of Continuous Emission Monitoring System Fouling in a Coal-Fired Power Plant after Ultra-Low Emission Transformation

Scanning electron microscopy (SEM) micro-morphology analysis, X-ray diffraction (XRD) and energy-dispersive X-ray diffraction (EDX) component analysis were conducted on the fouling of continuous emission monitoring system (CEMS) sampling tube at the outlet of limestone-gypsum wet flue gas desulfurization (WFGD) of unit 1 in a 600 MW supercritical coal-fired power plant in Inner Mongolia Autonomous Region. The results show that the main component of fouling was ammonium dihydrogen phosphate, which was generated by the reaction between phosphoric acid in the phosphoric acid titration device and the NH3 escaping from the selective catalyst reduction (SCR) denitrification system, and corresponding treatment measures were taken. It indicates that the average value of ammonia escape was reduced from 1.79 ppm to 1.54 ppm through the ammonia injection optimization test of the SCR denitrification system (at the load of 410 MW of the unit), which effectively reduced the generation of fouling. This research provides reference for improving the reliability of coal-fired unit operation after ultra-low emission transformation.

Evaluating fire effluents during combustion of wood boards

Effluents generated during the flaming as well as non-flaming burning of materials may be regarded as the main cause of death and injuries from fires. The structure of fire gases highly depends on the physical condition and chemistry of fuel as well as burning conditions. During the combustion of organic materials, complex mixtures of fire gases may be created. This paper investigates fire effluent yields during the well-ventilated burning tests of lumber products - board samples from two common wood species: oak and fir. Experiments were performed in custom-designed laboratory installation hyphenating mass loss calorimeter (with chimney and thermopiles for heat release rate measurement) and FTIR gas analyzer for subsequent on-line analysis of evolved fire gases. Tests were conducted with two different heat fluxes: 30 and 40 kW/m2 . The focus was on continuous emission monitoring of three principal fire gas components: H2O, CO2, and CO with a particular emphasis on CO rates.