Simultaneous NO/SO2 removal by coconut shell char/CaO from calcium looping in a fluidized bed reactor

Boyu Li,Yingjie Li,Wan Zhang,Yuqi Qian,Zeyan Wang 한국화학공학회 2020 Korean Journal of Chemical Engineering Vol.37 No.4

A simultaneous NOx/SO2 removal system using bio-char and CaO combined with calcium looping process for CO2 capture was proposed. The simultaneous NO/SO2 removal performance of coconut shell char/CaO experienced CO2 capture cycles was investigated in a fluidized bed reactor. The effects of reaction temperature, mass ratio of CaO to coconut shell coke, CaO particle size and number of CO2 capture cycles from calcium looping process were discussed. The NO removal efficiency of char is improved under the catalysis of CaO. The reaction temperature plays an important role in the simultaneous NO/SO2 removal. Coconut shell char/CaO achieve the highest NO and SO2 removal efficiencies at 825 oC, which are 98% and 100%, respectively. The mass ratio of CaO to coconut shell char of 60 : 100 is a good choice for the simultaneous NO/SO2 removal. Smaller CaO particle size contributes to higher NO and SO2 removal efficiencies of coconut shell char/CaO. The NO and SO2 removal efficiencies of coconut shell char and cycled CaO from calcium looping declined slightly with the number of CO2 capture cycles. In addition, the Ca-based materials balance in process of simultaneous NOx/SO2 removal combined with calcium looping is given. The novel simultaneous NO/SO2 removal method using bio-char and cycled CaO from calcium looping process appears promising.

NADH 센서를 이용한 생물학적 동시 탈질·질산화공정에서 질소, 인제거 영향인자 및 거동 평가

김한래,이시진(Si-Jin Lee) 한국환경보건학회 2008 한국환경보건학회지 Vol.34 No.5

In this study, the factors affecting on biological N and P removal using SND (simultaneous nitrification and denitrification) process were investigated and evaluated to find the possibility for treating N and P through SND with NADH by surveying N and P trace in aeration tank. The results on surveying the variation of NH₄+-N+NO₃−-N concentration in order to estimate the degree of SND in each point (P2, P3, P4, P5) of aeration tank showed that denitrification efficiency in P2 (front zone), nitrification and denitrification efficiencies in P4 (middle zone) were 67%, 86% and 39%, respectively. When it analyzed PO₄-³-P concentration in each point of aeration tank, PO₄-³-P concentration into P2 was 1.25 mg/L, increased to 2.22 mg/L by P release in P2 zone, decreased to 0.74 mg/L by P uptake in P4. Consequently, we could estimate which high P removal efficiency observed in this study was caused by biological phosphorus removal. To find the operating factors affecting effluent T-N, we analyzed the correlation among FN/M ratio, C/N ratio, Temp. and SRT etc and then the results showed that the correlation among FN/M ratio, C/N ratio and Temp was no high. However, in the relationship of SRT and other parameters (effluent NH₄+-N and effluent BOD), the short SRT could be affected on effluent NH₄+-N and so effluent BOD could be increased. Thus, SRT operation should be controlled over 10 days. The results for analyzing the correlation between SRT and influent NO₃--N in order to investigate the operating factors affecting effluent T-P showed that T-P or PO₄-³-P was no high correlation with SRT, whereas PO₄-³-P concentration increased along with increasing NO₃--N concentration into P2. Based on these results, we could obtain the conclusion which effluent PO₄-³-P concentration depend on NO₃--N concentration into P2 using regression analysis (R²=0.97). In this study, the factors affecting on biological N and P removal using SND (simultaneous nitrification and denitrification) process were investigated and evaluated to find the possibility for treating N and P through SND with NADH by surveying N and P trace in aeration tank. The results on surveying the variation of NH₄+-N+NO₃−-N concentration in order to estimate the degree of SND in each point (P2, P3, P4, P5) of aeration tank showed that denitrification efficiency in P2 (front zone), nitrification and denitrification efficiencies in P4 (middle zone) were 67%, 86% and 39%, respectively. When it analyzed PO₄-³-P concentration in each point of aeration tank, PO₄-³-P concentration into P2 was 1.25 mg/L, increased to 2.22 mg/L by P release in P2 zone, decreased to 0.74 mg/L by P uptake in P4. Consequently, we could estimate which high P removal efficiency observed in this study was caused by biological phosphorus removal. To find the operating factors affecting effluent T-N, we analyzed the correlation among FN/M ratio, C/N ratio, Temp. and SRT etc and then the results showed that the correlation among FN/M ratio, C/N ratio and Temp was no high. However, in the relationship of SRT and other parameters (effluent NH₄+-N and effluent BOD), the short SRT could be affected on effluent NH₄+-N and so effluent BOD could be increased. Thus, SRT operation should be controlled over 10 days. The results for analyzing the correlation between SRT and influent NO₃--N in order to investigate the operating factors affecting effluent T-P showed that T-P or PO₄-³-P was no high correlation with SRT, whereas PO₄-³-P concentration increased along with increasing NO₃--N concentration into P2. Based on these results, we could obtain the conclusion which effluent PO₄-³-P concentration depend on NO₃--N concentration into P2 using regression analysis (R²=0.97).

전해산화제를 이용한 악취물질 제거

이태호,양한규,유승렬,오혁진,류희욱 한국냄새환경학회 2023 실내환경 및 냄새 학회지 Vol.22 No.4

We conducted research on the removal performance of various odor substances using a deodorizing agent, hypochlorite ion (OCl- ), in odor emission sites where various odor-causing substances occur simultaneously. In experiments treating odor gases containing mixtures of aldehydes (acetaldehyde, n-butyl aldehyde, iso-valeraldehyde, propionaldehyde), sulfur compounds (hydrogen sulfide, methyl mercaptan, and dimethyl sulfide), and nitrogen compounds (ammonia and trimethyl amine), it was demonstrated that the introduced odor substances could be simultaneously removed when electrolyzed water was used. The overall removal efficiency was found to be significantly higher than when water alone was used. Particularly, it showed simultaneous effectiveness against acidic, neutral, and alkaline odor substances such as ammonia and hydrogen sulfide. Considering the positive aspects with regard to chemical safety, the use of salt instead of chemicals, and the continuous regeneration of the oxidizing agent, this environmentally friendly deodorization technology is expected to contribute to securing excellent odor removal capabilities and wide-ranging deodorization applications.

촉매 담지 코디어라이트 다공성 필터의 NOx/SOx 동시제거에 대한 연구

이시희,정구춘,김지웅,신민철,이희수 한국분석과학회 2002 분석과학 Vol.15 No.3

porous filters were manufactured using cordierite powder whose mean paricle size was 200㎛, they were loaded with catalysts such as V2O5, CuO and LaCoO3 by vacuum impregnation method. And the NOx/SOx simultaneous removal efficiency was measured by passing NO and SO2 through catalyst-loaded ceramic filters. The cordierite porous filters had the apparent porosity of 61.6%, the compressive strength of 12.3 MPa and the pressure drop of 147 pa at the face velocity of 5 cm/sec. According to the analysis of NO/SO2 simultaneous removal efficiency, perovskite LaCoO3 catalyst was the most efficient for the simultaneous NO and SO2 removal. The LaCoO3 catalyst-loaded filter could remove more than 90% for NO and more than 80% for SO2.

The simultaneous removal of sulfur dioxide and nitrogen dioxide by the limestone slurry with addition of organic acid additives

정지은,이창용 한국화학공학회 2021 Korean Journal of Chemical Engineering Vol.38 No.10

This study investigates the effects of organic acid on the simultaneous absorption of SO2 and NO2 in the packed column. Organic acids, i.e., formic acid, acetic acid, and propionic acid, were used as additives. In the case of the absence of additives, when SO2 and NO2 were simultaneously absorbed into the limestone slurry, both SO2 and NO2 contributed to increasing the mutual absorption efficiency. In the simultaneous absorption of SO2 and NO2 with addition of additives, the SO2 removal efficiency appeared in the order of formic acid<no addition<propionic acid<acetic acid. Acetic acid has a superior buffer capacity and intermediate hydrophobic interaction, resulting in the highest SO2 absorption efficiency. In the slurry with the addition of acetic acid and propionic acid, the reactions of absorbed SO2 and NO2 predominantly took place; thus, the SO4 2/SO3 2 ratio was greater than 1. In terms of formic acid, the slurry pH was maintained at approximately 4.0, which departs from the appropriate range, attributed to the small pKa value, showing a negative effect on SO2 and NO2 removal. In the slurry with formic acid added, the SO2 predominantly reacted with formic acid; hence, the SO4 2/SO3 2 ratio was less than 1.

MBR 단일 반응조에서 용존산소 농도에 따른 동시 질산화-탈질반응(SND)의 영향

박노백 ( Noh Back Park ),최우영 ( Woo Yung Choi ),윤애화 ( Ae Hwa Yoon ),전항배 ( Hang Bae Jun ) 韓國環境農學會 2009 한국환경농학회지 Vol.28 No.4

MBR(Membrane Bio-reactor) 반응조 내 동시 질산화·탈질(Simultaneous Nitrification and Denitrification, SND)반응을 적용하여 폐수의 유기물 및 질소(N) 제거를 위해 적절한 용존산소(DO) 농도를 도출 및 질산화 및 탈질반응에 미치는 영향을 관찰하기 위해 실험을 수행하였다. 연속 운전실험 결과 반응조 내 pH는 7.5-8.0을 유지하면서 특별한 외부 탄소원의 주입 없이 질소제거가 가능하였다. 용존산소 농도에 따른 유출수의 CODcr 평균 농도는 각각 2.39, 2.95, 12.18 mg/L로 나타났으며, 제거율은 각각 99.3, 99.0, 96.0%로 안정적인 처리 효율을 나타내었다. 운전 조건별(Run 1, 2, 3) 용존산소(DO) 농도에 따른 유출수의 총질소(TN) 농도는 8.62, 7.75, 11.82 mg/L로, 제거효율은 69.88, 72.92, 58.70% 이었고, 용존산소의 농도가 1.3-1.6 mg/L 범위일 때, SND 반응을 적용한 질소제거가 가능한 것으로 나타났다. 회분식 실험 결과 암모니아성 질소(NH4+-N)의 질산화 반응속도의 경우 용존산소 농도에 증가하였으며, 탈질 반응의 경우 반응조 내 적정 C/N비를 유지하였을 때 용존산소 1.0-1.3 mg/L 범위에서 탈질 반응이 일어나는 것을 확인하였다. In this study, simultaneous nitrification and denitrification (SND) from synthetic wastewater were performed to evaluate dissolved oxygen(DO) effects on chemical oxygen demand(COD) and nitrogen removal in a single membarne bio-reactor(MBR). DO levels in MBR at Run 1, 2, and 3 were 1.9~2.2, 1.3~1.6, and 0.7~1.0 mg/L, respectively. Experimental results indicated that DO had an important factor to affect COD and total nitrogen(TN) removal. SND were able to be accomplished in the continuous-aeration MBR by controlling ambient DO concentration. It is postulated that, because of the oxygen diffusion limitation, an anoxic micro-zone was formed inside the flocs where the denitrification might occur. From the results of this study, 96% of COD could be removed at DO of 0.7mg/L. At run 2 72.92% of nitrogen was removed by the mechanisms of SND (7.75mg-TN/L in effluent). In this study, SND was successfully occurred in a MBR due to high MLSS that could help to form anoxic zone inside microbial floc at bulk DO concentrations of 1.3~1.6mg/L.

Process modeling and optimization of biological removal of carbon, nitrogen and phosphorus from hospital wastewater in a continuous feeding & intermittent discharge (CFID) bioreactor

Meghdad Pirsaheb,Mitra Mohamadi,Amir Mohammad Mansouri,Ali Akbar Lorestani Zinatizadeh,Sethupathi Sumathi,Kiomars Sharafi 한국화학공학회 2015 Korean Journal of Chemical Engineering Vol.32 No.7

We evaluated the feasibility and treatment performance of a continuous feeding and intermittent discharge (CFID) bioreactor treating real hospital wastewater with the emphasis on simultaneous carbon, nitrogen and phosphorus (CNP) removal. The experiments were based on a central composite design (CCD) and analyzed by response surface methodology (RSM). To analyze the process, three significant variables, aeration time (2-4 h), mixing time without aeration (30-90 min) and MLSS concentration (2,000-6,000mg/l), were studied. Results show that an increase in aeration time increased the nitrogen and phosphorous removal efficiency. However, when the aeration time was more than 3 h, the efficiency of phosphorous removal was decreased due to insufficient acidification. A similar scenario was observed when mixing time was increased for phosphorus and nitrogen removal efficiency. MLSS had a positive effect on all the responses. Under optimal conditions, the concentrations of quality parameter in the influent in average were recorded as 586 mg COD/l, 296mg BOD5/l, 97mgTN/l and 16.47mg TP/l, which yields the following removal efficiencies, 95.6%, 98.3%, 88.0% and 92.0%, respectively.

The combined removal of methyl mercaptan and hydrogen sulfide via an electro-reactor process using a low concentration of continuously regenerable Ag(II) active catalyst

Muthuraman, Govindan,Chung, Sang Joon,Moon, Il Shik Elsevier 2011 Journal of hazardous materials Vol.193 No.-

<P><B>Highlights</B></P><P>► Simultaneous removal of H<SUB>2</SUB>S and CH<SUB>3</SUB>SH was achieved at electro-reactor. ► Active catalyst Ag(II) perpetually regenerated in HNO<SUB>3</SUB> medium by electrochemical cell. ► CH<SUB>3</SUB>SH destruction follows two reaction pathways. ► H<SUB>2</SUB>S induced destruction of CH<SUB>3</SUB>SH has identified. ► Low concentration of active Ag(II) (12.5×10<SUP>−4</SUP>molL<SUP>−1</SUP>) is enough for complete destruction.</P> <P><B>Abstract</B></P><P>In this study, an electrocatalytic wet scrubbing process was developed for the simultaneous removal of synthetic odorous gases namely, methyl mercaptan (CH<SUB>3</SUB>SH) and hydrogen sulfide (H<SUB>2</SUB>S). The initial process consists of the absorption of CH<SUB>3</SUB>SH and H<SUB>2</SUB>S gases by an absorbing solution, followed by their mediated electrochemical oxidation using a low concentration of active Ag(II) in 6M HNO<SUB>3</SUB>. Experiments were conducted under different reaction conditions, such as CH<SUB>3</SUB>SH and H<SUB>2</SUB>S loadings, active Ag(II) concentrations and molar flow rates. The cyclic voltammetry for the oxidation of CH<SUB>3</SUB>SH corroborated the electro-reactor results, in that the silver in the 6M HNO<SUB>3</SUB> reaction solution significantly influences the oxidation of CH<SUB>3</SUB>SH. At a low active Ag(II) concentration of 0.0012M, the CH<SUB>3</SUB>SH removal experiments demonstrated that the CH<SUB>3</SUB>SH degradation was steady, with 100% removal at a CH<SUB>3</SUB>SH loading of 5gm<SUP>−3</SUP>h<SUP>−1</SUP>. The electro-reactor and cyclic voltammetry results indicated that the removal of H<SUB>2</SUB>S (100%) follows a mediated electrocatalytic oxidation reaction. The simultaneous removal of 100% of the CH<SUB>3</SUB>SH and H<SUB>2</SUB>S was achieved, even with a very low active Ag(II) concentration (0.0012M), as a result of the high efficiency of the Ag(II). The parallel cyclic voltammetry results demonstrated that a process of simultaneous destruction of both CH<SUB>3</SUB>SH and H<SUB>2</SUB>S follows an H<SUB>2</SUB>S influenced mediated electrocatalytic oxidation. The use of a very low concentration of the Ag(II) mediator during the electro-reactor process is promising for the complete removal of CH<SUB>3</SUB>SH and H<SUB>2</SUB>S.</P>

Combination of ion exchange system and biological reactors for simultaneous removal of ammonia and organics

Park, Wooshin,Jang, Eunhee,Lee, Myun-Joo,Yu, Seungho,Kim, Tak-Hyun Elsevier 2011 Journal of environmental management Vol.92 No.4

<P><B>Abstract</B></P><P>A novel process for a simultaneous removal of ammonia and organics was developed on the basis of ion exchange and biological reactions. From batch experiments, it was found out that NH<SUB>4</SUB><SUP>+</SUP> could be removed effectively by combining cation exchange and biological nitrification showing 0.98 mg N/m<SUP>2</SUP>∙s of a maximum flux. On the other hand, the removal of NO<SUB>3</SUB><SUP>−</SUP> was 3.5 times faster than NH<SUB>4</SUB><SUP>+</SUP> and the maximum flux was calculated to be 3.4 mg N/m<SUP>2</SUP>∙s. The systems for NH<SUB>4</SUB><SUP>+</SUP> and NO<SUB>3</SUB><SUP>−</SUP> removal were combined for establishing the IEBR process. When the process was operated in a continuous mode, approximately 95.8% of NH<SUB>4</SUB><SUP>+</SUP> was removed showing an average flux of 0.22 mg N/m<SUP>2</SUP>·s. The removal efficiency of total nitrogen was calculated as 94.5% whereas that of organics was 99.5%. It was concluded that the IEBR process would be effectively used for a simultaneous removal of NH<SUB>4</SUB><SUP>+</SUP> and organics.</P>

호기성 입상활성슬러지에서 DPB에 의한 질소 및 인 제거

김광수 ( Kim Gwang Su ),이희자 ( Lee Hui Ja ) 한국수처리학회 2003 한국수처리학회지 Vol.11 No.3

N/A Bench scale experiment was carried out two modes. One was conducted to test the self-granulation of suspended activated sludge and the other to certify simultaneous nitrogen and phosphorus removal under anoxic condition. The pilot scale experiment was studied on the reaction of simultaneous nitrogen and phosphorus removal by the granular activated sludge. In one mode of bench experiments, when an activated sludge is put in a granulation reactor, it becomes suspended. With interparticle bridging due to turbulence, the granulation process starts and results in a decrease of SVI. As granulation process goes on, an anaerobic condition developed inside the granulated sludge particles produces black spots on them. And then the growth of filamentous bacteria renders increased SVI. but eventually SVI decreases due to regranulation through interparticle bridging between filamentous bacteria. In other mode of bench experiments, simultaneous reactions of phosphorus release and uptake, and also denitrification were observed under anoxic condition with high organic and nitrate loading. However the rate and the degree of P release were lower than that occurred under anaerobic condition. From the pilot scale experiment operated to granular activated sludge, simultaneous phosphorus and nitrogen removal were showed. The results of the pilot experiment were due to the inner part of granular sludge to be anoxic and anaerobic condition.