ABSTRACT Selective catalytic reduction technology effectively controls nitrogen oxide emissions from coal-fired power plants. In denitrification systems, exceeding nitrogen oxide emissions and excessive local pressure drop are common issues. Numerical simulation methods are used in this study to optimize the flow field to enhance denitrification efficiency and reduce pollutant emissions. Specifically, four deflector plate schemes for the variable-section flue duct segment are proposed. In actual retrofitting, the optimization scheme led to a reduction in nitrogen oxide emissions from 97.3 mg/Nm3 to 48.6 mg/Nm3 and an increase in the outlet pressure of the denitrification system from −3000 Pa to −2959 Pa, resulting in a 41 Pa decrease in local pressure drop. This optimization will further reduce pollutant emissions from power plants and the power consumption of induced draft fans.

Deflector device optimization for controlling nitrogen oxide emissions and pressure drop in selective catalytic reduction denitrification system

Abstract The dynamic operation and deep peak‐shaving of power‐generating units cause significant fluctuations in flue gas flowrate, thus affecting the accuracy of CO 2 emissions measured by continuous emission monitoring systems (CEMS). This study established a long short‐term memory network with an attention mechanism (LSTM‐AM) for the soft measurement of the flue gas flowrate in real‐time. First, flue gas flowrate data and continuous operation parameters over 25 days were sampled from a typical 660 MW coal‐fired boiler in China. Then, a carbon balance model was established to verify the data reliability. The LSTM‐AM model was trained and testified at the 660 MW coal‐fired boiler. Results show that the LSTM‐AM model significantly surpassed the pristine LSTM model without attention, the convolutional neural network (CNN) with LSTM, and the static support vector regression (SVR) model in the real‐time prediction of flue gas flowrate. Finally, the LSTM‐AM model was generalized to a 630 MW coal‐fired power unit via transfer learning, which was further demonstrated to outperform the model re‐trained from scratch. This work manifests the feasibility of deep learning for the soft measurement of flue gas flowrate, which is promising to solve data‐lagging issues when measuring CO 2 emissions from coal‐fired power plants. 

Leveraging long short‐term memory networks and transfer learning for the soft‐measurement of flue gas flowrate from coal‐fired boilers

Research on Short-Term Prediction Method of Liquefied Gas Concentration based on Mixed Intelligence

The precise prediction of NOx generation concentration in coal‐fired boilers serves as the foundational cornerstone for the judicious optimization and control of selective catalytic reduction denitrification (SCR) systems. Owing to the intricate nature of the denitrification process within SCR, there exists a temporal delay in regulating the ammonia injection rate based on the monitored data of NOx concentration at the SCR inlet. Such delays can give rise to ammonia leakage and subsequent obstruction of the air preheater. In light of this, a predictive model, CEEMDAN‐LSTM‐SA, is proposed as an amalgamation of data decomposition and the LSTM (long short‐term memory) fusion self‐attention mechanism within a deep learning network, which is introduced to forecast the NOx emission concentration at the SCR inlet of coal‐fired units. To mitigate the impact of data outliers on the training effectiveness of the model, a clustering method coupled with a statistical testing strategy is initially applied to refine the dataset first. CEEMDAN data decomposition technology is leveraged to facilitate the breakdown of data, alleviating its non‐stationary and intricate characteristics. Subsequently, through spectral analysis, the decomposed components are grouped and aggregated to form novel data elements, which are then subjected to prediction by the constructed LSTM‐SA deep learning network. The ultimate NOx emission concentration prediction value is derived through a process of fusion. Upon scrutinizing and comparing the predictions derived from various models using coal‐fired power plant data, it is evident that the performance metrics of CEEMDAN‐LSTM‐SA predictions exhibit a mean absolute error of 7.425, mean absolute percentage error of 2.415%, root mean square error of 9.715, R‐squared (R2) value of .789, mean absolute relative error of 2.109%, and a Theil's information criterion of .016. In contrast to other models, including traditional self‐attention networks, LSTM, and LSTM‐SA combination networks, CEEMDAN‐LSTM‐SA proposed in this study demonstrates superior prediction accuracy and enhanced generalization capabilities. Consequently, this predictive model stands poised to furnish an efficacious framework for the SCR ammonia injection strategy within thermal power units.

A novel hybrid forecasting approach for NOx emission of coal‐fired boiler combined with CEEMDAN and self‐attention improved by LSTM

Measuring the nitrogen oxides concentration accurately at the inlet of the selective catalytic reduction denitrification system plays an important role in controlling the nitrogen oxides concentration for coal-fired power plants, and a coupling relationship exists between nitrogen oxides concentration and multiple operational variables. Here, a modeling method based on feature fusion and long short-term memory network is proposed to mine the spatial and temporal coupling relationship between input variables for improving the prediction accuracy. First, the collected data were converted to image-like sequences. Then, the high-dimensional features of image-like sequences were fused by a convolutional neural network, and the spatial coupling features among the variables were mined. Finally, the constructed fusion features were input into the long short-term memory network to further explore the time coupling characteristics among the variables and complete the prediction of nitrogen oxides concentration at the inlet of the selective catalytic reduction denitrification system. The simulation results show that the prediction error of nitrogen oxides concentration at the inlet of selective catalytic reduction denitrification system based on CNN-LSTM model is 15.15% lower than that of traditional LSTM model.

NOx concentration prediction in coal-fired power plant based on CNN-LSTM algorithm

Based on the idea of combining models to improve prediction accuracy and robustness, this paper uses FCM to separate a whole training data set into several clusters with different centers. Each subset is trained by BP neural network. The degrees of membership are used for combining these models to obtain the final result. It has higher approaching precision and better generalization capability than the BP neural network. The result is satisfying when it is used in the soft sensing of outlet concentration of acetylene hydrogenation reactor. Practice has proved that this method is worthy of further application.

https://ieeexplore.ieee.org/iel5/9294/29581/01343175.pdf

Soft sensor of outlet acetylene concentration in acetylene hydrogenation reactor based on multiple neural network structure

Handle everyday research tasks with reliable, citation-backed results

Your personal Research Agent to handle research tasks with citation-backed results

Popular Tasks used by Researchers

How can I help with your research?

Meet SciSpace

Get more enhanced response by uploading the PDFs you want me to reference.

No relevant PDFs in your library

SciSpace is the AI research assistant for academics. Run systematic literature reviews on 280M+ papers, and write papers with cited sources. Trusted by 1M+ students, PhDs & researchers.

SciSpace | AI for Research

Analyze PDFs

Code & Manuscripts

Funding & Grants

Literature & Patents

Medical & Clinical Data

Systematic Review

Visualize & Present

Web & Data

Build a Google Scholar-like website for your research.

Build a website

Create charts and images for your research

Create a Chart

Write a paper for submission to a journal

Draft a manuscript

Patent Search

Design eye-catching scientific posters in minutes.

Scientific Poster Generation

Systematic Literature Review

One task is running at the moment. Your messages will be shown right after.

Drag and drop or click here to browse

Loved by <highlight>1 million+</highlight> researchers

Extract a list of specific topics and their sources from unstructured text

Topics

Compare and analyze relevant papers that matches with your search

Papers

Get insights from PDFs and bookmarked papers from your library

My library

Recent searches

Try searching for:

Catch AI-generated content in scholarly and non-scholarly content

{ai} Detector

Ai Writer

Get PDF Summaries, highlighted text explanations 

Chat with PDF

Effortlessly create in-text citations and bibliographies in APA and 2,500 other formats

Citation generator

Get explanations, summaries, and answers on academic papers

Ease up your research workflow with {scispace}'s cohort of exciting AI tools

Elevate your academic writing skills and convey your ideas the way you want

Paraphraser

Explore our range of reading and writing tools

Your file is being prepared and should be ready in a few minutes. If it's a large file, it might take a bit longer. You can close this window, and we'll email you the file when it's done.

You have reached a maximum limit of <strong>{limit}</strong> columns in the table. Remove at least <strong>1</strong> column to add or create another one.

Bin Wu

Author Tools

Chat about Author

Papers

NOx concentration prediction in coal-fired power plant based on CNN-LSTM algorithm

Soft sensor of outlet acetylene concentration in acetylene hydrogenation reactor based on multiple neural network structure