tailieunhanh - ENVIRONMENTAL ENGINEER’S MATHEMATICS HANDBOOK - CHAPTER 8

Hạn chế phát thải khí vào không khí là kỹ thuật khó khăn và tốn kém. Mặc dù nó là sự thật rằng mưa là "máy hút bụi của thiên nhiên" - không khí tự nhiên làm sạch cơ chế có sẵn - không phải là rất hiệu quả. Chất lượng không khí tốt phụ thuộc về phòng, chống ô nhiễm (hạn chế những gì được phát ra) và các chính sách kỹ thuật âm thanh, thủ tục, và thực hành. Việc kiểm soát khí thải khí có thể được thực hiện trong một số cách khác nhau. Trong chương. | Chapter 8 Gaseous Emission Control Be it known to all within the sound of my voice Whoever shall be found guilty of burning coal Shall suffer the loss of his head. King Edward II introduction Limiting gaseous emissions into the air is technically difficult as well as expensive. Although it is true that rain is Nature s vacuum cleaner the only natural air-cleansing mechanism available it is not very efficient. Good air quality depends on pollution prevention limiting what is emitted and sound engineering policies procedures and practices. The control of gaseous air emissions may be realized in a number of ways. In this chapter we discuss many of these technologies as well as the sources of gaseous pollutants emitted from various sources and their control points see Figure . The applicability of a given technique depends on the properties of the pollutant and the discharge system. In making the difficult and often complex decision of which gaseous air pollution control to employ follow the guidelines based on experience and set forth by Buonicore and Davis 1992 in their prestigious engineering text Air Pollution Engineering Manual. Table summarizes the main techniques and technologies used to control gaseous emissions. In the following we discuss the air control technologies given in Table . Much of the information contained in this chapter is heavily adapted from Spellman s The Science of Air 1999 and USEPA-81 12 1981 Control of Gaseous Emissions Course 415. The excerpted materials are rearranged and edited to make the materials more accessible for the reader. ABSORPTION Absorption or scrubbing is a major chemical engineering unit operation that involves bringing contaminated effluent gas into contact with a liquid absorbent so that one or more constituents of the effluent gas are selectively dissolved into a relatively nonvolatile liquid. Key terms used when discussing the absorption process include Absorbent the liquid usually water mixed with .