Why is partial combustion messy

Three of these processes tend to confuse all newcomers to gasification. Once you understand these three processes, all the others pieces fall in place quickly.

These three non-obvious processes are Pyrolysis, Cracking, and Reduction. Pyrolysis is the application of heat to raw biomass, in an absence of air, so as to break it down into charcoal and various tar gasses and liquids. It is essentially the process of charring.

The biomass breaks down into a combination of solids, liquids and gasses. The solids that remain we commonly call charcoal. The gasses and liquids that are released we collectively call tars. The gasses and liquids produced during lower temp pyrolysis are simply fragments of the original biomass that break off with heat.

These fragments are the more complicated H, C and O molecules in the biomass that we collectively refer to as volatiles. As the name suggests, volatiles are reactive. Or more accurately, they are less strongly bonded in the biomass than the fixed carbon, which is the direct C to C bonds.

The input to gasification is some form of solid carbonaceous material— typically biomass or coal. All organic carbonaceous material is made up of carbon C , hydrogen H , an oxygen O atoms— though in a dizzying variety of molecular forms.

The goal in gasification is to break down this wide variety of forms into the simple fuel gasses of H 2 and CO— hydrogen and carbon monoxide. Both hydrogen and carbon monoxide are burnable fuel gasses.

We do not usually think of carbon monoxide as a fuel gas, but it actually has very good combustion characteristics despite its poor characteristics when interacting with human hemoglobin. Carbon monoxide and hydrogen have about the same energy density by volume. Both are very clean burning as they only need to take on one oxygen atom, in one simple step, to arrive at the proper end states of combustion, CO 2 and H 2 O. This is why an engine run on producer gas can have such clean emissions.

The volatiles in the biomass are evaporated off as tar gases, and the fixed carbon-to-carbon chains are what remains— otherwise known as charcoal. Cracking is the process of breaking down large complex molecules such as tar into lighter gases by exposure to heat. This process is crucial for the production of clean gas that is compatible with an internal combustion engine because tar gases condense into sticky tar that will rapidly foul the valves of an engine.

Cracking is also necessary to ensure proper combustion because complete combustion only occurs when combustible gases thoroughly mix with oxygen.

Carbon is the basic chemical element found in living beings; carbon-containing chemicals are called organic. Example VOCs include some hairspray, cleaners, air fresheners and paints. Human Matching: Print out the air sayings and meanings see Table 1 or the Air Sayings attachment , and cut apart each of the boxes.

You may want to add more of your own before doing this. At the end, give a brief explanation of concepts. Table 1. Briefly discuss the contents. Ask students to keep these for reference during the lesson. Flashcards: Have students create flashcards of the air pollution vocabulary terms using the Air Pollution Flashcards attachment.

Note: You need one set of flashcards per student. The cards are set up so that you can print two-sided copies on your printer: the odd pages are the terms and the even pages are the definitions. If you cannot print double-sided automatically, print the odd pages first, and then print the even pages on the back side of each odd page.

Make sure you put the odd pages back in the printer in the right order and the correct way. It may help to copy them onto a heavy weight card stock. Ask students to pretend to be engineers trying to pass a new bill in Congress.

They should use specific information that they have learned in this lesson. Review the worksheets during the next class period. Find our about factories in your area. What do they make? What types of waste do they produce? How do they dispose of the waste? Check them out on the EPA website. Invite an employee from the EPA or other local person responsible for monitoring air quality to your classroom.

Encourage students to ask questions about the types, causes, and levels of air pollution found in your community. Discuss the examples and effects of air pollution. Ask students to write their own versions of this book using what they have learned about air pollution.

Have students compare the U. Have students research and explore how lichens can indicate levels of air pollution. It's a Problem All over the World! Imagine that you are at a meeting of great leaders from all over the world.

They are waiting to hear you speak about what is happening to our fresh air. You want to convince more of them to use the new technologies that you have just studied. What will you tell them? How will you get them to work together? Write down your ideas and make a presentation to the class. Project A. Students can investigate how they can improve their school's indoor air quality. Bosak, Susan V. Science is Markham, Ontario: Scholastic Canada Ltd.

Kerrod, Robin and Evans, Ted. Prentice Hall Science. Stille, Darlene. However, these contents do not necessarily represent the policies of the Department of Education or National Science Foundation, and you should not assume endorsement by the federal government. Why Teach Engineering in K? Find more at TeachEngineering. Quick Look. Partial design process. Print this lesson Toggle Dropdown Print lesson and its associated curriculum. Suggest an edit.

Discuss this lesson. Curriculum in this Unit Units serve as guides to a particular content or subject area. What Color is Your Air Today?

What's Hiding in the Air? TE Newsletter. Subscribe to TE Newsletter. Summary Students are introduced to the concepts of air pollution and technologies that engineers have developed to reduce air pollution. They develop an understanding of visible air pollutants with an incomplete combustion demonstration, a "smog in a jar" demonstration, construction of simple particulate matter collectors and by exploring engineering roles related to air pollution.

Next, students develop awareness and understanding of the daily air quality and trends in air quality using the air quality index AQI listed in the newspaper or online. Finally, students build and observe a variety of simple models in order to develop an understanding of how engineers use these technologies to clean up and prevent air pollution.

Engineering Connection It is an engineering challenge to find solutions to clean our air, because so many factors contribute to air pollution.

Grade 5 Do you agree with this alignment? Human activities in agriculture, industry, and everyday life have had major effects on the land, vegetation, streams, ocean, air, and even outer space. But individuals and communities are doing things to help protect Earth's resources and environments. A system can be described in terms of its components and their interactions. Science findings are limited to questions that can be answered with empirical evidence.

The use of technology affects the environment in good and bad ways. Grades 3 - 5 More Details View aligned curriculum Do you agree with this alignment? Colorado - Science Analyze and interpret a variety of data to understand the origin, utilization, and concerns associated with natural resources Grade 5 More Details View aligned curriculum Do you agree with this alignment? Air Sayings printable strips, unscramble game and overhead transparency pdf.

Air Pollution Flashcards pdf. Sources of Air Pollution Handout pdf. One estimate is that hydrogen could meet 24 per cent of total energy demand across Europe by Caution is needed. We must first produce it. That can be done cleanly by splitting water into hydrogen and oxygen using renewable electricity from solar and wind power. But the cheaper and more prevalent method is to extract it from natural gas or coal, which emits carbon dioxide and locks us into further exploitation of fossil fuels.

Hydrogen can be part of the solution — if we do it right.