How Biofuel (Ethanol) is Produced: A Step-by-Step Process
Overview
This essay describes the process of biofuel (ethanol) production, starting from energy absorption from the atmosphere and ending with the release of energy back into the air. It divides the process into pre-processing and processing stages, highlighting the transformation of plants into cellulose and the subsequent conversion into ethanol for use in transportation. The cycle concludes with the release of carbon dioxide back into the atmosphere.
Key Features
- Begins with plants absorbing sunlight and carbon dioxide.
- Involves harvesting trees and grinding them into cellulose.
- Uses chemical substances to transform cellulose into sugar.
- Adds microbes to sugar to produce ethanol.
- Utilizes ethanol in vehicles, releasing carbon dioxide back into the atmosphere.
Our Review
We found the essay provides a basic overview of biofuel production, but it lacks depth and precision. The language is simple, and the explanation of the chemical processes is vague. The division into "pre-process" and "process" isn't clearly executed, and the logical flow could be improved. To enhance the essay, adding more specific details about the chemical reactions and using a wider range of vocabulary would be beneficial. The structure also needs improvement with a clearer overview and more defined transitions between stages.
Student Submission
The illustration depicts the process of biofuel which is also known as ethanol step by step. The production begins with absorbing energy from the atmosphere to form ethanol to release the energy back into the air. It is divided into two parts: pre-process and the process. Firstly, the greens absorb sunlight and carbon dioxide as a natural process of plants. The trees are then harvested by using machinery. Next step is a pre-process stage where the plants and the tree are being put in a grinding machine to convert them into cellulose. After being transformed into cellulose, the big preparation of making ethanol starts by involving chemical substances in a process. At this stage, the sugar is formed. Next, the microbes are added to the sugar. After that, the ethanol is ready to use by transports such as cars, trucks and planes. The carbon dioxide by these vehicles are released again into the atmosphere and the cycle commences again.
IELTS Essay Assessment
1. Topic Analysis:
- Topic Category: Process
- Key Requirements: A clear description of the stages involved in biofuel (ethanol) production, presented in a logical sequence. The essay should accurately reflect the process shown in the illustration (although no illustration is provided).
- Coverage Assessment: The essay attempts to describe the process, but it lacks detail and accuracy in several areas. The description is overly simplistic and omits crucial steps. The connection between the diagram (which is missing) and the written description is unclear.
- Time Period (if applicable): Not applicable.
- Data Type: Descriptive, not numerical.
2. Structure Analysis:
- Introduction: The introduction is brief and adequately introduces the topic. However, it should mention the stages of the process more explicitly.
- Overview: There is no overview paragraph summarizing the main stages of the process. This is a significant omission in an IELTS Task 1 response.
- Body Paragraphs: The body paragraphs attempt to describe the process in a step-by-step manner, but the organization is somewhat disjointed. The division into "pre-process" and "process" is not clearly defined or consistently followed.
- Logical Flow: The logical flow is weak. Some steps are unclear and lack sufficient detail. The connection between stages is not always explicit. For instance, the transition from cellulose to sugar is not well explained.
- Paragraph Division: Paragraphing is adequate, but the content within each paragraph could be better organized for clarity.
3. Language Usage:
- Vocabulary Range: The vocabulary is basic and repetitive. There is limited use of technical vocabulary related to biofuel production. The use of phrases like "chemical substances" is vague and lacks precision.
- Grammar Control: The grammar contains several errors. For example, "The trees are then harvested by using machinery" is grammatically awkward. The tense is inconsistent; the present simple and present continuous are mixed without clear purpose. Article usage is inconsistent. Subject-verb agreement is mostly correct but could be improved.
4. Detailed Band Scores:
- Task Achievement: 5/9: The essay attempts to describe the process, but it omits key steps, lacks detail, and fails to provide a clear and accurate representation. The absence of an overview significantly impacts the score. The description is simplistic and lacks the precision expected at a higher band.
- Coherence & Cohesion: 5/9: The essay lacks a clear overview and the logical flow between stages is weak. The connection between steps is not always apparent. While paragraphs are used, the internal organization within paragraphs could be improved.
- Lexical Resource: 5/9: The vocabulary is limited and lacks precision. More specific and technical vocabulary related to biofuel production is needed. The repetitive use of simple words limits the score.
- Grammar: 5/9: The grammar contains several errors, including awkward phrasing, inconsistent tense usage, and imprecise article usage. Sentence structure is often simple and lacks variety.
Overall Band: 5/9
5. Task 1 Specific Feedback:
- Overview Quality: Absent. This is a major weakness.
- Key Feature Coverage: Several key steps in the biofuel production process are missing or inadequately explained. The chemical processes involved are not detailed.
- Data Accuracy: The description is inaccurate in several places and lacks the necessary detail to be considered accurate. The connection between the (missing) diagram and the text is absent.
- Compare/Contrast: Not applicable to this process description.
6. Improvement Suggestions:
- Task Achievement Improvements: Include all the steps in the process, provide more detail, and add an overview paragraph. Use more precise and technical vocabulary. Ensure the description accurately reflects the information in the (missing) diagram.
- Coherence Improvements: Add an overview paragraph summarizing the main stages. Use cohesive devices (e.g., transition words) to improve the logical flow between steps. Ensure a clear progression from one stage to the next.
- Vocabulary Improvements: Replace vague terms like "chemical substances" with more precise terminology. Use technical vocabulary related to biofuel production (e.g., fermentation, distillation).
- Grammar Improvements: Proofread carefully to correct grammatical errors. Vary sentence structures to improve the flow and readability. Ensure consistent tense usage.
7. Model Essay:
(Note: A model essay cannot be provided without the original illustration. The following is a hypothetical example assuming a typical biofuel process diagram.)
Hypothetical Model Essay:
The diagram illustrates the process of biofuel (ethanol) production from plant matter. The process can be broadly divided into three main stages: harvesting and pre-processing, fermentation, and distillation.
Firstly, plants, such as corn or sugarcane, are harvested using machinery. The harvested material is then pre-processed, involving cleaning, milling, and potentially enzymatic treatment to break down complex carbohydrates into simpler sugars. This pre-processing stage is crucial for efficient fermentation.
Next, the sugars are fermented. This involves adding yeast or other microorganisms to the sugar solution. During fermentation, the microorganisms convert the sugars into ethanol through anaerobic respiration, producing carbon dioxide as a byproduct.
Finally, the ethanol is separated from the remaining mixture through distillation. This process involves heating the fermented solution to vaporize the ethanol, which is then condensed and collected as a relatively pure product. This ethanol can then be used as a biofuel. The carbon dioxide released during fermentation and combustion is absorbed by plants, completing the cycle.
This process demonstrates a sustainable approach to energy production, utilizing renewable resources and reducing reliance on fossil fuels.
Higher Band Score Version Highlights:
- Clear overview paragraph summarizing the three main stages.
- More precise and technical vocabulary (e.g., "enzymatic treatment," "anaerobic respiration," "distillation").
- Improved sentence structure and grammar.
- Logical flow and clear connections between stages.
- Accurate and detailed description of the process.
Key Features to Note: The model essay demonstrates improved task achievement, coherence, lexical resource, and grammar compared to the original response. The inclusion of an overview and the use of more precise language are key improvements. The logical flow is significantly enhanced, making the process easier to understand.
