Measurement report: Method for evaluating CO<sub>2</sub> emissions from a cement plant using atmospheric <i>δ</i>(O<sub>2</sub> ∕ N<sub>2</sub>) and CO<sub>2</sub> measurements and its implication for future detection of CO<sub>2</sub> capture signals
oleh: S. Ishidoya, K. Tsuboi, H. Kondo, K. Ishijima, N. Aoki, H. Matsueda, K. Saito
| Format: | Article |
|---|---|
| Diterbitkan: | Copernicus Publications 2024-01-01 |
Deskripsi
<p>Continuous observations of atmospheric <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M8" display="inline" overflow="scroll" dspmath="mathml"><mrow><mi mathvariant="italic">δ</mi><mo>(</mo><mrow class="chem"><msub><mi mathvariant="normal">O</mi><mn mathvariant="normal">2</mn></msub><mo>/</mo><msub><mi mathvariant="normal">N</mi><mn mathvariant="normal">2</mn></msub></mrow><mo>)</mo></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="49pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="46ad310e28a389e1a35b4106f34f1429"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-24-1059-2024-ie00003.svg" width="49pt" height="14pt" src="acp-24-1059-2024-ie00003.png"/></svg:svg></span></span> and CO<span class="inline-formula"><sub>2</sub></span> amount fractions have been carried out at Ryori (RYO), Japan, since August 2017. In these observations, the O<span class="inline-formula"><sub>2</sub></span> : CO<span class="inline-formula"><sub>2</sub></span> exchange ratio (ER, <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M12" display="inline" overflow="scroll" dspmath="mathml"><mrow><mo>-</mo><mi mathvariant="normal">Δ</mi><mi>y</mi><mo>(</mo><mrow class="chem"><msub><mi mathvariant="normal">O</mi><mn mathvariant="normal">2</mn></msub></mrow><mo>)</mo><mi mathvariant="normal">Δ</mi><mi>y</mi><mo>(</mo><mrow class="chem"><msub><mi mathvariant="normal">CO</mi><mn mathvariant="normal">2</mn></msub></mrow><msup><mo>)</mo><mrow><mo>-</mo><mn mathvariant="normal">1</mn></mrow></msup></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="98pt" height="16pt" class="svg-formula" dspmath="mathimg" md5hash="58eebad1b32ed607403a01273750a5d6"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-24-1059-2024-ie00004.svg" width="98pt" height="16pt" src="acp-24-1059-2024-ie00004.png"/></svg:svg></span></span>) has frequently been lower than expected from short-term variations in emissions from terrestrial biospheric activities and combustion of liquid, gas, and solid fuels. This finding suggests a substantial effect of CO<span class="inline-formula"><sub>2</sub></span> emissions from a cement plant located about 6 km northwest of RYO. To evaluate this effect quantitatively, we simulated CO<span class="inline-formula"><sub>2</sub></span> amount fractions in the area around RYO by using a fine-scale atmospheric transport model that incorporated CO<span class="inline-formula"><sub>2</sub></span> fluxes from terrestrial biospheric activities, fossil fuel combustion, and cement production. The simulated CO<span class="inline-formula"><sub>2</sub></span> amount fractions were converted to O<span class="inline-formula"><sub>2</sub></span> amount fractions by using the respective ER values of 1.1, 1.4, and 0 for the terrestrial biospheric activities, fossil fuel combustion, and cement production. Thus obtained O<span class="inline-formula"><sub>2</sub></span> and CO<span class="inline-formula"><sub>2</sub></span> amount fraction changes were used to derive a simulated ER for comparison with the observed ER. To extract the contribution of CO<span class="inline-formula"><sub>2</sub></span> emissions from the cement plant, we used <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M21" display="inline" overflow="scroll" dspmath="mathml"><mrow><mi>y</mi><mo>(</mo><msup><mrow class="chem"><msub><mi mathvariant="normal">CO</mi><mn mathvariant="normal">2</mn></msub></mrow><mo>∗</mo></msup><mo>)</mo></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="41pt" height="13pt" class="svg-formula" dspmath="mathimg" md5hash="e7be3a8f822fc0a49db161cb629aae30"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-24-1059-2024-ie00005.svg" width="41pt" height="13pt" src="acp-24-1059-2024-ie00005.png"/></svg:svg></span></span> as an indicator variable, where <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M22" display="inline" overflow="scroll" dspmath="mathml"><mrow><mi>y</mi><mo>(</mo><msup><mrow class="chem"><msub><mi mathvariant="normal">CO</mi><mn mathvariant="normal">2</mn></msub></mrow><mo>∗</mo></msup><mo>)</mo></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="41pt" height="13pt" class="svg-formula" dspmath="mathimg" md5hash="a6dc21c26f947682bb1a877a35778f37"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-24-1059-2024-ie00006.svg" width="41pt" height="13pt" src="acp-24-1059-2024-ie00006.png"/></svg:svg></span></span> is a conservative variable for terrestrial biospheric activities and fossil fuel combustion obtained by simultaneous analysis of observed <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M23" display="inline" overflow="scroll" dspmath="mathml"><mrow><mi mathvariant="italic">δ</mi><mo>(</mo><mrow class="chem"><msub><mi mathvariant="normal">O</mi><mn mathvariant="normal">2</mn></msub><mo>/</mo><msub><mi mathvariant="normal">N</mi><mn mathvariant="normal">2</mn></msub></mrow><mo>)</mo></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="49pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="47a2d6f5902b506f19014043bd82bb18"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-24-1059-2024-ie00007.svg" width="49pt" height="14pt" src="acp-24-1059-2024-ie00007.png"/></svg:svg></span></span> and CO<span class="inline-formula"><sub>2</sub></span> amount fractions and simulated ERs. We confirmed that the observed and simulated ER values and also the <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M25" display="inline" overflow="scroll" dspmath="mathml"><mrow><mi>y</mi><mo>(</mo><msup><mrow class="chem"><msub><mi mathvariant="normal">CO</mi><mn mathvariant="normal">2</mn></msub></mrow><mo>∗</mo></msup><mo>)</mo></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="41pt" height="13pt" class="svg-formula" dspmath="mathimg" md5hash="f4a1c8e4c357fe5260bd9ea6eafa2915"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-24-1059-2024-ie00008.svg" width="41pt" height="13pt" src="acp-24-1059-2024-ie00008.png"/></svg:svg></span></span> values and simulated CO<span class="inline-formula"><sub>2</sub></span> amount fractions due only to cement production were generally consistent. These results suggest that combined measurements of <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M27" display="inline" overflow="scroll" dspmath="mathml"><mrow><mi mathvariant="italic">δ</mi><mo>(</mo><mrow class="chem"><msub><mi mathvariant="normal">O</mi><mn mathvariant="normal">2</mn></msub><mo>/</mo><msub><mi mathvariant="normal">N</mi><mn mathvariant="normal">2</mn></msub></mrow><mo>)</mo></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="49pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="41bf68a7ab544e23a5ec4d614349d0bd"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-24-1059-2024-ie00009.svg" width="49pt" height="14pt" src="acp-24-1059-2024-ie00009.png"/></svg:svg></span></span> and CO<span class="inline-formula"><sub>2</sub></span> amount fractions will be useful for evaluating CO<span class="inline-formula"><sub>2</sub></span> capture from flue gas at carbon capture and storage (CCS) plants, which, similar to a cement plant, change CO<span class="inline-formula"><sub>2</sub></span> amount fractions without changing O<span class="inline-formula"><sub>2</sub></span> values, although CCS plants differ from cement plants in the direction of CO<span class="inline-formula"><sub>2</sub></span> exchange with the atmosphere.</p>