The "degradable plastic" defined by the national standard is not a good way to solve the problem of plastic grunge. Although the environmental impact of biodegradable plastics is less than non-degradable plastic, it still leads to many environmental issues, so it can only see it as a substitute for alleviating plastic problems, rather than a solution of plastic problems. Although we can have expectations for technology development, in accordance with the current level of science and technology, only reduce consumption can minimize the impact of plastic products on the environment. To completely compare biological degradation plastics and traditional plastics, we may wish to disassemble the lifecycle of plastics.
1. Običajna razgradljiva plastika
Trenutno se razpravlja, da biološko razgradljiva plastika, ki uporablja obnovljive biološke vire, kot so pridelki, mikroorganizmi itd., in nekateri uporabljajo fosilne vire. Najpogosteje uporabljena komercialna biološko razgradljiva plastika je PHA (ester polihidroksi maščobne kisline) in PLA (polimlečna kislina), ki sta izpostavljeni mikroorganizmom (krmljenje s pridelkom) in koruzi kot glavni surovini.
2, proizvodnja razgradljive plastike
2.. Since the current source of biodegradable plastic raw materials is crops (corn, sugar cane, etc.), rather than fossil fuels, so from raw materials, biodegradable plastics can save approximately half of fossil fuel than traditional plastics. If the world's traditional plastics are replaced by biodegradable plastics, it can save approximately 3.49 million barrel fuels per day, accounting for about 4 percent fossil fuel consumption in the world.
2.2. Tradicionalna plastika, ki med proizvodnim procesom biološko razgradljive plastike porabi manj energije od lastnosti. V proizvodnem procesu biološko razgradljive plastike je na splošno 2500-45 milijonov energije koksa, najpogostejša PLA pa zahteva 44,7 milijona volt energije. Tradicionalna plastika mora porabiti 7300-86 milijonov energije koksa na kilogram, kar je veliko več kot pri biorazgradljivi plastiki. Če globalno nerazgradljivo plastiko nadomestimo z biološko razgradljivo plastiko, lahko vsako leto prihrani 1-2,2 1019 joula energije glede na globalno proizvodnjo plastike za leto 2019. Leta 2019 je predstavljal 1,7-3,8 odstotka svetovne porabe energije v višini 5,8 1020 Joulov.
2.3. Glede na stroške proizvodnje je cena biorazgradljive plastike zdaj nekoliko višja od tradicionalne plastike (med 1-2 krat), vendar se bo glede na hitrost razvoja industrije v bližnji prihodnosti cena še naprej zniževala.
2.4. Za proizvodnjo 1 kg biološko razgradljive PLA plastike je potrebno približno 2,65 kg koruze, za proizvodnjo 1 kg biološko razgradljive PHA plastike pa je potrebno približno 3,7 kg koruze. Po podatkih za leto 2019, če vso tradicionalno plastiko zamenjamo z PLA, se vsako leto porabi približno 975 milijonov ton koruze; če vso tradicionalno plastiko zamenjamo s PHA, se vsako leto porabi približno 1,36 milijarde ton koruze. Hkrati je svetovna proizvodnja koruze 2018/2019 1,09 milijarde ton, kar je blizu stroškov nadomestne plastike. Poleg tega se bodo cene koruze in drugih pridelkov naravno zvišale, kar bo še naprej ogrožalo prehranska jamstva na območju z nizko vsebnostjo hrane, saj se več koruze ali obdelovalne zemlje uporablja za sajenje surovin, kot je biološko razgradljiva plastika. Vidimo lahko, da je biorazgradljiva plastika velika grožnja globalni oskrbi s hrano in je težko v celoti zamenjati tradicionalno plastiko, preden je tehnologija dosežena.
2.5. Med sajenjem surovin biološko razgradljive plastike se uporablja velika količina gnojil in insekticidov, kjer strupena snov prodre v vodo, varnost pitne vode pa je varna, prostoživeče živali in varnost tal.
3, recikliranje razgradljive plastike
3.1. Because the production of biodegradable plastics is too small, there is still lack of systematic, large-scale recovery methods. To give a simple example, when the garbage classification is proposed in Shanghai, many people need to shake the kitchen waste garbage when they are throwing garbage, and it is easy to stain your hands. So creating a creative wetting garbage bag, people want to throw the biodegradable garbage bag and wet garbage into wet trash. However, the garbage treatment department quickly sounded, indicating that although "degradable garbage bag" will most degrade, but it still has indiscriminated, even toxic and harmful ingredients, will affect the treatment of wet rubbish. Also, such garbage bag degradation speed is much slower than the kitchen waste, and cannot be treated synchronously. It can only be treated as dry waste incineration. Although biodegradable plastics can be degraded by biodegradation, it does not mean that they will ultimately break the recovery treatment, which is degraded.
3.2. Če kreativne razgradne plastike ne pridobimo učinkovito, bo v aerobnem okolju razgradila veliko količino toplogrednega plina-metana.
3.3. Kadar kreativna razgradljiva plastika ni učinkovito obnovljena, se po vstopu v morsko okolje močno zmanjša zaradi zadostne količine mikroorganizmov in kisika ter učinkovitosti biološke razgradnje. Ker ni mogoče pravočasno razgraditi, ima ta razgradljiva plastika še vedno veliko verjetnost, da bo škodovala morskim organizmom, preden je razgradnja končana.
4 primerjavesin skupnih emisij ogljika
Zaradi različnih surovin je biološko razgradljive plastike v celotnem življenjskem ciklu manj kot tradicionalne plastike. Ker so surovine biološko razgradljive plastike večinoma rastline, je njihova razgradnja manjša od ogljikovega dioksida v rasti rastlin, zato emisije ogljikovega dioksida biorazgradljive plastike v glavnem izhajajo iz mehanskih emisij med proizvodnjo in transportom. Tradicionalna plastika na kilogram tradicionalne plastike bo v svojem celotnem življenjskem ciklu sprostila 2,5-3,4 kilograma ogljikovega dioksida, biološko razgradljiva plastika pa 1,8 kg ogljikovega dioksida na kilogram biološko razgradljive plastike. Če tradicionalno plastiko nadomestimo z biološko razgradljivo plastiko, bo, odvisno od vrste, svet vsako leto sprostil 0-830 milijonov ton ogljikovega dioksida (upoštevajte življenjski cikel celotnega izdelka). Ta vrstni red je približno 2,3 odstotka v primerjavi s približno 36 milijardami ton emisij ogljika na leto17.
5 potencialna grožnja
When the environmental impact of degradable plastic (oil consumption, carbon emissions, energy consumption, agricultural pollution, etc.) still exists, and that degradable plastics will still cause environmental issues. If we are in this time, due to mistakes, it is harmless, and a large amount of "degradable" plastic product is used, the overall environmental impact (the impact of unit plastic products plastic products) may It will be greater than the era of traditional plastics. Not to mention the definition of degradation of plastics, it is still blurred. When it is "degradable plastic", "only needs a long time to degrade in the ideal environment", the environmental hazard Only increasing.
In summary, if you use a biodegradable plastic to replace the traditional plastic, 4 percent fossil fuel can be saved, reducing 2.3 percent carbon emissions worldwide, saving 2 percent of the world's energy consumption. Even if we use biodegradable plastics to replace all disposable plastics (approximately half of global plastics production), it can reach half of the results. At the same time, at the same time, replacement of disposable plastic products to degrade plastics can consume more than half of corn production, and cause risk from methane, pesticides, fertilizers, can't degrade in time. Therefore, it is necessary to emphasize that "degradable" does not explain that this plastic product can be simply harmless, which will still trigger a series of energy consumption, carbon emissions, food shortages, and so on. According to the current level of technology, "degradable plastic" is a way to slow the problem, it is not a way to solve the problem, and it is impossible to use degradable plastic products due to the word "degradable". If we all completely abandon the use of disposable products, it will not cause pollution and consumption of those fuel, energy, carbon emissions, etc., etc. Therefore, under the existing technological conditions, the use of conventional plastics is replaced with degradable / stacui plastics, and the use of a disposable plastic article is better.
