University:
Boston University
Course:
CAS CH 214 | Organic Chemistry with Qualitative Analysis
Academic year:

2023
Views:

260

Pages:

15
Author:

Marquise Washington

Energy and CO2 Implications of the Global Cement Industry Concrete is the world’s most used material • 17-20 billion metric tons of concrete per year globally Concrete mixing truck holds 7-9 cubic yards of concrete with 5 to 8 sacks of cement (94 lb. each) per cubic yard • 4.6 billion metric tons cement produced per year globally 626 kg/per capita, higher than human food consumption Cement manufacturing is energy-intensive • To produce 1 ton of portland cement requires up to 7000 MJ (2000kWh) of electrical power and fuel energy ~1450°C NRC (Canada) Cement manufacturing produces CO2 • “If the cement industry were a country, it would be the third largest emitter in the world - behind China and the US. It contributes more CO2 than aviation fuel (2.5%) and is not far behind the global agriculture business (12%).” - BBC News, 17 December 2018 3CaCO3 + SiO2 ↔ Ca3SiO5 + 3CO2 Levers for change 1. Thermal and electric efficiency (equipment and process changes) 2. Alternative fuels (equipment and process) 3. Clinker substitution – supplementary cementitious materials and alternative cements (material changes) 4. Carbon capture and storage (equipment, process and material changes) 5. Efficiency of materials use (material changes) Planning strategies Eisenhower Decision Matrix Ideas with rapid implementation potential 1. Thermal & electric efficiency Ideas with long term potential 2. Alternative fuels 4. Carbon capture 3. Clinker substitution Bad ideas! Red herrings Impact of changes in processes and materials BBC News, 2018 Impact of changes in processes and materials Alternative fuels • Alternative fuels can play an important role • Moisture content, burning rate, and contamination need consideration Clinker substitution: SCMs • More than 60% of ready-mixed concrete in the US uses supplementary cementitious materials (SCMs) to replace a portion of cement in concrete Clinker substitution: alternative cements • Alkali-activated materials (“Geopolymers”) • Calcium sulfoaluminate belite cements (CSAB) • Magnesium-based cement Clinker substitution: alternative cements Carbon capture technologies • • • Amine Scrubbing - Norcem Brevik, Norway Calcium Looping - Heping Cement Plant, Taiwan Oxyfuel Combustion - CEMCAP in EU Carbon capture + alternative cements Conclusions • Cement and concrete are the most important materials for development of infrastructure globally • The CO2 and energy footprints of the cement and concrete industries are large, but there are several strategies being used to reduce emissions: - Use more alternative fuels - Reduce clinker/cement content in concrete - Implement technologies for CO2 capture and reuse • The need for change is urgent, and we need to explore short-term and long-term solutions simultaneously