PTQ Q1 2024 Issue

Adding CHP to refinery power infrastructures

CI scores and delivered economic impact at downstream facilities improve when adding CHP units to increase electrical and thermal efficiency

Rene Gonzalez Editor, PTQ

I mplementing combined heat and power (CHP) plants fuelled by natural gas (NG), renewable natural gas (RNG), or hydrogen can reduce refinery operating costs during normal run lengths or extended downtime for a unit revamp. The end game is a huge reduction in the process gas emis- sions footprint. Financially, this means that with proper equipment selection and layout design, the return on invest- ment (ROI) of the CHP cogeneration power plant in the refin - ing and petrochemical industry could be less than a year. Cogeneration facilities have been a mainstay in commercial and industrial facilities worldwide, with capacities approach- ing 100 MW in various applications. In addition, CHP cogen- eration units under 20 MW are used throughout the oil and gas industry, including the refining and petrochemical sec - tors, particularly during a major revamp or turnaround, as well as during normal operations. Although the demand for CHP units has remained rela- tively flat until recently, that market is projected to expand as these portable systems are part of the broader effort towards transitioning to more sustainable energy sources, reducing GHG emissions, and promoting circular economy practices by reusing waste materials, such as in the produc- tion of RNG. For example, combining CHP units powered by fuels such as RNG or hydrogen benefits project carbon intensity (CI) scores in the long term. Energy efficiency Downstream processing facilities have significant energy requirements, both for electricity (compressors, pumps) and thermal energy (heat and steam), making CHP systems an efficient and cost-effective solution for the following applications: Steam and power generation: Refineries use steam for various processes, including distillation, desalting, and heating. CHP systems can simultaneously generate elec- tricity and steam, optimising energy use and reducing over- all energy costs. Waste heat recovery: Refineries produce a substantial amount of waste heat as a byproduct of their operations. CHP systems can capture and use this waste heat to gen- erate electricity or provide supplementary process heating, improving energy efficiency. Process heating: High-temperature heat is often required

for specific processes. CHP systems can provide this heat, reducing the need for separate heating systems and improv- ing overall energy efficiency. Energy cost reduction: By generating electricity on-site, refineries can reduce their reliance on external power sources, potentially leading to cost savings, particularly when energy prices are high. Environmental benefits: CHP systems can help reduce greenhouse gas emissions (GHG) and other pollutants, as they are more energy efficient compared to traditional power generation methods. Energy security and reliability: CHP systems enhance the reliability of power supply in refineries, offering a back-up power source during grid outages or other disruptions. Specific configurations of CHP systems in a refinery or petrochemical unit will depend on the plant’s energy needs, available energy sources, and operational processes. The choice of technology, such as gas turbines, steam turbines, reciprocating engines, will also be based on the refinery’s specific requirements, such as the volatile process of upgrad - ing refinery-grade propylene to higher margins polypropyl - ene via thermocompression benefits from an integrated CHP and chiller design to balance cooling water requirements. In some cases, refineries and chemical plants with CHP systems can contribute excess electricity back to the grid, potentially earning revenue through power sales. CHP tech- nology can be deployed quickly, cost-effectively, and with few geographic limitations. Natural gas-powered CHP has quietly provided highly efficient electricity and process heat to some facilities. Improve CI scores To date, NG-powered CHP operations provide the leverage to decouple from grid electricity affected by high GHG emis- sions and unreliable grid connectivity. In the future, combin- ing RNG and NG, or pure RNG, improves a facility’s CI scores, but other factors also influence whether a refinery or chemi - cal plant benefits from CHP. For example: • Would there be substantial business, safety, or health impacts if the electricity supply were interrupted, such as during a major turnaround or weather-related outage? • Is there interest in reducing a facility’s impact on the environment?

PTQ Q1 2024