The phrase "are used to replace" is correct and usable in written English.
It can be used when discussing the function or purpose of something that serves as a substitute for another item or concept.
Example: "In this recipe, eggs are used to replace the butter for a healthier option."
Alternatives: "are utilized as substitutes" or "serve to substitute".
If NNSs are used to replace caloric sweeteners, without caloric compensation, then NNSs may be useful in reducing caloric and carbohydrate intake (146), although further research is needed to confirm these results (147).
Sometimes, they are used to replace the noise from planes flying overhead.
This procedure - in which healthy veins from other parts of the body are used to replace arteries supplying the heart with blood - suggests that Fiennes suffered from coronary heart disease.
That is because they have been issued with so-called 'buyout' personal contracts, which are usually given to more senior staff on high salaries and are used to replace the separate elements of pay such as unpredictability allowances, overtime and additional days payments with an all-inclusive payment.
Many children who are born with heart defects face a series of major operations over the course of their lives because the implants - known as conduits - that are used to replace their malformed blood vessels, do not grow in line with their heart and the rest of the body.
Synthetic materials are used to replace the human skin.
Patching materials are used to replace localized areas of deteriorated concrete.
All histograms (256 bins) are used to replace the classical "pupil-glint" vector.
Micro-coral sand and coral sand are used to replace cement and sand, respectively.
Computer programs are used to replace manual computation to find solutions to various engineering problems.
To improve the computation efficiency, surrogate models are used to replace expensive simulations of engineering problems.
