I am a consultant to the petroleum coke industry. There is a lot of talk that high sulphur pet coke (7-8 per cent) is a low cost feed to cement plants that meets US emission standards. The theory is that the suphur is thoroughly consumed or bound up by the limestone and converted to calcium sulphate. I have been recently asked by a US cement plant contemplating burning coke for more specific information in order for them to meet their EPA permit. Do you have anything re solid scientific statistics of the SO_x formation in cement kilns when burning coke??

There are a number of case studies of cement kilns burning petcoke and having no SO_x emission problems. It is correct that the predominantly alkaline feed absorbs any SO₂ in the kiln exhaust gases due to the intimate contact between the gases and the feed in the preheater cyclones. There is a greater potential for SO_x emissions with long kilns (ie without preheaters).

What will be the effect of clinker on cement grinding which is produced from 100 per cent petcoke. The chemistry of clinker is as equivalent as when produced with other fuels. Also nodulisation of petcoke clinker is good. Kindly advice how to improve cement grinding performance with petcoke clinker.

It is not clear what problem you are suffering from. With petcoke clinker I expect there is a higher sulphate content in the clinker. Therefore you have to reduce the amount of gypsum addition and that will adversely affect the performance of the cement mill. I'm afrain there is no ready solution to that problem. The clinker might also be denser resulting in loss of milling efficiency. In that case addition of calcium fluoride to the kiln feed will probably help.