Dear Sir. Concerning your issue about the alkali that can be replaced with lime in beamhouse stage. Most unhairing systems are based on the use of lime, sodium sulphide and sodium hydrosulphide – all highly alkaline chemicals. When we add alkalis to collagen it becomes more negatively charged causing the collagen molecules to repel each other thus forcing themselves apart. When the collagen molecules are pushed apart in this way, more water is taken up to fill the now larger gap between them, ie swelling occurs. This is why hides become thick and turgid during liming. Because the molecules have been pushed apart by the swelling effect, they are now much less stable and, as such, much more easily damaged by abrasion and heat. Therefore, when hides and skins are at liming pH they must not be exposed to high temperatures otherwise the normally robust collagen structure will be irreversibly damaged; the shrinkage temperature of limed collagen can be as low 35°C. So, if temperatures rise much above 30°C there is a serious risk of the delicate grain surface becoming damaged. For more details, I think the following below link may help you in your issue: