Need information regarding acceptance of resignation

Sir, i am working in a central govt job since past 13 years and due to some reasons not satisfied with the working environment. I have been selected in a private organization and wish to resign from the govt job. But since i have been trained in govt job while doing the service, i fear that my employer may not accept my resignation. In that state of affairs, if i write resignation and he doesn't releives me, that situation will be embarrasiing for me and i shall not be able to get any job nhietherr my existing govt job nor that private job.Please note that i haven't filled any bond with my employer. Please advice whether resignation based on personal grounds can be rejected by the employer in such a state when he has no substitute for me and i am trained in the system.