A method for purifying waste gas with a waste gas purification system , - wherein the waste gas purification system comprises at least three heat-storing regenerators connected to a reaction chamber , - wherein the waste gas is alternately fed to the regenerators in cycles, and wherein one cycle of the method comprises the following steps: - feeding the waste gas to the reaction chamber through at least one regenerator , which has been heated in a previous cycle to convert the waste gas in the reaction chamber to clean gas, - discharging the clean gas from the waste gas purification system through at least one further regenerator , whereby the at least one further regenerator is heated, - purging at least one other further regenerator with purge gas, in particular with clean gas, in order to avoid contamination of the clean gas in a subsequent cycle, and wherein the purged regenerator , in particular its storage mass, is used as a heat storage medium for the heat exchange during a cycle, - wherein the regenerator for purging takes up heat from the purge gas during a cycle when flowing through in a first flow direction and releases heat to the purge gas again when flowing through in a second flow direction - in particular wherein the heat transmitted from the purge gas to the regenerator is thereby essentially completely returned to the reaction chamber , characterized - in that the flow direction of the purge gas is reversed at least once during the cycle, - and in that during a cycle, for purging, purge gas first flows through the regenerator from the reaction chamber in the direction of its clean gas outlet , - and in that purge gas flows through the same regenerator , during the same cycle, for purging thereafter or subsequently from the clean gas outlet in the direction of the reaction chamber . - wherein the waste gas purification system comprises at least three heat-storing regenerators connected to a reaction chamber , - wherein the waste gas is alternately fed to the regenerators in cycles, - feeding the waste gas to the reaction chamber through at least one regenerator , which has been heated in a previous cycle to convert the waste gas in the reaction chamber to clean gas, - discharging the clean gas from the waste gas purification system through at least one further regenerator , whereby the at least one further regenerator is heated, - purging at least one other further regenerator with purge gas, in particular with clean gas, in order to avoid contamination of the clean gas in a subsequent cycle, - wherein the regenerator for purging takes up heat from the purge gas during a cycle when flowing through in a first flow direction and releases heat to the purge gas again when flowing through in a second flow direction - in particular wherein the heat transmitted from the purge gas to the regenerator is thereby essentially completely returned to the reaction chamber , - in that the flow direction of the purge gas is reversed at least once during the cycle, - and in that during a cycle, for purging, purge gas first flows through the regenerator from the reaction chamber in the direction of its clean gas outlet , - and in that purge gas flows through the same regenerator , during the same cycle, for purging thereafter or subsequently from the clean gas outlet in the direction of the reaction chamber . <EOS>