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.