MINIMIZATION OF CARBONATE DEPOSITS ON THE HEAT TRANSFER SURFACES OF HEAT EXCHANGERS IN THE QUENCH WATER CIRCUIT OF A FLOW GASIFICATION INSTALLATION

摘要

The invention relates to a method for minimizing carbonate deposits on the heat transfer surfaces of heat exchangers in the quench water circuit of a flow gasification installation wherein the excess quench water from the quencher (1) is calmed and cleaned (2) and raised to the operating pressure of the gasification installation (3), carbon dioxide is dosed to the quench water (4) at such an amount that a lime-carbonic acid ratio results that equals at least the prevailing lime-carbonic acid weight, the quench water is heated at maximum to a temperature at which the dissolved content of carbon dioxide in the pre-heated process water is over the content of carbon dioxide before the pressure increase of the process water and the pre-heated quench water is supplied to the quencher for cooling the raw gas. According to the invention, an excess of carbon dioxide in the process water is achieved by the solution of carbon dioxide, which has lime-dissolving effects.