Conditioning and/or dewatering difficult sludges - successively freezing and thawing using the condenser for the refrigerant only when thawing is compl-ete

摘要

Difficult sluges such as those from sewage installations, water purification systems, hydroxide and titanium dioxide sludges, etc., which are conditioned and/or dewatered by freezing and thawing on heat exchanging surfaces chilled with a refrigerant and then reheated, are processed by pressing out all that has thawed between the still frozen and the heat-exchanging surfaces and, only when the sludge has fully thawed out, is a condenser of normal type set on to condense the refrigerant. By removal of the heat-insulating thawed-out fluid from the zone between frozen and heat-exchanging surfaces, the condensation temperature of the refrigerant and thus running costs of the refrigeration plant are considerably reduced. By combining conditioning and dewatering in one operation, the economics of the process are improved.