A total heat energy recovery system for furnace-process phosphoric acid is disclosed by the present disclosure, and relates to the technical field of phosphorus chemical industry. The system comprises a phosphorus burning tower, a hydration tower, an absorption tower, a Venturi tube, a demister, an induced draft fan, a deaerator, an economizer, a dilute acid circulating tank, a phosphoric acid pump, and a feedwater pump. In consideration of the whole process system, fresh soft water is deoxidized after being heated by an upper head of the phosphorus burning tower and a gas guide tube, and the deoxidized water is then pumped into the economizer by a high-pressure pump to recover the heat of the hydration tower and then enters a steam pocket of the phosphorus burning tower to generate medium-high pressure steam. Therefore, unified recovery of the heat of a furnace-process phosphoric acid device is achieved, the medium-high pressure steam is generated, the effective energy is improved, a circulating cooling tower of the furnace-process phosphoric acid device is omitted, and the production system is efficient, energy-saving, environment-friendly, and green.

Furnace operation includes consecutive cycles of a heating step, a stopping step and a restarting step. The fuel and/or the oxidizing agent is preheated upstream of the furnace by indirect exchange with the discharged fumes through a medium passing through a chamber. A first wall separates the fumes from the medium in the chamber. The fuel and/or oxidizing agent is separated from the medium in the chamber by a second wall. During restarting, the medium's flow rate Dm is regulated to limit the heating rate of the first wall until it reaches the operational temperature at an end thereof.

A cooling system is configured to cool exhaust gases exiting a furnace of a steel production system through an exhaust hood, a dropout box, and a hot gas duct of the steel production system. The cooling system includes an inlet configured to receive water from a water pump for cooling the exhaust gases, and an outlet configured to exhaust the water from the cooling system. The cooling system further includes a first water line configured to supply the water to the exhaust hood of the steel production system for cooling the exhaust gas received therein, and a second water line configured to supply the water to the dropout box of the steel production system for cooling the exhaust gas received therein. The cooling system also includes a third water line configured to supply the water to the hot gas duct of the steel production system for cooling the exhaust gas received therein, and each of the first water line, the second water line, and the third water line are operably coupled between the inlet and the outlet of the cooling system. The cooling system also includes a controller configured to control and maintain a defined temperature of the water circulating within the cooling system.

This disclosure provides a method of recycling heat during operation of a plant in which equipment for processing at least two different materials is co-located. The method comprises a first process for processing a first material and a second process for processing a second material. The second material has a melting point that is less than a melting point of the first material. During the first process, the first material is subjected to a first melting process and then subjected to a first cooling process that includes solidification of the first material. During the second process, the second material is subjected to a second melting process and then subjected to a second cooling process that includes solidification of the second material. The method comprises recovering heat from the first cooling process and using at least some of the heat as a heat source for the second melting process.

A process for the production of potassium sulphate by conversion of potassium chloride and sulphuric acid using a muffle furnace, said furnace comprising a reaction chamber and a combustion chamber, wherein in the reaction chamber potassium chloride (KCI) and potassium hydrogen sulfate (KHSO.sub.4) are reacted to form potassium sulphate while supplying heat to the reaction chamber from the combustion chamber, wherein the combustion chamber has at least a pair of regenerative burners and wherein the process comprises the steps of alternatingly causing one of the regenerative burners to perform a combustion operation in the combustion chamber to heat the reaction chamber and another of the regenerative burners to perform a heat-regenerating operation in a regenerator, wherein the pressure in the combustion chamber is kept at a pressure of between 0.2 and 3 mbarg.

A radiative recuperator preheats oxidant and/or fuel for combustion at one or more burners of a furnace. The recuperator includes a duct, at least portions of which comprise a material having a thermal conductivity of greater than 1 W/(m.Math.K), preferably greater than 3 W/(m.Math.K), that receives hot flue gas produced by the burner(s). The duct radiatively transfers heat to oxidant or fuel (for preheating) flowing through one or more metallic pipes disposed in between the duct and an insulating wall.

A method for producing burnt end products from an educt (starting raw materials) of carbonate-containing materials involves preheating the educt using heat recovered from the reaction. The educt and a fluidizing medium including steam are input into a first reaction zone. Heat is transferred to the first reaction zone using mechanical components so as to heat the first reaction zone to a predetermined temperature range for a predetermined time period. The educt is burned in the first reaction zone over the predetermined time period during which the first reaction zone is maintained within the predetermined temperature range. The hot gases that form in the first reaction zone include CO.sub.2 and steam. Hot end product is discharged from the first reaction zone after the predetermined time period elapses. Heat contained in the hot gases and end product that are discharged from the first reaction zone is used to preheat the educt.

A multitubular rotary heat exchanger has a stationary shielding unit. The shielding unit is positioned in close proximity to a tube plate outside a heating or cooling region. A stationary surface of the shielding unit is positioned in opposition to and in close proximity to an end opening of a heat transfer tube moving in an upper zone of the heating or cooling region, thereby transiently reducing or restricting the flow rate of the thermal medium fluid flowing through the heat transfer tube moving in the upper zone.

An apparatus for feeding and preheating a metal charge toward a melting furnace of a melting plant, comprising at least one conveyor channel for said metal charge, at least one hood disposed above said conveyor channel and scrap detection means able to identify the profile of the metal charge entering said conveyor channel. The present invention also concerns a plant for melting metal comprising said apparatus, and a method to feed and preheat a metal charge.

A heat recovery apparatus, system and method of using the same. The heat recovery apparatus includes a particulate inlet, a particulate distributor in fluid communication with the particulate inlet, a cavity in fluid communication with the particulate distributor, a plurality of pipes contained within the cavity and configured for transmission of a heat transfer fluid therethrough, and a particulate outlet in fluid communication with the cavity.