Taiheiyo Cement Corporation

Nippon Shokubai Co., Ltd.

Junichi Terasaki

Shinichiro Saito

Yasuhiro Uchiyama

Shinyuki Masaki

Hisashi Kondo

Mitsuharu Hagi

Soichiro Okamura

Osamu Yamaguchi

Hajime Wada

Kenzaburou Kondou

Kouji Kondou

Takahiro Hayashida

Harutoshi Kidachi

Masafumi Nakazaki

In accordance with the present invention, there is provided a treat chlorine bypass dust while preventing increases in chemical cost and concentrations of heavy metals in clinker, and ensuring stability in quality of cement. In a chlorine bypass facilityextracting a part G of combustion gas, while cooling it, from a kiln exhaust gas passage, which runs from an inlet end of a cement kiln to a bottom cyclone, and recovering a high chlorine concentration chlorine bypass dust Dfrom the extracted gas G, a slurry S containing chlorine bypass dust and SO2 gas or/and CO2 gas are contacted with each other to obtain solid content. The slurry containing chlorine bypass dust and an exhaust gas from the chlorine bypass facility or/and the exhaust gas from the cement kiln can be contacted with each other, and the solid content can be fed to a cement finishing process, which allows cement with low CaO and Ca(OH)2 contents and with stable property such as setting time to be produced.

Treatment device and treatment method for chlorine bypass dust

A combustion exhaust gas processing device comprises: a dust collector collecting dust in a cement kiln combustion exhaust gas; a wet dust collector using sodium hypochlorite as a catalyst-poisoning-substance stripper for removing a catalyst-poisoning substance and mercury from a combustion exhaust gas which passed the dust collector; heaters downstream of the wet dust collector for heating the combustion exhaust gas from the wet dust collector; and a catalyst device from which NOx, a persistent organic pollutant, etc. in the heated combustion exhaust gas, are removed. An upstream side of the catalyst device is installed with an oxide catalyst such as titanium-vanadium and a downstream side is installed with a platinum catalyst as a noble-metal catalyst. The temperature of the combustion exhaust gas after the wet dust collector is increased up to 140&#xb0; C. or more with the heaters to prevent decline in denitration efficiency of and the decomposition efficiency of a volatile organic compound. A mercury adsorbing tower is provided for adsorbing the mercury in liquid exhausted from the wet dust collector and wastewater from the liquid is used to generate sodium hypochlorite for use in the wet dust collector.

Device and method for processing cement kiln combustion exhaust gas

In accordance with the present invention, there is provide and device and method to facilitate the treatment of chlorine bypass dust while preventing increases in chemical cost and concentrations of heavy metals in clinker, and ensuring stability in quality of cement, and to treat chlorine bypass exhaust gas while avoiding coating troubles in a cement kiln etc., and preventing heat losses in a preheater etc., without degradation of clinker production amount.

Method and device for treating chlorine bypass dust and discharge gas

A combustion exhaust gas processing device comprises: a dust collector collecting dust in a cement kiln combustion exhaust gas: a wet dust collector as a catalyst-poisoning-substance stripper removing a catalyst-poisoning substance from a combustion exhaust gas which passed the wet dust collector; and a catalyst device from which NOx, a persistent organic pollutant, etc. in the preheated combustion exhaust gas, are removed. A titanium-vanadium catalyst etc. as an oxide catalyst is used upstream of the catalyst device, and a platinum catalyst etc. as a noble-metal catalyst downstream of the catalyst device. The temperature of the combustion exhaust gas after the catalyst-poisoning substance is removed is increased up to 140&#xb0; C. or more with the preheaters to prevent decline in denitration efficiency of and the decomposition efficiency of a volatile organic compound.

Device and method for processing cement kiln combustion exhaust

A method to efficiently reduce lead content of cement without exerting influence upon quality of the cement. The method comprises the steps of: controlling O2 concentration of combustion gas in an inlet end of a cement kiln to 5% or lower and/or CO concentration thereof 1000 ppm or more; extracting a part of combustion gas from the cement kiln and collecting dust contained in the combustion gas; and collecting lead from the dust collected. With this, the area where raw material temperature in the cement kiln is between 800&#xb0; and 1100&#xb0; can be turned into reducing atmosphere to sharply increase volatilization rate of lead, and collection of lead from the dust allows lead content of cement to efficiently be reduced without exerting influence upon quality of the cement.

Method for removing lead from cement burning furnace

An exhaust gas treatment method including: (A) a step of treating exhaust gas from cement manufacturing equipment by using a dust collectorto collect dust containing chlorinated organic compounds, and discharging the exhaust gas after the treatment by the dust collector, and (B) a step of charging all or part of the dust collected by the dust collectorinto a place (e.g. a rotary kiln, a pre-calciner, and a cyclone) having a temperature of at least 800&#xb0; C. inside the cement manufacturing equipment. The remainder of the dust from step (B) maybe charged into a place (e.g. a raw material supply passage) having a temperature below 800&#xb0; C. inside the cement manufacturing equipment, provided the amount of the remainder to be charged is smaller than a certain amount. Chlorinated organic compounds such as dioxins in the exhaust gas can be decomposed efficiently to be made harmless, merely by including simple and low-cost means (e.g. a dust feeding means, etc.).

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Kumagaya, Japan

Junichi Terasaki