tailieunhanh - Coal America’s Energy Future phần 3

Nâng cao thấp NOX PC đốt cháy hệ thống, được sử dụng rộng rãi trong nồi hơi tiện ích và công nghiệp, cung cấp giảm đáng kể lượng khí thải NOX một cách an toàn, hiệu quả. Các hệ thống này đã được trang bị thêm cho nhiều đơn vị hiện có | Coal for Gasifiers Oxygen-blown gasifiers typically operate better with bituminous and lower volatile coal. In most gasification systems sulfur content of the coal is only a design consideration for the sulfur-removal system and not an operating limitation on the gasifier. The composition of coal and some of its physical properties have important influences on the gasification process. Young coals such as lignite and sub-bituminous coal generally contain a high percentage of moisture and oxygen while old coal such as bituminous coals and anthracite tend to become sticky as they are heated. As a result in the entrained flow gasifier the coal must be dried because if the water enters the gasifier some of it will react with CO to form hydrogen and CO2. Moisture content has no effect on the gasification process in the fixed bed gasifier because the hot gas leaving the gasifier dries the coal as it enters the gasifier. Since oxygen is present in the gasification process coals containing more oxygen will need less oxygen or air to be added. For example an E-gas gasifier system requires 2 220 tons per day of oxygen for sub-bituminous coal 2 330 tons per day of oxygen for bituminous coal and 2 540 tons per day for pet coke. The oxygen in coals is particularly important in air-blown gasification as any oxygen in the coal will reduce the amount of air required for the gasification reaction and thereby reduce the resulting nitrogen in the syngas. Mercury Control with Gasification Mercury control from coal gasification is applied to the syngas before it is burned resulting in a significant volumetric reduction from handling flue gas. For entrained flow systems essentially all of the mercury in the coal will be present in the syngas. Since syngas volume is considerably less than flue gas mercury removal systems greater than 90 can be relatively easily applied to the syngas stream. ELECTRICITY GENERATION IGCC OPERATIONS Owner Location Gasification Technology Syngas Output MWth .