Coke oven gas calorific value, power generation, production volume
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This post was last edited by hanhai taosdu on 2009-7-27 at 15:41. Several design firms prepared feasibility studies for coking projects for us, and they mentioned the quantities of coke and coke oven gas. 1. The first plant: 420 Nm3 of coke oven gas per ton of coke, of which 48% is returned to the coke oven and the remaining 52% is used for chemical production. 2. The second plant produces 393 Nm3 of coke oven gas per ton of coke; 42% of this gas is reused in the coke oven, while the remaining 58% is used for chemical production. According to other sources, generally 300-350 Nm3 of coke oven gas can be produced per ton of dry coal. The calorific value of coke oven gas ranges from 4100 to 4600 Kcal/m3. When using coke oven gas for power generation, 1 Nm3 of coke oven gas produces 1.1–1.2 kwh of electricity. There may be inaccuracies in these figures; please point them out.
Generally, the calculations are based on 330 Nm3 per ton of dry coal; about 45% of this is gas returned to the furnace, while approximately 55% remains as gas. Calculated on a low calorific value basis, coke oven gas has a value of 17900 kJ/Nm3. Currently, gas turbines are used to generate electricity from coke oven gas with high efficiency; there are several types of such systems, among which combined cycle power generation or cogeneration is the most effective. These systems consist of gas turbines and generators, along with waste heat boilers, steam turbines, or heat-supplying steam turbines (suction-type or back-pressure type). In these systems, the high-temperature exhaust gases released by the gas turbines are recovered and converted into steam using waste heat boilers; this steam is then used to drive steam turbines for electricity generation, or part of the exhaust steam after power generation is utilized for heating purposes. There are single-axis combined cycles in which a gas turbine and a steam turbine drive a single generator coaxially, as well as multi-axis combined cycles in which the gas turbine and the steam turbine each drive their own generator. It is mainly used for power generation and combined heat and power production. The combined cycle system with the highest efficiency for power generation is ABB’s GT26-1, with an efficiency of 58.5%. Calculated at an efficiency of 58.5%, one cubic meter of gas can generate 2.9098 kWh of electricity.
2# sniper.yukai: 2.9 kWh of electricity generated from 1m3 of coke oven gas? ? It’s too high; it seems that such a high level cannot be achieved in the domestic market. I asked a design firm, and they said it’s 1.1–1.2 kWh/m3 for coke oven gas.
When generating electricity solely using the heat of combustion of coke oven gas, the efficiency can generally reach 1.3 kW per cubic meter; in better cases, it can go up to 1.8 kW per cubic meter. If the waste heat from the flue gases is recovered and used to generate electricity via steam, the efficiency can reach around 2.2 kW per cubic meter. In China, this level is generally achievable. I’ve heard that only companies like GE and ABB manage to achieve an electricity generation efficiency of over 55%. The efficiency for the third option can be calculated by using the calorific value of the gas and the combined power generation efficiency.
To generate electricity using a gas turbine, it is necessary to have conditions like these. If coke oven gas with a flow rate of 7500–8800 Nm3/h and a lower heating value of 17–19 MJ/Nm3 is to be utilized for power generation through a gas turbine, what size should the gas turbine unit be? Additionally, if a back-pressure steam turbine is used in conjunction with a waste heat boiler, what will be the steam output, and what is the approximate investment cost?
When generating electricity from coke oven gas, it is necessary to calculate the overall efficiency. When considering combined heat and power generation, an efficiency of 72% can be achieved using internal combustion engines, and the investment required is also much lower than that for gas turbines
5# tomtony1314 An investment of this scale is roughly around 600 million!
The gas generated from our 2 million tons of coking is used to power a 12,000 KW generator set, while the remaining gas is supplied to external customers; approximately 800,000 cubic meters of gas are used per day, resulting in a roughly balanced gas supply.