Incineration of phthalic anhydride off-gas by the adjacent method
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In the long run, the treatment of exhaust gases generated from phthalic anhydride produced by adjacent plants will ultimately rely on incineration; the current method of washing and absorption will eventually be rendered obsolete by regulatory regulations. Regarding incineration, is it better to use an RTO or catalytic incineration? Or do they each have their advantages and disadvantages? I’ll explain my doubts here; please help analyze them. 1. We use a 90g process with an air flow rate of 80,000 Nm3; the initial investment is high in both cases, and the cost may be even higher for catalytic combustion. For subsequent operation and maintenance, a large amount of natural gas as well as waste heat recovery steam is required; given our company’s approach to utilizing waste heat steam, there should be no significant waste ； Before the catalytic combustion reaction, the exhaust gas at 60-70 degrees Celsius needs to be preheated to nearly 300 degrees Celsius in order to enable the reaction. The waste heat generated by the reaction certainly has limited heating capacity, which requires a large amount of electricity; so which approach is more economical? 2. Catalytic incineration: How long is the service life of the catalyst? Is the catalytic effect stable? If there are fluctuations in the exhaust intake temperature, will it have a significant impact on the catalytic effect? In the early stages of driving, the temperature of the exhaust gases certainly cannot reach the desired level in a short time. Although the driving load is low, there is still a large amount of organic compounds and water vapor in the exhaust gases; could this lead to uncontrolled emissions or even damage to the catalyst? Regarding these two incineration methods, I have some basic data available. Those in the phthalic anhydride industry who are interested can discuss this further; after all, it is an inevitable trend, and meeting environmental standards is key for chemical companies to survive.
Ours uses a 90g process with an air volume of 60,000. . . During inspection, the water scrubber tower is replenished with large amounts of water. . . . . .
I don’t know if you’ve joined yet. Let me share my opinion. First, regarding energy consumption, RTO is undoubtedly more energy-efficient than CO; after all, heat exchangers cannot match the high heat recovery efficiency of regenerative ceramics (95% heat recovery). The heat exchanger is also 50-70%. Secondly, cost: RTOs are certainly more expensive than catalytic combustion for CO treatment. With an air handling capacity of 80,000 cubic feet per minute (without taking in the need for fresh air), the price of the heat exchanger should also be high. Moreover, air leakage from heat exchangers is a common problem, which can lead to exhaust gases not meeting the required standards. Third, operating costs: catalyst manufacturers generally state that the service life is two years. However, if the actual exhaust gas contains halogens or viscous components as well as dust, it will lead to a decrease in catalytic efficiency, and the replacement cost is also high. RTO is more resistant to misuse. There are no special requirements for the exhaust gas, resulting in more stable operation. Of course, CO also has its advantages; in cases of low airflow, high concentration, and intermittent production, CO remains a good choice.