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The impact of the operating speed of valves in the Φ2610 gas generation furnace on gas production. The operating speed of valves in the Φ2610 gas generation furnace has a significant influence on gas production. Source: www.bbspace.cn, 2007-11-09; Source: China Industrial Control Network. Over the years, many manufacturers have made continuous efforts and inquiries aimed at ensuring stable production, low consumption, efficient operation, and technological advancement in the gas generation process. As a result, great progress has been achieved in the intermittent gas production method using fixed-bed gas generators, and many new operating methods have been developed and adopted in practice, such as “three highs and one low,” “three lows and one high,” “three twos and three ones,” etc. These various operating methods share some similarities, but they also have differences and even contradictions among them. By drawing on the relevant experience of affiliated manufacturers as well as our own operational practices and by reflecting on related theories, we believe that for any operating method to function stably, it is first necessary to ensure that the oil pressure valves are in good condition – meaning there are no leaks and their response speed is fast. 1.0 Hazards of slow operation speed of hydraulic valves As is well known, in an intermittent fixed-bed gas furnace, the transition between different stages within one working cycle is accomplished entirely through the opening and closing of hydraulic valves; if the valves do not open or close fully, it is not possible to proceed to the next stage. 1.1 Hazards of slow operation speed of chimney valves When a chimney valve closes slowly, it does not reach its fully closed position after the blowing phase is over, leaving the system in an air defense state. At the same time, the blowdown valve has been closed, and the main steam valve as well as the top-blowing steam valve have been adjusted to their proper positions, entering the top-blowing gas supply stage. Since the chimney valve was not closed properly, the gas produced by the upper combustion process would escape through the chimney, resulting in the waste of the raw materials (steam, lump coal) inside the furnace. After the gas generation stage is completed, the valves of the steam system are closed and the blowing valve is opened; once the air has been blown out completely, the blowing stage begins, and the chimney valve should be opened. Due to the overly slow operating speed of the chimney valve (it took about 3 seconds longer to open before the modification), it failed to open in time, resulting in an excessively high level of N2 in the gas. Over an extended period, the oxygen content in the system increased. 1.2 Hazards of slow operation speed of the three-way valve When the three-way valve moves upward (from upper blowing to lower blowing), it does so slowly; at this time, the upper blowing steam valve closes while the lower blowing steam valve opens. Due to the slow operation speed of the three-way valve, some of the steam takes a shortcut and is sent directly from the upper steam path to the gas cleaning tower. As a result, the amount of steam entering the furnace decreases, the steam pressure drops, and it becomes difficult to send coal gas into the gas cleaning tower system in a timely manner. During this period, both steam and coal are consumed to varying degrees. It can also lead to excessively high temperatures in the upper airway, increased heat loss, and consequently higher raw material consumption. When the three-way valve moves downward (changing from downward steam injection to secondary upward steam injection), its movement is slow; at this time, the downward steam valve closes while the upward steam valve opens. Due to the slow movement of the three-way valve, some of the steam takes a shortcut and is sent directly into the scrubber tower through the lower steam duct, resulting in a situation similar to that when the three-way valve moves upward. Furthermore, if the upward blowing time is short or the amount of steam used for upward blowing is low, the gas at the bottom of the furnace is not completely blown away; this, along with the cleaning process using air, can easily lead to roaring noises at the bottom of the furnace. 1.3 Hazards of slow operation speed of the primary air valve When the primary air valve opens slowly, and the valves in the steam system are closed as well, the slow operation of the blowing valve results in a reduced blowing time. This leads to a decrease in the amount of air entering the furnace, thereby reducing the load on the gas generator, lowering the furnace temperature, decreasing the gas production of the gas furnace, and increasing raw material consumption. The blowing valve operates slowly when it is supposed to close; at that time the valves in the steam system are open and the blowing valve should close. However, due to its slow operation, it fails to close in time before the start of upper blowing, which prolongs the blowing time. Air continues to flow into the furnace during the gas production phase, reducing the quality of the gas and increasing the N2 content in the system. 2.0 Reasons for slow valve operation The control of all automatic oil pressure valves in gas stove systems is currently generally achieved using a micro oil pressure system. The slow operation of the valve is mainly due to the following reasons: first, the effective diameter is too small. The main issues are an excessively small oil hole in the solenoid valve (inner diameter of 8 mm), overly thin oil pipes (inner diameter of 8 mm), and a too-small interface for the hydraulic cylinder (inner diameter of 8 mm) ； Secondly, the oil pressure is too low; more precisely, there are excessive fluctuations in the oil pressure (3.5–5.5 MPa). Low pressure can lead to a low-pressure interlock in the gas generation furnace system, while high pressure exerts excessive stress on the pipelines and valves ； Third is the impact of oil temperature: in cold winter conditions, the viscosity of the power oil increases, which leads to higher pressure in the power oil system; however, the flow rate is lower, and the speed at which valves operate slows down. In the hot summer weather, the viscosity of the power oil is too low, which makes it difficult for the power oil pump to increase pressure; as a result, the valves operate at a slow speed ； Fourth, the oil quality is poor; there are many impurities in the power oil, and the solenoid valves are clogged ； Fifth, there is leakage in the piston of the valve hydraulic cylinder. Among these, the oil temperature and the diameter of the solenoid valve are the main influencing factors. A small inner diameter of the solenoid valve results in slow valve operation; especially for valves with a diameter of Φ600mm or more, it can take 5–9 seconds for them to close (or open) completely.