Introduction RMS is designed to reduce the pressure of natural gas from high pressure to  low pressure, and calculate how much gas flow passes through the station. As a standard practice, a RMS for the natural gas power station usually consists of gas conditioning, regulating and metering systems. Gas conditioning system usually consists of inlet Knock-Out Drum, Two-stage Filter Separator, Water Bath Heater and Liquid Separator and related instruments. For a simple RMS, Dry Gas Filter is widely used. Conditioning system is used to remove the liquid such as heavy hydrocarbons, water etc. which are usually carried by the gas and will cause damage to regulator seats, turbine meter blades, and customer equipment. Conditioning system is also used to remove the sand, welding slag, pipeline scale, and other solids which can damage equipment. In order to remove the liquids and particles, stations can be protected by separators. Knock-out Drum, Filter Separator, Liquid Separator and Dry Gas Filter are widely used in this application. Water vapor is also a common impurity that can cause pilot or main regulator freezing, loss of control, loss of flow capacity, and internal corrosion. Water vapor can be controlled by either removing it or by limiting its detrimental effects, using a heater to avoid freezing. And also, the temperature of natural gas supplied is very important for gas generators. Water Bath Heater is widely used to heat the natural gas and maintain the temperature supplied to gas generator. Thus, gas conditioning system is usually used in a typical RMS. Gas Regulating System usually consists of inlet insulating valve, Slam Shut-off Valve, Gas Regulators (Monitor regulator and Active Regulator), outlet insulating valves and related instruments. Regulating system is to reducing the gas pressure from a high pressure to a certain lower pressure which normally required by customer. Over pressure protection is included in this system. Gas Metering System usually consists of inlet insulating valve, Gas Flow Meter, outlet insulating valve and related instruments. Metering system is to measure how much gas flow pass through the RMS. Other than the systems mentioned above, some other equipments such as flow control, chromatography, composite sampling, odorization etc. may also required.