The bottom of the gas-fired pot is very black

Some families are still using gas, which can cause the ground under the pot to be particularly black. After all, coal gas is a gas because it contains carbon. If the carbon is not completely burned, a black substance will be produced at the bottom of the pot. There are many types of gas. When using gas, be sure to remember to turn off the main valve. Otherwise it may cause gas poisoning, so be sure to pay attention to safety when using it.

The reason why the bottom of the pot is black is because coal gas is an organic gas. The main element of this gas is carbon. In the case of incomplete combustion, excess carbon will accumulate at the bottom of the pot, forming a black layer of ash.

Coal gas is a gas containing combustible components that is processed from coal as raw material. According to the processing method, gas properties and uses, coal gasification can be divided into water gas, semi-water gas and air gas (or producer gas).

These gases have a low calorific value, so they are collectively called low calorific value gases; the gas obtained by coking in the coal dry distillation method is called coke oven gas and blast furnace gas. It is a medium calorific value gas and can be used as a civilian fuel in cities. Carbon monoxide and hydrogen in coal gas are important chemical raw materials.

Producer

Producer gas is a type of artificial gas. It is a kind of coal gas obtained in a special equipment generator using solid carbon-containing fuel as raw material. The gasifying agents used to produce producer gas are air and water vapor. Depending on the gasifying agent used, producer gas with different components and properties can be produced, which are usually divided into four categories:

Air gas - uses air (actually oxygen in the air) as the gasifying agent;

gas

Mixed gas - a mixture of air and water vapor as the gasifying agent;

Water gas - uses water vapor as the gasifying agent;

Oxygen-enriched gas - a mixture of air, water vapor and oxygen (added pure oxygen) is used as the gasifying agent.

Air Gas

Since solid fuel of air gas only reacts with oxygen, the combustible component in the gas is mainly carbon monoxide, so its calorific value is low, generally only 800~900 kcal/standard cubic meter, or even lower. Therefore, it is rarely used in industry and is generally a by-product of blast furnace production.

Water Gas

Water gas is obtained by the reaction of water vapor and high-temperature carbon. Since the reaction is endothermic, intermittent production is necessary to maintain the furnace temperature. The obtained coal gas contains high levels of CO and H2, and has a high calorific value, but low thermal efficiency, about 54%, high cost and complex equipment. It is generally used as raw gas for synthetic ammonia and is less commonly used as industrial fuel gas. Sometimes, a small amount of air is added during the water gas production process, and the resulting gas is called semi-water gas[1].

Mixed gas

The mixed gas combines the characteristics of air gas and water gas. A mixture of water vapor and air is blown into the generator to produce a mixed generator gas with a higher calorific value than air gas and a lower calorific value than water gas. It is generally referred to as generator gas in production. The calorific value of this gas fluctuates between 1200 and 1500 kcal/standard meter depending on the properties of the fuel used. It is widely used as heating fuel in various industrial furnaces.