How can industrial gas be used safely?

Foreword

Gas is a high-quality gas fuel. It has the advantages of cleanliness, convenience, energy conservation, etc. It plays an active role in improving people's living standards, promoting economic development, and protecting the environment. Gas is also a kind of flammable, explosive and poisonous gas. If it is used improperly, it will also cause danger and cause accidents. Lack of necessary safety knowledge may result in property damage and personal injury. Therefore, popularizing common knowledge of gas and enhancing safety awareness is a task that requires long-term adherence.

I. Characteristics and types of gas

(a) The characteristics of the gas are:

1 , gas toxic. The main components of gas are combustible gases such as carbon monoxide, hydrogen and methane, among which carbon monoxide is toxic. Carbon monoxide is a colorless, odorless, non-irritating gas. It is an incomplete product of burning carbonaceous materials. It is lighter than air and easy to burn. It is a blue flame when burned. If the content of carbon monoxide in the air reaches 0.04%-0.06% , it can be Poisoning people.

2 , gas flammable and explosive. When the concentration of coal gas reaches 4.5-34.5% in the air , it will burn explosively when it encounters an open flame or tiny Mars .

3 , the proportion of gas is lighter. A carbon monoxide gas density under standard conditions <of l.25g / L, and the air density (1.29 g / L) difference is small, which is one of the factors susceptible to gas poisoning.

(b) Types of gas:

Industry usually has blast furnace gas, coke oven gas and water gas

Second, gas safety prevention and countermeasures

(i) Prevention and countermeasures for personal safety. Formulate a maintenance system for gas equipment, check it in time, and discover that the leakage has been dealt with in a timely manner. According to the content of carbon monoxide, the working area is divided into Class A, B, and C gas hazardous areas.

( 1 ) Grade A area refers to the area where the concentration of C0 in the air is above 0.3 mg / l, and the following is the Grade A area:

1 Blast furnace top, around the tuyere .

2 hot stove, bag dust removal.

3 Sinter ignition around.

4 Puff coal gas pipeline tail section.

5 Bakehouses for steel making workshops and gas pipe network valves. For operation in dangerous areas of Category A gas, workers must wear oxygen breathing apparatus or ventilation masks and should be on site.

( 2 ) Class B area refers to area B in the air where C0 concentration is 0.03 - 0.25 mg / L:

1 All outlet valves and valves around the gas pipe network.

2 at the front iron gate.

3 All overflows under the gas pipe network. When operating in a Class B gas hazardous area, prepare an oxygen breathing apparatus or be monitored.

( 3 ) Class C area refers to the C class area where the C0 concentration in the air is below 0.03 mg / l:

1 furnace operation room and furnace front.

2 Gravity dedusting, bag dusting, ash discharge, and surrounding areas.

3 Sintering looks at the fire operating area and the upper side of the operating platform.

4 steelworks gas valve network around the valve and so on. In the hazardous area of ​​Class C gas, although oxygen breathing apparatus can be used, it is also necessary to strengthen the detection. In addition, carbon monoxide gas alarms are installed in places where carbon monoxide gas may be generated. When the carbon monoxide gas in the air exceeds the standard, sound and light alarms can be used to remind people to take hedging measures early.

(b) Prevention of equipment safety and countermeasures. In the final analysis, any explosion was caused by improper operation or installation of equipment. Therefore, in order to reduce the loss of human, financial, and material goods in order to smoothly produce, the gas must be treated cleanly to maintain natural internal ventilation when the gas equipment is stopped for maintenance. And the normal production of gas equipment with blind plate or gate valve and water seal cut off the gas equipment on the steam pipe, water pipe disconnected.

When working in a gas facility, carbon monoxide and oxygen levels should be measured. After passing the test, if it is allowed to work in the gas facility, it shall carry a carbon monoxide and oxygen monitoring device and take protective measures to set up a full-time guardian. When the carbon monoxide content does not exceed 0-30mg/m3 , it can work for a longer time; when the carbon monoxide content does not exceed 30-50 mg/m3 , the continuous working time shall not exceed 1 hour; when it does not exceed 50-100 mg/m3 , Continuous work should not exceed 30 minutes; when it does not exceed 100-200 mg/m3 , continuous work should not exceed 15-20 minutes. Every time the staff enters the interior of the facility, the time interval is at least 2 hours.

Before the fire on the gas equipment, the safety office should be informed to apply for a fire permit and submit a hot work construction plan. The ignition test can be carried out after permission, and it should be done on the equipment installation.

(1) The following provisions shall be complied with in the installation of blast furnaces:

1 blast furnace cooling equipment and furnace shell, sealing, slag hole and water jacket should be sealed;

2 The bottom of the soft probe, the flange of the hole cover, the shaft bearing of the sprocket or the sheave must be tightly sealed;

3 Use a steam or nitrogen seal between the hard probe and the probe hole;

4 Newly built or reconstructed discharge capacity of the discharge pipe, under normal pressure, it should be able to disperse all the gas, and the gas should be discharged as soon as possible when the blast furnace is off wind;

5 The height of the furnace top discharge pipe should be more than 5 meters above the winch sheave platform. The installation position of the relief valve discharge valve should be easy to operate on the furnace table. The contact between the diffuse valve seat and the valve disc should be kept tight, and the contact surface should adopt external contact.

(b) Gravity dust collectors should meet the following requirements:

1 The dust collector should be equipped with steam or nitrogen fittings;

2 Between the top of the precipitator and the shut-off valve, there should be steam and nitrogen pipe joints. The top of the dust collector and the gas pipeline should be set at the highest point.

(c) Bag filter should meet the following requirements:

1 Each outlet of the bag filter should be provided with a reliable blocking device;

2 Bag filter Each cabinet should be equipped with a discharge tube;

3 bag filter should be equipped with gas high and low temperature alarm and low pressure alarm device;

4 The baghouse filter box body should be used explosion vent device;

5 When the bag filter removes dust, it should not use the method of backflushing with the crude gas to the atmosphere during normal operation;

6 When the baghouse discharges ash to the outside, measures should be taken to prevent gas leakage.

(4) Anti-corrosion of gas pipelines: Overhead pipelines, after the steel pipe is manufactured, the inner wall (the request of the design) and the outer surface shall be painted with anti-rust paint. After the pipes are installed and tested, all pipes shall be painted with anti-rust paint. The outer surface of the pipe shall be repainted once every four to five years.

(five) water seal:

1 Water is a reliable blocking device when it is used after other partition devices. The effective height of the water seal shall be at least 500mm above the calculated pressure of the gas , and the height of the water seal shall be regularly checked;

2 Water seals and check valves shall be provided on the water supply pipe of the water seal;

3 It is forbidden to directly insert the drain pipe and full-flow pipe into the sewer. The cleaning hole and water head should be installed on the side wall of the water seal. U -type water seals should be installed on both sides of the diffuser tube, blowing the near gas and sampling tube.

(f) Pipeline installations and warning signs:

1 The main gas pipelines in the plant area should be marked with signs of gas flow and types;

2 Warning signs that alert people should be posted in all places that may leak gas. Only in this way can we ensure that employees' personal safety and equipment integrity in high-risk areas can create more value.

Third, gas safety treatment

(a) The treatment of gas poisoning.

1 The patient should be allowed to leave the poisonous environment as soon as possible, and the air should be circulated.

2 Patients should rest quietly, avoid heavy heart and lung burden and increase oxygen consumption after the activity.

3 Have spontaneous breathing, give adequate oxygen inhalation.

(4) Poorly poisoned patients must carry out the poisoning environment as soon as possible and carry out emergency treatment according to the circumstances within the shortest possible time.

5 Breathing The heartbeat stops and artificial respiration and cardiac compression are performed immediately.

After the condition became stable, the patient was escorted to the hospital for further examination and treatment.

7 Try to treat hyperbaric oxygen chamber as soon as possible to reduce sequelae.

(b) Treatment of equipment safety.

Gas fires are often raging fires, and fires in gas pipelines are often smoky. According to the gas fire situation, should be partially stopped using gas, trying to close the gate valve to reduce the gas pressure, and pass into the equipment in the fire a lot of steam or nitrogen.

1 The gas pipeline diameter is less than 150mm , and the gate valve can be directly shut off. In case of an explosion, the maximum explosion pressure is about 0 . 7 MPa (7kg / cm2) , the small diameter pipe is enough to take the gas explosion pressure.

2 Pipe diameter above 150mm , closing the gate valve to reduce the minimum gas pressure must not be less than 49 ~ 98h , it is strictly forbidden to suddenly close the gate valve or water seal to prevent tempering and explosion.

The information in this article comes from the Internet and was reorganized and edited by China Rescue Equipment Network.